diff --git a/conda_lock/conda_lock.py b/conda_lock/conda_lock.py
index 4390ef092..6715739ca 100644
--- a/conda_lock/conda_lock.py
+++ b/conda_lock/conda_lock.py
@@ -63,7 +63,6 @@
 except ImportError:
     PIP_SUPPORT = False
 from conda_lock.lockfile import (
-    Dependency,
     GitMeta,
     InputMeta,
     LockedDependency,
@@ -76,12 +75,8 @@
     write_conda_lock_file,
 )
 from conda_lock.lookup import set_lookup_location
-from conda_lock.src_parser import LockSpecification, aggregate_lock_specs
-from conda_lock.src_parser.environment_yaml import parse_environment_file
-from conda_lock.src_parser.meta_yaml import parse_meta_yaml_file
-from conda_lock.src_parser.pyproject_toml import parse_pyproject_toml
+from conda_lock.src_parser import LockSpecification, make_lock_spec
 from conda_lock.virtual_package import (
-    FakeRepoData,
     default_virtual_package_repodata,
     virtual_package_repo_from_specification,
 )
@@ -114,8 +109,6 @@
     sys.exit(1)
 
 
-DEFAULT_PLATFORMS = ["osx-64", "linux-64", "win-64"]
-
 KIND_EXPLICIT: Literal["explicit"] = "explicit"
 KIND_LOCK: Literal["lock"] = "lock"
 KIND_ENV: Literal["env"] = "env"
@@ -243,44 +236,6 @@ def fn_to_dist_name(fn: str) -> str:
     return fn
 
 
-def make_lock_spec(
-    *,
-    src_files: List[pathlib.Path],
-    virtual_package_repo: FakeRepoData,
-    channel_overrides: Optional[Sequence[str]] = None,
-    platform_overrides: Optional[Sequence[str]] = None,
-    required_categories: Optional[AbstractSet[str]] = None,
-) -> LockSpecification:
-    """Generate the lockfile specs from a set of input src_files.  If required_categories is set filter out specs that do not match those"""
-    lock_specs = parse_source_files(
-        src_files=src_files, platform_overrides=platform_overrides
-    )
-
-    lock_spec = aggregate_lock_specs(lock_specs)
-    lock_spec.virtual_package_repo = virtual_package_repo
-    lock_spec.channels = (
-        [Channel.from_string(co) for co in channel_overrides]
-        if channel_overrides
-        else lock_spec.channels
-    )
-    lock_spec.platforms = (
-        list(platform_overrides) if platform_overrides else lock_spec.platforms
-    ) or list(DEFAULT_PLATFORMS)
-
-    if required_categories is not None:
-
-        def dep_has_category(d: Dependency, categories: AbstractSet[str]) -> bool:
-            return d.category in categories
-
-        lock_spec.dependencies = [
-            d
-            for d in lock_spec.dependencies
-            if dep_has_category(d, categories=required_categories)
-        ]
-
-    return lock_spec
-
-
 def make_lock_files(
     *,
     conda: PathLike,
@@ -353,11 +308,12 @@ def make_lock_files(
 
     with virtual_package_repo:
         lock_spec = make_lock_spec(
-            src_files=src_files,
+            src_file_paths=src_files,
             channel_overrides=channel_overrides,
-            platform_overrides=platform_overrides,
+            platform_overrides=set(platform_overrides) if platform_overrides else set(),
             virtual_package_repo=virtual_package_repo,
             required_categories=required_categories if filter_categories else None,
+            pip_support=PIP_SUPPORT,
         )
         lock_content: Optional[Lockfile] = None
 
@@ -704,12 +660,8 @@ def _solve_for_arch(
     """
     if update_spec is None:
         update_spec = UpdateSpecification()
-    # filter requested and locked dependencies to the current platform
-    dependencies = [
-        dep
-        for dep in spec.dependencies
-        if (not dep.selectors.platform) or platform in dep.selectors.platform
-    ]
+    dependencies = spec.dependencies[platform]
+
     locked = [dep for dep in update_spec.locked if dep.platform == platform]
     requested_deps_by_name = {
         manager: {dep.name: dep for dep in dependencies if dep.manager == manager}
@@ -867,42 +819,6 @@ def create_lockfile_from_spec(
     )
 
 
-def parse_source_files(
-    src_files: List[pathlib.Path],
-    platform_overrides: Optional[Sequence[str]],
-) -> List[LockSpecification]:
-    """
-    Parse a sequence of dependency specifications from source files
-
-    Parameters
-    ----------
-    src_files :
-        Files to parse for dependencies
-    platform_overrides :
-        Target platforms to render environment.yaml and meta.yaml files for
-    """
-    desired_envs: List[LockSpecification] = []
-    for src_file in src_files:
-        if src_file.name == "meta.yaml":
-            desired_envs.append(
-                parse_meta_yaml_file(
-                    src_file, list(platform_overrides or DEFAULT_PLATFORMS)
-                )
-            )
-        elif src_file.name == "pyproject.toml":
-            desired_envs.append(parse_pyproject_toml(src_file))
-        else:
-            desired_envs.append(
-                parse_environment_file(
-                    src_file,
-                    platform_overrides,
-                    default_platforms=DEFAULT_PLATFORMS,
-                    pip_support=PIP_SUPPORT,
-                )
-            )
-    return desired_envs
-
-
 def _add_auth_to_line(line: str, auth: Dict[str, str]) -> str:
     matching_auths = [a for a in auth if a in line]
     if not matching_auths:
diff --git a/conda_lock/src_parser/__init__.py b/conda_lock/src_parser/__init__.py
index 102262f76..62eab5697 100644
--- a/conda_lock/src_parser/__init__.py
+++ b/conda_lock/src_parser/__init__.py
@@ -5,18 +5,30 @@
 import typing
 
 from itertools import chain
-from typing import Dict, List, Optional, Tuple, Union
+from typing import (
+    AbstractSet,
+    Dict,
+    Iterable,
+    List,
+    Optional,
+    Sequence,
+    Set,
+    Tuple,
+    Union,
+)
 
 from pydantic import BaseModel, validator
 from typing_extensions import Literal
 
-from conda_lock.common import ordered_union, suffix_union
+from conda_lock.common import suffix_union
 from conda_lock.errors import ChannelAggregationError
 from conda_lock.models import StrictModel
 from conda_lock.models.channel import Channel
 from conda_lock.virtual_package import FakeRepoData
 
 
+DEFAULT_PLATFORMS = {"osx-64", "linux-64", "win-64"}
+
 logger = logging.getLogger(__name__)
 
 
@@ -42,7 +54,9 @@ class _BaseDependency(StrictModel):
     optional: bool = False
     category: str = "main"
     extras: List[str] = []
-    selectors: Selectors = Selectors()
+
+    def to_source(self) -> "SourceDependency":
+        return SourceDependency(dep=self)  # type: ignore
 
 
 class VersionedDependency(_BaseDependency):
@@ -59,23 +73,56 @@ class URLDependency(_BaseDependency):
 Dependency = Union[VersionedDependency, URLDependency]
 
 
+class SourceDependency(StrictModel):
+    dep: Dependency
+    selectors: Selectors = Selectors()
+
+
 class Package(StrictModel):
     url: str
     hash: str
 
 
+class SourceFile(StrictModel):
+    file: pathlib.Path
+    dependencies: List[SourceDependency]
+    # TODO: Should we store the auth info in here?
+    channels: List[Channel]
+    platforms: Set[str]
+
+    @validator("channels", pre=True)
+    def validate_channels(cls, v: List[Union[Channel, str]]) -> List[Channel]:
+        for i, e in enumerate(v):
+            if isinstance(e, str):
+                v[i] = Channel.from_string(e)
+        return typing.cast(List[Channel], v)
+
+    def spec(self, platform: str) -> List[Dependency]:
+        from conda_lock.src_parser.selectors import dep_in_platform_selectors
+
+        return [
+            dep.dep
+            for dep in self.dependencies
+            if dep.selectors.platform is None
+            or dep_in_platform_selectors(dep, platform)
+        ]
+
+
 class LockSpecification(BaseModel):
-    dependencies: List[Dependency]
+    dependencies: Dict[str, List[Dependency]]
     # TODO: Should we store the auth info in here?
     channels: List[Channel]
-    platforms: List[str]
     sources: List[pathlib.Path]
     virtual_package_repo: Optional[FakeRepoData] = None
 
+    @property
+    def platforms(self) -> List[str]:
+        return list(self.dependencies.keys())
+
     def content_hash(self) -> Dict[str, str]:
         return {
             platform: self.content_hash_for_platform(platform)
-            for platform in self.platforms
+            for platform in self.dependencies.keys()
         }
 
     def content_hash_for_platform(self, platform: str) -> str:
@@ -83,8 +130,9 @@ def content_hash_for_platform(self, platform: str) -> str:
             "channels": [c.json() for c in self.channels],
             "specs": [
                 p.dict()
-                for p in sorted(self.dependencies, key=lambda p: (p.manager, p.name))
-                if p.selectors.for_platform(platform)
+                for p in sorted(
+                    self.dependencies[platform], key=lambda p: (p.manager, p.name)
+                )
             ],
         }
         if self.virtual_package_repo is not None:
@@ -105,34 +153,97 @@ def validate_channels(cls, v: List[Union[Channel, str]]) -> List[Channel]:
         return typing.cast(List[Channel], v)
 
 
-def aggregate_lock_specs(
-    lock_specs: List[LockSpecification],
-) -> LockSpecification:
-
-    # unique dependencies
+def aggregate_deps(grouped_deps: List[List[Dependency]]) -> List[Dependency]:
+    # List unique dependencies
     unique_deps: Dict[Tuple[str, str], Dependency] = {}
-    for dep in chain.from_iterable(
-        [lock_spec.dependencies for lock_spec in lock_specs]
-    ):
+    for dep in chain.from_iterable(grouped_deps):
         key = (dep.manager, dep.name)
-        if key in unique_deps:
-            # Override existing, but merge selectors
-            previous_selectors = unique_deps[key].selectors
-            previous_selectors |= dep.selectors
-            dep.selectors = previous_selectors
         unique_deps[key] = dep
 
-    dependencies = list(unique_deps.values())
-    try:
-        channels = suffix_union(lock_spec.channels or [] for lock_spec in lock_specs)
-    except ValueError as e:
-        raise ChannelAggregationError(*e.args)
+    return list(unique_deps.values())
+
+
+def aggregate_channels(
+    channels: Iterable[List[Channel]],
+    channel_overrides: Optional[Sequence[str]] = None,
+) -> List[Channel]:
+    if channel_overrides:
+        return [Channel.from_string(co) for co in channel_overrides]
+    else:
+        # Ensure channels are correctly ordered
+        try:
+            return suffix_union(channels)
+        except ValueError as e:
+            raise ChannelAggregationError(*e.args)
+
+
+def parse_source_files(
+    src_file_paths: List[pathlib.Path], pip_support: bool = True
+) -> List[SourceFile]:
+    """
+    Parse a sequence of dependency specifications from source files
+
+    Parameters
+    ----------
+    src_files :
+        Files to parse for dependencies
+    pip_support :
+        Support pip dependencies
+    """
+    from conda_lock.src_parser.environment_yaml import parse_environment_file
+    from conda_lock.src_parser.meta_yaml import parse_meta_yaml_file
+    from conda_lock.src_parser.pyproject_toml import parse_pyproject_toml
+
+    src_files: List[SourceFile] = []
+    for src_file_path in src_file_paths:
+        if src_file_path.name in ("meta.yaml", "meta.yml"):
+            src_files.append(parse_meta_yaml_file(src_file_path))
+        elif src_file_path.name == "pyproject.toml":
+            src_files.append(parse_pyproject_toml(src_file_path))
+        else:
+            src_files.append(
+                parse_environment_file(
+                    src_file_path,
+                    pip_support=pip_support,
+                )
+            )
+    return src_files
+
+
+def make_lock_spec(
+    *,
+    src_file_paths: List[pathlib.Path],
+    virtual_package_repo: FakeRepoData,
+    channel_overrides: Optional[Sequence[str]] = None,
+    platform_overrides: Optional[Set[str]] = None,
+    required_categories: Optional[AbstractSet[str]] = None,
+    pip_support: bool = True,
+) -> LockSpecification:
+    """Generate the lockfile specs from a set of input src_files. If required_categories is set filter out specs that do not match those"""
+    src_files = parse_source_files(src_file_paths, pip_support)
+
+    # Determine Platforms to Render for
+    platforms = (
+        platform_overrides
+        or {plat for sf in src_files for plat in sf.platforms}
+        or DEFAULT_PLATFORMS
+    )
+
+    spec = {
+        plat: aggregate_deps([sf.spec(plat) for sf in src_files]) for plat in platforms
+    }
+
+    if required_categories is not None:
+        spec = {
+            plat: [d for d in deps if d.category in required_categories]
+            for plat, deps in spec.items()
+        }
 
     return LockSpecification(
-        dependencies=dependencies,
-        # Ensure channel are correctly ordered
-        channels=channels,
-        # uniquify metadata, preserving order
-        platforms=ordered_union(lock_spec.platforms or [] for lock_spec in lock_specs),
-        sources=ordered_union(lock_spec.sources or [] for lock_spec in lock_specs),
+        dependencies=spec,
+        channels=aggregate_channels(
+            (sf.channels for sf in src_files), channel_overrides
+        ),
+        sources=src_file_paths,
+        virtual_package_repo=virtual_package_repo,
     )
diff --git a/conda_lock/src_parser/conda_common.py b/conda_lock/src_parser/conda_common.py
index 4d3c146d0..0ec7665d0 100644
--- a/conda_lock/src_parser/conda_common.py
+++ b/conda_lock/src_parser/conda_common.py
@@ -2,10 +2,10 @@
 
 from .._vendor.conda.models.channel import Channel
 from .._vendor.conda.models.match_spec import MatchSpec
-from ..src_parser import VersionedDependency
+from ..src_parser import SourceDependency, VersionedDependency
 
 
-def conda_spec_to_versioned_dep(spec: str, category: str) -> VersionedDependency:
+def conda_spec_to_versioned_dep(spec: str, category: str) -> SourceDependency:
     """Convert a string form conda spec into a versioned dependency for a given category.
 
     This is used by the environment.yaml and meta.yaml specification parser
@@ -30,4 +30,4 @@ def conda_spec_to_versioned_dep(spec: str, category: str) -> VersionedDependency
         extras=[],
         build=ms.get("build"),
         conda_channel=channel_str,
-    )
+    ).to_source()
diff --git a/conda_lock/src_parser/environment_yaml.py b/conda_lock/src_parser/environment_yaml.py
index a021203fb..d6e94a73c 100644
--- a/conda_lock/src_parser/environment_yaml.py
+++ b/conda_lock/src_parser/environment_yaml.py
@@ -2,161 +2,86 @@
 import re
 import sys
 
-from typing import List, Optional, Sequence, Tuple
+from typing import List, Set
 
-import yaml
+from ruamel.yaml import YAML
 
-from conda_lock.src_parser import Dependency, LockSpecification, aggregate_lock_specs
+from conda_lock.src_parser import SourceDependency, SourceFile
 from conda_lock.src_parser.conda_common import conda_spec_to_versioned_dep
-from conda_lock.src_parser.selectors import filter_platform_selectors
+from conda_lock.src_parser.selectors import parse_selector_comment_for_dep
 
 from .pyproject_toml import parse_python_requirement
 
 
-_whitespace = re.compile(r"\s+")
-_conda_package_pattern = re.compile(r"^(?P<name>[A-Za-z0-9_-]+)\s?(?P<version>.*)?$")
-
-
-def parse_conda_requirement(req: str) -> Tuple[str, str]:
-    match = _conda_package_pattern.match(req)
-    if match:
-        return match.group("name"), _whitespace.sub("", match.group("version"))
-    else:
-        raise ValueError(f"Can't parse conda spec from '{req}'")
-
-
-def _parse_environment_file_for_platform(
+def parse_environment_file(
     environment_file: pathlib.Path,
-    content: str,
-    platform: str,
     *,
     pip_support: bool = False,
-) -> LockSpecification:
+) -> SourceFile:
     """
-    Parse dependencies from a conda environment specification for an
-    assumed target platform.
-
-    Parameters
-    ----------
-    environment_file :
-        Path to environment.yml
-    pip_support :
-        Emit dependencies in pip section of environment.yml. If False, print a
-        warning and ignore pip dependencies.
-    platform :
-        Target platform to use when parsing selectors to filter lines
+    Parse an simple environment-yaml file in a platform and version independent way.
     """
-    filtered_content = "\n".join(filter_platform_selectors(content, platform=platform))
-    env_yaml_data = yaml.safe_load(filtered_content)
-
-    specs = env_yaml_data["dependencies"]
-    channels: List[str] = env_yaml_data.get("channels", [])
+    if not environment_file.exists():
+        raise FileNotFoundError(f"Environment File {environment_file} not found")
+    env_yaml_data = YAML().load(environment_file)
 
-    # These extension fields are nonstandard
-    platforms: List[str] = env_yaml_data.get("platforms", [])
-    category: str = env_yaml_data.get("category") or "main"
+    # Get any (nonstandard) given values in the environment file
+    platforms: Set[str] = set(env_yaml_data.get("platforms", []))
+    category: str = str(env_yaml_data.get("category", "main"))
+    channels: List[str] = env_yaml_data.get("channels", []).copy()
 
-    # Split out any sub spec sections from the dependencies mapping
-    mapping_specs = [x for x in specs if not isinstance(x, str)]
-    specs = [x for x in specs if isinstance(x, str)]
+    all_specs = env_yaml_data["dependencies"]
+    specs = [x for x in all_specs if isinstance(x, str)]
+    mapping_specs = [x for x in all_specs if not isinstance(x, str)]
 
-    dependencies: List[Dependency] = []
-    for spec in specs:
-        vdep = conda_spec_to_versioned_dep(spec, category)
-        vdep.selectors.platform = [platform]
-        dependencies.append(vdep)
+    # Get and Parse Dependencies
+    dependencies: List[SourceDependency] = []
+    for idx, spec in enumerate(specs):
+        sdep = conda_spec_to_versioned_dep(spec, category)
+        sdep.selectors.platform = parse_selector_comment_for_dep(all_specs.ca, idx)
+        dependencies.append(sdep)
 
     for mapping_spec in mapping_specs:
-        if "pip" in mapping_spec:
-            if pip_support:
-                for spec in mapping_spec["pip"]:
-                    if re.match(r"^-e .*$", spec):
-                        print(
-                            (
-                                f"Warning: editable pip dep '{spec}' will not be included in the lock file. "
-                                "You will need to install it separately."
-                            ),
-                            file=sys.stderr,
-                        )
-                        continue
-
-                    dependencies.append(
-                        parse_python_requirement(
-                            spec,
-                            manager="pip",
-                            optional=category != "main",
-                            category=category,
-                            normalize_name=False,
-                        )
+        if "pip" not in mapping_spec:
+            continue
+
+        if pip_support:
+            for spec in mapping_spec["pip"]:
+                if re.match(r"^-e .*$", spec):
+                    print(
+                        (
+                            f"Warning: editable pip dep '{spec}' will not be included in the lock file. "
+                            "You will need to install it separately."
+                        ),
+                        file=sys.stderr,
+                    )
+                    continue
+
+                dependencies.append(
+                    parse_python_requirement(
+                        spec,
+                        manager="pip",
+                        optional=category != "main",
+                        category=category,
+                        normalize_name=False,
                     )
-
-                # ensure pip is in target env
-                dependencies.append(parse_python_requirement("pip", manager="conda"))
-            else:
-                print(
-                    (
-                        "Warning: found pip deps, but conda-lock was installed without pypi support. "
-                        "pip dependencies will not be included in the lock file. Either install them "
-                        "separately, or install conda-lock with `-E pip_support`."
-                    ),
-                    file=sys.stderr,
                 )
 
-    return LockSpecification(
+            # ensure pip is in target env
+            dependencies.append(parse_python_requirement("pip", manager="conda"))
+        else:
+            print(
+                (
+                    "Warning: found pip deps, but conda-lock was installed without pypi support. "
+                    "pip dependencies will not be included in the lock file. Either install them "
+                    "separately, or install conda-lock with `-E pip_support`."
+                ),
+                file=sys.stderr,
+            )
+
+    return SourceFile(
+        file=environment_file,
         dependencies=dependencies,
         channels=channels,  # type: ignore
         platforms=platforms,
-        sources=[environment_file],
     )
-
-
-def parse_environment_file(
-    environment_file: pathlib.Path,
-    given_platforms: Optional[Sequence[str]],
-    *,
-    default_platforms: List[str] = [],
-    pip_support: bool = False,
-) -> LockSpecification:
-    """Parse a simple environment-yaml file for dependencies assuming the target platforms.
-
-    * This will emit one dependency set per target platform. These may differ
-      if the dependencies depend on platform selectors.
-    * This does not support multi-output files and will ignore all lines with
-      selectors other than platform.
-    """
-    if not environment_file.exists():
-        raise FileNotFoundError(f"{environment_file} not found")
-
-    with environment_file.open("r") as fo:
-        content = fo.read()
-        env_yaml_data = yaml.safe_load(content)
-
-    # Get list of platforms from the input file
-    yaml_platforms: Optional[List[str]] = env_yaml_data.get("platforms")
-    # Final list of platforms is the following order of priority
-    # 1) List Passed in via the -p flag (if any given)
-    # 2) List From the YAML File (if specified)
-    # 3) Default List of Platforms to Render
-    platforms = list(given_platforms or yaml_platforms or default_platforms)
-
-    # Parse with selectors for each target platform
-    spec = aggregate_lock_specs(
-        [
-            _parse_environment_file_for_platform(
-                environment_file, content, platform, pip_support=pip_support
-            )
-            for platform in platforms
-        ]
-    )
-
-    # Remove platform selectors if they apply to all targets
-    for dep in spec.dependencies:
-        if dep.selectors.platform == platforms:
-            dep.selectors.platform = None
-
-    # Use the list of rendered platforms for the output spec only if
-    # there is a dependency that is not used on all platforms.
-    # This is unlike meta.yaml because environment-yaml files can contain an
-    # internal list of platforms, which should be used as long as it
-    spec.platforms = platforms
-    return spec
diff --git a/conda_lock/src_parser/meta_yaml.py b/conda_lock/src_parser/meta_yaml.py
index fd377133e..c52a2bf7a 100644
--- a/conda_lock/src_parser/meta_yaml.py
+++ b/conda_lock/src_parser/meta_yaml.py
@@ -1,13 +1,18 @@
 import pathlib
 
-from typing import Any, Dict, List, Optional
+from typing import TYPE_CHECKING, List, Optional
 
 import jinja2
-import yaml
 
-from conda_lock.common import get_in
-from conda_lock.src_parser import Dependency, LockSpecification, aggregate_lock_specs
-from conda_lock.src_parser.selectors import filter_platform_selectors
+from ruamel.yaml import YAML
+
+from conda_lock.src_parser import SourceDependency, SourceFile
+from conda_lock.src_parser.conda_common import conda_spec_to_versioned_dep
+from conda_lock.src_parser.selectors import parse_selector_comment_for_dep
+
+
+if TYPE_CHECKING:
+    from ruamel.yaml.comments import CommentedMap, CommentedSeq
 
 
 class UndefinedNeverFail(jinja2.Undefined):
@@ -81,80 +86,45 @@ def _return_value(self, value=None):  # type: ignore
         return value
 
 
-def parse_meta_yaml_file(
-    meta_yaml_file: pathlib.Path,
-    platforms: List[str],
-) -> LockSpecification:
-    """Parse a simple meta-yaml file for dependencies assuming the target platforms.
+def parse_meta_yaml_file(meta_yaml_file: pathlib.Path) -> SourceFile:
+    """Parse a simple meta-yaml file for dependencies.
 
-    * This will emit one dependency set per target platform. These may differ
-      if the dependencies depend on platform selectors.
     * This does not support multi-output files and will ignore all lines with
       selectors other than platform.
     """
-    # parse with selectors for each target platform
-    spec = aggregate_lock_specs(
-        [
-            _parse_meta_yaml_file_for_platform(meta_yaml_file, platform)
-            for platform in platforms
-        ]
-    )
-    # remove platform selectors if they apply to all targets
-    for dep in spec.dependencies:
-        if dep.selectors.platform == platforms:
-            dep.selectors.platform = None
-
-    return spec
-
-
-def _parse_meta_yaml_file_for_platform(
-    meta_yaml_file: pathlib.Path,
-    platform: str,
-) -> LockSpecification:
-    """Parse a simple meta-yaml file for dependencies, assuming the target platform.
-
-    * This does not support multi-output files and will ignore all lines with selectors other than platform
-    """
     if not meta_yaml_file.exists():
         raise FileNotFoundError(f"{meta_yaml_file} not found")
 
     with meta_yaml_file.open("r") as fo:
-        filtered_recipe = "\n".join(
-            filter_platform_selectors(fo.read(), platform=platform)
-        )
-        t = jinja2.Template(filtered_recipe, undefined=UndefinedNeverFail)
-        rendered = t.render()
-
-        meta_yaml_data = yaml.safe_load(rendered)
-
-    channels = get_in(["extra", "channels"], meta_yaml_data, [])
-    dependencies: List[Dependency] = []
+        recipe = fo.read()
 
-    def add_spec(spec: str, category: str) -> None:
-        if spec is None:
-            return
+    t = jinja2.Template(recipe, undefined=UndefinedNeverFail)
+    rendered = t.render()
+    meta_yaml_data = YAML().load(rendered)
 
-        from .conda_common import conda_spec_to_versioned_dep
+    channels = meta_yaml_data.mlget(["extra", "channels"], []).copy()
+    dependencies: List[SourceDependency] = []
 
-        dep = conda_spec_to_versioned_dep(spec, category)
-        dep.selectors.platform = [platform]
-        dependencies.append(dep)
+    def add_specs(group: "CommentedSeq", category: str) -> None:
+        for idx, spec in enumerate(group):
+            if spec is None:
+                continue
+            dep = conda_spec_to_versioned_dep(spec, category)
+            dep.selectors.platform = parse_selector_comment_for_dep(group.ca, idx)
+            dependencies.append(dep)
 
-    def add_requirements_from_recipe_or_output(yaml_data: Dict[str, Any]) -> None:
-        for s in get_in(["requirements", "host"], yaml_data, []):
-            add_spec(s, "main")
-        for s in get_in(["requirements", "run"], yaml_data, []):
-            add_spec(s, "main")
-        for s in get_in(["test", "requires"], yaml_data, []):
-            add_spec(s, "dev")
+    def add_requirements_from_recipe_or_output(yaml_data: "CommentedMap") -> None:
+        add_specs(yaml_data.mlget(["requirements", "host"], []), "main")
+        add_specs(yaml_data.mlget(["requirements", "run"], []), "main")
+        add_specs(yaml_data.mlget(["test", "requires"], []), "dev")
 
     add_requirements_from_recipe_or_output(meta_yaml_data)
-    for output in get_in(["outputs"], meta_yaml_data, []):
+    for output in meta_yaml_data.get("outputs", []):
         add_requirements_from_recipe_or_output(output)
 
-    return LockSpecification(
+    return SourceFile(
+        file=meta_yaml_file,
         dependencies=dependencies,
-        channels=channels,
-        platforms=[platform],
-        sources=[meta_yaml_file],
+        channels=channels,  # type: ignore
+        platforms=set(),
     )
diff --git a/conda_lock/src_parser/pyproject_toml.py b/conda_lock/src_parser/pyproject_toml.py
index 61bf4f3a7..88bb3393e 100644
--- a/conda_lock/src_parser/pyproject_toml.py
+++ b/conda_lock/src_parser/pyproject_toml.py
@@ -29,8 +29,8 @@
 from conda_lock.common import get_in
 from conda_lock.lookup import get_forward_lookup as get_lookup
 from conda_lock.src_parser import (
-    Dependency,
-    LockSpecification,
+    SourceDependency,
+    SourceFile,
     URLDependency,
     VersionedDependency,
 )
@@ -86,7 +86,7 @@ def poetry_version_to_conda_version(version_string: Optional[str]) -> Optional[s
 def parse_poetry_pyproject_toml(
     path: pathlib.Path,
     contents: Mapping[str, Any],
-) -> LockSpecification:
+) -> SourceFile:
     """
     Parse dependencies from a poetry pyproject.toml file
 
@@ -102,7 +102,7 @@ def parse_poetry_pyproject_toml(
     * markers are not supported
 
     """
-    dependencies: List[Dependency] = []
+    dependencies: List[SourceDependency] = []
 
     categories: Dict[Tuple[str, ...], str] = {
         ("dependencies",): "main",
@@ -169,7 +169,7 @@ def parse_poetry_pyproject_toml(
                         optional=optional,
                         category=category,
                         extras=extras,
-                    )
+                    ).to_source()
                 )
             else:
                 dependencies.append(
@@ -180,15 +180,17 @@ def parse_poetry_pyproject_toml(
                         optional=optional,
                         category=category,
                         extras=extras,
-                    )
+                    ).to_source()
                 )
 
     return specification_with_dependencies(path, contents, dependencies)
 
 
 def specification_with_dependencies(
-    path: pathlib.Path, toml_contents: Mapping[str, Any], dependencies: List[Dependency]
-) -> LockSpecification:
+    path: pathlib.Path,
+    toml_contents: Mapping[str, Any],
+    dependencies: List[SourceDependency],
+) -> SourceFile:
     force_pypi = set()
     for depname, depattrs in get_in(
         ["tool", "conda-lock", "dependencies"], toml_contents, {}
@@ -203,7 +205,7 @@ def specification_with_dependencies(
                     optional=False,
                     category="main",
                     extras=[],
-                )
+                ).to_source()
             )
         elif isinstance(depattrs, collections.abc.Mapping):
             if depattrs.get("source", None) == "pypi":
@@ -213,14 +215,14 @@ def specification_with_dependencies(
 
     if force_pypi:
         for dep in dependencies:
-            if dep.name in force_pypi:
-                dep.manager = "pip"
+            if dep.dep.name in force_pypi:
+                dep.dep.manager = "pip"
 
-    return LockSpecification(
+    return SourceFile(
         dependencies=dependencies,
         channels=get_in(["tool", "conda-lock", "channels"], toml_contents, []),
-        platforms=get_in(["tool", "conda-lock", "platforms"], toml_contents, []),
-        sources=[path],
+        platforms=set(get_in(["tool", "conda-lock", "platforms"], toml_contents, [])),
+        file=path,
     )
 
 
@@ -232,51 +234,13 @@ def to_match_spec(conda_dep_name: str, conda_version: Optional[str]) -> str:
     return spec
 
 
-def parse_pyproject_toml(
-    pyproject_toml: pathlib.Path,
-) -> LockSpecification:
-    with pyproject_toml.open("rb") as fp:
-        contents = toml_load(fp)
-    build_system = get_in(["build-system", "build-backend"], contents)
-    pep_621_probe = get_in(["project", "dependencies"], contents)
-    pdm_probe = get_in(["tool", "pdm"], contents)
-    parse = parse_poetry_pyproject_toml
-    if pep_621_probe is not None:
-        if pdm_probe is None:
-            parse = partial(
-                parse_requirements_pyproject_toml,
-                prefix=("project",),
-                main_tag="dependencies",
-                optional_tag="optional-dependencies",
-            )
-        else:
-            parse = parse_pdm_pyproject_toml
-    elif build_system.startswith("poetry"):
-        parse = parse_poetry_pyproject_toml
-    elif build_system.startswith("flit"):
-        parse = partial(
-            parse_requirements_pyproject_toml,
-            prefix=("tool", "flit", "metadata"),
-            main_tag="requires",
-            optional_tag="requires-extra",
-        )
-    else:
-        import warnings
-
-        warnings.warn(
-            "Could not detect build-system in pyproject.toml.  Assuming poetry"
-        )
-
-    return parse(pyproject_toml, contents)
-
-
 def parse_python_requirement(
     requirement: str,
     manager: Literal["conda", "pip"] = "conda",
     optional: bool = False,
     category: str = "main",
     normalize_name: bool = True,
-) -> Dependency:
+) -> SourceDependency:
     """Parse a requirements.txt like requirement to a conda spec"""
     requirement_specifier = requirement.split(";")[0].strip()
     from pkg_resources import Requirement
@@ -305,7 +269,7 @@ def parse_python_requirement(
             extras=extras,
             url=url,
             hashes=[frag.replace("=", ":")],
-        )
+        ).to_source()
     else:
         return VersionedDependency(
             name=conda_dep_name,
@@ -314,7 +278,7 @@ def parse_python_requirement(
             optional=optional,
             category=category,
             extras=extras,
-        )
+        ).to_source()
 
 
 def parse_requirements_pyproject_toml(
@@ -324,11 +288,11 @@ def parse_requirements_pyproject_toml(
     main_tag: str,
     optional_tag: str,
     dev_tags: AbstractSet[str] = {"dev", "test"},
-) -> LockSpecification:
+) -> SourceFile:
     """
     PEP621 and flit
     """
-    dependencies: List[Dependency] = []
+    dependencies: List[SourceDependency] = []
 
     sections = {(*prefix, main_tag): "main"}
     for extra in dev_tags:
@@ -352,7 +316,7 @@ def parse_requirements_pyproject_toml(
 def parse_pdm_pyproject_toml(
     path: pathlib.Path,
     contents: Mapping[str, Any],
-) -> LockSpecification:
+) -> SourceFile:
     """
     PDM support. First, a regular PEP621 pass; then, add all dependencies listed
     in the 'tool.pdm.dev-dependencies' table with the 'dev' category.
@@ -367,7 +331,7 @@ def parse_pdm_pyproject_toml(
 
     dev_reqs = []
 
-    for section, deps in get_in(["tool", "pdm", "dev-dependencies"], contents).items():
+    for _, deps in get_in(["tool", "pdm", "dev-dependencies"], contents).items():
         dev_reqs.extend(
             [
                 parse_python_requirement(
@@ -380,3 +344,41 @@ def parse_pdm_pyproject_toml(
     res.dependencies.extend(dev_reqs)
 
     return res
+
+
+def parse_pyproject_toml(pyproject_toml: pathlib.Path) -> SourceFile:
+    with pyproject_toml.open("rb") as fp:
+        contents = toml_load(fp)
+
+    build_system: Optional[str] = get_in(["build-system", "build-backend"], contents)
+    pep_621_probe: Optional[str] = get_in(["project", "dependencies"], contents)
+    pdm_probe: Optional[str] = get_in(["tool", "pdm"], contents)
+
+    parse = parse_poetry_pyproject_toml
+    if pep_621_probe is not None:
+        if pdm_probe is None:
+            parse = partial(
+                parse_requirements_pyproject_toml,
+                prefix=("project",),
+                main_tag="dependencies",
+                optional_tag="optional-dependencies",
+            )
+        else:
+            parse = parse_pdm_pyproject_toml
+    elif build_system and build_system.startswith("poetry"):
+        parse = parse_poetry_pyproject_toml
+    elif build_system and build_system.startswith("flit"):
+        parse = partial(
+            parse_requirements_pyproject_toml,
+            prefix=("tool", "flit", "metadata"),
+            main_tag="requires",
+            optional_tag="requires-extra",
+        )
+    else:
+        import warnings
+
+        warnings.warn(
+            "Could not detect build-system in pyproject.toml.  Assuming poetry"
+        )
+
+    return parse(pyproject_toml, contents)
diff --git a/conda_lock/src_parser/selectors.py b/conda_lock/src_parser/selectors.py
index acefffe87..772933ae0 100644
--- a/conda_lock/src_parser/selectors.py
+++ b/conda_lock/src_parser/selectors.py
@@ -1,16 +1,37 @@
 import logging
 import re
 
-from typing import Iterator, Optional
+from typing import TYPE_CHECKING, List, Optional
+
+
+if TYPE_CHECKING:
+    from ruamel.yaml.comments import Comment
+
+    from conda_lock.src_parser import SourceDependency
 
 
 logger = logging.getLogger(__name__)
+sel_pat = re.compile(r"(#.*)\[([^\[\]]+)\](?(2)[^\(\)]*)$")
+
+
+def parse_selector_comment_for_dep(
+    yaml_comments: "Comment", dep_idx: int
+) -> Optional[List[str]]:
+    if dep_idx not in yaml_comments.items:
+        return None
 
+    comment: str = yaml_comments.items[dep_idx][0].value
+    parsed_comment = comment.partition("\n")[0].rstrip()
 
-def filter_platform_selectors(
-    content: str, platform: Optional[str] = None
-) -> Iterator[str]:
-    """ """
+    # This code is adapted from conda-build
+    m = sel_pat.match(parsed_comment)
+    return [m.group(2)] if m else None
+
+
+def dep_in_platform_selectors(
+    source_dep: "SourceDependency",
+    platform: str,
+) -> bool:
     # we support a very limited set of selectors that adhere to platform only
     # https://docs.conda.io/projects/conda-build/en/latest/resources/define-metadata.html#preprocessing-selectors
 
@@ -25,19 +46,10 @@ def filter_platform_selectors(
         "win-64": {"win", "win64"},
     }
 
-    # This code is adapted from conda-build
-    sel_pat = re.compile(r"(.+?)\s*(#.*)\[([^\[\]]+)\](?(2)[^\(\)]*)$")
-    for line in content.splitlines(keepends=False):
-        if line.lstrip().startswith("#"):
-            continue
-        m = sel_pat.match(line)
-        if platform and m:
-            cond = m.group(3)
-            if cond in platform_sel[platform]:
-                yield line
-            else:
-                logger.warning(
-                    "filtered out line `%s` due to unmatchable selector", line
-                )
-        else:
-            yield line
+    return platform in platform_sel and (
+        source_dep.selectors.platform is None
+        or any(
+            sel_elem in platform_sel[platform]
+            for sel_elem in source_dep.selectors.platform
+        )
+    )
diff --git a/tests/test-lock-spec-platforms/base-env.yml b/tests/test-lock-spec-platforms/base-env.yml
new file mode 100644
index 000000000..d3a363532
--- /dev/null
+++ b/tests/test-lock-spec-platforms/base-env.yml
@@ -0,0 +1,8 @@
+channels:
+  - conda-forge
+
+platforms:
+  - linux-64
+
+dependencies:
+  - python =3.7  #[linux64]
diff --git a/tests/test-lock-spec-platforms/osx-stuff.yml b/tests/test-lock-spec-platforms/osx-stuff.yml
new file mode 100644
index 000000000..acfa5b10b
--- /dev/null
+++ b/tests/test-lock-spec-platforms/osx-stuff.yml
@@ -0,0 +1,8 @@
+channels:
+  - conda-forge
+
+platforms:
+  - osx-64
+
+dependencies:
+  - python =3.7  #[osx64]
diff --git a/tests/test-lock-spec/base-env.yml b/tests/test-lock-spec/base-env.yml
new file mode 100644
index 000000000..0f7774b5f
--- /dev/null
+++ b/tests/test-lock-spec/base-env.yml
@@ -0,0 +1,8 @@
+channels:
+  - conda-forge
+
+platforms:
+  - linux-64
+
+dependencies:
+  - python =3.7
diff --git a/tests/test-lock-spec/ml-stuff.yml b/tests/test-lock-spec/ml-stuff.yml
new file mode 100644
index 000000000..4e44dbffb
--- /dev/null
+++ b/tests/test-lock-spec/ml-stuff.yml
@@ -0,0 +1,9 @@
+channels:
+  - pytorch
+  - conda-forge
+
+platforms:
+  - linux-64
+
+dependencies:
+  - pytorch
diff --git a/tests/test_conda_lock.py b/tests/test_conda_lock.py
index ed8530945..5078b97d3 100644
--- a/tests/test_conda_lock.py
+++ b/tests/test_conda_lock.py
@@ -13,8 +13,9 @@
 import uuid
 
 from glob import glob
+from itertools import chain
 from pathlib import Path
-from typing import Any, Dict
+from typing import Any, Dict, List, Optional
 from unittest.mock import MagicMock
 from urllib.parse import urldefrag, urlsplit
 
@@ -30,20 +31,17 @@
 from conda_lock.conda_lock import (
     DEFAULT_FILES,
     DEFAULT_LOCKFILE_NAME,
-    DEFAULT_PLATFORMS,
     _add_auth_to_line,
     _add_auth_to_lockfile,
     _extract_domain,
     _strip_auth_from_line,
     _strip_auth_from_lockfile,
-    aggregate_lock_specs,
     create_lockfile_from_spec,
     default_virtual_package_repodata,
     determine_conda_executable,
     extract_input_hash,
     main,
     make_lock_spec,
-    parse_meta_yaml_file,
     run_lock,
 )
 from conda_lock.conda_solver import extract_json_object, fake_conda_environment
@@ -66,8 +64,17 @@
 )
 from conda_lock.models.channel import Channel
 from conda_lock.pypi_solver import parse_pip_requirement, solve_pypi
-from conda_lock.src_parser import LockSpecification, Selectors, VersionedDependency
+from conda_lock.src_parser import (
+    Dependency,
+    LockSpecification,
+    Selectors,
+    SourceDependency,
+    VersionedDependency,
+    aggregate_channels,
+    aggregate_deps,
+)
 from conda_lock.src_parser.environment_yaml import parse_environment_file
+from conda_lock.src_parser.meta_yaml import parse_meta_yaml_file
 from conda_lock.src_parser.pyproject_toml import (
     parse_pyproject_toml,
     poetry_version_to_conda_version,
@@ -117,6 +124,18 @@ def gdal_environment(tmp_path: Path):
     return x
 
 
+@pytest.fixture
+def lock_spec_env(tmp_path: Path):
+    main = clone_test_dir("test-lock-spec", tmp_path)
+    return [main.joinpath("base-env.yml"), main.joinpath("ml-stuff.yml")]
+
+
+@pytest.fixture
+def lock_spec_env_platforms(tmp_path: Path):
+    main = clone_test_dir("test-lock-spec-platforms", tmp_path)
+    return [main.joinpath("base-env.yml"), main.joinpath("osx-stuff.yml")]
+
+
 @pytest.fixture
 def filter_conda_environment(tmp_path: Path):
     x = clone_test_dir("test-env-filter-platform", tmp_path).joinpath("environment.yml")
@@ -307,17 +326,26 @@ def test_lock_poetry_ibis(
         ), "Extra category not found in lockfile"
 
 
+def _make_source_dep(
+    name: str, platform: Optional[str] = None, **kwargs
+) -> SourceDependency:
+    return SourceDependency(
+        dep=VersionedDependency(name=name, **kwargs),
+        selectors=Selectors(platform=([platform] if platform else None)),
+    )
+
+
 def test_parse_environment_file(gdal_environment: Path):
-    res = parse_environment_file(gdal_environment, DEFAULT_PLATFORMS, pip_support=True)
+    res = parse_environment_file(gdal_environment, pip_support=True)
     assert all(
         x in res.dependencies
         for x in [
-            VersionedDependency(
+            _make_source_dep(
                 name="python",
                 manager="conda",
                 version=">=3.7,<3.8",
             ),
-            VersionedDependency(
+            _make_source_dep(
                 name="gdal",
                 manager="conda",
                 version="",
@@ -325,7 +353,7 @@ def test_parse_environment_file(gdal_environment: Path):
         ]
     )
     assert (
-        VersionedDependency(
+        _make_source_dep(
             name="toolz",
             manager="pip",
             version="*",
@@ -338,9 +366,9 @@ def test_parse_environment_file(gdal_environment: Path):
 
 
 def test_parse_environment_file_with_pip(pip_environment: Path):
-    res = parse_environment_file(pip_environment, DEFAULT_PLATFORMS, pip_support=True)
-    assert [dep for dep in res.dependencies if dep.manager == "pip"] == [
-        VersionedDependency(
+    res = parse_environment_file(pip_environment, pip_support=True)
+    assert [dep for dep in res.dependencies if dep.dep.manager == "pip"] == [
+        _make_source_dep(
             name="requests-toolbelt",
             manager="pip",
             optional=False,
@@ -352,66 +380,64 @@ def test_parse_environment_file_with_pip(pip_environment: Path):
 
 
 def test_parse_env_file_with_filters_no_args(filter_conda_environment: Path):
-    res = parse_environment_file(filter_conda_environment, None, pip_support=False)
+    res = parse_environment_file(filter_conda_environment, pip_support=False)
     assert all(x in res.platforms for x in ["osx-arm64", "osx-64", "linux-64"])
     assert res.channels == [Channel.from_string("conda-forge")]
 
     assert all(
         x in res.dependencies
         for x in [
-            VersionedDependency(
+            _make_source_dep(
                 name="python",
                 manager="conda",
                 version="<3.11",
             ),
-            VersionedDependency(
+            _make_source_dep(
                 name="clang_osx-arm64",
                 manager="conda",
                 version="",
-                selectors=Selectors(platform=["osx-arm64"]),
+                platform="arm64",
             ),
-            VersionedDependency(
+            _make_source_dep(
                 name="clang_osx-64",
                 manager="conda",
                 version="",
-                selectors=Selectors(platform=["osx-64"]),
+                platform="osx64",
             ),
-            VersionedDependency(
+            _make_source_dep(
                 name="gcc_linux-64",
                 manager="conda",
                 version=">=6",
-                selectors=Selectors(platform=["linux-64"]),
+                platform="linux64",
             ),
         ]
     )
 
 
 def test_parse_env_file_with_filters_defaults(filter_conda_environment: Path):
-    res = parse_environment_file(
-        filter_conda_environment, DEFAULT_PLATFORMS, pip_support=False
-    )
-    assert all(x in res.platforms for x in DEFAULT_PLATFORMS)
+    res = parse_environment_file(filter_conda_environment, pip_support=False)
+    assert all(x in res.platforms for x in ["osx-arm64", "osx-64", "linux-64"])
     assert res.channels == [Channel.from_string("conda-forge")]
 
     assert all(
         x in res.dependencies
         for x in [
-            VersionedDependency(
+            _make_source_dep(
                 name="python",
                 manager="conda",
                 version="<3.11",
             ),
-            VersionedDependency(
+            _make_source_dep(
                 name="clang_osx-64",
                 manager="conda",
                 version="",
-                selectors=Selectors(platform=["osx-64"]),
+                platform="osx64",
             ),
-            VersionedDependency(
+            _make_source_dep(
                 name="gcc_linux-64",
                 manager="conda",
                 version=">=6",
-                selectors=Selectors(platform=["linux-64"]),
+                platform="linux64",
             ),
         ]
     )
@@ -530,31 +556,28 @@ def test_parse_pip_requirement(
 
 
 def test_parse_meta_yaml_file(meta_yaml_environment: Path):
-    res = parse_meta_yaml_file(meta_yaml_environment, ["linux-64", "osx-64"])
-    specs = {dep.name: dep for dep in res.dependencies}
+    res = parse_meta_yaml_file(meta_yaml_environment)
+    specs = {dep.dep.name: dep for dep in res.dependencies}
     assert all(x in specs for x in ["python", "numpy"])
-    assert all(
-        dep.selectors
-        == Selectors(
-            platform=None
-        )  # Platform will be set to None if all dependencies are the same
-        for dep in specs.values()
-    )
+
     # Ensure that this dep specified by a python selector is ignored
-    assert "enum34" not in specs
+    assert "enum34" in specs
+    assert specs["enum34"].selectors == Selectors(platform=["py27"])
+
     # Ensure that this platform specific dep is included
     assert "zlib" in specs
-    assert specs["pytest"].category == "dev"
-    assert specs["pytest"].optional is True
+    assert specs["zlib"].selectors == Selectors(platform=["unix"])
+
+    assert specs["pytest"].dep.category == "dev"
+    assert specs["pytest"].dep.optional is True
 
 
 def test_parse_poetry(poetry_pyproject_toml: Path):
-    res = parse_pyproject_toml(
-        poetry_pyproject_toml,
-    )
+    res = parse_pyproject_toml(poetry_pyproject_toml)
 
     specs = {
-        dep.name: typing.cast(VersionedDependency, dep) for dep in res.dependencies
+        dep.dep.name: typing.cast(VersionedDependency, dep.dep)
+        for dep in res.dependencies
     }
 
     assert specs["requests"].version == ">=2.13.0,<3.0.0"
@@ -576,41 +599,43 @@ def test_spec_poetry(poetry_pyproject_toml: Path):
     virtual_package_repo = default_virtual_package_repodata()
     with virtual_package_repo:
         spec = make_lock_spec(
-            src_files=[poetry_pyproject_toml], virtual_package_repo=virtual_package_repo
+            src_file_paths=[poetry_pyproject_toml],
+            virtual_package_repo=virtual_package_repo,
         )
-        deps = {d.name for d in spec.dependencies}
-        assert "tomlkit" in deps
-        assert "pytest" in deps
-        assert "requests" in deps
+        for plat_deps in spec.dependencies.values():
+            deps = {d.name for d in plat_deps}
+            assert "tomlkit" in deps
+            assert "pytest" in deps
+            assert "requests" in deps
 
         spec = make_lock_spec(
-            src_files=[poetry_pyproject_toml],
+            src_file_paths=[poetry_pyproject_toml],
             virtual_package_repo=virtual_package_repo,
             required_categories={"main", "dev"},
         )
-        deps = {d.name for d in spec.dependencies}
-        assert "tomlkit" not in deps
-        assert "pytest" in deps
-        assert "requests" in deps
+        for plat_deps in spec.dependencies.values():
+            deps = {d.name for d in plat_deps}
+            assert "tomlkit" not in deps
+            assert "pytest" in deps
+            assert "requests" in deps
 
         spec = make_lock_spec(
-            src_files=[poetry_pyproject_toml],
+            src_file_paths=[poetry_pyproject_toml],
             virtual_package_repo=virtual_package_repo,
             required_categories={"main"},
         )
-        deps = {d.name for d in spec.dependencies}
-        assert "tomlkit" not in deps
-        assert "pytest" not in deps
-        assert "requests" in deps
+        for plat_deps in spec.dependencies.values():
+            deps = {d.name for d in plat_deps}
+            assert "tomlkit" not in deps
+            assert "pytest" not in deps
+            assert "requests" in deps
 
 
 def test_parse_flit(flit_pyproject_toml: Path):
-    res = parse_pyproject_toml(
-        flit_pyproject_toml,
-    )
-
+    res = parse_pyproject_toml(flit_pyproject_toml)
     specs = {
-        dep.name: typing.cast(VersionedDependency, dep) for dep in res.dependencies
+        dep.dep.name: typing.cast(VersionedDependency, dep.dep)
+        for dep in res.dependencies
     }
 
     assert specs["requests"].version == ">=2.13.0"
@@ -627,12 +652,10 @@ def test_parse_flit(flit_pyproject_toml: Path):
 
 
 def test_parse_pdm(pdm_pyproject_toml: Path):
-    res = parse_pyproject_toml(
-        pdm_pyproject_toml,
-    )
-
+    res = parse_pyproject_toml(pdm_pyproject_toml)
     specs = {
-        dep.name: typing.cast(VersionedDependency, dep) for dep in res.dependencies
+        dep.dep.name: typing.cast(VersionedDependency, dep.dep)
+        for dep in res.dependencies
     }
 
     # Base dependencies
@@ -951,11 +974,11 @@ def test_run_lock_with_local_package(
 
     with virtual_package_repo:
         lock_spec = make_lock_spec(
-            src_files=[pip_local_package_environment],
+            src_file_paths=[pip_local_package_environment],
             virtual_package_repo=virtual_package_repo,
         )
     assert not any(
-        p.manager == "pip" for p in lock_spec.dependencies
+        p.manager == "pip" for p in chain(*lock_spec.dependencies.values())
     ), "conda-lock ignores editable pip deps"
 
 
@@ -1016,18 +1039,19 @@ def test_poetry_version_parsing_constraints(
     with vpr, capsys.disabled():
         with tempfile.NamedTemporaryFile(dir=".") as tf:
             spec = LockSpecification(
-                dependencies=[
-                    VersionedDependency(
-                        name=package,
-                        version=poetry_version_to_conda_version(version) or "",
-                        manager="conda",
-                        optional=False,
-                        category="main",
-                        extras=[],
-                    )
-                ],
+                dependencies={
+                    "linux-64": [
+                        VersionedDependency(
+                            name=package,
+                            version=poetry_version_to_conda_version(version) or "",
+                            manager="conda",
+                            optional=False,
+                            category="main",
+                            extras=[],
+                        )
+                    ]
+                },
                 channels=[Channel.from_string("conda-forge")],
-                platforms=["linux-64"],
                 # NB: this file must exist for relative path resolution to work
                 # in create_lockfile_from_spec
                 sources=[Path(tf.name)],
@@ -1072,145 +1096,79 @@ def _make_spec(name: str, constraint: str = "*"):
     )
 
 
-def _make_dependency_with_platforms(
-    name: str, platforms: typing.List[str], constraint: str = "*"
-):
-    return VersionedDependency(
-        name=name,
-        version=constraint,
-        selectors=Selectors(platform=platforms),
-    )
-
-
-def test_aggregate_lock_specs():
-    """Ensure that the way two specs combine when both specify channels is correct"""
-    base_spec = LockSpecification(
-        dependencies=[_make_spec("python", "=3.7")],
-        channels=[Channel.from_string("conda-forge")],
-        platforms=["linux-64"],
-        sources=[Path("base-env.yml")],
-    )
-
-    gpu_spec = LockSpecification(
-        dependencies=[_make_spec("pytorch")],
-        channels=[Channel.from_string("pytorch"), Channel.from_string("conda-forge")],
-        platforms=["linux-64"],
-        sources=[Path("ml-stuff.yml")],
-    )
-
-    # NB: content hash explicitly does not depend on the source file names
-    actual = aggregate_lock_specs([base_spec, gpu_spec])
+def test_lock_spec(lock_spec_env: List[Path]):
+    """Ensure that the way two files combine when both specify channels is correct"""
+    actual = make_lock_spec(src_file_paths=lock_spec_env, virtual_package_repo=None)  # type: ignore
     expected = LockSpecification(
-        dependencies=[
-            _make_spec("python", "=3.7"),
-            _make_spec("pytorch"),
-        ],
+        dependencies={
+            "linux-64": [
+                _make_spec("python", "3.7.*"),
+                _make_spec("pytorch", constraint=""),
+            ]
+        },
         channels=[
             Channel.from_string("pytorch"),
             Channel.from_string("conda-forge"),
         ],
-        platforms=["linux-64"],
-        sources=[],
+        sources=lock_spec_env,
     )
     assert actual.dict(exclude={"sources"}) == expected.dict(exclude={"sources"})
+    # NB: content hash explicitly does not depend on the source file names
     assert actual.content_hash() == expected.content_hash()
 
 
-def test_aggregate_lock_specs_multiple_platforms():
+def test_aggregate_lock_specs_multiple_platforms(lock_spec_env_platforms: List[Path]):
     """Ensure that plaforms are merged correctly"""
-    linux_spec = LockSpecification(
-        dependencies=[_make_dependency_with_platforms("python", ["linux-64"], "=3.7")],
-        channels=[Channel.from_string("conda-forge")],
-        platforms=["linux-64"],
-        sources=[Path("base-env.yml")],
-    )
-
-    osx_spec = LockSpecification(
-        dependencies=[_make_dependency_with_platforms("python", ["osx-64"], "=3.7")],
-        channels=[Channel.from_string("conda-forge")],
-        platforms=["osx-64"],
-        sources=[Path("base-env.yml")],
-    )
-
-    # NB: content hash explicitly does not depend on the source file names
-    actual = aggregate_lock_specs([linux_spec, osx_spec])
+    actual = make_lock_spec(src_file_paths=lock_spec_env_platforms, virtual_package_repo=None)  # type: ignore
     expected = LockSpecification(
-        dependencies=[
-            _make_dependency_with_platforms("python", ["linux-64", "osx-64"], "=3.7")
-        ],
+        dependencies={
+            "linux-64": [_make_spec("python", "3.7.*")],
+            "osx-64": [_make_spec("python", "3.7.*")],
+        },
         channels=[
             Channel.from_string("conda-forge"),
         ],
-        platforms=["linux-64", "osx-64"],
-        sources=[],
+        sources=lock_spec_env_platforms,
     )
     assert actual.dict(exclude={"sources"}) == expected.dict(exclude={"sources"})
+    # NB: content hash explicitly does not depend on the source file names
     assert actual.content_hash() == expected.content_hash()
 
 
 def test_aggregate_lock_specs_override_version():
-    base_spec = LockSpecification(
-        dependencies=[_make_spec("package", "=1.0")],
-        channels=[Channel.from_string("conda-forge")],
-        platforms=["linux-64"],
-        sources=[Path("base.yml")],
-    )
+    base_deps: List[Dependency] = [_make_spec("package", "=1.0")]
+    override_deps: List[Dependency] = [_make_spec("package", "=2.0")]
+    agg_deps = aggregate_deps([base_deps, override_deps])
+    assert agg_deps == override_deps
 
-    override_spec = LockSpecification(
-        dependencies=[_make_spec("package", "=2.0")],
-        channels=[Channel.from_string("internal"), Channel.from_string("conda-forge")],
-        platforms=["linux-64"],
-        sources=[Path("override.yml")],
-    )
 
-    agg_spec = aggregate_lock_specs([base_spec, override_spec])
-
-    assert agg_spec.dependencies == override_spec.dependencies
-
-
-def test_aggregate_lock_specs_invalid_channels():
+def test_aggregate_channels():
     """Ensure that aggregating specs from mismatched channel orderings raises an error."""
-    base_spec = LockSpecification(
-        dependencies=[],
-        channels=[Channel.from_string("defaults")],
-        platforms=[],
-        sources=[],
-    )
+    base = [Channel.from_string("defaults")]
 
-    add_conda_forge = base_spec.copy(
-        update={
-            "channels": [
-                Channel.from_string("conda-forge"),
-                Channel.from_string("defaults"),
-            ]
-        }
-    )
-    agg_spec = aggregate_lock_specs([base_spec, add_conda_forge])
-    assert agg_spec.channels == add_conda_forge.channels
+    add_conda_forge = [
+        Channel.from_string("conda-forge"),
+        Channel.from_string("defaults"),
+    ]
+    agg_spec = aggregate_channels([base, add_conda_forge])
+    assert agg_spec == add_conda_forge
 
     # swap the order of the two channels, which is an error
-    flipped = base_spec.copy(
-        update={
-            "channels": [
-                Channel.from_string("defaults"),
-                Channel.from_string("conda-forge"),
-            ]
-        }
-    )
+    flipped = [
+        Channel.from_string("defaults"),
+        Channel.from_string("conda-forge"),
+    ]
 
     with pytest.raises(ChannelAggregationError):
-        agg_spec = aggregate_lock_specs([base_spec, add_conda_forge, flipped])
+        agg_spec = aggregate_channels([base, add_conda_forge, flipped])
+
+    add_pytorch = [
+        Channel.from_string("pytorch"),
+        Channel.from_string("defaults"),
+    ]
 
-    add_pytorch = base_spec.copy(
-        update={
-            "channels": [
-                Channel.from_string("pytorch"),
-                Channel.from_string("defaults"),
-            ]
-        }
-    )
     with pytest.raises(ChannelAggregationError):
-        agg_spec = aggregate_lock_specs([base_spec, add_conda_forge, add_pytorch])
+        agg_spec = aggregate_channels([base, add_conda_forge, add_pytorch])
 
 
 @pytest.fixture(scope="session")
@@ -1548,9 +1506,8 @@ def test_virtual_package_input_hash_stability():
 
     vpr = virtual_package_repo_from_specification(vspec)
     spec = LockSpecification(
-        dependencies=[],
+        dependencies={"linux-64": []},
         channels=[],
-        platforms=["linux-64"],
         sources=[],
         virtual_package_repo=vpr,
     )
@@ -1573,9 +1530,8 @@ def test_default_virtual_package_input_hash_stability():
     }
 
     spec = LockSpecification(
-        dependencies=[],
+        dependencies={key: [] for key in expected.keys()},
         channels=[],
-        platforms=list(expected.keys()),
         sources=[],
         virtual_package_repo=vpr,
     )