From 0f861f3c1c35bf649e727931bdc899e6f7e387e1 Mon Sep 17 00:00:00 2001
From: Raniere Gaia Costa da Silva <Raniere.CostadaSilva@gesis.org>
Date: Sat, 16 Aug 2025 14:50:47 +0200
Subject: [PATCH 01/14] Start implementation of support for pyproject.yml

Related to https://github.com/jupyterhub/repo2docker/issues/1427
---
 repo2docker/buildpacks/pyproject/__init__.py | 125 +++++++++++++++++++
 1 file changed, 125 insertions(+)
 create mode 100644 repo2docker/buildpacks/pyproject/__init__.py

diff --git a/repo2docker/buildpacks/pyproject/__init__.py b/repo2docker/buildpacks/pyproject/__init__.py
new file mode 100644
index 000000000..0c3e27929
--- /dev/null
+++ b/repo2docker/buildpacks/pyproject/__init__.py
@@ -0,0 +1,125 @@
+"""Buildpack for Git repositories with pyproject.toml
+
+Support to pyproject.toml was added to pip v10.0,
+see https://pip.pypa.io/en/latest/reference/build-system/pyproject-toml/.
+"""
+
+import os
+import re
+import tomllib
+from functools import lru_cache
+
+from ..conda import CondaBuildPack
+
+VERSION_PAT = re.compile(r"\d+(\.\d+)*")
+
+
+class PyprojectBuildPack(CondaBuildPack):
+    """Setup Python with pyproject.toml for use with a repository."""
+
+    @property
+    def python_version(self):
+        """
+        Detect the Python version declared in a `pyproject.toml`.
+        Will return 'x.y' if version is found (e.g '3.6'),
+        or a Falsy empty string '' if not found.
+        """
+
+        if hasattr(self, "_python_version"):
+            return self._python_version
+
+        pyproject_file = self.binder_path("pyproject.toml")
+        with open(pyproject_file, "rb") as _pyproject_file:
+            pyproject_toml = tomllib.load(_pyproject_file)
+
+        if "project" in pyproject_toml:
+            if "requires-python" in pyproject_toml["project"]:
+                raw_version = pyproject_toml["project"]["requires-python"]
+
+                match = VERSION_PAT.match(raw_version)
+                if match:
+                    return match.group()
+
+        return ""
+
+    @lru_cache
+    def get_preassemble_script_files(self):
+        """Return files needed for preassembly"""
+        files = super().get_preassemble_script_files()
+        path = self.binder_path("pyproject.toml")
+        if os.path.exists(path):
+            files[path] = path
+        return files
+
+    @lru_cache
+    def get_preassemble_scripts(self):
+        """scripts to run prior to staging the repo contents"""
+        scripts = super().get_preassemble_scripts()
+        # install pipenv to install dependencies within Pipfile.lock or Pipfile
+        if V(self.python_version) < V("3.6"):
+            # last pipenv version to support 2.7, 3.5
+            pipenv_version = "2021.5.29"
+        else:
+            pipenv_version = "2022.1.8"
+        scripts.append(
+            (
+                "${NB_USER}",
+                f"${{KERNEL_PYTHON_PREFIX}}/bin/pip install --no-cache-dir pipenv=={pipenv_version}",
+            )
+        )
+        return scripts
+
+    @lru_cache
+    def get_assemble_scripts(self):
+        """Return series of build-steps specific to this repository."""
+        # If we have pyproject.toml declare the
+        # use of Python 2, Python 2.7 will be made available in the *kernel*
+        # environment. The notebook servers environment on the other hand
+        # requires Python 3 but may require something additional installed in it
+        # still such as `nbgitpuller`. For this purpose, a "requirements3.txt"
+        # file will be used to install dependencies for the notebook servers
+        # environment, if Python 2 had been specified for the kernel
+        # environment.
+        assemble_scripts = super().get_assemble_scripts()
+
+        if self.separate_kernel_env:
+            # using legacy Python (e.g. 2.7) as a kernel
+
+            # requirements3.txt allows for packages to be installed to the
+            # notebook servers Python environment
+            nb_requirements_file = self.binder_path("requirements3.txt")
+            if os.path.exists(nb_requirements_file):
+                assemble_scripts.append(
+                    (
+                        "${NB_USER}",
+                        f'${{NB_PYTHON_PREFIX}}/bin/pip install --no-cache-dir -r "{nb_requirements_file}"',
+                    )
+                )
+
+        assemble_scripts.append(
+            (
+                "${NB_USER}",
+                """(cd  && \\
+                    PATH="${{KERNEL_PYTHON_PREFIX}}/bin:$PATH" \\
+                        pip install --no-cache-dir --editable {working_directory}
+                )""".format(
+                    working_directory=working_directory,
+                ),
+            )
+        )
+
+        return assemble_scripts
+
+    def detect(self):
+        """Check if current repo should be built with the pyproject.toml buildpack."""
+        # first make sure python is not explicitly unwanted
+        runtime_txt = self.binder_path("runtime.txt")
+        if os.path.exists(runtime_txt):
+            with open(runtime_txt) as f:
+                runtime = f.read().strip()
+            if not runtime.startswith("python-"):
+                return False
+
+        pyproject_file = self.binder_path("pyproject.toml")
+
+        return os.path.exists(pyproject_file)

From c1eedaa0774b44f2bcc52a7962e8bb75b0d10978 Mon Sep 17 00:00:00 2001
From: Raniere Gaia Costa da Silva <Raniere.CostadaSilva@gesis.org>
Date: Mon, 18 Aug 2025 10:38:18 +0200
Subject: [PATCH 02/14] Add builldpack for pyproject to list of buildpack

Related to https://github.com/jupyterhub/repo2docker/issues/1427
---
 repo2docker/app.py                           |  2 +
 repo2docker/buildpacks/__init__.py           |  1 +
 repo2docker/buildpacks/pyproject/__init__.py | 68 +++++++++++++-------
 3 files changed, 49 insertions(+), 22 deletions(-)

diff --git a/repo2docker/app.py b/repo2docker/app.py
index 7a70a470d..cdd0fadea 100755
--- a/repo2docker/app.py
+++ b/repo2docker/app.py
@@ -33,6 +33,7 @@
     LegacyBinderDockerBuildPack,
     NixBuildPack,
     PipfileBuildPack,
+    PyprojectBuildPack,
     PythonBuildPack,
     RBuildPack,
 )
@@ -100,6 +101,7 @@ def _default_log_level(self):
             RBuildPack,
             CondaBuildPack,
             PipfileBuildPack,
+            PyprojectBuildPack,
             PythonBuildPack,
         ],
         config=True,
diff --git a/repo2docker/buildpacks/__init__.py b/repo2docker/buildpacks/__init__.py
index 7568000bd..21a512a81 100644
--- a/repo2docker/buildpacks/__init__.py
+++ b/repo2docker/buildpacks/__init__.py
@@ -5,5 +5,6 @@
 from .legacy import LegacyBinderDockerBuildPack
 from .nix import NixBuildPack
 from .pipfile import PipfileBuildPack
+from .pyproject import PyprojectBuildPack
 from .python import PythonBuildPack
 from .r import RBuildPack
diff --git a/repo2docker/buildpacks/pyproject/__init__.py b/repo2docker/buildpacks/pyproject/__init__.py
index 0c3e27929..21eedfb7c 100644
--- a/repo2docker/buildpacks/pyproject/__init__.py
+++ b/repo2docker/buildpacks/pyproject/__init__.py
@@ -28,19 +28,58 @@ def python_version(self):
         if hasattr(self, "_python_version"):
             return self._python_version
 
+        try:
+            with open(self.binder_path("runtime.txt")) as f:
+                runtime = f.read().strip()
+        except FileNotFoundError:
+            runtime = ""
+
+        if runtime.startswith("python-"):
+            runtime_python_version = runtime.split("-", 1)[1]
+        else:
+            # not a Python runtime (e.g. R, which subclasses this)
+            # use the default Python
+            runtime_python_version = self.major_pythons["3"]
+            self.log.warning(
+                f"Python version unspecified in runtime.txt, using current default Python version {runtime_python_version}. This will change in the future."
+            )
+
+        runtime_python_version_info = runtime_python_version.split(".")
+        if len(runtime_python_version_info) == 1:
+            runtime_python_version = self.major_pythons[runtime_python_version_info[0]]
+            runtime_python_version_info = runtime_python_version.split(".")
+
         pyproject_file = self.binder_path("pyproject.toml")
         with open(pyproject_file, "rb") as _pyproject_file:
             pyproject_toml = tomllib.load(_pyproject_file)
 
         if "project" in pyproject_toml:
             if "requires-python" in pyproject_toml["project"]:
-                raw_version = pyproject_toml["project"]["requires-python"]
+                # This is the minumum version!
+                raw_pyproject_minimum_version = pyproject_toml["project"][
+                    "requires-python"
+                ]
 
-                match = VERSION_PAT.match(raw_version)
+                match = VERSION_PAT.match(raw_pyproject_minimum_version)
                 if match:
-                    return match.group()
+                    pyproject_minimum_version = match.group()
+                    pyproject_minimum_version_info = pyproject_minimum_version.split(
+                        "."
+                    )
 
-        return ""
+                    if (
+                        runtime_python_version_info[0]
+                        < pyproject_minimum_version_info[0]
+                    ) or (
+                        runtime_python_version_info[1]
+                        < pyproject_minimum_version_info[1]
+                    ):
+                        raise RuntimeError(
+                            "runtime.txt version not supported by pyproject.toml."
+                        )
+
+        self._python_version = runtime_python_version
+        return self._python_version
 
     @lru_cache
     def get_preassemble_script_files(self):
@@ -55,18 +94,6 @@ def get_preassemble_script_files(self):
     def get_preassemble_scripts(self):
         """scripts to run prior to staging the repo contents"""
         scripts = super().get_preassemble_scripts()
-        # install pipenv to install dependencies within Pipfile.lock or Pipfile
-        if V(self.python_version) < V("3.6"):
-            # last pipenv version to support 2.7, 3.5
-            pipenv_version = "2021.5.29"
-        else:
-            pipenv_version = "2022.1.8"
-        scripts.append(
-            (
-                "${NB_USER}",
-                f"${{KERNEL_PYTHON_PREFIX}}/bin/pip install --no-cache-dir pipenv=={pipenv_version}",
-            )
-        )
         return scripts
 
     @lru_cache
@@ -99,12 +126,9 @@ def get_assemble_scripts(self):
         assemble_scripts.append(
             (
                 "${NB_USER}",
-                """(cd  && \\
-                    PATH="${{KERNEL_PYTHON_PREFIX}}/bin:$PATH" \\
-                        pip install --no-cache-dir --editable {working_directory}
-                )""".format(
-                    working_directory=working_directory,
-                ),
+                """PATH="${KERNEL_PYTHON_PREFIX}/bin:$PATH" \\
+                    pip install --no-cache-dir --editable .
+                """,
             )
         )
 

From 3dcaa44e277039280f2c2ea9214350fa34de1888 Mon Sep 17 00:00:00 2001
From: Raniere Gaia Costa da Silva <Raniere.CostadaSilva@gesis.org>
Date: Tue, 19 Aug 2025 09:27:23 +0200
Subject: [PATCH 03/14] Change requirement to Python 3.11

because of tomllib.
---
 setup.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/setup.py b/setup.py
index c8fcbbd73..577254ed6 100644
--- a/setup.py
+++ b/setup.py
@@ -62,7 +62,7 @@ def get_identifier(json):
         "toml",
         "traitlets",
     ],
-    python_requires=">=3.9",
+    python_requires=">=3.11",
     author="Project Jupyter Contributors",
     author_email="jupyter@googlegroups.com",
     url="https://repo2docker.readthedocs.io/en/latest/",

From 616b3ecaf88a85f5cafee8ad479787850622f23b Mon Sep 17 00:00:00 2001
From: Raniere Gaia Costa da Silva <Raniere.CostadaSilva@gesis.org>
Date: Tue, 19 Aug 2025 09:34:54 +0200
Subject: [PATCH 04/14] Remove test with Python 3.9

since Python 3.9 is no longer supported as it does not have tomllib.
---
 .github/workflows/test.yml | 5 -----
 1 file changed, 5 deletions(-)

diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index 4645d8c43..d70da9ee9 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -68,11 +68,6 @@ jobs:
           - norun
           # Playwright test
           - ui
-        include:
-          # The earliest actions/setup-python versions depend on the runner.
-          - ubuntu_version: "22.04"
-            python_version: "3.9"
-            repo_type: venv
 
     steps:
       - uses: actions/checkout@v5

From d9cb6a0b937847f840c8676986069272d15456a0 Mon Sep 17 00:00:00 2001
From: Raniere Gaia Costa da Silva <Raniere.CostadaSilva@gesis.org>
Date: Tue, 19 Aug 2025 09:36:43 +0200
Subject: [PATCH 05/14] Avoid change PATH during bash command

---
 repo2docker/buildpacks/pyproject/__init__.py | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/repo2docker/buildpacks/pyproject/__init__.py b/repo2docker/buildpacks/pyproject/__init__.py
index 21eedfb7c..a952c8af1 100644
--- a/repo2docker/buildpacks/pyproject/__init__.py
+++ b/repo2docker/buildpacks/pyproject/__init__.py
@@ -126,9 +126,7 @@ def get_assemble_scripts(self):
         assemble_scripts.append(
             (
                 "${NB_USER}",
-                """PATH="${KERNEL_PYTHON_PREFIX}/bin:$PATH" \\
-                    pip install --no-cache-dir --editable .
-                """,
+                "${KERNEL_PYTHON_PREFIX}/bin/pip install --no-cache-dir --editable .",
             )
         )
 

From 8632198e45076d54d670e86985c40c9d1e830705 Mon Sep 17 00:00:00 2001
From: Raniere Gaia Costa da Silva <Raniere.CostadaSilva@gesis.org>
Date: Tue, 19 Aug 2025 09:56:57 +0200
Subject: [PATCH 06/14] Change Python version used by ReadTheDocks

because now repo2docker requires Python >= 3.11 given the requirement of tomllib.
---
 .readthedocs.yaml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/.readthedocs.yaml b/.readthedocs.yaml
index 7bb04d170..c0e4658d6 100644
--- a/.readthedocs.yaml
+++ b/.readthedocs.yaml
@@ -11,7 +11,7 @@ sphinx:
 build:
   os: ubuntu-22.04
   tools:
-    python: "3.10"
+    python: "3.11"
 
 python:
   install:

From 8d987039b8207f8dff199074c52408fed458a06a Mon Sep 17 00:00:00 2001
From: Raniere Gaia Costa da Silva <Raniere.CostadaSilva@gesis.org>
Date: Mon, 8 Sep 2025 16:54:27 +0200
Subject: [PATCH 07/14] Reduce code duplication in PyprojectBuildPack

---
 repo2docker/buildpacks/pyproject/__init__.py | 26 ++++++--------------
 1 file changed, 7 insertions(+), 19 deletions(-)

diff --git a/repo2docker/buildpacks/pyproject/__init__.py b/repo2docker/buildpacks/pyproject/__init__.py
index a952c8af1..9de1bdf70 100644
--- a/repo2docker/buildpacks/pyproject/__init__.py
+++ b/repo2docker/buildpacks/pyproject/__init__.py
@@ -28,26 +28,17 @@ def python_version(self):
         if hasattr(self, "_python_version"):
             return self._python_version
 
-        try:
-            with open(self.binder_path("runtime.txt")) as f:
-                runtime = f.read().strip()
-        except FileNotFoundError:
-            runtime = ""
-
-        if runtime.startswith("python-"):
-            runtime_python_version = runtime.split("-", 1)[1]
+        name, version, _ = self.runtime
+
+        if name == "python":
+            runtime_python_version = version
         else:
-            # not a Python runtime (e.g. R, which subclasses this)
-            # use the default Python
             runtime_python_version = self.major_pythons["3"]
             self.log.warning(
                 f"Python version unspecified in runtime.txt, using current default Python version {runtime_python_version}. This will change in the future."
             )
 
         runtime_python_version_info = runtime_python_version.split(".")
-        if len(runtime_python_version_info) == 1:
-            runtime_python_version = self.major_pythons[runtime_python_version_info[0]]
-            runtime_python_version_info = runtime_python_version.split(".")
 
         pyproject_file = self.binder_path("pyproject.toml")
         with open(pyproject_file, "rb") as _pyproject_file:
@@ -135,12 +126,9 @@ def get_assemble_scripts(self):
     def detect(self):
         """Check if current repo should be built with the pyproject.toml buildpack."""
         # first make sure python is not explicitly unwanted
-        runtime_txt = self.binder_path("runtime.txt")
-        if os.path.exists(runtime_txt):
-            with open(runtime_txt) as f:
-                runtime = f.read().strip()
-            if not runtime.startswith("python-"):
-                return False
+        name, _, _ = self.runtime
+        if name != "python":
+            return False
 
         pyproject_file = self.binder_path("pyproject.toml")
 

From ddd6d2fcc1364663efcaa8d13608a2e53767fa1b Mon Sep 17 00:00:00 2001
From: Raniere Gaia Costa da Silva <Raniere.CostadaSilva@gesis.org>
Date: Mon, 20 Oct 2025 09:36:10 +0200
Subject: [PATCH 08/14] Use tomli for Python < 3.11

---
 repo2docker/buildpacks/pyproject/__init__.py | 6 +++++-
 setup.py                                     | 2 +-
 2 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/repo2docker/buildpacks/pyproject/__init__.py b/repo2docker/buildpacks/pyproject/__init__.py
index 9de1bdf70..11db16f79 100644
--- a/repo2docker/buildpacks/pyproject/__init__.py
+++ b/repo2docker/buildpacks/pyproject/__init__.py
@@ -6,9 +6,13 @@
 
 import os
 import re
-import tomllib
 from functools import lru_cache
 
+try:
+    import tomllib
+except ImportError:
+    import tomli as tomllib
+
 from ..conda import CondaBuildPack
 
 VERSION_PAT = re.compile(r"\d+(\.\d+)*")
diff --git a/setup.py b/setup.py
index 577254ed6..c8fcbbd73 100644
--- a/setup.py
+++ b/setup.py
@@ -62,7 +62,7 @@ def get_identifier(json):
         "toml",
         "traitlets",
     ],
-    python_requires=">=3.11",
+    python_requires=">=3.9",
     author="Project Jupyter Contributors",
     author_email="jupyter@googlegroups.com",
     url="https://repo2docker.readthedocs.io/en/latest/",

From c972f45d113bfa3f615e888a40938bbb20693dbd Mon Sep 17 00:00:00 2001
From: Raniere Gaia Costa da Silva <Raniere.CostadaSilva@gesis.org>
Date: Mon, 20 Oct 2025 09:41:27 +0200
Subject: [PATCH 09/14] Check that pyproject.toml has required fields

---
 repo2docker/buildpacks/pyproject/__init__.py | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/repo2docker/buildpacks/pyproject/__init__.py b/repo2docker/buildpacks/pyproject/__init__.py
index 11db16f79..294d92501 100644
--- a/repo2docker/buildpacks/pyproject/__init__.py
+++ b/repo2docker/buildpacks/pyproject/__init__.py
@@ -135,5 +135,14 @@ def detect(self):
             return False
 
         pyproject_file = self.binder_path("pyproject.toml")
+        with open(pyproject_file, "rb") as _pyproject_file:
+            pyproject_toml = tomllib.load(_pyproject_file)
+
+        if (
+            ("project" in pyproject_toml)
+            and ("build-system" in pyproject_toml)
+            and ("requires" in pyproject_toml["build-system"])
+        ):
+            return os.path.exists(pyproject_file)
 
-        return os.path.exists(pyproject_file)
+        return False

From 8b99430984858932b68ed5a236fa669672c1e335 Mon Sep 17 00:00:00 2001
From: Raniere Gaia Costa da Silva <Raniere.CostadaSilva@gesis.org>
Date: Mon, 20 Oct 2025 09:52:45 +0200
Subject: [PATCH 10/14] Add one test for pyproject

---
 tests/pyproject/pyproject-toml/README.rst     |  4 +++
 .../pyproject/pyproject-toml/mwt/__init__.py  |  0
 tests/pyproject/pyproject-toml/pyproject.toml | 26 +++++++++++++++++++
 tests/pyproject/pyproject-toml/verify         |  5 ++++
 4 files changed, 35 insertions(+)
 create mode 100644 tests/pyproject/pyproject-toml/README.rst
 create mode 100644 tests/pyproject/pyproject-toml/mwt/__init__.py
 create mode 100644 tests/pyproject/pyproject-toml/pyproject.toml
 create mode 100755 tests/pyproject/pyproject-toml/verify

diff --git a/tests/pyproject/pyproject-toml/README.rst b/tests/pyproject/pyproject-toml/README.rst
new file mode 100644
index 000000000..86564f364
--- /dev/null
+++ b/tests/pyproject/pyproject-toml/README.rst
@@ -0,0 +1,4 @@
+Python - pyproject.toml
+-----------------------
+
+``pyproject.toml`` should be used over ``setup.py``.
diff --git a/tests/pyproject/pyproject-toml/mwt/__init__.py b/tests/pyproject/pyproject-toml/mwt/__init__.py
new file mode 100644
index 000000000..e69de29bb
diff --git a/tests/pyproject/pyproject-toml/pyproject.toml b/tests/pyproject/pyproject-toml/pyproject.toml
new file mode 100644
index 000000000..800af7eda
--- /dev/null
+++ b/tests/pyproject/pyproject-toml/pyproject.toml
@@ -0,0 +1,26 @@
+[build-system]
+requires = ["hatchling"]
+build-backend = "hatchling.build"
+
+[project]
+name = "mwt"
+version = "1.0.0"
+dependencies = [
+  "numpy",
+]
+requires-python = ">=3.12"
+authors = [
+  {name = "Project Jupyter Contributors", email = "jupyter@googlegroups.com"},
+]
+maintainers = [
+  {name = "Project Jupyter Contributors", email = "jupyter@googlegroups.com"},
+]
+description = "Test for repo2docker"
+readme = "README.rst"
+license = "MIT"
+
+[project.urls]
+Homepage = "https://repo2docker.readthedocs.io/"
+Documentation = "https://repo2docker.readthedocs.io/"
+Repository = "https://github.com/jupyterhub/repo2docker.git"
+"Bug Tracker" = "https://github.com/jupyterhub/repo2docker/issues"
\ No newline at end of file
diff --git a/tests/pyproject/pyproject-toml/verify b/tests/pyproject/pyproject-toml/verify
new file mode 100755
index 000000000..4d7131e1e
--- /dev/null
+++ b/tests/pyproject/pyproject-toml/verify
@@ -0,0 +1,5 @@
+#!/usr/bin/env python
+try:
+    import mwt
+except ImportError:
+    raise Exception("'mwt' shouldn't have been installed!")

From 1a393bb5ecf255fd3fd37e6a9a8e10a04af20e89 Mon Sep 17 00:00:00 2001
From: Raniere Gaia Costa da Silva <Raniere.CostadaSilva@gesis.org>
Date: Mon, 20 Oct 2025 10:00:28 +0200
Subject: [PATCH 11/14] Add documentation about pyproject.toml

---
 docs/source/configuration/development.md | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/docs/source/configuration/development.md b/docs/source/configuration/development.md
index a770f0cb7..8cd1c5e75 100644
--- a/docs/source/configuration/development.md
+++ b/docs/source/configuration/development.md
@@ -24,10 +24,22 @@ environment. Our
 [example `requirements.txt` file](https://github.com/binder-examples/requirements/blob/HEAD/requirements.txt)
 on GitHub shows a typical requirements file.
 
+(pyproject)=
+
+## `pyproject.toml` - Install Python packages
+
+To install your reprository like a Python package, you may include a
+`pyproject.toml` file. `repo2docker`install `pyproject.toml` files by running
+`pip install -e .`.
+
 (setup-py)=
 
 ## `setup.py` - Install Python packages
 
+```{note}
+We recommend to use `pyproject.toml` as it is the recommended way since 2020 when PEPs [621](https://peps.python.org/pep-0621/) and [631](https://peps.python.org/pep-0631/) were accepted.
+```
+
 To install your repository like a Python package, you may include a
 `setup.py` file. `repo2docker` installs `setup.py` files by running
 `pip install -e .`.

From 22234b9ee45de5f408f8c6cfa7f80624c5548834 Mon Sep 17 00:00:00 2001
From: Raniere Gaia Costa da Silva <Raniere.CostadaSilva@gesis.org>
Date: Mon, 20 Oct 2025 15:48:34 +0200
Subject: [PATCH 12/14] Fix English typos

---
 docs/source/configuration/development.md     | 4 ++--
 repo2docker/buildpacks/pyproject/__init__.py | 2 +-
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/docs/source/configuration/development.md b/docs/source/configuration/development.md
index 8cd1c5e75..632bcd136 100644
--- a/docs/source/configuration/development.md
+++ b/docs/source/configuration/development.md
@@ -28,8 +28,8 @@ on GitHub shows a typical requirements file.
 
 ## `pyproject.toml` - Install Python packages
 
-To install your reprository like a Python package, you may include a
-`pyproject.toml` file. `repo2docker`install `pyproject.toml` files by running
+To install your repository like a Python package, you may include a
+`pyproject.toml` file. `repo2docker`installs `pyproject.toml` files by running
 `pip install -e .`.
 
 (setup-py)=
diff --git a/repo2docker/buildpacks/pyproject/__init__.py b/repo2docker/buildpacks/pyproject/__init__.py
index 294d92501..814d5ed0e 100644
--- a/repo2docker/buildpacks/pyproject/__init__.py
+++ b/repo2docker/buildpacks/pyproject/__init__.py
@@ -1,6 +1,6 @@
 """Buildpack for Git repositories with pyproject.toml
 
-Support to pyproject.toml was added to pip v10.0,
+Support for pyproject.toml was added to pip v10.0,
 see https://pip.pypa.io/en/latest/reference/build-system/pyproject-toml/.
 """
 

From 8e96d3ebdf6bdacb3268b7fe73823aed3292596f Mon Sep 17 00:00:00 2001
From: Raniere Gaia Costa da Silva <Raniere.CostadaSilva@gesis.org>
Date: Mon, 20 Oct 2025 16:17:07 +0200
Subject: [PATCH 13/14] Only read pyproject.toml if file exists

---
 repo2docker/buildpacks/pyproject/__init__.py | 19 ++++++++++---------
 1 file changed, 10 insertions(+), 9 deletions(-)

diff --git a/repo2docker/buildpacks/pyproject/__init__.py b/repo2docker/buildpacks/pyproject/__init__.py
index 814d5ed0e..4b6376057 100644
--- a/repo2docker/buildpacks/pyproject/__init__.py
+++ b/repo2docker/buildpacks/pyproject/__init__.py
@@ -135,14 +135,15 @@ def detect(self):
             return False
 
         pyproject_file = self.binder_path("pyproject.toml")
-        with open(pyproject_file, "rb") as _pyproject_file:
-            pyproject_toml = tomllib.load(_pyproject_file)
-
-        if (
-            ("project" in pyproject_toml)
-            and ("build-system" in pyproject_toml)
-            and ("requires" in pyproject_toml["build-system"])
-        ):
-            return os.path.exists(pyproject_file)
+        if os.path.exists(pyproject_file):
+            with open(pyproject_file, "rb") as _pyproject_file:
+                pyproject_toml = tomllib.load(_pyproject_file)
+
+            if (
+                ("project" in pyproject_toml)
+                and ("build-system" in pyproject_toml)
+                and ("requires" in pyproject_toml["build-system"])
+            ):
+                return os.path.exists(pyproject_file)
 
         return False

From b755b7a8345734b2df279a852a86b0faae10fd1d Mon Sep 17 00:00:00 2001
From: Raniere Gaia Costa da Silva <Raniere.CostadaSilva@gesis.org>
Date: Tue, 21 Oct 2025 13:38:51 +0200
Subject: [PATCH 14/14] Merge PyprojectBuildPack into PythonBuildPack

---
 repo2docker/app.py                            |   2 -
 repo2docker/buildpacks/__init__.py            |   1 -
 repo2docker/buildpacks/pyproject/__init__.py  | 149 ------------------
 repo2docker/buildpacks/python/__init__.py     |  66 +++++++-
 tests/pyproject/pyproject-toml/pyproject.toml |   2 +-
 5 files changed, 60 insertions(+), 160 deletions(-)
 delete mode 100644 repo2docker/buildpacks/pyproject/__init__.py

diff --git a/repo2docker/app.py b/repo2docker/app.py
index cdd0fadea..7a70a470d 100755
--- a/repo2docker/app.py
+++ b/repo2docker/app.py
@@ -33,7 +33,6 @@
     LegacyBinderDockerBuildPack,
     NixBuildPack,
     PipfileBuildPack,
-    PyprojectBuildPack,
     PythonBuildPack,
     RBuildPack,
 )
@@ -101,7 +100,6 @@ def _default_log_level(self):
             RBuildPack,
             CondaBuildPack,
             PipfileBuildPack,
-            PyprojectBuildPack,
             PythonBuildPack,
         ],
         config=True,
diff --git a/repo2docker/buildpacks/__init__.py b/repo2docker/buildpacks/__init__.py
index 21a512a81..7568000bd 100644
--- a/repo2docker/buildpacks/__init__.py
+++ b/repo2docker/buildpacks/__init__.py
@@ -5,6 +5,5 @@
 from .legacy import LegacyBinderDockerBuildPack
 from .nix import NixBuildPack
 from .pipfile import PipfileBuildPack
-from .pyproject import PyprojectBuildPack
 from .python import PythonBuildPack
 from .r import RBuildPack
diff --git a/repo2docker/buildpacks/pyproject/__init__.py b/repo2docker/buildpacks/pyproject/__init__.py
deleted file mode 100644
index 4b6376057..000000000
--- a/repo2docker/buildpacks/pyproject/__init__.py
+++ /dev/null
@@ -1,149 +0,0 @@
-"""Buildpack for Git repositories with pyproject.toml
-
-Support for pyproject.toml was added to pip v10.0,
-see https://pip.pypa.io/en/latest/reference/build-system/pyproject-toml/.
-"""
-
-import os
-import re
-from functools import lru_cache
-
-try:
-    import tomllib
-except ImportError:
-    import tomli as tomllib
-
-from ..conda import CondaBuildPack
-
-VERSION_PAT = re.compile(r"\d+(\.\d+)*")
-
-
-class PyprojectBuildPack(CondaBuildPack):
-    """Setup Python with pyproject.toml for use with a repository."""
-
-    @property
-    def python_version(self):
-        """
-        Detect the Python version declared in a `pyproject.toml`.
-        Will return 'x.y' if version is found (e.g '3.6'),
-        or a Falsy empty string '' if not found.
-        """
-
-        if hasattr(self, "_python_version"):
-            return self._python_version
-
-        name, version, _ = self.runtime
-
-        if name == "python":
-            runtime_python_version = version
-        else:
-            runtime_python_version = self.major_pythons["3"]
-            self.log.warning(
-                f"Python version unspecified in runtime.txt, using current default Python version {runtime_python_version}. This will change in the future."
-            )
-
-        runtime_python_version_info = runtime_python_version.split(".")
-
-        pyproject_file = self.binder_path("pyproject.toml")
-        with open(pyproject_file, "rb") as _pyproject_file:
-            pyproject_toml = tomllib.load(_pyproject_file)
-
-        if "project" in pyproject_toml:
-            if "requires-python" in pyproject_toml["project"]:
-                # This is the minumum version!
-                raw_pyproject_minimum_version = pyproject_toml["project"][
-                    "requires-python"
-                ]
-
-                match = VERSION_PAT.match(raw_pyproject_minimum_version)
-                if match:
-                    pyproject_minimum_version = match.group()
-                    pyproject_minimum_version_info = pyproject_minimum_version.split(
-                        "."
-                    )
-
-                    if (
-                        runtime_python_version_info[0]
-                        < pyproject_minimum_version_info[0]
-                    ) or (
-                        runtime_python_version_info[1]
-                        < pyproject_minimum_version_info[1]
-                    ):
-                        raise RuntimeError(
-                            "runtime.txt version not supported by pyproject.toml."
-                        )
-
-        self._python_version = runtime_python_version
-        return self._python_version
-
-    @lru_cache
-    def get_preassemble_script_files(self):
-        """Return files needed for preassembly"""
-        files = super().get_preassemble_script_files()
-        path = self.binder_path("pyproject.toml")
-        if os.path.exists(path):
-            files[path] = path
-        return files
-
-    @lru_cache
-    def get_preassemble_scripts(self):
-        """scripts to run prior to staging the repo contents"""
-        scripts = super().get_preassemble_scripts()
-        return scripts
-
-    @lru_cache
-    def get_assemble_scripts(self):
-        """Return series of build-steps specific to this repository."""
-        # If we have pyproject.toml declare the
-        # use of Python 2, Python 2.7 will be made available in the *kernel*
-        # environment. The notebook servers environment on the other hand
-        # requires Python 3 but may require something additional installed in it
-        # still such as `nbgitpuller`. For this purpose, a "requirements3.txt"
-        # file will be used to install dependencies for the notebook servers
-        # environment, if Python 2 had been specified for the kernel
-        # environment.
-        assemble_scripts = super().get_assemble_scripts()
-
-        if self.separate_kernel_env:
-            # using legacy Python (e.g. 2.7) as a kernel
-
-            # requirements3.txt allows for packages to be installed to the
-            # notebook servers Python environment
-            nb_requirements_file = self.binder_path("requirements3.txt")
-            if os.path.exists(nb_requirements_file):
-                assemble_scripts.append(
-                    (
-                        "${NB_USER}",
-                        f'${{NB_PYTHON_PREFIX}}/bin/pip install --no-cache-dir -r "{nb_requirements_file}"',
-                    )
-                )
-
-        assemble_scripts.append(
-            (
-                "${NB_USER}",
-                "${KERNEL_PYTHON_PREFIX}/bin/pip install --no-cache-dir --editable .",
-            )
-        )
-
-        return assemble_scripts
-
-    def detect(self):
-        """Check if current repo should be built with the pyproject.toml buildpack."""
-        # first make sure python is not explicitly unwanted
-        name, _, _ = self.runtime
-        if name != "python":
-            return False
-
-        pyproject_file = self.binder_path("pyproject.toml")
-        if os.path.exists(pyproject_file):
-            with open(pyproject_file, "rb") as _pyproject_file:
-                pyproject_toml = tomllib.load(_pyproject_file)
-
-            if (
-                ("project" in pyproject_toml)
-                and ("build-system" in pyproject_toml)
-                and ("requires" in pyproject_toml["build-system"])
-            ):
-                return os.path.exists(pyproject_file)
-
-        return False
diff --git a/repo2docker/buildpacks/python/__init__.py b/repo2docker/buildpacks/python/__init__.py
index 6c9a6d6e0..d4ec0331a 100644
--- a/repo2docker/buildpacks/python/__init__.py
+++ b/repo2docker/buildpacks/python/__init__.py
@@ -1,8 +1,14 @@
 """Generates Dockerfiles based on an input matrix based on Python."""
 
 import os
+import re
 from functools import lru_cache
 
+try:
+    import tomllib
+except ImportError:
+    import tomli as tomllib
+
 from ...utils import is_local_pip_requirement, open_guess_encoding
 from ..conda import CondaBuildPack
 
@@ -34,6 +40,35 @@ def python_version(self):
             # get major.minor
             py_version = ".".join(py_version_info[:2])
         self._python_version = py_version
+
+        pyproject_toml = "pyproject.toml"
+        if not self.binder_dir and os.path.exists(pyproject_toml):
+            with open(pyproject_toml, "rb") as _pyproject_file:
+                pyproject = tomllib.load(_pyproject_file)
+
+            if "project" in pyproject:
+                if "requires-python" in pyproject["project"]:
+                    # This is the minumum version!
+                    raw_pyproject_minimum_version = pyproject["project"][
+                        "requires-python"
+                    ]
+
+                    match = re.compile(r"\d+(\.\d+)*").match(
+                        raw_pyproject_minimum_version
+                    )
+                    if match:
+                        pyproject_minimum_version = match.group()
+                        pyproject_minimum_version_info = (
+                            pyproject_minimum_version.split(".")
+                        )
+
+                        if (py_version_info[0] < pyproject_minimum_version_info[0]) or (
+                            py_version_info[1] < pyproject_minimum_version_info[1]
+                        ):
+                            raise RuntimeError(
+                                "runtime.txt version not supported by pyproject.toml."
+                            )
+
         return self._python_version
 
     def _get_pip_scripts(self):
@@ -78,9 +113,11 @@ def _should_preassemble_pip(self):
         If there are any local references, e.g. `-e .`,
         stage the whole repo prior to installation.
         """
-        if not os.path.exists("binder") and os.path.exists("setup.py"):
-            # can't install from subset if we're using setup.py
-            return False
+        # can't install from subset
+        for _configuration_file in ("pyproject.toml", "setup.py"):
+            if not os.path.exists("binder") and os.path.exists(_configuration_file):
+                return False
+
         for name in ("requirements.txt", "requirements3.txt"):
             requirements_txt = self.binder_path(name)
             if not os.path.exists(requirements_txt):
@@ -119,26 +156,41 @@ def get_assemble_scripts(self):
         # and requirements3.txt (if it exists)
         # will be installed in the python 3 notebook server env.
         assemble_scripts = super().get_assemble_scripts()
-        setup_py = "setup.py"
         # KERNEL_PYTHON_PREFIX is the env with the kernel,
         # whether it's distinct from the notebook or the same.
         pip = "${KERNEL_PYTHON_PREFIX}/bin/pip"
         if not self._should_preassemble_pip:
             assemble_scripts.extend(self._get_pip_scripts())
 
-        # setup.py exists *and* binder dir is not used
-        if not self.binder_dir and os.path.exists(setup_py):
-            assemble_scripts.append(("${NB_USER}", f"{pip} install --no-cache-dir ."))
+        for _configuration_file in ("pyproject.toml", "setup.py"):
+            if not self.binder_dir and os.path.exists(_configuration_file):
+                assemble_scripts.append(
+                    ("${NB_USER}", f"{pip} install --no-cache-dir .")
+                )
+                break
+
         return assemble_scripts
 
     def detect(self):
         """Check if current repo should be built with the Python buildpack."""
         requirements_txt = self.binder_path("requirements.txt")
+        pyproject_toml = "pyproject.toml"
         setup_py = "setup.py"
 
         name = self.runtime[0]
         if name:
             return name == "python"
+        if not self.binder_dir and os.path.exists(pyproject_toml):
+            with open(pyproject_toml, "rb") as _pyproject_file:
+                pyproject = tomllib.load(_pyproject_file)
+
+            if (
+                ("project" in pyproject)
+                and ("build-system" in pyproject)
+                and ("requires" in pyproject["build-system"])
+            ):
+                return True
+
         if not self.binder_dir and os.path.exists(setup_py):
             return True
         return os.path.exists(requirements_txt)
diff --git a/tests/pyproject/pyproject-toml/pyproject.toml b/tests/pyproject/pyproject-toml/pyproject.toml
index 800af7eda..530f83977 100644
--- a/tests/pyproject/pyproject-toml/pyproject.toml
+++ b/tests/pyproject/pyproject-toml/pyproject.toml
@@ -8,7 +8,7 @@ version = "1.0.0"
 dependencies = [
   "numpy",
 ]
-requires-python = ">=3.12"
+requires-python = ">=3.10"
 authors = [
   {name = "Project Jupyter Contributors", email = "jupyter@googlegroups.com"},
 ]