fix: ignore phantom targets and ensure unique target label names (#401)

- The description manifests from SPM can contain undeclared targets
(i.e. phantom targets). We ignore these when constructing a Bazel build
file.
- It is critical that the Bazel label name for an SPM target not
conflict with the label name from a product. Typically, we do this by
using the path of the SPM target as the basis for the label name. This
PR fixes a bug where a non-unique label name was generated when an SPM
target's name and path were equal (i.e., no parent directory in the
path).

Related to #400.

gazelle/internal/swift/bazel_label.go

@@ -9,10 +9,13 @@ import (
 )
 
 // BazelLabelFromTarget creates a Bazel label from a Swift target.
+// The logic in this function must stay in sync with
+// pkginfo_targets.bazel_label_name_from_parts() in the Starlark code.
 func BazelLabelFromTarget(repoName string, target *swiftpkg.Target) *label.Label {
 	var name string
 	basename := path.Base(target.Path)
-	if basename == target.Name {
+	dirname := path.Dir(target.Path)
+	if basename == target.Name && dirname != "." {
 		name = target.Path
 	} else {
 		name = path.Join(target.Path, target.Name)

gazelle/internal/swift/bazel_label_test.go

@@ -10,12 +10,36 @@ import (
 )
 
 func TestBazelLabelFromTarget(t *testing.T) {
-	target := &swiftpkg.Target{
-		Name: "Foo",
-		Path: "Sources/Foo",
+	tests := []struct {
+		msg        string
+		repoName   string
+		targetName string
+		targetPath string
+		exp        string
+	}{
+		{
+			msg:        "regular path",
+			repoName:   "example_cool_repo",
+			targetName: "Foo",
+			targetPath: "Sources/Foo",
+			exp:        "@example_cool_repo//:Sources_Foo",
+		},
+		{
+			msg:        "simple path",
+			repoName:   "example_cool_repo",
+			targetName: "simple_path",
+			targetPath: "simple_path",
+			exp:        "@example_cool_repo//:simple_path_simple_path",
+		},
+	}
+	for _, tt := range tests {
+		target := &swiftpkg.Target{
+			Name: tt.targetName,
+			Path: tt.targetPath,
+		}
+		actual := swift.BazelLabelFromTarget(tt.repoName, target)
+		expected, err := label.Parse(tt.exp)
+		assert.NoError(t, err)
+		assert.Equal(t, &expected, actual, tt.msg)
 	}
-	actual := swift.BazelLabelFromTarget("example_cool_repo", target)
-	expected, err := label.Parse("@example_cool_repo//:Sources_Foo")
-	assert.NoError(t, err)
-	assert.Equal(t, &expected, actual)
 }

gazelle/internal/swiftpkg/package_info.go

@@ -63,7 +63,8 @@ func NewPackageInfo(sw swiftbin.Executor, dir string) (*PackageInfo, error) {
 	for _, descT := range descManifest.Targets {
 		dumpT := dumpManifest.Targets.FindByName(descT.Name)
 		if dumpT == nil {
-			return nil, fmt.Errorf("dump manifest info for %s target not found", descT.Name)
+			// Ignore phantom targets (i.e., appear in description but not in the dump)
+			continue
 		}
 		t, err := NewTargetFromManifestInfo(&descT, dumpT, prodNames)
 		if err != nil {

swiftpkg/internal/pkginfo_targets.bzl

@@ -66,11 +66,29 @@ def _join_path(target, path):
     return _join_path_from_parts(target.path, path)
 
 def _bazel_label_name_from_parts(target_path, target_name):
+    """Create a Bazel label name from a target path and name.
+
+    The logic in this function must stay in sync with BazelLabelFromTarget() in
+    bazel_label.go.
+
+    Args:
+        target_path: The target's path as a `string`.
+        target_name: The target's name as a `string`.
+
+    Returns:
+        A Bazel label name as a `string`.
+    """
     basename = paths.basename(target_path)
-    if basename == target_name:
+    dirname = paths.dirname(target_path)
+
+    # We are trying to construct the shortest, unique target name. We need to
+    # be sure that a target label does not conflict with a product label with
+    # the same name.
+    if basename == target_name and dirname != "":
         name = target_path
     else:
         name = _join_path_from_parts(target_path, target_name)
+
     return name.replace("/", "_")
 
 def _bazel_label_name(target):

swiftpkg/internal/pkginfos.bzl

@@ -82,13 +82,19 @@ def _get(repository_ctx, directory, deps_index, env = {}):
         env = env,
         working_directory = directory,
     )
-    return _new_from_parsed_json(
+    pkg_info = _new_from_parsed_json(
         dump_manifest = dump_manifest,
         desc_manifest = desc_manifest,
         repo_name = repository_utils.package_name(repository_ctx),
         deps_index = deps_index,
     )
 
+    # Dump the merged pkg_info for debug purposes
+    json_str = json.encode_indent(pkg_info, indent = "  ")
+    repository_ctx.file("pkg_info.json", content = json_str, executable = False)
+
+    return pkg_info
+
 def _new_dependency_requirement_from_desc_json_map(req_map):
     ranges = req_map.get("range")
     if ranges != None:
@@ -204,6 +210,7 @@ def _new_target_from_json_maps(dump_map, desc_map, repo_name, deps_index):
     if dep_module == None:
         return None
     product_memberships = dep_module.product_memberships
+
     if len(product_memberships) == 0:
         return None
     dependencies = [

swiftpkg/tests/pkginfo_targets_tests.bzl

@@ -41,7 +41,6 @@ _chocolate_target = pkginfos.new_target(
     sources = [],
     dependencies = [],
 )
-
 _dot_path_target = pkginfos.new_target(
     name = "DotPath",
     type = target_types.library,
@@ -51,6 +50,15 @@ _dot_path_target = pkginfos.new_target(
     sources = ["Chicken.swift", "Smidgen/Hello.swift"],
     dependencies = [],
 )
+_simple_path_target = pkginfos.new_target(
+    name = "simple_path",
+    type = target_types.library,
+    c99name = "simple_path",
+    module_type = module_types.swift,
+    path = "simple_path",
+    sources = ["Simple.swift"],
+    dependencies = [],
+)
 
 def _get_test(ctx):
     env = unittest.begin(ctx)
@@ -125,6 +133,10 @@ def _bazel_label_name_test(ctx):
     expected = "DotPath"
     asserts.equals(env, expected, actual)
 
+    actual = pkginfo_targets.bazel_label_name(_simple_path_target)
+    expected = "simple_path_simple_path"
+    asserts.equals(env, expected, actual)
+
     return unittest.end(env)
 
 bazel_label_name_test = unittest.make(_bazel_label_name_test)