fix(gazelle): __init__.py in per-file targets

gazelle/python/generate.go

@@ -252,18 +252,16 @@ func (py *Python) GenerateRules(args language.GenerateArgs) language.GenerateRes
 		result.Imports = append(result.Imports, pyLibrary.PrivateAttr(config.GazelleImportsKey))
 	}
 	if cfg.PerFileGeneration() {
+		hasInit, nonEmptyInit := hasLibraryEntrypointFile(args.Dir)
 		pyLibraryFilenames.Each(func(index int, filename interface{}) {
-			if filename == pyLibraryEntrypointFilename {
-				stat, err := os.Stat(filepath.Join(args.Dir, filename.(string)))
-				if err != nil {
-					log.Fatalf("ERROR: %v\n", err)
-				}
-				if stat.Size() == 0 {
-					return // ignore empty __init__.py
-				}
+			pyLibraryTargetName := strings.TrimSuffix(filepath.Base(filename.(string)), ".py")
+			if filename == pyLibraryEntrypointFilename && !nonEmptyInit {
+				return // ignore empty __init__.py.
 			}
 			srcs := treeset.NewWith(godsutils.StringComparator, filename)
-			pyLibraryTargetName := strings.TrimSuffix(filepath.Base(filename.(string)), ".py")
+			if hasInit && nonEmptyInit {
+				srcs.Add(pyLibraryEntrypointFilename)
+			}
 			appendPyLibrary(srcs, pyLibraryTargetName)
 		})
 	} else if !pyLibraryFilenames.Empty() {
@@ -463,6 +461,19 @@ func hasEntrypointFile(dir string) bool {
 	return false
 }
 
+// hasLibraryEntrypointFile returns if the given directory has the library
+// entrypoint file, and if it is non-empty.
+func hasLibraryEntrypointFile(dir string) (bool, bool) {
+	stat, err := os.Stat(filepath.Join(dir, pyLibraryEntrypointFilename))
+	if os.IsNotExist(err) {
+		return false, false
+	}
+	if err != nil {
+		log.Fatalf("ERROR: %v\n", err)
+	}
+	return true, stat.Size() != 0
+}
+
 // isEntrypointFile returns whether the given path is an entrypoint file. The
 // given path can be absolute or relative.
 func isEntrypointFile(path string) bool {

gazelle/python/resolve.go

@@ -61,11 +61,17 @@ func (py *Resolver) Imports(c *config.Config, r *rule.Rule, f *rule.File) []reso
 	provides := make([]resolve.ImportSpec, 0, len(srcs)+1)
 	for _, src := range srcs {
 		ext := filepath.Ext(src)
-		if ext == ".py" {
-			pythonProjectRoot := cfg.PythonProjectRoot()
-			provide := importSpecFromSrc(pythonProjectRoot, f.Pkg, src)
-			provides = append(provides, provide)
+		if ext != ".py" {
+			continue
 		}
+		if cfg.PerFileGeneration() && len(srcs) > 1 && src == pyLibraryEntrypointFilename {
+			// Do not provide import spec from __init__.py when it is being included as
+			// part of another module.
+			continue
+		}
+		pythonProjectRoot := cfg.PythonProjectRoot()
+		provide := importSpecFromSrc(pythonProjectRoot, f.Pkg, src)
+		provides = append(provides, provide)
 	}
 	if len(provides) == 0 {
 		return nil

gazelle/python/testdata/per_file_non_empty_init/BUILD.out

@@ -11,6 +11,9 @@ py_library(
 
 py_library(
     name = "foo",
-    srcs = ["foo.py"],
+    srcs = [
+        "__init__.py",
+        "foo.py",
+    ],
     visibility = ["//:__subpackages__"],
 )

gazelle/python/testdata/per_file_subdirs/bar/BUILD.out

@@ -6,9 +6,21 @@ py_library(
     visibility = ["//:__subpackages__"],
 )
 
+py_library(
+    name = "bar",
+    srcs = [
+        "__init__.py",
+        "bar.py",
+    ],
+    visibility = ["//:__subpackages__"],
+)
+
 py_library(
     name = "foo",
-    srcs = ["foo.py"],
+    srcs = [
+        "__init__.py",
+        "foo.py",
+    ],
     visibility = ["//:__subpackages__"],
 )