Remove invalid srcs in gazelle

Author: yushan8

gazelle/python/generate.go

@@ -66,6 +66,35 @@ func matchesAnyGlob(s string, globs []string) bool {
 	return false
 }
 
+// validateExistingRules checks existing Python rules in the BUILD file and return the rules with invalid srcs.
+func (py *Python) validateExistingRules(args language.GenerateArgs) (emptyRules []*rule.Rule) {
+	if args.File == nil {
+		return
+	}
+	regularFiles := args.RegularFiles
+	regularFilesMap := make(map[string]struct{})
+	for _, file := range regularFiles {
+		regularFilesMap[file] = struct{}{}
+	}
+	for _, existingRule := range args.File.Rules {
+		if _, ok := py.Kinds()[existingRule.Kind()]; !ok {
+			continue
+		}
+		allInvalidSrcs := true
+		for _, src := range existingRule.AttrStrings("srcs") {
+			if _, ok := regularFilesMap[src]; ok {
+				allInvalidSrcs = false
+				break
+			}
+		}
+		// If all srcs are invalid, delete the rule.
+		if allInvalidSrcs {
+			emptyRules = append(emptyRules, newTargetBuilder(existingRule.Kind(), existingRule.Name(), args.Config.RepoRoot, args.Rel, nil).build())
+		}
+	}
+	return emptyRules
+}
+
 // GenerateRules extracts build metadata from source files in a directory.
 // GenerateRules is called in each directory where an update is requested
 // in depth-first post-order.
@@ -230,7 +259,6 @@ func (py *Python) GenerateRules(args language.GenerateArgs) language.GenerateRes
 
 	var result language.GenerateResult
 	result.Gen = make([]*rule.Rule, 0)
-
 	collisionErrors := singlylinkedlist.New()
 
 	appendPyLibrary := func(srcs *treeset.Set, pyLibraryTargetName string) {
@@ -478,7 +506,11 @@ func (py *Python) GenerateRules(args language.GenerateArgs) language.GenerateRes
 		result.Gen = append(result.Gen, pyTest)
 		result.Imports = append(result.Imports, pyTest.PrivateAttr(config.GazelleImportsKey))
 	}
-
+	// Validate existing rules have valid srcs
+	if !cfg.CoarseGrainedGeneration() {
+		emptyRules := py.validateExistingRules(args)
+		result.Empty = append(result.Empty, emptyRules...)
+	}
 	if !collisionErrors.Empty() {
 		it := collisionErrors.Iterator()
 		for it.Next() {

gazelle/python/kinds.go

@@ -70,7 +70,6 @@ var pyKinds = map[string]rule.KindInfo{
 		MatchAny: false,
 		NonEmptyAttrs: map[string]bool{
 			"deps":    true,
-			"main":    true,
 			"srcs":    true,
 			"imports": true,
 		},

gazelle/python/testdata/remove_invalid_binary/BUILD.in

@@ -0,0 +1,7 @@
+load("@rules_python//python:defs.bzl", "py_binary")
+
+py_binary(
+    name = "remove_invalid_binary",
+    srcs = ["__main__.py"],
+    visibility = ["//:__subpackages__"],
+)

gazelle/python/testdata/remove_invalid_binary/BUILD.out

@@ -0,0 +1,3 @@
+# Remove invalid binary
+
+This test case asserts that `py_binary` should be deleted if invalid (no source files).

gazelle/python/testdata/remove_invalid_binary/README.md

@@ -0,0 +1 @@
+workspace(name = "remove_invalid_binary")

gazelle/python/testdata/remove_invalid_binary/WORKSPACE

@@ -0,0 +1,15 @@
+# Copyright 2023 The Bazel Authors. All rights reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+---

gazelle/python/testdata/remove_invalid_binary/test.yaml

@@ -1,10 +0,0 @@
-load("@rules_python//python:defs.bzl", "py_library")
-
-py_library(
-    name = "deps_with_no_srcs_library",
-    deps = [
-        "//:remove_invalid_library",
-        "@pypi//bar",
-        "@pypi//foo",
-    ],
-)

gazelle/python/testdata/remove_invalid_library/BUILD.out

@@ -0,0 +1,17 @@
+load("@rules_python//python:defs.bzl", "py_test")
+
+py_test(
+    name = "remove_invalid_test",
+    srcs = ["__test__.py"],
+    visibility = ["//:__subpackages__"],
+)
+
+py_test(
+    name = "test_with_deps",
+    srcs = ["test_main.py"],
+    deps = [
+        "//:remove_invalid_test",
+        "@pypi//bar",
+        "@pypi//foo",
+    ],
+)