Fix excluded_type imports for implicitly excluded extensions

private/bufpkg/bufimage/bufimageutil/bufimageutil.go

@@ -395,6 +395,9 @@ func (t *transitiveClosure) includeType(
 	}
 	for _, file := range pkg.files {
 		fileDescriptor := file.FileDescriptorProto()
+		if mode := t.elements[fileDescriptor]; mode == inclusionModeExcluded {
+			return fmt.Errorf("inclusion of excluded package %q", typeName)
+		}
 		if err := t.addElement(fileDescriptor, "", false, imageIndex, options); err != nil {
 			return fmt.Errorf("inclusion of type %q: %w", typeName, err)
 		}
@@ -428,8 +431,11 @@ func (t *transitiveClosure) addElement(
 	opts *imageFilterOptions,
 ) error {
 	descriptorInfo := imageIndex.ByDescriptor[descriptor]
-	t.addImport(referrerFile, descriptorInfo.file.Path())
 	if existingMode, ok := t.elements[descriptor]; ok && existingMode != inclusionModeEnclosing {
+		if existingMode == inclusionModeExcluded {
+			return nil // already excluded
+		}
+		t.addImport(referrerFile, descriptorInfo.file.Path())
 		if existingMode == inclusionModeImplicit && !impliedByCustomOption {
 			// upgrade from implied to explicitly part of closure
 			t.elements[descriptor] = inclusionModeExplicit
@@ -589,6 +595,9 @@ func (t *transitiveClosure) addElement(
 		return errorUnsupportedFilterType(descriptor, descriptorInfo.fullName)
 	}
 
+	// Add the file to the imports for this file.
+	t.addImport(referrerFile, descriptorInfo.file.Path())
+
 	// if this type is enclosed inside another, add enclosing types
 	if err := t.addEnclosing(descriptorInfo.parent, descriptorInfo.file.Path(), imageIndex, opts); err != nil {
 		return err
@@ -812,6 +821,10 @@ func (t *transitiveClosure) addExtensions(
 		}
 		descriptorInfo := imageIndex.ByDescriptor[msgDescriptor]
 		for _, extendsDescriptor := range imageIndex.NameToExtensions[descriptorInfo.fullName] {
+			if mode := t.elements[extendsDescriptor]; mode == inclusionModeExcluded {
+				// This extension field is excluded.
+				continue
+			}
 			if err := t.addElement(extendsDescriptor, "", false, imageIndex, opts); err != nil {
 				return err
 			}

private/bufpkg/bufimage/bufimageutil/bufimageutil_test.go

@@ -498,6 +498,11 @@ func TestDependencies(t *testing.T) {
 		t.Parallel()
 		runDiffTest(t, "testdata/deps", "test.PublicOrder.txtar", WithIncludeTypes("test.PublicOrder"))
 	})
+	// Test an included type with implicitly excluded extensions fields.
+	t.Run("IncludeWithExcludeExtensions", func(t *testing.T) {
+		t.Parallel()
+		runDiffTest(t, "testdata/deps", "test.IncludeWithExcludeExt.txtar", WithIncludeTypes("google.protobuf.MessageOptions"), WithExcludeTypes("a", "b", "c"), WithAllowIncludeOfImportedType())
+	})
 }
 
 func getImage(ctx context.Context, logger *slog.Logger, testdataDir string, options ...bufimage.BuildImageOption) (storage.ReadWriteBucket, bufimage.Image, error) {

private/bufpkg/bufimage/bufimageutil/image_filter.go

@@ -94,7 +94,17 @@ func filterImage(image bufimage.Image, options *imageFilterOptions) (bufimage.Im
 		}
 		dirty = dirty || newImageFile != imageFile
 		if newImageFile == nil {
-			return nil, fmt.Errorf("imported file %q was filtered out", imageFilePath)
+			// The file was filtered out. Check if it was used by another file.
+			for filePath, dependencies := range closure.imports {
+				if _, isImported := dependencies[imageFilePath]; isImported {
+					return nil, syserror.Newf("file %q was filtered out, but is still used by %q", imageFilePath, filePath)
+				}
+			}
+			// Currently, with an explicitly included type we add the extensions
+			// to the import list. If all the extension fields types are excluded,
+			// the file may be empty. The import list still contains the empty file.
+			// Skip the file. See: TestDeps/IncludeWithExcludeExtensions
+			continue
 		}
 		newImageFiles = append(newImageFiles, newImageFile)
 	}

private/bufpkg/bufimage/bufimageutil/testdata/deps/test.IncludeWithExcludeExt.txtar

@@ -0,0 +1,166 @@
+-- google/protobuf/descriptor.proto --
+syntax = "proto2";
+package google.protobuf;
+option cc_enable_arenas = true;
+option csharp_namespace = "Google.Protobuf.Reflection";
+option go_package = "google.golang.org/protobuf/types/descriptorpb";
+option java_outer_classname = "DescriptorProtos";
+option java_package = "com.google.protobuf";
+option objc_class_prefix = "GPB";
+option optimize_for = SPEED;
+message FeatureSet {
+  optional FieldPresence field_presence = 1 [
+    edition_defaults = { value: "EXPLICIT", edition: EDITION_LEGACY },
+    edition_defaults = { value: "IMPLICIT", edition: EDITION_PROTO3 },
+    edition_defaults = { value: "EXPLICIT", edition: EDITION_2023 },
+    feature_support = { edition_introduced: EDITION_2023 },
+    retention = RETENTION_RUNTIME,
+    targets = TARGET_TYPE_FIELD,
+    targets = TARGET_TYPE_FILE
+  ];
+  optional EnumType enum_type = 2 [
+    edition_defaults = { value: "CLOSED", edition: EDITION_LEGACY },
+    edition_defaults = { value: "OPEN", edition: EDITION_PROTO3 },
+    feature_support = { edition_introduced: EDITION_2023 },
+    retention = RETENTION_RUNTIME,
+    targets = TARGET_TYPE_ENUM,
+    targets = TARGET_TYPE_FILE
+  ];
+  optional RepeatedFieldEncoding repeated_field_encoding = 3 [
+    edition_defaults = { value: "EXPANDED", edition: EDITION_LEGACY },
+    edition_defaults = { value: "PACKED", edition: EDITION_PROTO3 },
+    feature_support = { edition_introduced: EDITION_2023 },
+    retention = RETENTION_RUNTIME,
+    targets = TARGET_TYPE_FIELD,
+    targets = TARGET_TYPE_FILE
+  ];
+  optional Utf8Validation utf8_validation = 4 [
+    edition_defaults = { value: "NONE", edition: EDITION_LEGACY },
+    edition_defaults = { value: "VERIFY", edition: EDITION_PROTO3 },
+    feature_support = { edition_introduced: EDITION_2023 },
+    retention = RETENTION_RUNTIME,
+    targets = TARGET_TYPE_FIELD,
+    targets = TARGET_TYPE_FILE
+  ];
+  optional MessageEncoding message_encoding = 5 [
+    edition_defaults = { value: "LENGTH_PREFIXED", edition: EDITION_LEGACY },
+    feature_support = { edition_introduced: EDITION_2023 },
+    retention = RETENTION_RUNTIME,
+    targets = TARGET_TYPE_FIELD,
+    targets = TARGET_TYPE_FILE
+  ];
+  optional JsonFormat json_format = 6 [
+    edition_defaults = { value: "LEGACY_BEST_EFFORT", edition: EDITION_LEGACY },
+    edition_defaults = { value: "ALLOW", edition: EDITION_PROTO3 },
+    feature_support = { edition_introduced: EDITION_2023 },
+    retention = RETENTION_RUNTIME,
+    targets = TARGET_TYPE_MESSAGE,
+    targets = TARGET_TYPE_ENUM,
+    targets = TARGET_TYPE_FILE
+  ];
+  optional EnforceNamingStyle enforce_naming_style = 7 [
+    edition_defaults = { value: "STYLE_LEGACY", edition: EDITION_LEGACY },
+    edition_defaults = { value: "STYLE2024", edition: EDITION_2024 },
+    feature_support = { edition_introduced: EDITION_2024 },
+    retention = RETENTION_SOURCE,
+    targets = TARGET_TYPE_FILE,
+    targets = TARGET_TYPE_EXTENSION_RANGE,
+    targets = TARGET_TYPE_MESSAGE,
+    targets = TARGET_TYPE_FIELD,
+    targets = TARGET_TYPE_ONEOF,
+    targets = TARGET_TYPE_ENUM,
+    targets = TARGET_TYPE_ENUM_ENTRY,
+    targets = TARGET_TYPE_SERVICE,
+    targets = TARGET_TYPE_METHOD
+  ];
+  enum EnforceNamingStyle {
+    ENFORCE_NAMING_STYLE_UNKNOWN = 0;
+    STYLE2024 = 1;
+    STYLE_LEGACY = 2;
+  }
+  enum EnumType {
+    ENUM_TYPE_UNKNOWN = 0;
+    OPEN = 1;
+    CLOSED = 2;
+  }
+  enum FieldPresence {
+    FIELD_PRESENCE_UNKNOWN = 0;
+    EXPLICIT = 1;
+    IMPLICIT = 2;
+    LEGACY_REQUIRED = 3;
+  }
+  enum JsonFormat {
+    JSON_FORMAT_UNKNOWN = 0;
+    ALLOW = 1;
+    LEGACY_BEST_EFFORT = 2;
+  }
+  enum MessageEncoding {
+    MESSAGE_ENCODING_UNKNOWN = 0;
+    LENGTH_PREFIXED = 1;
+    DELIMITED = 2;
+  }
+  enum RepeatedFieldEncoding {
+    REPEATED_FIELD_ENCODING_UNKNOWN = 0;
+    PACKED = 1;
+    EXPANDED = 2;
+  }
+  enum Utf8Validation {
+    UTF8_VALIDATION_UNKNOWN = 0;
+    VERIFY = 2;
+    NONE = 3;
+    reserved 1;
+  }
+  extensions 1000 to 9994 [
+    declaration = {
+      number: 1000,
+      full_name: ".pb.cpp",
+      type: ".pb.CppFeatures"
+    },
+    declaration = {
+      number: 1001,
+      full_name: ".pb.java",
+      type: ".pb.JavaFeatures"
+    },
+    declaration = {
+      number: 1002,
+      full_name: ".pb.go",
+      type: ".pb.GoFeatures"
+    },
+    declaration = {
+      number: 1003,
+      full_name: ".pb.python",
+      type: ".pb.PythonFeatures"
+    },
+    declaration = {
+      number: 9990,
+      full_name: ".pb.proto1",
+      type: ".pb.Proto1Features"
+    }
+  ];
+  extensions 9995 to 9999, 10000;
+  reserved 999;
+}
+message MessageOptions {
+  optional bool message_set_wire_format = 1 [default = false];
+  optional bool no_standard_descriptor_accessor = 2 [default = false];
+  optional bool deprecated = 3 [default = false];
+  optional bool map_entry = 7;
+  optional bool deprecated_legacy_json_field_conflicts = 11 [deprecated = true];
+  optional FeatureSet features = 12;
+  repeated UninterpretedOption uninterpreted_option = 999;
+  extensions 1000 to max;
+  reserved 4, 5, 6, 8, 9;
+}
+message UninterpretedOption {
+  repeated NamePart name = 2;
+  optional string identifier_value = 3;
+  optional uint64 positive_int_value = 4;
+  optional int64 negative_int_value = 5;
+  optional double double_value = 6;
+  optional bytes string_value = 7;
+  optional string aggregate_value = 8;
+  message NamePart {
+    required string name_part = 1;
+    required bool is_extension = 2;
+  }
+}