feat: Add directive to disable manual tag (#632)

This PR introduces a directive to disable the addition of the manual tag
to generated swift_library targets.

I understand the intent behind the tag and am ok with keeping it the
default. But for more advanced users who understand that they need to
pass the apple platform type configuration, it is useful to be able to
build globs of these targets without a dedicated build test target.

examples/pkg_manifest_minimal/BUILD.bazel

@@ -15,6 +15,9 @@ tidy(
 # Ignore the Swift build folder
 # gazelle:exclude .build
 
+# Omit tags = ["manual"] from the generated swift library targets
+# gazelle:swift_library_tags -
+
 gazelle_binary(
     name = "gazelle_bin",
     languages = [

examples/pkg_manifest_minimal/Sources/MyLibrary/BUILD.bazel

@@ -4,7 +4,6 @@ swift_library(
     name = "MyLibrary",
     srcs = ["World.swift"],
     module_name = "MyLibrary",
-    tags = ["manual"],
     visibility = ["//visibility:public"],
     deps = ["@swiftpkg_my_local_package//:Sources_GreetingsFramework"],
 )

gazelle/config.go

@@ -4,6 +4,7 @@ import (
 	"flag"
 	"os"
 	"path/filepath"
+	"strings"
 
 	"github.com/bazelbuild/bazel-gazelle/config"
 	"github.com/bazelbuild/bazel-gazelle/rule"
@@ -127,11 +128,13 @@ func (sl *swiftLang) CheckFlags(fs *flag.FlagSet, c *config.Config) error {
 
 const moduleNamingConventionDirective = "swift_module_naming_convention"
 const defaultModuleNameDirective = "swift_default_module_name"
+const swiftLibraryTags = "swift_library_tags"
 
 func (*swiftLang) KnownDirectives() []string {
 	return []string{
 		moduleNamingConventionDirective,
 		defaultModuleNameDirective,
+		swiftLibraryTags,
 	}
 }
 
@@ -148,6 +151,19 @@ func (*swiftLang) Configure(c *config.Config, rel string, f *rule.File) {
 			} else {
 				sc.ModuleNamingConvention = swiftcfg.MatchCaseModuleNamingConvention
 			}
+		case swiftLibraryTags:
+			var tags []string
+			if d.Value == "" {
+				// Mark swift_library targets as manual.
+				// We do this so that they are always built as a dependency of a target
+				// which can provide critical configuration information.
+				tags = []string{"manual"}
+			} else if d.Value == "-" {
+				tags = nil
+			} else {
+				tags = strings.Split(d.Value, ",")
+			}
+			sc.SwiftLibraryTags = tags
 		case defaultModuleNameDirective:
 			sc.DefaultModuleNames[rel] = d.Value
 		}

gazelle/generate.go

@@ -65,7 +65,7 @@ func genRulesFromSrcFiles(sc *swiftcfg.SwiftConfig, args language.GenerateArgs)
 
 	// Generate the rules from sources:
 	defaultName, defaultModuleName := defaultNameAndModuleName(args)
-	rules = swift.RulesFromSrcs(args, srcs, defaultName, defaultModuleName)
+	rules = swift.RulesFromSrcs(args, srcs, defaultName, defaultModuleName, sc.SwiftLibraryTags)
 	result.Gen = append(result.Gen, rules...)
 	result.Imports = swift.Imports(result.Gen)
 	result.Empty = generateEmpty(args, srcs)

gazelle/internal/swift/rules_common.go

@@ -14,16 +14,17 @@ func rulesForLibraryModule(
 	srcs []string,
 	swiftImports []string,
 	shouldSetVis bool,
+	swiftLibraryTags []string,
 	buildFile *rule.File,
 ) []*rule.Rule {
 	name, moduleName := ruleNameAndModuleName(buildFile, LibraryRuleKind, defaultName, defaultModuleName)
 	r := rule.NewRule(LibraryRuleKind, name)
 	setCommonSwiftAttrs(r, moduleName, srcs, swiftImports)
 	setVisibilityAttr(r, shouldSetVis, []string{"//visibility:public"})
-	// Mark swift_library targets as manual. We do this so that they are always
-	// built from a leaf node which can provide critical configuration
-	// information.
-	r.SetAttr("tags", []string{"manual"})
+	if len(swiftLibraryTags) > 0 {
+		r.SetAttr("tags", swiftLibraryTags)
+	}
+
 	return []*rule.Rule{r}
 }
 

gazelle/internal/swift/rules_from_protos.go

@@ -9,7 +9,7 @@ import (
 	"github.com/bazelbuild/bazel-gazelle/rule"
 )
 
-// RulesFromSrcs returns the Bazel build rule declarations for the provided source files.
+// RulesFromProtos returns the Bazel build rule declarations for the provided source files.
 func RulesFromProtos(args language.GenerateArgs) []*rule.Rule {
 
 	// Extract information about proto files.

gazelle/internal/swift/rules_from_srcs.go

@@ -15,6 +15,7 @@ func RulesFromSrcs(
 	srcs []string,
 	defaultName string,
 	defaultModuleName string,
+	swiftLibraryTags []string,
 ) []*rule.Rule {
 	fileInfos := swiftpkg.NewSwiftFileInfosFromRelPaths(args.Dir, srcs)
 	swiftImports, moduleType := collectSwiftInfo(fileInfos)
@@ -24,7 +25,7 @@ func RulesFromSrcs(
 	var rules []*rule.Rule
 	switch moduleType {
 	case LibraryModuleType:
-		rules = rulesForLibraryModule(defaultName, defaultModuleName, srcs, swiftImports, shouldSetVis, args.File)
+		rules = rulesForLibraryModule(defaultName, defaultModuleName, srcs, swiftImports, shouldSetVis, swiftLibraryTags, args.File)
 	case BinaryModuleType:
 		rules = rulesForBinaryModule(defaultName, defaultModuleName, srcs, swiftImports, shouldSetVis, args.File)
 	case TestModuleType:

gazelle/internal/swiftcfg/swift_config.go

@@ -43,8 +43,14 @@ type SwiftConfig struct {
 
 	GenerateSwiftDepsForWorkspace bool
 
+	// The naming convention to apply to the module names derived from the directory names.
+	// The default behavior uses the name verbatim while PascalCase will convert snake_case to PascalCase.
 	ModuleNamingConvention string
 
+	// The set of tags to apply to generated swift library targets.
+	// Defaults to ["manual"]
+	SwiftLibraryTags []string
+
 	// Mapping of relative path to default module name. These values are populated from directives
 	// that can be applied to
 	DefaultModuleNames map[string]string