feat: implement support for PascalCase module names with snake_case d…

…irectory names (#534)

This PR introduces an optional Gazelle directive to convert module names
from snake_case to PascalCase for consistency with platform idioms.
Currently the module name is the same as the target name, derived
typically from the directory name.

Secondly, the current heuristic for detecting whether a directory is a
swift_test or swift_library / swift_binary checks for case sensitive,
"Test" or "Tests" directory names or "Test.swift" / "Tests.swift" file
names. This breaks if the directory name is in snake_case.

To address this issue I just made the checks case insensitive. I also
unified the DirSuffixes and fileSuffixes types into a PathSuffixes type
and added tests for both files and paths with both casings.

.bazelrc

@@ -1,7 +1,7 @@
 # To update these lines, execute 
 # `bazel run @rules_bazel_integration_test//tools:update_deleted_packages`
-build --deleted_packages=bzlmod/workspace,bzlmod/workspace/Sources/MyExecutable,bzlmod/workspace/Sources/MyLibrary,bzlmod/workspace/Tests/MyLibraryTests,examples/firebase_example,examples/firebase_example/abtesting,examples/firebase_example/abtesting/SharedApp,examples/firebase_example/analytics/AnalyticsExample,examples/firebase_example/appdistribution,examples/firebase_example/appdistribution/AppDistributionExample,examples/firebase_example/appdistribution/AppDistributionTests,examples/firebase_example/crashlytics,examples/grpc_example,examples/grpc_example/protos,examples/grpc_example/protos/echoservice,examples/grpc_example/protos/echoservice/messages,examples/grpc_example/sources,examples/grpc_example/sources/client,examples/grpc_example/sources/server,examples/grpc_example/sources/test,examples/http_archive_ext_deps,examples/http_archive_ext_deps/Sources/MyDequeModule,examples/http_archive_ext_deps/Sources/PrintStuff,examples/http_archive_ext_deps/Tests/MyDequeModuleTests,examples/http_archive_ext_deps/third_party,examples/interesting_deps,examples/ios_sim,examples/ios_sim/Sources/Foo,examples/ios_sim/Tests/FooTests,examples/ios_sim/third-party/swift-cmark,examples/nimble_example,examples/nimble_example/Sources/NimbleExample,examples/objc_code,examples/phone_number_kit,examples/phone_number_kit/Tests/PhoneNumberKitTests,examples/pkg_manifest_minimal,examples/pkg_manifest_minimal/Sources/MyExecutable,examples/pkg_manifest_minimal/Sources/MyLibrary,examples/pkg_manifest_minimal/Tests/MyLibraryTests,examples/pkg_manifest_minimal/third_party,examples/resources_example,examples/resources_example/Sources/MyApp,examples/resources_example/Tests/MyAppTests,examples/resources_example/third_party,examples/snapkit_example,examples/soto_example,examples/soto_example/Tests/SotoTests,examples/stripe_example,examples/stripe_example/PaymentSheet/PaymentSheetExample,examples/stripe_example/PaymentSheet/PaymentSheetUITest,examples/tca_example,examples/tca_example/SwiftUICaseStudies,examples/tca_example/SwiftUICaseStudies/04-HigherOrderReducers-ResuableOfflineDownloads,examples/tca_example/SwiftUICaseStudies/Internal,examples/tca_example/SwiftUICaseStudiesTests,examples/vapor_example,examples/vapor_example/Sources/App,examples/vapor_example/Sources/Run,examples/vapor_example/Tests/AppTests,examples/vapor_example/swift,examples/xcmetrics_example
-query --deleted_packages=bzlmod/workspace,bzlmod/workspace/Sources/MyExecutable,bzlmod/workspace/Sources/MyLibrary,bzlmod/workspace/Tests/MyLibraryTests,examples/firebase_example,examples/firebase_example/abtesting,examples/firebase_example/abtesting/SharedApp,examples/firebase_example/analytics/AnalyticsExample,examples/firebase_example/appdistribution,examples/firebase_example/appdistribution/AppDistributionExample,examples/firebase_example/appdistribution/AppDistributionTests,examples/firebase_example/crashlytics,examples/grpc_example,examples/grpc_example/protos,examples/grpc_example/protos/echoservice,examples/grpc_example/protos/echoservice/messages,examples/grpc_example/sources,examples/grpc_example/sources/client,examples/grpc_example/sources/server,examples/grpc_example/sources/test,examples/http_archive_ext_deps,examples/http_archive_ext_deps/Sources/MyDequeModule,examples/http_archive_ext_deps/Sources/PrintStuff,examples/http_archive_ext_deps/Tests/MyDequeModuleTests,examples/http_archive_ext_deps/third_party,examples/interesting_deps,examples/ios_sim,examples/ios_sim/Sources/Foo,examples/ios_sim/Tests/FooTests,examples/ios_sim/third-party/swift-cmark,examples/nimble_example,examples/nimble_example/Sources/NimbleExample,examples/objc_code,examples/phone_number_kit,examples/phone_number_kit/Tests/PhoneNumberKitTests,examples/pkg_manifest_minimal,examples/pkg_manifest_minimal/Sources/MyExecutable,examples/pkg_manifest_minimal/Sources/MyLibrary,examples/pkg_manifest_minimal/Tests/MyLibraryTests,examples/pkg_manifest_minimal/third_party,examples/resources_example,examples/resources_example/Sources/MyApp,examples/resources_example/Tests/MyAppTests,examples/resources_example/third_party,examples/snapkit_example,examples/soto_example,examples/soto_example/Tests/SotoTests,examples/stripe_example,examples/stripe_example/PaymentSheet/PaymentSheetExample,examples/stripe_example/PaymentSheet/PaymentSheetUITest,examples/tca_example,examples/tca_example/SwiftUICaseStudies,examples/tca_example/SwiftUICaseStudies/04-HigherOrderReducers-ResuableOfflineDownloads,examples/tca_example/SwiftUICaseStudies/Internal,examples/tca_example/SwiftUICaseStudiesTests,examples/vapor_example,examples/vapor_example/Sources/App,examples/vapor_example/Sources/Run,examples/vapor_example/Tests/AppTests,examples/vapor_example/swift,examples/xcmetrics_example
+build --deleted_packages=bzlmod/workspace,bzlmod/workspace/Sources/MyExecutable,bzlmod/workspace/Sources/MyLibrary,bzlmod/workspace/Tests/MyLibraryTests,examples/firebase_example,examples/firebase_example/abtesting,examples/firebase_example/abtesting/SharedApp,examples/firebase_example/analytics/AnalyticsExample,examples/firebase_example/appdistribution,examples/firebase_example/appdistribution/AppDistributionExample,examples/firebase_example/appdistribution/AppDistributionTests,examples/firebase_example/crashlytics,examples/grpc_example,examples/grpc_example/protos/echoservice,examples/grpc_example/protos/echoservice/messages,examples/grpc_example/sources,examples/grpc_example/sources/client,examples/grpc_example/sources/server,examples/grpc_example/sources/test,examples/http_archive_ext_deps,examples/http_archive_ext_deps/Sources/MyDequeModule,examples/http_archive_ext_deps/Sources/PrintStuff,examples/http_archive_ext_deps/Tests/MyDequeModuleTests,examples/http_archive_ext_deps/third_party,examples/interesting_deps,examples/ios_sim,examples/ios_sim/Sources/Foo,examples/ios_sim/Tests/FooTests,examples/ios_sim/third-party/swift-cmark,examples/nimble_example,examples/nimble_example/Sources/NimbleExample,examples/objc_code,examples/phone_number_kit,examples/phone_number_kit/Tests/PhoneNumberKitTests,examples/pkg_manifest_minimal,examples/pkg_manifest_minimal/Sources/MyExecutable,examples/pkg_manifest_minimal/Sources/MyLibrary,examples/pkg_manifest_minimal/Tests/MyLibraryTests,examples/pkg_manifest_minimal/third_party,examples/resources_example,examples/resources_example/Sources/MyApp,examples/resources_example/Tests/MyAppTests,examples/resources_example/third_party,examples/snapkit_example,examples/soto_example,examples/soto_example/Tests/SotoTests,examples/stripe_example,examples/stripe_example/PaymentSheet/PaymentSheetExample,examples/stripe_example/PaymentSheet/PaymentSheetUITest,examples/tca_example,examples/tca_example/SwiftUICaseStudies,examples/tca_example/SwiftUICaseStudies/04-HigherOrderReducers-ResuableOfflineDownloads,examples/tca_example/SwiftUICaseStudies/Internal,examples/tca_example/SwiftUICaseStudiesTests,examples/vapor_example,examples/vapor_example/Sources/App,examples/vapor_example/Sources/Run,examples/vapor_example/Tests/AppTests,examples/vapor_example/swift,examples/xcmetrics_example
+query --deleted_packages=bzlmod/workspace,bzlmod/workspace/Sources/MyExecutable,bzlmod/workspace/Sources/MyLibrary,bzlmod/workspace/Tests/MyLibraryTests,examples/firebase_example,examples/firebase_example/abtesting,examples/firebase_example/abtesting/SharedApp,examples/firebase_example/analytics/AnalyticsExample,examples/firebase_example/appdistribution,examples/firebase_example/appdistribution/AppDistributionExample,examples/firebase_example/appdistribution/AppDistributionTests,examples/firebase_example/crashlytics,examples/grpc_example,examples/grpc_example/protos/echoservice,examples/grpc_example/protos/echoservice/messages,examples/grpc_example/sources,examples/grpc_example/sources/client,examples/grpc_example/sources/server,examples/grpc_example/sources/test,examples/http_archive_ext_deps,examples/http_archive_ext_deps/Sources/MyDequeModule,examples/http_archive_ext_deps/Sources/PrintStuff,examples/http_archive_ext_deps/Tests/MyDequeModuleTests,examples/http_archive_ext_deps/third_party,examples/interesting_deps,examples/ios_sim,examples/ios_sim/Sources/Foo,examples/ios_sim/Tests/FooTests,examples/ios_sim/third-party/swift-cmark,examples/nimble_example,examples/nimble_example/Sources/NimbleExample,examples/objc_code,examples/phone_number_kit,examples/phone_number_kit/Tests/PhoneNumberKitTests,examples/pkg_manifest_minimal,examples/pkg_manifest_minimal/Sources/MyExecutable,examples/pkg_manifest_minimal/Sources/MyLibrary,examples/pkg_manifest_minimal/Tests/MyLibraryTests,examples/pkg_manifest_minimal/third_party,examples/resources_example,examples/resources_example/Sources/MyApp,examples/resources_example/Tests/MyAppTests,examples/resources_example/third_party,examples/snapkit_example,examples/soto_example,examples/soto_example/Tests/SotoTests,examples/stripe_example,examples/stripe_example/PaymentSheet/PaymentSheetExample,examples/stripe_example/PaymentSheet/PaymentSheetUITest,examples/tca_example,examples/tca_example/SwiftUICaseStudies,examples/tca_example/SwiftUICaseStudies/04-HigherOrderReducers-ResuableOfflineDownloads,examples/tca_example/SwiftUICaseStudies/Internal,examples/tca_example/SwiftUICaseStudiesTests,examples/vapor_example,examples/vapor_example/Sources/App,examples/vapor_example/Sources/Run,examples/vapor_example/Tests/AppTests,examples/vapor_example/swift,examples/xcmetrics_example
 
 # Import Shared settings
 import %workspace%/shared.bazelrc

MODULE.bazel

@@ -43,6 +43,7 @@ use_repo(
     "com_github_stretchr_testify",
     "in_gopkg_yaml_v3",
     "org_golang_x_exp",
+    "org_golang_x_text",
 )
 
 # MARK: - Dev Dependencies

examples/grpc_example/BUILD.bazel

@@ -14,6 +14,7 @@ tidy(
 
 # Ignore the Swift build folder
 # gazelle:exclude .build
+# gazelle:swift_module_naming_convention pascal_case
 
 gazelle_binary(
     name = "gazelle_bin",

examples/grpc_example/sources/client/BUILD.bazel

@@ -3,7 +3,7 @@ load("@build_bazel_rules_swift//swift:swift.bzl", "swift_binary")
 swift_binary(
     name = "client",
     srcs = ["client_main.swift"],
-    module_name = "client",
+    module_name = "Client",
     visibility = ["//visibility:public"],
     deps = [
         "//protos/echoservice:echoservice_client_swift_grpc",

examples/grpc_example/sources/server/BUILD.bazel

@@ -3,7 +3,7 @@ load("@build_bazel_rules_swift//swift:swift.bzl", "swift_binary")
 swift_binary(
     name = "server",
     srcs = ["server_main.swift"],
-    module_name = "server",
+    module_name = "Server",
     visibility = ["//visibility:public"],
     deps = [
         "//protos/echoservice:echoservice_server_swift_grpc",

examples/grpc_example/sources/test/BUILD.bazel

@@ -6,8 +6,7 @@ swift_test(
         "client_unit_test.swift",
         "main.swift",
     ],
-    module_name = "test",
-    visibility = ["//visibility:public"],
+    module_name = "Test",
     deps = [
         "//protos/echoservice:echoservice_client_swift_grpc",
         "//protos/echoservice:echoservice_server_swift_grpc",

gazelle/BUILD.bazel

@@ -44,6 +44,8 @@ go_library(
         "@bazel_gazelle//resolve:go_default_library",
         "@bazel_gazelle//rule:go_default_library",
         "@org_golang_x_exp//slices:go_default_library",
+        "@org_golang_x_text//cases:go_default_library",
+        "@org_golang_x_text//language:go_default_library",
     ],
 )
 

gazelle/config.go

@@ -125,10 +125,14 @@ func (sl *swiftLang) CheckFlags(fs *flag.FlagSet, c *config.Config) error {
 
 // Directives
 
+const moduleNamingConventionDirective = "swift_module_naming_convention"
 const defaultModuleNameDirective = "swift_default_module_name"
 
 func (*swiftLang) KnownDirectives() []string {
-	return []string{defaultModuleNameDirective}
+	return []string{
+		moduleNamingConventionDirective,
+		defaultModuleNameDirective,
+	}
 }
 
 func (*swiftLang) Configure(c *config.Config, rel string, f *rule.File) {
@@ -138,6 +142,12 @@ func (*swiftLang) Configure(c *config.Config, rel string, f *rule.File) {
 	sc := swiftcfg.GetSwiftConfig(c)
 	for _, d := range f.Directives {
 		switch d.Key {
+		case moduleNamingConventionDirective:
+			if d.Value == swiftcfg.PascalCaseModuleNamingConvention {
+				sc.ModuleNamingConvention = swiftcfg.PascalCaseModuleNamingConvention
+			} else {
+				sc.ModuleNamingConvention = swiftcfg.MatchCaseModuleNamingConvention
+			}
 		case defaultModuleNameDirective:
 			sc.DefaultModuleNames[rel] = d.Value
 		}

gazelle/generate.go

@@ -12,6 +12,8 @@ import (
 	"github.com/cgrindel/rules_swift_package_manager/gazelle/internal/swift"
 	"github.com/cgrindel/rules_swift_package_manager/gazelle/internal/swiftcfg"
 	"golang.org/x/exp/slices"
+	"golang.org/x/text/cases"
+	lang "golang.org/x/text/language"
 )
 
 func (l *swiftLang) GenerateRules(args language.GenerateArgs) language.GenerateResult {
@@ -62,44 +64,56 @@ func genRulesFromSrcFiles(sc *swiftcfg.SwiftConfig, args language.GenerateArgs)
 	sort.Strings(srcs)
 
 	// Generate the rules from sources:
-	defaultModuleName := defaultModuleName(args)
-	rules = swift.RulesFromSrcs(args, srcs, defaultModuleName)
+	defaultName, defaultModuleName := defaultNameAndModuleName(args)
+	rules = swift.RulesFromSrcs(args, srcs, defaultName, defaultModuleName)
 	result.Gen = append(result.Gen, rules...)
 	result.Imports = swift.Imports(result.Gen)
 	result.Empty = generateEmpty(args, srcs)
 
 	return result
 }
 
-func defaultModuleName(args language.GenerateArgs) string {
-	// Order of names to use
-	// 1. Value specified via directive.
-	// 2. Directory name.
-	// 3. Repository name.
-	// 4. "DefaultModule"
+func defaultNameAndModuleName(args language.GenerateArgs) (string, string) {
 
-	// Check for a value configured via directive
+	// If the name is specified by a directive, short cirucit and return that:
 	sc := swiftcfg.GetSwiftConfig(args.Config)
-	var defaultModuleName string
-	var ok bool
-	if defaultModuleName, ok = sc.DefaultModuleNames[args.Rel]; ok {
-		return defaultModuleName
+	if defaultModuleName, ok := sc.DefaultModuleNames[args.Rel]; ok {
+		return defaultModuleName, defaultModuleName
 	}
+
+	// Otherwise, derive the name from the:
+	// 1. Directory name.
+	// 2. Repository name.
+	// 3. "DefaultModule"
+	var defaultName string
 	if args.Rel == "" {
-		defaultModuleName = filepath.Base(args.Config.WorkDir)
+		defaultName = filepath.Base(args.Config.WorkDir)
 	} else {
-		defaultModuleName = filepath.Base(args.Rel)
+		defaultName = filepath.Base(args.Rel)
 	}
-	if ext := filepath.Ext(defaultModuleName); ext != "" {
-		defaultModuleName = strings.TrimSuffix(defaultModuleName, ext)
+	if ext := filepath.Ext(defaultName); ext != "" {
+		defaultName = strings.TrimSuffix(defaultName, ext)
 	}
-	if defaultModuleName == "." || defaultModuleName == "" {
-		defaultModuleName = args.Config.RepoName
+	if defaultName == "." || defaultName == "" {
+		defaultName = args.Config.RepoName
 	}
-	if defaultModuleName == "" {
-		defaultModuleName = "DefaultModule"
+	if defaultName == "" {
+		defaultName = "DefaultModule"
 	}
-	return defaultModuleName
+
+	// If configured to use PascalCase for module names, convert to that naming convention:
+	defaultModuleName := defaultName
+	if sc.ModuleNamingConvention == swiftcfg.PascalCaseModuleNamingConvention {
+		moduleNameComponents := strings.Split(defaultModuleName, "_")
+		caser := cases.Title(lang.English)
+		pascalCaseModuleName := ""
+		for _, component := range moduleNameComponents {
+			pascalCaseModuleName += caser.String(component)
+		}
+		defaultModuleName = pascalCaseModuleName
+	}
+
+	return defaultName, defaultModuleName
 }
 
 // Look for any rules in the existing BUILD file that do not reference one of the source files. If

gazelle/internal/swift/rules_common.go

@@ -9,42 +9,45 @@ import (
 // Rule Creation
 
 func rulesForLibraryModule(
+	defaultName string,
 	defaultModuleName string,
 	srcs []string,
 	swiftImports []string,
 	shouldSetVis bool,
 	buildFile *rule.File,
 ) []*rule.Rule {
-	name, moduleName := ruleNameAndModuleName(buildFile, LibraryRuleKind, defaultModuleName)
+	name, moduleName := ruleNameAndModuleName(buildFile, LibraryRuleKind, defaultName, defaultModuleName)
 	r := rule.NewRule(LibraryRuleKind, name)
 	setCommonSwiftAttrs(r, moduleName, srcs, swiftImports)
 	setVisibilityAttr(r, shouldSetVis, []string{"//visibility:public"})
 	return []*rule.Rule{r}
 }
 
 func rulesForBinaryModule(
+	defaultName string,
 	defaultModuleName string,
 	srcs []string,
 	swiftImports []string,
 	shouldSetVis bool,
 	buildFile *rule.File,
 ) []*rule.Rule {
-	name, moduleName := ruleNameAndModuleName(buildFile, BinaryRuleKind, defaultModuleName)
+	name, moduleName := ruleNameAndModuleName(buildFile, BinaryRuleKind, defaultName, defaultModuleName)
 	r := rule.NewRule(BinaryRuleKind, name)
 	setCommonSwiftAttrs(r, moduleName, srcs, swiftImports)
 	setVisibilityAttr(r, shouldSetVis, []string{"//visibility:public"})
 	return []*rule.Rule{r}
 }
 
 func rulesForTestModule(
+	defaultName string,
 	defaultModuleName string,
 	srcs []string,
 	swiftImports []string,
 	shouldSetVis bool,
 	buildFile *rule.File,
 ) []*rule.Rule {
 	// Detect the type of rule that should be used to build the Swift sources.
-	r := buildRuleForTestSrcs(buildFile, defaultModuleName)
+	r := buildRuleForTestSrcs(buildFile, defaultName, defaultModuleName)
 	setCommonSwiftAttrs(r, defaultModuleName, srcs, swiftImports)
 	return []*rule.Rule{r}
 }
@@ -79,7 +82,7 @@ func setVisibilityAttr(r *rule.Rule, shouldSetVis bool, visibility []string) {
 // Name and Module Name
 
 // Determine the rule name and module name from existing rules
-func ruleNameAndModuleName(buildFile *rule.File, kind, defaultModuleName string) (string, string) {
+func ruleNameAndModuleName(buildFile *rule.File, kind, defaultName, defaultModuleName string) (string, string) {
 	var existingRules []*rule.Rule
 	if buildFile != nil {
 		existingRules = findRulesByKind(buildFile.Rules, kind)
@@ -91,7 +94,7 @@ func ruleNameAndModuleName(buildFile *rule.File, kind, defaultModuleName string)
 		name = first.Name()
 		moduleName = first.AttrString(ModuleNameAttrName)
 	} else {
-		name = defaultModuleName
+		name = defaultName
 		moduleName = defaultModuleName
 	}
 	return name, moduleName

gazelle/internal/swift/rules_from_srcs.go

@@ -13,6 +13,7 @@ import (
 func RulesFromSrcs(
 	args language.GenerateArgs,
 	srcs []string,
+	defaultName string,
 	defaultModuleName string,
 ) []*rule.Rule {
 	fileInfos := swiftpkg.NewSwiftFileInfosFromRelPaths(args.Dir, srcs)
@@ -23,11 +24,11 @@ func RulesFromSrcs(
 	var rules []*rule.Rule
 	switch moduleType {
 	case LibraryModuleType:
-		rules = rulesForLibraryModule(defaultModuleName, srcs, swiftImports, shouldSetVis, args.File)
+		rules = rulesForLibraryModule(defaultName, defaultModuleName, srcs, swiftImports, shouldSetVis, args.File)
 	case BinaryModuleType:
-		rules = rulesForBinaryModule(defaultModuleName, srcs, swiftImports, shouldSetVis, args.File)
+		rules = rulesForBinaryModule(defaultName, defaultModuleName, srcs, swiftImports, shouldSetVis, args.File)
 	case TestModuleType:
-		rules = rulesForTestModule(defaultModuleName, srcs, swiftImports, shouldSetVis, args.File)
+		rules = rulesForTestModule(defaultName, defaultModuleName, srcs, swiftImports, shouldSetVis, args.File)
 	}
 	return rules
 }
@@ -61,10 +62,14 @@ func collectSwiftInfo(fileInfos []*swiftpkg.SwiftFileInfo) ([]string, ModuleType
 		}
 	}
 
-	// Adjust the rule kind, if necessary
-	// Check for test files first. On Linux, a main.swift is necessary for swift_test rules.
-	// GUI applications can use the @main directive. So, we need to see if the module contains any
-	// of the GUI related modules. If no GUI modules and it has a main, then create a swift_binary.
+	// Adjust the rule kind, if necessary.
+	// Check if this is a test module first. On Linux, a main.swift is necessary for swift_test rules.
+	// rules_swift_package_manager does not currently support generating rules_apple targets.
+	// However, applications using Apple's UI frameworks can use the @main directive.
+	// To build these with rules_apple, we must first compile a swift_library target,
+	// and then pass this as a dependency to the application or extension target.
+	// So, we need to see if the module contains a main function and imports any of the GUI related modules.
+	// If it does not import any GUI modules and it has a main, then create a swift_binary.
 	if hasTestFiles {
 		moduleType = TestModuleType
 	} else if hasMain && !importsGUIModules {