Refine the change to ignore .docc files rather than emit warnings to avoid having multiple definitions for the same file extension

Ignore .docc files rather than emitting warnings, since it's useful to have them in packages without warnings.

Unlike other Xcode-specific file types, such as Storyboards and Asset Catalogs, the .docc bundles are not needed for correctness during the build, and should therefore not trigger warnings.

This is a refinement of the fix in #3609.

rdar://78133445

Author: abertelrud

Sources/Commands/SwiftTool.swift

@@ -561,7 +561,7 @@ public class SwiftTool {
             config: try getSwiftPMConfig(),
             repositoryProvider: provider,
             netrcFilePath: try resolvedNetrcFilePath(),
-            additionalFileRules: isXcodeBuildSystemEnabled ? FileRuleDescription.xcbuildFileTypes : [],
+            additionalFileRules: isXcodeBuildSystemEnabled ? FileRuleDescription.xcbuildFileTypes : FileRuleDescription.swiftpmFileTypes,
             isResolverPrefetchingEnabled: options.shouldEnableResolverPrefetching,
             skipUpdate: options.skipDependencyUpdate,
             enableResolverTrace: options.enableResolverTrace,

Sources/PackageLoading/TargetSourcesBuilder.swift

@@ -66,15 +66,9 @@ public struct TargetSourcesBuilder {
         self.defaultLocalization = defaultLocalization
         self.diags = diags
         self.targetPath = path
-        
-        // Configure the file rules that determine how files of various types are processed.  We always start with the builtins.
-        var fileRules = FileRuleDescription.builtinRules
-        // In version 5.4 and earlier, we did not support `additionalFileRules` and always implicitly included the XCBuild file types.
-        fileRules += (toolsVersion <= ToolsVersion.v5_4) ? FileRuleDescription.xcbuildFileTypes : additionalFileRules
-        // At the end we add the ignored types.  They might duplicate some of the rules in `additionalFileRules`, but in that case, the rule to ignore the file type will never be reached.
-        fileRules += FileRuleDescription.ignoredFileTypes
-        self.rules = fileRules
-        
+        // In version 5.4 and earlier, SwiftPM did not support `additionalFileRules` and always implicitly included XCBuild file types.
+        let actualAdditionalRules = (toolsVersion <= ToolsVersion.v5_4 ? FileRuleDescription.xcbuildFileTypes : additionalFileRules)
+        self.rules = FileRuleDescription.builtinRules + actualAdditionalRules
         self.toolsVersion = toolsVersion
         self.fs = fs
         let excludedPaths = target.exclude.map{ path.appending(RelativePath($0)) }
@@ -611,7 +605,7 @@ public struct FileRuleDescription {
         )
     }()
 
-    /// File types related to DocC.
+    /// File rule to ignore .docc (in the SwiftPM build system).
     public static let docc: FileRuleDescription = {
         .init(
             rule: .ignored,
@@ -637,9 +631,8 @@ public struct FileRuleDescription {
         metal,
     ]
 
-    /// List of file types that are ignored in this version of SwiftPM CLI
-    /// (that don't generate warnings for being unhandled).
-    public static let ignoredFileTypes: [FileRuleDescription] = [
+    /// List of file types that apply just to the SwiftPM build system.
+    public static let swiftpmFileTypes: [FileRuleDescription] = [
         docc,
     ]
 }

Sources/SPMTestSupport/misc.swift

@@ -239,7 +239,7 @@ public func loadPackageGraph(
     return try PackageGraph.load(
         root: graphRoot,
         identityResolver: identityResolver,
-        additionalFileRules: useXCBuildFileRules ? FileRuleDescription.xcbuildFileTypes : [],
+        additionalFileRules: useXCBuildFileRules ? FileRuleDescription.xcbuildFileTypes : FileRuleDescription.swiftpmFileTypes,
         externalManifests: externalManifests,
         binaryArtifacts: binaryArtifacts,
         diagnostics: diagnostics,

Tests/PackageLoadingTests/TargetSourcesBuilderTests.swift

@@ -662,7 +662,7 @@ class TargetSourcesBuilderTests: XCTestCase {
         XCTAssertEqual(diags.diagnostics.map { $0.description }, ["found 1 file(s) which are unhandled; explicitly declare them as resources or exclude from the target\n    /Foo.xcdatamodel\n"])
     }
 
-    func testIgnoredFileTypesDoNoCauseWarnings() throws {
+    func testDocCFilesDoNotCauseWarningOutsideXCBuild() throws {
         let target = try TargetDescription(
             name: "Foo",
             path: nil,
@@ -687,6 +687,7 @@ class TargetSourcesBuilderTests: XCTestCase {
             target: target,
             path: .root,
             defaultLocalization: nil,
+            additionalFileRules: FileRuleDescription.swiftpmFileTypes,
             toolsVersion: .v5_5,
             fs: fs,
             diags: diags