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

Sources/Commands/SwiftTool.swift

@@ -574,7 +574,7 @@ 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

@@ -1,7 +1,7 @@
 /*
  This source file is part of the Swift.org open source project
 
- Copyright (c) 2014 - 2019 Apple Inc. and the Swift project authors
+ Copyright (c) 2014 - 2021 Apple Inc. and the Swift project authors
  Licensed under Apache License v2.0 with Runtime Library Exception
 
  See http://swift.org/LICENSE.txt for license information
@@ -66,12 +66,9 @@ public struct TargetSourcesBuilder {
         self.defaultLocalization = defaultLocalization
         self.diags = diags
         self.targetPath = path
-        if toolsVersion <= ToolsVersion.v5_4 {
-            // In version 5.4 and earlier, we did not support `additionalFileRules` and always implicitly included XCBuild file types.
-            self.rules = FileRuleDescription.builtinRules + FileRuleDescription.xcbuildFileTypes
-        } else {
-            self.rules = FileRuleDescription.builtinRules + additionalFileRules
-        }
+        // 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)) }
@@ -253,7 +250,7 @@ public struct TargetSourcesBuilder {
     /// Returns the `Resource` file associated with a file and a particular rule, if there is one.
     private func resource(for path: AbsolutePath, with rule: Rule) -> Resource? {
         switch rule.rule {
-        case .compile, .header, .none, .modulemap:
+        case .compile, .header, .none, .modulemap, .ignored:
             return nil
         case .processResource:
             let implicitLocalization: String? = {
@@ -490,6 +487,9 @@ public struct FileRuleDescription {
 
         /// A header file.
         case header
+
+        /// Indicates that the file should be treated as ignored, without causing an unhandled-file warning.
+        case ignored
 
         /// Sentinal to indicate that no rule was chosen for a given file.
         case none
@@ -605,6 +605,15 @@ public struct FileRuleDescription {
         )
     }()
 
+    /// File rule to ignore .docc (in the SwiftPM build system).
+    public static let docc: FileRuleDescription = {
+        .init(
+            rule: .ignored,
+            toolsVersion: .v5_5,
+            fileTypes: ["docc"]
+        )
+    }()
+
     /// List of all the builtin rules.
     public static let builtinRules: [FileRuleDescription] = [
         swift,
@@ -621,6 +630,11 @@ public struct FileRuleDescription {
         coredata,
         metal,
     ]
+
+    /// List of file types that apply just to the SwiftPM build system.
+    public static let swiftpmFileTypes: [FileRuleDescription] = [
+        docc,
+    ]
 }
 
 extension TargetDescription.Resource.Rule {

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

@@ -661,4 +661,39 @@ 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 testDocCFilesDoNotCauseWarningOutsideXCBuild() throws {
+        let target = try TargetDescription(
+            name: "Foo",
+            path: nil,
+            exclude: [],
+            sources: ["File.swift"],
+            resources: [],
+            publicHeadersPath: nil,
+            type: .regular
+        )
+
+        let fs = InMemoryFileSystem()
+        fs.createEmptyFiles(at: .root, files: [
+            "/File.swift",
+            "/Foo.docc"
+        ])
+
+        let diags = DiagnosticsEngine()
+
+        let builder = TargetSourcesBuilder(
+            packageName: "",
+            packagePath: .root,
+            target: target,
+            path: .root,
+            defaultLocalization: nil,
+            additionalFileRules: FileRuleDescription.swiftpmFileTypes,
+            toolsVersion: .v5_5,
+            fs: fs,
+            diags: diags
+        )
+        _ = try builder.run()
+
+        XCTAssertTrue(diags.diagnostics.isEmpty)
+    }
 }