Copy snippet symbol graphs to the correct final destination

The snippet symbol graph is currently being generated with the changes in
e013865, however they are not being copied to the correct final
destination.

The `snippet-extract` tool now takes input and output *files* instead of
directories, however there is still one place in the plugin where we are still
treating the output like a directory, so the snippet symbol graph basename path
component looks like a directory, and needs additional basenames to put it in
the right place with the correct file extension.

rdar://104045850

Author: bitjammer

IntegrationTests/Tests/SnippetDocumentationGenerationTests.swift

@@ -10,10 +10,11 @@ import XCTest
 
 final class SnippetDocumentationGenerationTests: ConcurrencyRequiringTestCase {
     func testGenerateDocumentationForPackageWithSnippets() throws {
+        let packageName = "PackageWithSnippets"
         let result = try swiftPackage(
             "generate-documentation",
             "--target", "Library",
-            workingDirectory: try setupTemporaryDirectoryForFixture(named: "PackageWithSnippets")
+            workingDirectory: try setupTemporaryDirectoryForFixture(named: packageName)
         )
 
         result.assertExitStatusEquals(0)
@@ -45,6 +46,19 @@ final class SnippetDocumentationGenerationTests: ConcurrencyRequiringTestCase {
                 "symbol-graphs/unified-symbol-graphs",
             ]
         )
+
+        let unifiedSymbolGraphDirectory = subDirectoriesOfSymbolGraphDirectory.first {
+            $0.pathComponents.last == "unified-symbol-graphs"
+        }!
+
+        let symbolGraphEnumerator = FileManager.default.enumerator(at: unifiedSymbolGraphDirectory,
+                                                                   includingPropertiesForKeys: [.isRegularFileKey])!
+        let symbolGraphPaths = try (symbolGraphEnumerator.allObjects as! [URL]).filter {
+            try $0.resourceValues(forKeys: [.isRegularFileKey]).isRegularFile!
+        }
+        XCTAssertNotNil(symbolGraphPaths.first {
+            $0.pathComponents.last == "\(packageName)-snippets.symbols.json"
+        })
     }
 
     func testPreviewDocumentationWithSnippets() throws {

Plugins/SharedPackagePluginExtensions/PackageManager+getSymbolGraphsForDocC.swift

@@ -13,22 +13,22 @@ extension PackageManager {
     struct DocCSymbolGraphResult {
         let unifiedSymbolGraphsDirectory: URL
         let targetSymbolGraphsDirectory: URL
-        let snippetSymbolGraphsDirectory: URL?
+        let snippetSymbolGraphFile: URL?
 
         init(
             unifiedSymbolGraphsDirectory: URL,
             targetSymbolGraphsDirectory: URL,
-            snippetSymbolGraphsDirectory: URL?
+            snippetSymbolGraphFile: URL?
         ) {
             self.unifiedSymbolGraphsDirectory = unifiedSymbolGraphsDirectory
             self.targetSymbolGraphsDirectory = targetSymbolGraphsDirectory
-            self.snippetSymbolGraphsDirectory = snippetSymbolGraphsDirectory
+            self.snippetSymbolGraphFile = snippetSymbolGraphFile
         }
 
         init(targetSymbolGraphsDirectory: URL) {
             self.unifiedSymbolGraphsDirectory = targetSymbolGraphsDirectory
             self.targetSymbolGraphsDirectory = targetSymbolGraphsDirectory
-            self.snippetSymbolGraphsDirectory = nil
+            self.snippetSymbolGraphFile = nil
         }
     }
 
@@ -70,7 +70,7 @@ extension PackageManager {
             print("snippet extractor provided, attempting to generate snippet symbol graph")
         }
 
-        guard let snippetSymbolGraphsDirectory = try snippetExtractor.generateSnippets(
+        guard let snippetSymbolGraphFile = try snippetExtractor.generateSnippets(
             for: target,
             context: context
         ) else {
@@ -82,7 +82,7 @@ extension PackageManager {
         }
 
         if verbose {
-            print("snippet symbol graph directory path: '\(snippetSymbolGraphsDirectory.path)'")
+            print("snippet symbol graph file: '\(snippetSymbolGraphFile.path)'")
         }
 
         // Since we successfully produced symbol graphs for snippets contained in the
@@ -125,20 +125,20 @@ extension PackageManager {
             toPath: targetSymbolGraphsUnifiedDirectory.path
         )
 
-        let snippetSymbolGraphsUnifiedDirectory = unifiedSymbolGraphsDirectory.appendingPathComponent(
-            "snippet-symbol-graphs", isDirectory: true
+        let snippetSymbolGraphFileInUnifiedDirectory = unifiedSymbolGraphsDirectory.appendingPathComponent(
+            snippetSymbolGraphFile.lastPathComponent, isDirectory: false
         )
 
         // Copy the snippet symbol graphs into the unified directory
         try FileManager.default.copyItem(
-            atPath: snippetSymbolGraphsDirectory.path,
-            toPath: snippetSymbolGraphsUnifiedDirectory.path
+            atPath: snippetSymbolGraphFile.path,
+            toPath: snippetSymbolGraphFileInUnifiedDirectory.path
         )
 
         return DocCSymbolGraphResult(
             unifiedSymbolGraphsDirectory: unifiedSymbolGraphsDirectory,
             targetSymbolGraphsDirectory: targetSymbolGraphsUnifiedDirectory,
-            snippetSymbolGraphsDirectory: snippetSymbolGraphsUnifiedDirectory
+            snippetSymbolGraphFile: snippetSymbolGraphFileInUnifiedDirectory
         )
     }
 }