Restore Swift-only index store occurrence filtering.

Filter non-Swift symbols before building the source graph so mixed Swift/Objective-C projects don't ingest raw extension metadata that triggers extension resolution failures and duplicate USR conflicts.

Author: ileitch

Package.resolved

@@ -7,7 +7,7 @@ var dependencies: [Package.Dependency] = [
     .package(url: "https://github.com/tadija/AEXML", from: "4.0.0"),
     .package(url: "https://github.com/apple/swift-argument-parser", from: "1.0.0"),
     // Use tag once https://github.com/MobileNativeFoundation/swift-index-store/issues/27 is resolved.
-    .package(url: "https://github.com/ileitch/swift-index-store", revision: "ad6f20532864a2cf3b1e1ee7a084267e94eb68b9"),
+    .package(url: "https://github.com/MobileNativeFoundation/swift-index-store", revision: "7edb9a64e084ed64f83b84fb9269d3d1a20c0687"),
     .package(url: "https://github.com/apple/swift-syntax", from: "603.0.0"),
     .package(url: "https://github.com/ileitch/swift-filename-matcher", from: "2.0.0"),
 ]

Package.swift

@@ -85,6 +85,10 @@ final class SwiftIndexer: Indexer {
         logger.debug("\(sourceFile.path.string) (\(modules)) (\(elapsed)s)")
     }
 
+    static func shouldProcessSymbolLanguage(_ language: SymbolLanguage) -> Bool {
+        language == .swift
+    }
+
     private final class Job {
         let sourceFile: SourceFile
 
@@ -162,7 +166,8 @@ final class SwiftIndexer: Indexer {
 
                     record.forEach(occurrence: { occurrence in
                         let usr = occurrence.symbol.usr
-                        guard let location = self.transformLocation(occurrence.location)
+                        guard Self.shouldProcessOccurrence(occurrence),
+                              let location = self.transformLocation(occurrence.location)
                         else { return }
 
                         var relations: [RawRelation] = []
@@ -701,6 +706,10 @@ final class SwiftIndexer: Indexer {
             Location(file: sourceFile, line: input.line, column: input.column)
         }
 
+        static func shouldProcessOccurrence(_ occurrence: SymbolOccurrence) -> Bool {
+            SwiftIndexer.shouldProcessSymbolLanguage(occurrence.symbol.language)
+        }
+
         private func transformDeclarationKind(_ kind: SymbolKind, _ subKind: SymbolSubkind) -> Declaration.Kind? {
             switch subKind {
             case .accessorGetter: return .functionAccessorGetter

Sources/Indexer/SwiftIndexer.swift

@@ -1,4 +1,5 @@
 import Configuration
+@testable import Indexer
 import Logger
 import Shared
 @testable import SourceGraph
@@ -54,6 +55,13 @@ final class DeterminismRegressionTest: XCTestCase {
         return reference
     }
 
+    func testSwiftIndexerFiltersNonSwiftSymbolLanguages() {
+        XCTAssertTrue(SwiftIndexer.shouldProcessSymbolLanguage(.swift))
+        XCTAssertFalse(SwiftIndexer.shouldProcessSymbolLanguage(.objc))
+        XCTAssertFalse(SwiftIndexer.shouldProcessSymbolLanguage(.c))
+        XCTAssertFalse(SwiftIndexer.shouldProcessSymbolLanguage(.cxx))
+    }
+
     func testExtendedDeclarationReferenceUsesDeterministicSelection() throws {
         let graph = makeGraph()