Fix: append extension when correcting extensionless files

src/modules/candidates/candidateExtensionCorrector.ts

@@ -1,5 +1,3 @@
-import path from 'node:path';
-
 import type { Semaphore } from 'async-mutex';
 
 import type ProgressBar from '../../console/progressBar.js';
@@ -166,7 +164,7 @@ export default class CandidateExtensionCorrector extends Module {
     await this.readerSemaphore.runExclusive(async () => {
       this.progressBar.incrementInProgress();
       this.progressBar.logTrace(
-        `${dat.getName()}: ${candidate.getName()}: correcting extension for: ${romWithFiles
+        `${dat.getName()}: ${candidate.getName()}: correcting ROM extension for: ${romWithFiles
           .getInputFile()
           .toString()}`,
       );
@@ -180,8 +178,15 @@ export default class CandidateExtensionCorrector extends Module {
           correctedRom,
           romWithFiles.getInputFile(),
         );
-        if (correctedRomName !== undefined) {
+        if (correctedRomName === undefined) {
+          this.progressBar.logTrace(
+            `${dat.getName()}: ${candidate.getName()}: didn't correct ROM extension`,
+          );
+        } else {
           correctedRom = correctedRom.withName(correctedRomName);
+          this.progressBar.logTrace(
+            `${dat.getName()}: ${candidate.getName()}: corrected ROM extension to: ${correctedRomName}`,
+          );
         }
       } finally {
         childBar.delete();
@@ -208,11 +213,10 @@ export default class CandidateExtensionCorrector extends Module {
       );
     }
     if (fileSignature !== undefined) {
-      const { dir, name } = path.parse(correctedRom.getName());
-      return path.format({
-        dir,
-        name: name + fileSignature.getExtension(),
-      });
+      // Replace the file's existing extension (if any) with the one detected from its signature.
+      // A strict extension regex is used rather than path.parse(), which would mistake a period
+      // inside the filename for an extension and truncate everything after it.
+      return correctedRom.getName().replace(/\.[a-zA-Z0-9]+$/, '') + fileSignature.getExtension();
     }
 
     // Strip the extension from files claiming to be an archive

test/modules/candidates/candidateExtensionCorrector.test.ts

@@ -163,6 +163,48 @@ it('should correct ROMs without DATs', async () => {
   }
 });
 
+it('should not truncate names with periods when correcting from file signature', async () => {
+  const options = new Options({
+    // No DAT has been provided, therefore all ROMs should be corrected
+    fixExtension: FixExtensionInverted[FixExtension.AUTO].toLowerCase(),
+  });
+  const dat = new LogiqxDAT({ header: new Header() });
+
+  const tempDir = await FsUtil.mkdtemp(Temp.getTempDir());
+  try {
+    // A CHD file whose name contains periods, but no extension on the inferred ROM name
+    const gameName = 'J. B. Harold Murder Club (USA) (En,Ja)';
+    const tempFile = path.join(tempDir, `${gameName}.chd`);
+    await FsUtil.copyFile(path.join('test', 'fixtures', 'roms', 'chd', 'CD-ROM.chd'), tempFile);
+    const inputFile = await File.fileOf({ filePath: tempFile });
+
+    // The inferred ROM name has no extension (this is what a raw CHD entry produces)
+    const rom = new ROM({ name: gameName, size: inputFile.getSize() });
+    const game = new Game({ name: gameName, roms: [rom] });
+    const outputFile = inputFile.withFilePath(path.join(tempDir, gameName));
+    const candidates = [new WriteCandidate(game, [new ROMWithFiles(rom, inputFile, outputFile)])];
+
+    const correctedCandidates = await new CandidateExtensionCorrector(
+      options,
+      new ProgressBarFake(),
+      new FileFactory(new FileCache(), LOGGER),
+      new Semaphore(os.availableParallelism()),
+    ).correct(dat, candidates);
+
+    expect(correctedCandidates).toHaveLength(1);
+    expect(correctedCandidates[0].getRomsWithFiles()).toHaveLength(1);
+    const correctedRomName = correctedCandidates
+      .at(0)
+      ?.getRomsWithFiles()
+      .at(0)
+      ?.getRom()
+      .getName();
+    expect(correctedRomName).toEqual(`${gameName}.chd`);
+  } finally {
+    await FsUtil.rm(tempDir, { recursive: true, force: true });
+  }
+});
+
 it('should correct ROMs with missing filenames', async () => {
   const options = new Options({
     dat: [path.join('test', 'fixtures', 'dats')],