refactor(workspaces): replace regex with string matching for file extensions

Replace regex-based pattern matching with simple string comparison in
`doesFilenameMatchExtension` and `replaceFileExtension` functions to
avoid unintended behavior with special characters.

Changes:
- Use `endsWith()` instead of regex for extension matching
- Add support for compound extensions (e.g., 'seqn.txt')
- Use string slicing instead of regex replacement
- Add validation check before replacing extension
- Remove tests for regex special character handling
- Add tests for compound extension scenarios

This prevents issues where special regex characters in extensions
(like `*`, `+`, `.`) would be interpreted as patterns rather than
literal strings, making extension matching more predictable and correct.

Author: duranb

src/utilities/workspaces.test.ts

@@ -1390,6 +1390,12 @@ describe('Workspace utility function tests', () => {
       expect(doesFilenameMatchExtension('txt', 'file.txt')).toBe(true);
       expect(doesFilenameMatchExtension('seq', 'test.seq')).toBe(true);
       expect(doesFilenameMatchExtension('json', 'data.json')).toBe(true);
+      expect(doesFilenameMatchExtension('seqn.txt', 'sequence.seqn.txt')).toBe(true);
+      expect(doesFilenameMatchExtension('seqn.txt', 'sequence.thing.seqn.txt')).toBe(true);
+      expect(doesFilenameMatchExtension('seqn.txt', 'sequence.seqn.txt.thing')).toBe(false);
+      expect(doesFilenameMatchExtension('seqn.txt', 'sequence.seqn')).toBe(false);
+      expect(doesFilenameMatchExtension('seqn.txt', 'sequence.txt')).toBe(false);
+      expect(doesFilenameMatchExtension('seqn.txt', 'seqn.txt')).toBe(false);
     });
 
     test('Should match extension with leading dot', () => {
@@ -1459,14 +1465,6 @@ describe('Workspace utility function tests', () => {
       expect(doesFilenameMatchExtension('seq', 'sequential.js')).toBe(false);
     });
 
-    test('Should handle special regex characters in extension', () => {
-      // Note: The function does NOT escape regex special characters
-      // So these are treated as regex patterns, not literal strings
-      expect(doesFilenameMatchExtension('t*t', 'file.tt')).toBe(true); // t*t means "zero or more t" + "t"
-      expect(doesFilenameMatchExtension('t+t', 'file.ttt')).toBe(true); // t+t means "one or more t" + "t"
-      expect(doesFilenameMatchExtension('t*t', 'file.t')).toBe(true); // matches .t (zero t's + t)
-    });
-
     test('Should match exact extension only', () => {
       expect(doesFilenameMatchExtension('js', 'file.js')).toBe(true);
       expect(doesFilenameMatchExtension('js', 'file.json')).toBe(false);

src/utilities/workspaces.ts

@@ -367,14 +367,24 @@ export function isFileConflictResponse(response: BulkOperationResponse) {
 }
 
 export function doesFilenameMatchExtension(extension: string, filename: string) {
-  return new RegExp(`\\.${extension.replace(/^\./, '')}$`, 'i').test(filename);
+  // Normalize extension to include leading dot
+  const normalizedExtension = extension.startsWith('.') ? extension : `.${extension}`;
+  // Case-insensitive check if filename ends with the extension
+  return filename.toLowerCase().endsWith(normalizedExtension.toLowerCase());
 }
 
 export function replaceFileExtension(filename: string, fromExtension: string, toExtension: string) {
-  return filename.replace(
-    new RegExp(`\\.${fromExtension.replace(/^\./, '')}$`, 'i'),
-    `.${toExtension.replace(/^\./, '')}`,
-  );
+  // Normalize extensions to include leading dots
+  const normalizedFromExtension = fromExtension.startsWith('.') ? fromExtension : `.${fromExtension}`;
+  const normalizedToExtension = toExtension.startsWith('.') ? toExtension : `.${toExtension}`;
+
+  // Check if filename ends with the fromExtension (case-insensitive)
+  if (!doesFilenameMatchExtension(normalizedFromExtension, filename)) {
+    return filename;
+  }
+
+  // Replace only the extension at the end, preserving the original case of the filename
+  return `${filename.slice(0, -normalizedFromExtension.length)}${normalizedToExtension}`;
 }
 
 export const WorkspaceApi = {