Fix Copybara ls-remote branch parsing for special characters

Update regexes in GitRepository.java to support branch names with special characters (using \S+ instead of \w+). Previously, branch names containing hyphens (e.g., `feature-branch`), dots (e.g., `v1.0.0`), slashes (e.g., `feature/foo`), or emojis (e.g., `branch-🚀`) failed to be handled.

BUG: 523347052
GWSQ_IGNORES: chriscampos@google.com
PiperOrigin-RevId: 931333663
Change-Id: I6bcd4aa04fad48b57433604120d232b2af25ed08

Author: chris-campos

java/com/google/copybara/git/GitRepository.java

@@ -108,14 +108,12 @@ public class GitRepository {
       "([0-9]{6}) (commit|tag|tree|blob) ([a-f0-9]{40})\t(.*)");
 
   private static final Pattern LS_REMOTE_OUTPUT_LINE =
-      Pattern.compile("([a-f0-9]{40}|ref: refs/heads/\\w+)\t(.+)");
+      Pattern.compile("([a-f0-9]{40}|ref: refs/heads/\\S+)\t(.+)");
 
   private static final Pattern SHA1_PATTERN = Pattern.compile("[a-f0-9]{6,40}");
 
   private static final Pattern DEFAULT_BRANCH_PATTERN =
-      Pattern.compile("(?s)ref: (refs/heads/(\\w+)).*");
-
-
+      Pattern.compile("(?s)ref: (refs/heads/(\\S+)).*");
 
   // Pattern for matching URLs with a scheme, such as http:// or rpc://.
   private static final Pattern URL_WITH_SCHEME_PATTERN =

javatests/com/google/copybara/git/GitRepositoryTest.java

@@ -1946,6 +1946,16 @@ public void testFindRemotePrimaryBranch() throws Exception {
         .matches("ma.*");
   }
 
+  @Test
+  public void testFindRemotePrimaryBranch_specialCharacters() throws Exception {
+    repository.simpleCommand("symbolic-ref", "HEAD", "refs/heads/test-branch.1.x");
+    Files.write(workdir.resolve("foo.txt"), new byte[] {});
+    repository.add().files("foo.txt").run();
+    repository.simpleCommand("commit", "foo.txt", "-m", "message");
+    assertThat(repository.getPrimaryBranch("file://" + repository.getGitDir()))
+        .isEqualTo("test-branch.1.x");
+  }
+
   @Test
   public void testFindRemotePrimaryBranch_noHead() throws Exception {
     Files.write(workdir.resolve("foo.txt"), new byte[]{});