revsets: stop jj parsing br as a git_ref refs/heads/br

Use `br@git` instead.

Before, if there is not a local branch `br`, jj tried to resolve
it as a git ref `refs/heads/br`. Unchanged from before, `br` can
still be resolved as a tag `refs/tag/br`.

CHANGELOG.md

@@ -38,6 +38,9 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 * `jj debug completion`, `jj debug mangen` and `jj debug config-schema` have
   been moved from `jj debug` to `jj util`.
 
+* `jj` will no longer parse `br` as a git_ref `refs/heads/br` when a branch `br`
+  does not exist but the git_ref does (this is rare). Use `br@git` instead.
+
 ### New features
 
 * `jj git push --deleted` will remove all locally deleted branches from the remote.

lib/src/revset.rs

@@ -1617,7 +1617,9 @@ pub fn walk_revs<'index>(
 
 fn resolve_git_ref(repo: &dyn Repo, symbol: &str) -> Option<Vec<CommitId>> {
     let view = repo.view();
-    for git_ref_prefix in &["", "refs/", "refs/heads/", "refs/tags/", "refs/remotes/"] {
+    // TODO: We should remove `refs/remotes` from this list once we have a better
+    // way to address local git repo's remote-tracking branches.
+    for git_ref_prefix in &["", "refs/", "refs/tags/", "refs/remotes/"] {
         if let Some(ref_target) = view.git_refs().get(&(git_ref_prefix.to_string() + symbol)) {
             return Some(ref_target.adds());
         }

lib/tests/test_revset.rs

@@ -452,7 +452,8 @@ fn test_resolve_symbol_git_refs() {
     // Nonexistent ref
     assert_matches!(
         resolve_symbol(mut_repo, "nonexistent", None),
-        Err(RevsetResolutionError::NoSuchRevision{name, candidates}) if name == "nonexistent" && candidates.is_empty()
+        Err(RevsetResolutionError::NoSuchRevision{name, candidates})
+            if name == "nonexistent" && candidates.is_empty()
     );
 
     // Full ref
@@ -470,27 +471,25 @@ fn test_resolve_symbol_git_refs() {
         "refs/heads/branch".to_string(),
         RefTarget::Normal(commit5.id().clone()),
     );
-    mut_repo.set_git_ref(
-        "refs/tags/branch".to_string(),
-        RefTarget::Normal(commit4.id().clone()),
-    );
-    assert_eq!(
-        resolve_symbol(mut_repo, "heads/branch", None).unwrap(),
-        vec![commit5.id().clone()]
-    );
-
-    // Unqualified branch name
-    mut_repo.set_git_ref(
-        "refs/heads/branch".to_string(),
-        RefTarget::Normal(commit3.id().clone()),
+    // branch alone is not recognized
+    assert_matches!(
+        resolve_symbol(mut_repo, "branch", None),
+        Err(RevsetResolutionError::NoSuchRevision{name, candidates})
+            if name == "branch" && candidates.is_empty()
     );
     mut_repo.set_git_ref(
         "refs/tags/branch".to_string(),
         RefTarget::Normal(commit4.id().clone()),
     );
+    // The *tag* branch is recognized
     assert_eq!(
         resolve_symbol(mut_repo, "branch", None).unwrap(),
-        vec![commit3.id().clone()]
+        vec![commit4.id().clone()]
+    );
+    // heads/branch does get resolved to the git ref refs/heads/branch
+    assert_eq!(
+        resolve_symbol(mut_repo, "heads/branch", None).unwrap(),
+        vec![commit5.id().clone()]
     );
 
     // Unqualified tag name

tests/test_branch_command.rs

@@ -140,11 +140,11 @@ fn test_branch_forget_export() {
     foo (deleted)
       @git: 65b6b74e0897 (no description set)
     "###);
-
-    // Aside: the way we currently resolve git refs means that `foo`
-    // resolves to `foo@git` when actual `foo` doesn't exist.
-    // Short-term TODO: This behavior will be changed in a subsequent commit.
-    let stdout = test_env.jj_cmd_success(&repo_path, &["log", "-r=foo", "--no-graph"]);
+    let stderr = test_env.jj_cmd_failure(&repo_path, &["log", "-r=foo", "--no-graph"]);
+    insta::assert_snapshot!(stderr, @r###"
+    Error: Revision "foo" doesn't exist
+    "###);
+    let stdout = test_env.jj_cmd_success(&repo_path, &["log", "-r=foo@git", "--no-graph"]);
     insta::assert_snapshot!(stdout, @r###"
     rlvkpnrzqnoo [email protected] 2001-02-03 04:05:08.000 +07:00 65b6b74e0897
     (empty) (no description set)