feat: support calling stg rebase without arguments

When calling "git rebase" without a target commit argument then it will
try to look up remote tracking branch and rebase onto that. This change
makes "stg rebase" behave the same way. This slightly changes the
behavior of `stg rebase --interactive`: previously when called without
argument it would rebase onto the stack base, now it will rebase onto
the upstream branch.

Signed-off-by: Frank Benkstein <[email protected]>

Author: fbenkstein

src/cmd/rebase.rs

@@ -49,8 +49,7 @@ fn make() -> clap::Command {
         .arg(
             Arg::new("committish")
                 .help("New base commit for the stack")
-                .value_parser(clap::value_parser!(SingleRevisionSpec))
-                .required_unless_present("interactive"),
+                .value_parser(clap::value_parser!(SingleRevisionSpec)),
         )
         .arg(
             Arg::new("interactive")
@@ -99,15 +98,36 @@ fn run(matches: &ArgMatches) -> Result<()> {
     let branch_name = stack.get_branch_name().to_string();
     let allow_push_conflicts = argset::resolve_allow_push_conflicts(&config, matches);
     let committer_date_is_author_date = matches.get_flag("committer-date-is-author-date");
+    let interactive = matches.get_flag("interactive");
 
-    let target_commit =
-        if let Some(target_rev_spec) = matches.get_one::<SingleRevisionSpec>("committish") {
-            target_rev_spec.resolve(&repo, Some(&stack))?.commit
-        } else {
-            stack.base().clone()
-        };
+    let target_commit = if let Some(target_rev_spec) =
+        matches.get_one::<SingleRevisionSpec>("committish")
+    {
+        target_rev_spec.resolve(&repo, Some(&stack))?.commit
+    } else if let Some(remote_ref) = repo
+        .branch_remote_tracking_ref_name(stack.get_branch_refname(), gix::remote::Direction::Fetch)
+        .transpose()?
+    {
+        let id = repo.rev_parse_single(remote_ref.as_bstr())?;
+        id.object()?.into_commit().into()
+    } else if interactive {
+        stack.base().clone()
+    } else {
+        print_info_message(
+            matches,
+            &format!(
+                "if you wish to set tracking information for this branch you can do so with:
+
+    git branch --set-upstream-to=<remote>/<branch> {branch_name}
+"
+            ),
+        );
+        return Err(anyhow!(
+            "there is no tracking information for the current branch"
+        ));
+    };
 
-    if !matches.get_flag("interactive") && target_commit.id == stack.base().id {
+    if !interactive && target_commit.id == stack.base().id {
         print_info_message(
             matches,
             &format!(

t/t2200-rebase.sh

@@ -45,7 +45,20 @@ test_expect_success 'Rebase to same base message' '
 
 test_expect_success 'Rebase without argument' '
     test_must_fail stg rebase 2>out &&
-    grep -q "error: the following required arguments were not provided" out
+    grep -q "error: there is no tracking information for the current branch" out &&
+    git checkout master &&
+    echo bar >>file2 &&
+    git add file2 &&
+    git commit -m c &&
+    git remote add origin "file://$(pwd)" &&
+    git fetch origin &&
+    git checkout stack &&
+    git branch --set-upstream-to=origin/master &&
+    stg rebase 2>out &&
+    grep "info: Rebasing to .*(master origin/master)" out &&
+    test $(stg series --applied -c) = 1 &&
+    grep bar file1 &&
+    grep bar file2
 '
 
 test_done