pcottle/learnGitBranching · error · GitError

-r is incompatible with -m

Error message

-r is incompatible with -m

What it means

The third mutual-exclusion check in the `hg branch` shim: -m (rename) combined with -r (rev) throws intl.todo('-r is incompatible with -m'). Renaming a branch takes old/new names, not a revision, so the combination is rejected before delegating to git's branch command.

Source

Thrown at src/js/mercurial/commands.js:118

      var options = command.getOptionsMap();
      var generalArgs = command.getGeneralArgs();
      var branchName;
      var rev;

      var delegate = {vcs: 'git'};

      if (options['-m'] && options['-d']) {
        throw new GitError({
          msg: intl.todo('-m and -d are incompatible')
        });
      }
      if (options['-d'] && options['-r']) {
        throw new GitError({
          msg: intl.todo('-r is incompatible with -d')
        });
      }
      if (options['-m'] && options['-r']) {
        throw new GitError({
          msg: intl.todo('-r is incompatible with -m')
        });
      }
      if (generalArgs.length + (options['-r'] ? options['-r'].length : 0) +
          (options['-d'] ? options['-d'].length : 0) === 0) {
        delegate.name = 'branch';
        return delegate;
      }

      if (options['-d']) {
        options['-D'] = options['-d'];
        delete options['-d'];
        delegate.name = 'branch';
      } else {
        if (options['-r']) {
          // we specified a revision with -r but
          // need to flip the order
          generalArgs = command.getGeneralArgs();

View on GitHub (pinned to 5b09d0ff96)

Solutions

  1. Remove -r when renaming; supply the new name as a general argument
  2. Sanity-check flag combinations if commands are generated programmatically

Example fix

// before
hg branch -m -r .
// after
hg branch -m oldname newname
Defensive patterns

Strategy: validation

Validate before calling

if (options['-m'] && options['-r']) { reject('drop -r when renaming (-m)'); }

Try / catch

try { exec(cmd); } catch (e) { if (e instanceof GitError) { showMsg(e.msg); } else throw e; }

Prevention

When it happens

Trigger: Executing `hg branch` with both -m and -r in the options map.

Common situations: Mirroring real-hg syntax where some commands accept -r; combining flags while experimenting in hg mode.

Related errors

AI-assisted analysis of pcottle/learnGitBranching@5b09d0ff96 (2026-08-27). Data as JSON: /api/errors/c575cd42f7976fa4. Report an issue: GitHub.