Extract the check for a rescheduled rebase command into a helper

We are going to need it for recovering from lock errors during a rebase.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

pkg/commands/git_commands/commit_loader.go

@@ -430,38 +430,7 @@ func (self *CommitLoader) getConflictedCommitImpl(hashPool *utils.StringPool, to
 		return nil
 	}
 
-	// In certain cases, git reschedules commands that failed. One example is if
-	// a patch would overwrite an untracked file (another one is an "exec" that
-	// failed, but we don't care about that here because we dealt with exec
-	// already above). To detect this, compare the last command of the "done"
-	// file against the first command of "git-rebase-todo"; if they are the
-	// same, the command was rescheduled.
-	if len(doneTodos) > 0 && len(todos) > 0 && doneTodos[len(doneTodos)-1] == todos[0] {
-		// Command was rescheduled, no need to display it
-		return nil
-	}
-
-	// Older versions of git have a bug whereby, if a command is rescheduled,
-	// the last successful command is appended to the "done" file again. To
-	// detect this, we need to compare the second-to-last done entry against the
-	// first todo entry, and also compare the last done entry against the
-	// last-but-two done entry; this latter check is needed for the following
-	// case:
-	//   pick A
-	//   exec make test
-	//   pick B
-	//   exec make test
-	// If pick B fails with conflicts, then the "done" file contains
-	//   pick A
-	//   exec make test
-	//   pick B
-	// and git-rebase-todo contains
-	//   exec make test
-	// Without the last condition we would erroneously treat this as the exec
-	// command being rescheduled, so we wouldn't display our fake entry for
-	// "pick B".
-	if len(doneTodos) >= 3 && len(todos) > 0 && doneTodos[len(doneTodos)-2] == todos[0] &&
-		doneTodos[len(doneTodos)-1] == doneTodos[len(doneTodos)-3] {
+	if utils.LastDoneTodoWasRescheduled(doneTodos, todos) {
 		// Command was rescheduled, no need to display it
 		return nil
 	}

pkg/utils/rebase_todo.go

@@ -68,6 +68,40 @@ func findTodo(todos []todo.Todo, todoToFind Todo) (int, bool) {
 	return idx, ok
 }
 
+// LastDoneTodoWasRescheduled tells whether git put the last command of
+// rebase-merge/done back into git-rebase-todo, given the parsed contents of
+// these two files. In certain cases, git reschedules commands that failed. One
+// example is if a patch would overwrite an untracked file; another one is an
+// "exec" that failed.
+func LastDoneTodoWasRescheduled(doneTodos []todo.Todo, todos []todo.Todo) bool {
+	// If the last command of the "done" file is the same as the first command
+	// of "git-rebase-todo", the command was rescheduled.
+	if len(doneTodos) > 0 && len(todos) > 0 && doneTodos[len(doneTodos)-1] == todos[0] {
+		return true
+	}
+
+	// Older versions of git have a bug whereby, if a command is rescheduled,
+	// the last successful command is appended to the "done" file again. To
+	// detect this, we need to compare the second-to-last done entry against the
+	// first todo entry, and also compare the last done entry against the
+	// last-but-two done entry; this latter check is needed for the following
+	// case:
+	//   pick A
+	//   exec make test
+	//   pick B
+	//   exec make test
+	// If pick B fails with conflicts, then the "done" file contains
+	//   pick A
+	//   exec make test
+	//   pick B
+	// and git-rebase-todo contains
+	//   exec make test
+	// Without the last condition we would erroneously treat this as the exec
+	// command being rescheduled.
+	return len(doneTodos) >= 3 && len(todos) > 0 && doneTodos[len(doneTodos)-2] == todos[0] &&
+		doneTodos[len(doneTodos)-1] == doneTodos[len(doneTodos)-3]
+}
+
 func ReadRebaseTodoFile(fileName string, commentChar byte) ([]todo.Todo, error) {
 	f, err := os.Open(fileName)
 	if err != nil {