feat: hackishly checkout remote branch locally if not checked out yet

Signed-off-by: Kipras Melnikovas <kipras@kipras.org>

branchSequencer.ts

@@ -138,6 +138,7 @@ export const branchSequencer: BranchSequencer = async ({
 			});
 
 		const cmd = cmds[0];
+
 		assert(cmd.rebaseKind === "stacked");
 
 		const targetCommitSHA: string | null = cmd.commitSHAThatBranchPointsTo;
@@ -148,9 +149,59 @@ export const branchSequencer: BranchSequencer = async ({
 
 		assert(cmd.targets?.length);
 
-		const targetBranch = cmd.targets[0].replace("refs/heads/", "");
+		let targetBranch = cmd.targets[0].replace("refs/heads/", "");
 		assert(targetBranch && typeof targetBranch === "string");
 
+		/**
+		 * if we only have the remote branch, but it's not checked out locally,
+		 * we'd end up in a detached state, and things would break.
+		 *
+		 * thus, we checkout the branch locally if it's not.
+		 */
+		// if (!Git.Branch.lookup(repo, targetBranch, Git.Branch.BRANCH.LOCAL)) {
+		// 	execSyncInRepo();
+		// }
+		if (targetBranch.startsWith("refs/remotes/")) {
+			/**
+			 * TODO - probably should handle this "checkout remote branch locally" logic
+			 * in a better place than here,
+			 *
+			 * especially since this is quite fragile,
+			 * e.g. if multiple remotes exist & have the same branch..
+			 *
+			 * here's a hint that git gives in this situation (& exits w/ 1 so good that errors)
+			 *
+			 * ```
+			 * hint: If you meant to check out a remote tracking branch on, e.g. 'origin',
+			 * hint: you can do so by fully qualifying the name with the --track option:
+			 * hint:
+			 * hint:     git checkout --track origin/<name>
+			 * hint:
+			 * hint: If you'd like to always have checkouts of an ambiguous <name> prefer
+			 * hint: one remote, e.g. the 'origin' remote, consider setting
+			 * hint: checkout.defaultRemote=origin in your config.
+			 * fatal: 'fork' matched multiple (2) remote tracking branches
+			 * ```
+			 *
+			 * seems like we should be checking all the branches somewhere early,
+			 * and either checking them out locally,
+			 * or if not possible because multiple remotes, then asking them
+			 * which remote to use (or individual, idk).
+			 *
+			 * tho, this might not always be necessary, so maybe not good
+			 * to ask for something that might not be needed?
+			 * or maybe it is always necessary, then yeah, should handle early.
+			 *
+			 * probably a good spot would be in the `branchSequencer`,
+			 * just not in an individual "checkout",
+			 * but rather - before any checkouts take place --
+			 * by doing the pre-checking logic if branches exists
+			 * before doing the checkouts.
+			 *
+			 */
+			targetBranch = targetBranch.replace(/refs\/remotes\/[^/]+\//, "");
+		}
+
 		// console.log({ targetCommitSHA, target: targetBranch });
 
 		/**