feat: libra add cherry-pick subcommand.

[yyjeqhc]

Part of #1239
实现libra cherry-pick 子命令的基本功能

rm -rf *.txt .libra
libra init
echo "✅ Repo initialized."

# --- 2. 创建共同的祖先提交 (C1) ---
echo "base" > base.txt
libra add base.txt
libra commit -m "C1: Initial commit, our common ancestor"
echo "✅ C1: Created common ancestor."

# --- 3. 创建并切换到 feature 分支 ---
libra switch -c feature
echo "✅ Switched to new branch 'feature'."

# --- 4. 在 feature 分支上创建两个提交 ---
# Commit C2: 我们想要 cherry-pick 的第一个目标
echo "feature A" > feature_a.txt
libra add feature_a.txt
libra commit -m "C2: Add feature_a.txt"
echo "✅ C2: Added feature_a.txt on feature branch."

# Commit C3: 我们想要 cherry-pick 的第二个目标
echo "feature B" > feature_b.txt
libra add feature_b.txt
libra commit -m "C3: Add feature_b.txt"
echo "✅ C3: Added feature_b.txt on feature branch."

# --- 5. 切换回 master 分支 ---
libra switch master
echo "✅ Switched back to master."

# --- 6. 显示最终状态 ---
# 此时 master 分支只包含 C1，没有任何 feature 分支的更改
echo
echo "🎉 Cherry-pick test repo is ready. Current state:"
libra log

测试：

root@MSI:~/724/2# libra switch feature
root@MSI:~/724/2# libra log
commit 448700f1cee34c9322bf9bda5349e9e2760a4594 (HEAD -> feature)
Author: mega <admin@mega.org>
Date: 2025-07-27 13:43:28 UTC +0800

C3: Add feature_b.txt

commit cb58e6cc6f9493ebd61c4b381d78b1356cf73dac
Author: mega <admin@mega.org>
Date: 2025-07-27 13:43:28 UTC +0800

C2: Add feature_a.txt

commit 4b62bb5159debe2173f4da00a759b9bb95afddcd (master)
Author: mega <admin@mega.org>
Date: 2025-07-27 13:43:28 UTC +0800

C1: Initial commit, our common ancestor

root@MSI:~/724/2# libra switch master
root@MSI:~/724/2# libra cherry-pick 448700f1cee34c9322bf9bda5349e9e2760a4594 cb58e6cc6f9493ebd61c4b381d78b1356cf73dac
Cherry-picking commit 448700f...
Finished cherry-pick for 448700f in new commit dc8340a
Cherry-picking commit cb58e6c...
Finished cherry-pick for cb58e6c in new commit 50d7745
root@MSI:~/724/2# ls
base.txt  feature_a.txt  feature_b.txt
root@MSI:~/724/2# cat feature_a.txt
feature A
root@MSI:~/724/2# cat feature_b.txt
feature B

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Name	Status	Preview	Comments	Updated (UTC)
mega	✅ Ready (Inspect)	Visit Preview	💬 Add feedback	Jul 27, 2025 2:28pm

[Copilot]

Pull Request Overview

This PR implements the libra cherry-pick subcommand to apply changes from existing commits onto the current branch. The feature allows selective application of commits from one branch to another without merging the entire branch.

Key Changes:

• Added cherry-pick command with support for single/multiple commits and --no-commit option
• Implemented three-way merge logic to apply commit changes
• Added comprehensive test coverage for various cherry-pick scenarios

Reviewed Changes

Copilot reviewed 7 out of 12 changed files in this pull request and generated 4 comments.

Show a summary per file

File	Description
libra/src/command/cherry_pick.rs	Core implementation of cherry-pick functionality with three-way merge logic
libra/src/command/mod.rs	Exposed the new cherry_pick module
libra/src/cli.rs	Added cherry-pick command to CLI interface
libra/tests/command/cherry_pick_test.rs	Comprehensive test suite covering basic, multi-commit, and error scenarios
libra/tests/command/mod.rs	Added cherry_pick_test module
libra/tests/command/revert_test.rs	Updated CommitArgs with new disable_pre field
aria/contents/docs/libra/command/cherry-pick/index.mdx	Documentation for the cherry-pick command

Comments suppressed due to low confidence (1)

libra/tests/command/cherry_pick_test.rs:434

• The test executes cherry-pick with a non-existent commit but doesn't assert that it actually fails or check the error behavior. Add assertions to verify the expected error handling.

    // Test cherry-picking non-existent commit should fail gracefully

[Copilot]

The Blob::load call doesn't handle potential errors. If the blob cannot be loaded, this will likely panic or return an invalid blob. Consider adding error handling with a Result return type.

Suggested change

	let blob = mercury::internal::object::blob::Blob::load(&hash);
	let blob = match mercury::internal::object::blob::Blob::load(&hash) {
	Ok(blob) => blob,
	Err(e) => {
	eprintln!("Failed to load blob for hash {}: {}", hash, e);
	return; // Exit the function if the blob cannot be loaded
	}
	};

[Copilot]

Same issue as line 245 - Blob::load call lacks error handling. This could cause the function to panic if the blob cannot be loaded from storage.

Suggested change

	let blob = mercury::internal::object::blob::Blob::load(&entry.hash);
	let blob = mercury::internal::object::blob::Blob::load(&entry.hash)
	.map_err(|e| format!("Failed to load blob: {}", e))?;

[Copilot]

[nitpick] This artificial limitation differs from Git's behavior and reduces functionality. Consider implementing proper multi-commit support with --no-commit or documenting this as a known limitation in the help text.

Suggested change

	if args.no_commit && args.commits.len() > 1 {
	eprintln!("fatal: cannot cherry-pick multiple commits with --no-commit");
	eprintln!("(use 'libra commit' to save the changes from the first cherry-pick)");
	return;
	}
	// TODO: Implement proper multi-commit support for --no-commit to align with Git's behavior.

[Copilot]

The TODO comment indicates incomplete conflict resolution functionality. This is a significant limitation that should be documented in the command help or user documentation, not just in code comments.

Suggested change

	/// TODO: Now, it will apply the picked commits exactly as they are,
	/// without resolving any conflicts, and it will not take the state of the staging area into account.
	pub async fn execute(args: CherryPickArgs) {
	if !util::check_repo_exist() {
	return;
	}
	///
	/// Note: The cherry-pick operation applies commits exactly as they are, without resolving conflicts
	/// or considering the state of the staging area.
	pub async fn execute(args: CherryPickArgs) {
	if !util::check_repo_exist() {
	return;
	}
	println!("Note: Conflicts will not be resolved, and the staging area will not be considered during cherry-pick.");