Checkout commit (#1499)

* Add keybind to checkout commit in log view
* Extract commit checkout into method
* add quckbar hint for checkout commit
* add a smoke test
* update changelog
* show an error in popup

---------

Co-authored-by: Omnikar <omnikar5@gmail.com>
Co-authored-by: extrawurst <776816+extrawurst@users.noreply.github.com>

9 files changed, 112 insertions, 4 deletions

diff --git a/CHANGELOG.md b/CHANGELOG.md
index ff5d7329..523ba413 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -9,6 +9,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Added
 * changes in commit message inside external editor [[@bc-universe]](https://github.com/bc-universe) ([#1420](https://github.com/extrawurst/gitui/issues/1420))
+* allow detaching HEAD and checking out specific commit from log view ([#1499](https://github.com/extrawurst/gitui/pull/1499))
 * add no-verify option on commits to not run hooks [[@dam5h]](https://github.com/dam5h) ([#1374](https://github.com/extrawurst/gitui/issues/1374))
 * allow `fetch` on status tab [[@alensiljak]](https://github.com/alensiljak) ([#1471](https://github.com/extrawurst/gitui/issues/1471))
 
diff --git a/asyncgit/src/sync/branch/mod.rs b/asyncgit/src/sync/branch/mod.rs
index c72a4845..89056ecf 100644
--- a/asyncgit/src/sync/branch/mod.rs
+++ b/asyncgit/src/sync/branch/mod.rs
@@ -301,6 +301,36 @@ pub fn checkout_branch(
 	}
 }
 
+/// Detach HEAD to point to a commit then checkout HEAD, does not work if there are uncommitted changes
+pub fn checkout_commit(
+	repo_path: &RepoPath,
+	commit_hash: CommitId,
+) -> Result<()> {
+	scope_time!("checkout_commit");
+
+	let repo = repo(repo_path)?;
+	let cur_ref = repo.head()?;
+	let statuses = repo.statuses(Some(
+		git2::StatusOptions::new().include_ignored(false),
+	))?;
+
+	if statuses.is_empty() {
+		repo.set_head_detached(commit_hash.into())?;
+
+		if let Err(e) = repo.checkout_head(Some(
+			git2::build::CheckoutBuilder::new().force(),
+		)) {
+			repo.set_head(
+				bytes2string(cur_ref.name_bytes())?.as_str(),
+			)?;
+			return Err(Error::Git(e));
+		}
+		Ok(())
+	} else {
+		Err(Error::UncommittedChanges)
+	}
+}
+
 ///
 pub fn checkout_remote_branch(
 	repo_path: &RepoPath,
@@ -666,6 +696,33 @@ mod tests_checkout {
 }
 
 #[cfg(test)]
+mod tests_checkout_commit {
+	use super::*;
+	use crate::sync::tests::{repo_init, write_commit_file};
+	use crate::sync::RepoPath;
+
+	#[test]
+	fn test_smoke() {
+		let (_td, repo) = repo_init().unwrap();
+		let root = repo.path().parent().unwrap();
+		let repo_path: &RepoPath =
+			&root.as_os_str().to_str().unwrap().into();
+
+		let commit =
+			write_commit_file(&repo, "test_1.txt", "test", "commit1");
+		write_commit_file(&repo, "test_2.txt", "test", "commit2");
+
+		checkout_commit(repo_path, commit).unwrap();
+
+		assert!(repo.head_detached().unwrap());
+		assert_eq!(
+			repo.head().unwrap().target().unwrap(),
+			commit.get_oid()
+		);
+	}
+}
+
+#[cfg(test)]
 mod test_delete_branch {
 	use super::*;
 	use crate::sync::tests::repo_init;
diff --git a/asyncgit/src/sync/mod.rs b/asyncgit/src/sync/mod.rs
index ed305b4a..9194bf03 100644
--- a/asyncgit/src/sync/mod.rs
+++ b/asyncgit/src/sync/mod.rs
@@ -34,9 +34,10 @@ pub mod utils;
 
 pub use blame::{blame_file, BlameHunk, FileBlame};
 pub use branch::{
-	branch_compare_upstream, checkout_branch, config_is_pull_rebase,
-	create_branch, delete_branch, get_branch_remote,
-	get_branches_info, merge_commit::merge_upstream_commit,
+	branch_compare_upstream, checkout_branch, checkout_commit,
+	config_is_pull_rebase, create_branch, delete_branch,
+	get_branch_remote, get_branches_info,
+	merge_commit::merge_upstream_commit,
 	merge_ff::branch_merge_upstream_fastforward,
 	merge_rebase::merge_upstream_rebase, rename::rename_branch,
 	validate_branch_name, BranchCompare, BranchInfo,
diff --git a/src/components/commitlist.rs b/src/components/commitlist.rs
index 2d2a42b3..603c5332 100644
--- a/src/components/commitlist.rs
+++ b/src/components/commitlist.rs
@@ -7,11 +7,14 @@ use crate::{
 	keys::{key_match, SharedKeyConfig},
 	queue::{InternalEvent, Queue},
 	strings::{self, symbol},
+	try_or_popup,
 	ui::style::{SharedTheme, Theme},
 	ui::{calc_scroll_top, draw_scrollbar, Orientation},
 };
 use anyhow::Result;
-use asyncgit::sync::{BranchInfo, CommitId, Tags};
+use asyncgit::sync::{
+	checkout_commit, BranchInfo, CommitId, RepoPathRef, Tags,
+};
 use chrono::{DateTime, Local};
 use crossterm::event::Event;
 use itertools::Itertools;
@@ -31,6 +34,7 @@ const ELEMENTS_PER_LINE: usize = 9;
 
 ///
 pub struct CommitList {
+	repo: RepoPathRef,
 	title: Box<str>,
 	selection: usize,
 	count_total: usize,
@@ -49,12 +53,14 @@ pub struct CommitList {
 impl CommitList {
 	///
 	pub fn new(
+		repo: RepoPathRef,
 		title: &str,
 		theme: SharedTheme,
 		queue: Queue,
 		key_config: SharedKeyConfig,
 	) -> Self {
 		Self {
+			repo,
 			items: ItemBatch::default(),
 			marked: Vec::with_capacity(2),
 			selection: 0,
@@ -435,6 +441,18 @@ impl CommitList {
 		self.selection = position;
 	}
 
+	pub fn checkout(&mut self) {
+		if let Some(commit_hash) =
+			self.selected_entry().map(|entry| entry.id)
+		{
+			try_or_popup!(
+				self,
+				"failed to checkout commit:",
+				checkout_commit(&self.repo.borrow(), commit_hash)
+			);
+		}
+	}
+
 	pub fn set_branches(&mut self, branches: Vec<BranchInfo>) {
 		self.branches.clear();
 
@@ -538,6 +556,12 @@ impl Component for CommitList {
 				) {
 					self.mark();
 					true
+				} else if key_match(
+					k,
+					self.key_config.keys.log_checkout_commit,
+				) {
+					self.checkout();
+					true
 				} else {
 					false
 				};
diff --git a/src/keys/key_list.rs b/src/keys/key_list.rs
index d1120549..96fbaeeb 100644
--- a/src/keys/key_list.rs
+++ b/src/keys/key_list.rs
@@ -87,6 +87,7 @@ pub struct KeysList {
 	pub cmd_bar_toggle: GituiKeyEvent,
 	pub log_tag_commit: GituiKeyEvent,
 	pub log_mark_commit: GituiKeyEvent,
+	pub log_checkout_commit: GituiKeyEvent,
 	pub commit_amend: GituiKeyEvent,
 	pub toggle_verify: GituiKeyEvent,
 	pub copy: GituiKeyEvent,
@@ -171,6 +172,7 @@ impl Default for KeysList {
 			cmd_bar_toggle: GituiKeyEvent::new(KeyCode::Char('.'),  KeyModifiers::empty()),
 			log_tag_commit: GituiKeyEvent::new(KeyCode::Char('t'),  KeyModifiers::empty()),
 			log_mark_commit: GituiKeyEvent::new(KeyCode::Char(' '),  KeyModifiers::empty()),
+			log_checkout_commit: GituiKeyEvent { code: KeyCode::Char('S'), modifiers: KeyModifiers::SHIFT },
 			commit_amend: GituiKeyEvent::new(KeyCode::Char('a'),  KeyModifiers::CONTROL),
 			toggle_verify: GituiKeyEvent::new(KeyCode::Char('f'),  KeyModifiers::CONTROL),
 			copy: GituiKeyEvent::new(KeyCode::Char('y'),  KeyModifiers::empty()),
diff --git a/src/keys/key_list_file.rs b/src/keys/key_list_file.rs
index b73f87bf..ae8b4f2f 100644
--- a/src/keys/key_list_file.rs
+++ b/src/keys/key_list_file.rs
@@ -58,6 +58,7 @@ pub struct KeysListFile {
 	pub cmd_bar_toggle: Option<GituiKeyEvent>,
 	pub log_tag_commit: Option<GituiKeyEvent>,
 	pub log_mark_commit: Option<GituiKeyEvent>,
+	pub log_checkout_commit: Option<GituiKeyEvent>,
 	pub commit_amend: Option<GituiKeyEvent>,
 	pub toggle_verify: Option<GituiKeyEvent>,
 	pub copy: Option<GituiKeyEvent>,
@@ -151,6 +152,7 @@ impl KeysListFile {
 			cmd_bar_toggle: self.cmd_bar_toggle.unwrap_or(default.cmd_bar_toggle),
 			log_tag_commit: self.log_tag_commit.unwrap_or(default.log_tag_commit),
 			log_mark_commit: self.log_mark_commit.unwrap_or(default.log_mark_commit),
+			log_checkout_commit: self.log_checkout_commit.unwrap_or(default.log_checkout_commit),
 			commit_amend: self.commit_amend.unwrap_or(default.commit_amend),
 			toggle_verify: self.toggle_verify.unwrap_or(default.toggle_verify),
 			copy: self.copy.unwrap_or(default.copy),
diff --git a/src/strings.rs b/src/strings.rs
index 561a853b..37609499 100644
--- a/src/strings.rs
+++ b/src/strings.rs
@@ -1195,6 +1195,19 @@ pub mod commands {
 			CMD_GROUP_LOG,
 		)
 	}
+	pub fn log_checkout_commit(
+		key_config: &SharedKeyConfig,
+	) -> CommandText {
+		CommandText::new(
+			format!(
+				"Checkout [{}]",
+				key_config
+					.get_hint(key_config.keys.log_checkout_commit),
+			),
+			"checkout commit",
+			CMD_GROUP_LOG,
+		)
+	}
 	pub fn inspect_file_tree(
 		key_config: &SharedKeyConfig,
 	) -> CommandText {
diff --git a/src/tabs/revlog.rs b/src/tabs/revlog.rs
index fd124025..0b0ad7d4 100644
--- a/src/tabs/revlog.rs
+++ b/src/tabs/revlog.rs
@@ -62,6 +62,7 @@ impl Revlog {
 				key_config.clone(),
 			),
 			list: CommitList::new(
+				repo.clone(),
 				&strings::log_title(&key_config),
 				theme,
 				queue.clone(),
@@ -419,6 +420,12 @@ impl Component for Revlog {
 		));
 
 		out.push(CommandInfo::new(
+			strings::commands::log_checkout_commit(&self.key_config),
+			self.selected_commit().is_some(),
+			self.visible || force_all,
+		));
+
+		out.push(CommandInfo::new(
 			strings::commands::open_tags_popup(&self.key_config),
 			true,
 			self.visible || force_all,
diff --git a/src/tabs/stashlist.rs b/src/tabs/stashlist.rs
index 89176e93..4a9e1449 100644
--- a/src/tabs/stashlist.rs
+++ b/src/tabs/stashlist.rs
@@ -32,6 +32,7 @@ impl StashList {
 		Self {
 			visible: false,
 			list: CommitList::new(
+				repo.clone(),
 				&strings::stashlist_title(&key_config),
 				theme,
 				queue.clone(),