feat(ci-new): preserve dirty changes across CI lock

Store dirty workspace changes in a temporary commit so `git-unlock` can
restore them, with the marker file content (`true`/`false`) recording
which restore path to take.

2 files changed, 57 insertions, 23 deletions

diff --git a/mingling_ci/src/cmd/cmd_git_lock.rs b/mingling_ci/src/cmd/cmd_git_lock.rs
index 4398593..0e9bf22 100644
--- a/mingling_ci/src/cmd/cmd_git_lock.rs
+++ b/mingling_ci/src/cmd/cmd_git_lock.rs
@@ -5,46 +5,63 @@ use mingling::{
 };
 
 use crate::Next;
-use crate::git::{LOCK_FILE, TEMP_COMMIT_MESSAGE, run_git, worktree_clean};
+use crate::git::{CI_TEMP_COMMIT_MESSAGE, LOCK_FILE, TEMP_COMMIT_MESSAGE, run_git, worktree_clean};
 use crate::res::{CargoError, MessagePrinter};
 
 /// Temporarily commits the workspace so CI can run on a stable tree.
 ///
 /// First pins the current HEAD to the `mingling/bkup` backup branch (created
-/// or force-reset), then commits everything with a `[DO NOT PUSH] CI TEMP`
-/// message. When the tree has no tracked changes, a `MINGLING-CI-CHECKING`
-/// marker file is created first so the commit is never empty.
+/// or force-reset). When the tree is dirty, all changes are packed into a
+/// plain `TEMP` commit first so they can be restored later; the `CI TEMP`
+/// commit then carries only the `MINGLING-CI-CHECKING` marker file, whose
+/// content (`true`/`false`) tells `git-unlock` which restore path to take.
 #[command(node = "git-lock")]
 pub fn git_lock() -> Next {
     if let Err(e) = run_git(["branch", "-f", "mingling/bkup", "HEAD"]) {
         return ErrorGitLock(e).to_chain();
     }
 
-    if worktree_clean()
-        && let Err(e) = std::fs::write(LOCK_FILE, "")
-    {
+    let dirty = !worktree_clean();
+    if dirty {
+        if let Err(e) = run_git(["add", "."]) {
+            return ErrorGitLock(e).to_chain();
+        }
+        if let Err(e) = run_git(["commit", "-m", TEMP_COMMIT_MESSAGE]) {
+            return ErrorGitLock(e).to_chain();
+        }
+    }
+
+    let marker = if dirty { "true" } else { "false" };
+    if let Err(e) = std::fs::write(LOCK_FILE, marker) {
         return ErrorGitLock(format!("failed to create {LOCK_FILE}: {e}")).to_chain();
     }
 
     if let Err(e) = run_git(["add", "."]) {
         return ErrorGitLock(e).to_chain();
     }
-    if let Err(e) = run_git(["commit", "-m", TEMP_COMMIT_MESSAGE]) {
+    if let Err(e) = run_git(["commit", "-m", CI_TEMP_COMMIT_MESSAGE]) {
         return ErrorGitLock(e).to_chain();
     }
 
-    ResultGitLock {}.to_chain()
+    ResultGitLock { dirty }.to_chain()
 }
 
+/// Whether the tree was dirty (a base `TEMP` commit exists) when locking.
 #[derive(Grouped)]
-pub struct ResultGitLock;
+pub struct ResultGitLock {
+    dirty: bool,
+}
 
 #[derive(Grouped, Default)]
 pub struct ErrorGitLock(pub String);
 
 #[renderer(buffer)]
-pub fn render_git_lock(_: ResultGitLock) {
-    r_println!("Locked: CI temp commit created");
+pub fn render_git_lock(r: ResultGitLock) {
+    if r.dirty {
+        r_println!("Locked: dirty workspace committed for CI");
+    } else {
+        r_println!("Locked: clean workspace marked for CI");
+    }
 }
 
 #[renderer]
diff --git a/mingling_ci/src/cmd/cmd_git_unlock.rs b/mingling_ci/src/cmd/cmd_git_unlock.rs
index 4d9ee80..6d7389d 100644
--- a/mingling_ci/src/cmd/cmd_git_unlock.rs
+++ b/mingling_ci/src/cmd/cmd_git_unlock.rs
@@ -10,11 +10,14 @@ use crate::res::{CargoError, MessagePrinter};
 
 /// Undoes a CI temporary commit created by [`crate::cmd::cmd_git_lock`].
 ///
-/// Only acts when the HEAD commit message contains `CI TEMP` (case-sensitive),
-/// which together with the `MINGLING-CI-CHECKING` marker means the workspace
-/// is in a CI phase and all uncommitted state may be discarded. Restores the
-/// tree in five steps: unstage, restore tracked files, delete untracked files,
-/// roll back the temporary commit, and remove the marker file.
+/// Only acts when the HEAD commit message contains `CI TEMP` (case-sensitive).
+/// The restore path is picked by the marker file content:
+///
+/// - `true`: a base `TEMP` commit with the dirty changes sits below; restore
+///   by hard-resetting past the marker commit, then soft-resetting and
+///   unstaging to put the user's changes back into the working tree.
+/// - `false`: the tree was clean; a single hard reset back to the original
+///   HEAD is enough.
 ///
 /// When the working tree is dirty (e.g. CI left tracked changes behind) the
 /// restore still runs, but the command reports a non-zero exit code so the
@@ -29,19 +32,33 @@ pub fn git_unlock() -> Next {
     // Record dirtiness before restoring: the restore discards those changes.
     let dirty = !worktree_clean();
 
-    if let Err(e) = undo_ci_phase() {
+    // The marker file lives in the HEAD (CI TEMP) commit, so it is readable
+    // from the working tree; a missing marker falls back to the clean path.
+    let based_on_dirty =
+        std::fs::read_to_string(LOCK_FILE).is_ok_and(|content| content.trim() == "true");
+
+    if let Err(e) = undo_ci_phase(based_on_dirty) {
         return ErrorGitUnlock(e).to_chain();
     }
 
     ResultGitUnlock { dirty }.to_chain()
 }
 
-/// The five-step restoration sequence of `git-unlock`.
-fn undo_ci_phase() -> Result<(), String> {
-    run_git(["reset"])?;
-    run_git(["restore", "."])?;
-    run_git(["clean", "-f", "-d"])?;
+/// Restores the workspace, keeping the user's pre-lock changes.
+///
+/// With a base `TEMP` commit (`true`) the marker commit is dropped by a hard
+/// reset to `HEAD~1`, the `TEMP` commit is unwrapped into the staging area by
+/// a soft reset, and a plain reset unstages it back into the working tree.
+/// Without one (`false`) a single hard reset to `HEAD~1` removes the marker
+/// commit and lands on the original HEAD.
+fn undo_ci_phase(based_on_dirty: bool) -> Result<(), String> {
     run_git(["reset", "--hard", "HEAD~1"])?;
+    if based_on_dirty {
+        // Unwrap the `TEMP` commit into the staging area, then unstage it
+        // back into the working tree.
+        run_git(["reset", "--soft", "HEAD~1"])?;
+        run_git(["reset"])?;
+    }
     std::fs::remove_file(LOCK_FILE).ok();
     Ok(())
 }