git: add workspace coordination forms and conversation trailers

userland/git/src/worktrees.rs

@@ -14,6 +14,7 @@ use std::{
 /// Attach a linked worktree, or adopt existing bytes onto an unborn branch.
 #[derive(serde::Serialize, serde::Deserialize)]
 pub(crate) struct AddParams {
+    pub detached: Option<bool>,
     /// Repository name or absolute worktree/bare path under /repos/ or /plugins/.
     pub repo: String,
     /// Absolute worktree path under /plugins/ or /repos/, without dot segments.
@@ -150,10 +151,28 @@ pub(crate) struct AttachParams {
     /// Existing short local branch name.
     pub branch: String,
 }
+pub(crate) fn prune(repo: &gix::Repository) -> Result<()> {
+    let base = repo.common_dir().join("worktrees");
+    if !base.exists() {
+        return Ok(());
+    }
+    for entry in fs::read_dir(base).map_err(|e| error("worktree prune", e))? {
+        let dir = entry.map_err(|e| error("worktree prune", e))?.path();
+        if dir.join("locked").exists() {
+            continue;
+        }
+        let gitdir = read(&dir.join("gitdir"))?;
+        if !Path::new(gitdir.trim()).exists() {
+            fs::remove_dir_all(dir).map_err(|e| error("worktree prune", e))?;
+        }
+    }
+    Ok(())
+}
 pub(crate) fn attach(repo: &gix::Repository, p: AttachParams) -> Result<WorktreeInfo> {
     add_with(
         repo,
         AddParams {
+            detached: None,
             repo: p.repo,
             path: p.path,
             branch: p.branch,
@@ -170,20 +189,24 @@ fn add_with(repo: &gix::Repository, p: AddParams, keep_files: bool) -> Result<Wo
     let path = absolute(&p.path)?;
     let common = canonical(repo.common_dir())?;
     separate(&path, &common)?;
+    let detached = p.detached.unwrap_or(false);
     let branch = branches::branch_name(&p.branch)?;
-    ensure_available(repo, &branch)?;
+    if !detached {
+        ensure_available(repo, &branch)?;
+    }
     if let Some(current_path) = repo.workdir() {
-        if crate::head_info(repo)?.branch.as_deref() == Some(&branch) {
+        if !detached && crate::head_info(repo)?.branch.as_deref() == Some(&branch) {
             return Err(error(
                 "branch checked out",
                 format!("{branch} is checked out at {}", current_path.display()),
             ));
         }
     }
-    let exists = repo
-        .try_find_reference(branch.as_str())
-        .map_err(|e| error("worktree branch", e))?
-        .is_some();
+    let exists = !detached
+        && repo
+            .try_find_reference(branch.as_str())
+            .map_err(|e| error("worktree branch", e))?
+            .is_some();
     let adopt = p.adopt.unwrap_or(false);
     if adopt && (exists || p.from.is_some()) {
         return Err(error(
@@ -296,8 +319,12 @@ fn add_with(repo: &gix::Repository, p: AddParams, keep_files: bool) -> Result<Wo
                     &linked,
                     branches::CheckoutParams {
                         repo: p.path.clone(),
-                        target: p.branch.clone(),
-                        create: Some(!exists),
+                        target: if detached {
+                            id.to_string()
+                        } else {
+                            p.branch.clone()
+                        },
+                        create: Some(!exists && !detached),
                         force: None,
                     },
                 )?