fix(nest): use buzz-dev symlink name for dev builds (#1587)

Co-authored-by: npub1mn7jgtj4w2pd0g0zeuhxsa6jy6p0rewxz4kujt98my82ahfmp72sxjexk7 <dcfd242e557282d7a1e2cf2e6877522682f1e5c6156dc92ca7d90eaedd3b0f95@sprout-oss.stage.blox.sqprod.co>

desktop/scripts/check-file-sizes.mjs

@@ -82,7 +82,10 @@ const overrides = new Map([
   // to split with the rest of this list.
   // dev-nest namespace: OnceLock<Option<PathBuf>> + init_nest_dir + constants
   // added to plumb the dev/prod discriminator. Load-bearing for the D2 nest fix.
-  ["src-tauri/src/managed_agents/nest.rs", 1501],
+  // dev-build CLI symlink: cli_link_name helper + is_dev param on
+  // ensure_cli_symlink + prod/dev test variants add ~68 lines. Load-bearing;
+  // queued to split with the rest of this list.
+  ["src-tauri/src/managed_agents/nest.rs", 1569],
   // harness-persona-sync: persona-runtime resolution threaded into the spawn
   // path here. Load-bearing feature growth; queued to split in the resolver
   // unify refactor followup. +26 for resolve_effective_prompt_model_provider

desktop/src-tauri/src/lib.rs

@@ -323,7 +323,7 @@ pub fn run() {
             // bundled CLI binary. Non-fatal: agents find CLI via PATH.
             if let Ok(exe) = std::env::current_exe() {
                 if let Some(parent) = exe.parent() {
-                    if let Err(error) = managed_agents::ensure_cli_symlink(parent) {
+                    if let Err(error) = managed_agents::ensure_cli_symlink(parent, is_dev_nest) {
                         eprintln!("buzz-desktop: failed to create CLI symlink: {error}");
                     }
                 }

desktop/src-tauri/src/managed_agents/nest.rs

@@ -306,16 +306,35 @@ fn ensure_skill_symlinks(_root: &Path) -> Result<(), String> {
     Ok(())
 }
 
-/// Ensures `~/.local/bin/buzz` is a symlink to the bundled CLI binary.
+/// Returns the `~/.local/bin` link name for the bundled CLI.
 ///
-/// On every boot: replaces any existing symlink unconditionally (the `buzz`
-/// name is our namespace), creates a new one if absent, and leaves regular
-/// files alone to avoid clobbering a user-compiled binary.
+/// Dev builds (`is_dev = true`) use `"buzz-dev"` so that a running DMG and a
+/// concurrent dev build each own a separate link and never clobber each other —
+/// the same isolation that separates `~/.buzz` (prod) from `~/.buzz-dev` (dev).
+pub fn cli_link_name(is_dev: bool) -> &'static str {
+    if is_dev {
+        "buzz-dev"
+    } else {
+        "buzz"
+    }
+}
+
+/// Ensures `~/.local/bin/buzz` (prod) or `~/.local/bin/buzz-dev` (dev) is a
+/// symlink to the bundled CLI binary.
+///
+/// The link name is split by `is_dev` so that an installed DMG and a
+/// concurrently running dev build each maintain their own symlink and never
+/// overwrite each other's target — the same isolation that separates the
+/// `~/.buzz` and `~/.buzz-dev` nests (see [`NEST_DIR_DEV`]).
+///
+/// On every boot: replaces any existing symlink unconditionally (the `buzz` /
+/// `buzz-dev` name is our namespace), creates a new one if absent, and leaves
+/// regular files alone to avoid clobbering a user-compiled binary.
 ///
 /// Non-fatal: callers should ignore errors — the symlink is a convenience
 /// for human Terminal use; agents find the CLI via PATH augmentation.
 #[cfg(unix)]
-pub fn ensure_cli_symlink(exe_parent: &Path) -> Result<(), String> {
+pub fn ensure_cli_symlink(exe_parent: &Path, is_dev: bool) -> Result<(), String> {
     let buzz_bin = exe_parent.join("buzz");
     if !buzz_bin.exists() {
         return Ok(()); // CLI not bundled (e.g., dev builds without sidecars).
@@ -327,7 +346,7 @@ pub fn ensure_cli_symlink(exe_parent: &Path) -> Result<(), String> {
         .join("bin");
     fs::create_dir_all(&local_bin).map_err(|e| format!("create {}: {e}", local_bin.display()))?;
 
-    let link = local_bin.join("buzz");
+    let link = local_bin.join(cli_link_name(is_dev));
     match link.symlink_metadata() {
         Ok(meta) if meta.file_type().is_symlink() => {
             let _ = fs::remove_file(&link);
@@ -351,7 +370,7 @@ pub fn ensure_cli_symlink(exe_parent: &Path) -> Result<(), String> {
 
 /// No-op on non-Unix platforms — symlink management is macOS/Linux only.
 #[cfg(not(unix))]
-pub fn ensure_cli_symlink(_exe_parent: &Path) -> Result<(), String> {
+pub fn ensure_cli_symlink(_exe_parent: &Path, _is_dev: bool) -> Result<(), String> {
     Ok(())
 }
 
@@ -983,19 +1002,29 @@ mod tests {
         );
     }
 
+    #[test]
+    fn cli_link_name_prod_is_buzz() {
+        assert_eq!(cli_link_name(false), "buzz");
+    }
+
+    #[test]
+    fn cli_link_name_dev_is_buzz_dev() {
+        assert_eq!(cli_link_name(true), "buzz-dev");
+    }
+
     #[cfg(unix)]
     #[test]
-    fn ensure_cli_symlink_creates_symlink() {
+    fn ensure_cli_symlink_creates_symlink_prod() {
         let tmp = tempfile::tempdir().unwrap();
         let exe_parent = tmp.path().join("MacOS");
         fs::create_dir(&exe_parent).unwrap();
         fs::write(exe_parent.join("buzz"), "binary").unwrap();
 
-        // Simulate the symlink creation path.
         let local_bin = tmp.path().join("local_bin");
         fs::create_dir_all(&local_bin).unwrap();
-        let link = local_bin.join("buzz");
 
+        // Prod link name is "buzz"; simulate the symlink creation path.
+        let link = local_bin.join(cli_link_name(false));
         std::os::unix::fs::symlink(exe_parent.join("buzz"), &link).unwrap();
         assert!(link.symlink_metadata().unwrap().file_type().is_symlink());
         assert_eq!(fs::read_link(&link).unwrap(), exe_parent.join("buzz"));
@@ -1003,11 +1032,33 @@ mod tests {
 
     #[cfg(unix)]
     #[test]
-    fn ensure_cli_symlink_does_not_clobber_regular_file() {
+    fn ensure_cli_symlink_creates_symlink_dev() {
+        let tmp = tempfile::tempdir().unwrap();
+        let exe_parent = tmp.path().join("MacOS");
+        fs::create_dir(&exe_parent).unwrap();
+        fs::write(exe_parent.join("buzz"), "binary").unwrap();
+
+        let local_bin = tmp.path().join("local_bin");
+        fs::create_dir_all(&local_bin).unwrap();
+
+        // Dev link must be "buzz-dev", never "buzz".
+        assert_eq!(cli_link_name(true), "buzz-dev");
+
+        let link = local_bin.join(cli_link_name(true));
+        std::os::unix::fs::symlink(exe_parent.join("buzz"), &link).unwrap();
+        assert!(link.symlink_metadata().unwrap().file_type().is_symlink());
+        assert_eq!(fs::read_link(&link).unwrap(), exe_parent.join("buzz"));
+        // Prod link must not exist — the two builds don't touch each other.
+        assert!(!local_bin.join("buzz").exists());
+    }
+
+    #[cfg(unix)]
+    #[test]
+    fn ensure_cli_symlink_does_not_clobber_regular_file_prod() {
         let tmp = tempfile::tempdir().unwrap();
         let local_bin = tmp.path().join("local_bin");
         fs::create_dir_all(&local_bin).unwrap();
-        let link = local_bin.join("buzz");
+        let link = local_bin.join(cli_link_name(false));
         fs::write(&link, "user-installed binary").unwrap();
 
         // Regular files are preserved — the Ok(_) branch skips them.
@@ -1015,6 +1066,23 @@ mod tests {
         assert_eq!(fs::read_to_string(&link).unwrap(), "user-installed binary");
     }
 
+    #[cfg(unix)]
+    #[test]
+    fn ensure_cli_symlink_does_not_clobber_regular_file_dev() {
+        let tmp = tempfile::tempdir().unwrap();
+        let local_bin = tmp.path().join("local_bin");
+        fs::create_dir_all(&local_bin).unwrap();
+        let link = local_bin.join(cli_link_name(true));
+        fs::write(&link, "user-installed buzz-dev binary").unwrap();
+
+        // Regular files at the dev path are also preserved.
+        assert!(link.symlink_metadata().unwrap().file_type().is_file());
+        assert_eq!(
+            fs::read_to_string(&link).unwrap(),
+            "user-installed buzz-dev binary"
+        );
+    }
+
     fn make_persona(id: &str, display_name: &str) -> PersonaRecord {
         PersonaRecord {
             id: id.to_string(),