wip

Author: gridbugs

src/dune_pkg/flock.ml

@@ -14,7 +14,7 @@ let rec attempt_to_lock flock lock ~timeout_s =
     then
       let* () = Scheduler.sleep sleep_duration_s in
       attempt_to_lock flock lock ~timeout_s:remaining_duration_s
-    else Fiber.return (Ok `Failure)
+    else Fiber.return (Ok `Timeout)
 ;;
 
 let with_flock lock_path ~name_for_messages ~timeout_s ~f =
@@ -24,7 +24,7 @@ let with_flock lock_path ~name_for_messages ~timeout_s ~f =
   let fd =
     Unix.openfile
       (Path.to_string lock_path)
-      [ Unix.O_CREAT; O_WRONLY; O_SHARE_DELETE; Unix.O_CLOEXEC ]
+      [ Unix.O_CREAT; O_WRONLY; O_SHARE_DELETE; O_CLOEXEC ]
       0o600
   in
   let out = Unix.out_channel_of_descr fd in
@@ -49,25 +49,32 @@ let with_flock lock_path ~name_for_messages ~timeout_s ~f =
             | Error ue ->
               Unix_error.Detailed.create ue ~syscall:"flock" ~arg:"unlock"
               |> Unix_error.Detailed.raise)
-      | Ok `Failure ->
+      | Ok `Timeout ->
         let pid = Io.read_file lock_path in
         User_error.raise
           ~hints:
             [ Pp.textf
-                "Another dune instance (pid %s) has locked the %s. If this is happening \
-                 in error, make sure to terminate that instance and re-run the command."
+                "Another instance of dune (pid %s) currently holds the %S lock. If this \
+                 is unexpected, terminate that process and re-run the command."
                 pid
                 name_for_messages
+            ; Pp.textf
+                "As a last resort, if the other instance of dune (pid %s) is no longer \
+                 running, manually delete the lock file %s."
+                pid
+                (Path.to_string_maybe_quoted lock_path)
             ]
           [ Pp.textf
-              "Couldn't acquire %s lock after %f seconds"
-              name_for_messages
+              "Timed out after %f seconds while waiting for another instance of dune \
+               (pid %s) to release the lock on the resource %S."
               timeout_s
+              pid
+              name_for_messages
           ]
       | Error error ->
         User_error.raise
           [ Pp.textf
-              "Failed to get a lock for the %s at %s: %s"
+              "Failed to get a lock for the resource %S with lock file %s: %s"
               name_for_messages
               (Path.to_string_maybe_quoted lock_path)
               (Unix.error_message error)