Better error message for old versions of Git (#11197)

* Better error message for old versions of Git Old versions of git don't support the flag. This patch detects this particular failure and prints an error message hinting that. Signed-off-by: Sudha Parimala <[email protected]> * fix(pkg): print stderr on git errors instead of discarding the stderr Signed-off-by: Rudi Grinberg <[email protected]> --------- Signed-off-by: Sudha Parimala <[email protected]> Signed-off-by: Rudi Grinberg <[email protected]> Co-authored-by: Rudi Grinberg <[email protected]>
ocaml · Dec 31, 2024 · 8bf833a · 8bf833a
1 parent 3b9d0fd
commit 8bf833a
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diff --git a/src/dune_pkg/dune b/src/dune_pkg/dune
@@ -4,6 +4,7 @@
  (libraries
   stdune
   fiber
+  fiber_util
   chrome_trace
   dune_engine
   dune_digest

diff --git a/src/dune_pkg/rev_store.ml b/src/dune_pkg/rev_store.ml
@@ -168,14 +168,37 @@ end
 
 let run_with_exit_code { dir; _ } ~allow_codes ~display args =
   let stdout_to = make_stdout () in
-  let stderr_to = make_stderr () in
   let git = Lazy.force Vcs.git in
-  let+ (), exit_code =
-    Process.run ~dir ~display ~stdout_to ~stderr_to ~env failure_mode git args
+  let+ stderr, exit_code =
+    Fiber_util.Temp.with_temp_file
+      ~prefix:"dune"
+      ~suffix:"run_with_exit_code"
+      ~dir:(Path.of_string (Filename.get_temp_dir_name ()))
+      ~f:(function
+        | Error exn -> raise exn
+        | Ok path ->
+          let+ (), exit_code =
+            let stderr_to = Process.Io.file path Out in
+            Process.run ~dir ~display ~stdout_to ~stderr_to ~env failure_mode git args
+          in
+          Io.read_file path, exit_code)
   in
   if allow_codes exit_code
   then Ok exit_code
-  else Error { Git_error.dir; args; exit_code; output = [] }
+  else (
+    match exit_code with
+    | 129
+      when String.is_prefix ~prefix:"error: unknown option `no-write-fetch-head'" stderr
+      ->
+      User_error.raise
+        [ User_message.command
+            "Your git version doesn't support the '--no-write-fetch-head' flag. The \
+             minimum supported version is Git 2.29."
+        ]
+        ~hints:[ User_message.command "Please update your git version." ]
+    | _ ->
+      Dune_console.print [ Pp.verbatim stderr ];
+      Error { Git_error.dir; args; exit_code; output = [] })
 ;;
 
 let run t ~display args =