From 41f598915cb6358b2aa222be74d1fb983d5face8 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?B=C3=A9n=C3=A9dikt=20Tran?=
 <10796600+picnixz@users.noreply.github.com>
Date: Sun, 4 Jun 2023 12:12:35 +0200
Subject: [PATCH] Improve traceback message in parallel build (#11451)

---
 CHANGES             |  2 ++
 sphinx/cmd/build.py | 11 ++++++++---
 2 files changed, 10 insertions(+), 3 deletions(-)

diff --git a/CHANGES b/CHANGES
index e66f11cbf7e..ce1c417ad1d 100644
--- a/CHANGES
+++ b/CHANGES
@@ -18,6 +18,8 @@ Deprecated
 Features added
 --------------
 
+* #11451: Improve the traceback displayed when using :option:`-T` in parallel
+  builds. Patch by Bénédikt Tran
 * #11415: Add a checksum to JavaScript and CSS asset URIs included within
   generated HTML, using the CRC32 algorithm.
 * :meth:`~sphinx.application.Sphinx.require_sphinx` now allows the version
diff --git a/sphinx/cmd/build.py b/sphinx/cmd/build.py
index ecc2a7d2cdd..4f427e0628f 100644
--- a/sphinx/cmd/build.py
+++ b/sphinx/cmd/build.py
@@ -18,7 +18,7 @@
 import sphinx.locale
 from sphinx import __display_version__
 from sphinx.application import Sphinx
-from sphinx.errors import SphinxError
+from sphinx.errors import SphinxError, SphinxParallelError
 from sphinx.locale import __
 from sphinx.util import Tee
 from sphinx.util.console import color_terminal, nocolor, red, terminal_safe  # type: ignore
@@ -41,8 +41,13 @@ def handle_exception(
     else:
         print(file=stderr)
         if args.verbosity or args.traceback:
-            traceback.print_exc(None, stderr)
-            print(file=stderr)
+            exc = sys.exc_info()[1]
+            if isinstance(exc, SphinxParallelError):
+                exc_format = '(Error in parallel process)\n' + exc.traceback
+                print(exc_format, file=stderr)
+            else:
+                traceback.print_exc(None, stderr)
+                print(file=stderr)
         if isinstance(exception, KeyboardInterrupt):
             print(__('Interrupted!'), file=stderr)
         elif isinstance(exception, SystemMessage):