From b0df023f6a01a8d2bc71e20b8bd3133b2e8dc25a Mon Sep 17 00:00:00 2001
From: Ihar Hrachyshka <ihar.hrachyshka@gmail.com>
Date: Sat, 15 Aug 2026 13:54:46 -0400
Subject: [PATCH] arrow-cpp: retry failed tests twice

If upstream believes it's an acceptable mitigation for flakiness, we
should follow their lead.
---
 pkgs/by-name/ar/arrow-cpp/package.nix | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/pkgs/by-name/ar/arrow-cpp/package.nix b/pkgs/by-name/ar/arrow-cpp/package.nix
index 9cf037401ee2..22987c23cce0 100644
--- a/pkgs/by-name/ar/arrow-cpp/package.nix
+++ b/pkgs/by-name/ar/arrow-cpp/package.nix
@@ -329,7 +329,16 @@ stdenv.mkDerivation (finalAttrs: {
     ''
       runHook preInstallCheck
 
-      ctest -L unittest --exclude-regex '^(${lib.concatStringsSep "|" disabledTests})$'
+      ctestArgs=(
+        -L unittest
+        --exclude-regex '^(${lib.concatStringsSep "|" disabledTests})$'
+      )
+
+      # Match ci/scripts/cpp_test.sh to fight flakiness.
+      # https://github.com/apache/arrow/issues/40121
+      ctestArgs+=(--repeat until-pass:3)
+
+      ctest "''${ctestArgs[@]}"
 
       runHook postInstallCheck
     '';