From c04f0d41317bfe1f6ff42da94dddb4023587fc26 Mon Sep 17 00:00:00 2001
From: Tobias Werth <twerth@google.com>
Date: Thu, 23 Mar 2023 01:33:53 -0700
Subject: [PATCH] Use less subshells and `tee`s in running tests with `bazel
 run`.

Fixes #17754.

What we have seen prior to this change was that sometimes for quick tests the output was swallowed. After a lot of poking it became clear that the culprit is the use of subshell and `tee`, e.g. if you remove `tee` completely from the picture the behavior never shows up.

The issue is that with a fast test, `tee` seems to be killed (or its parent subshell) before the printing the output to stdout.

With this change, we reduce the number of subshells and processes to set up and reduce the chance of the race condition but not remove it.

However, for practical purposes, the race condition is gone.

With the reproduction steps in #17754, and this command
```
for i in {1..10000}; do /tmp/bazel run :foo &> /tmp/log ; grep -q "useful echo" /tmp/log ; if [ $? -eq 0 ]; then echo -n '+'; else  echo -n '-'; fi; done
```
a bazel from head fails ~3900 out of 10000 times.

After this commit, it never failed.

Closes #17846.

PiperOrigin-RevId: 518794237
Change-Id: I8c1862d3a274799b864f0f5f42b85d6df5af78c7
---
 tools/test/test-setup.sh | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/tools/test/test-setup.sh b/tools/test/test-setup.sh
index b2912593d3d17b..952754c82dd62d 100755
--- a/tools/test/test-setup.sh
+++ b/tools/test/test-setup.sh
@@ -323,9 +323,9 @@ if [[ "${EXPERIMENTAL_SPLIT_XML_GENERATION}" == "1" ]]; then
   fi
 else
   if [ -z "$COVERAGE_DIR" ]; then
-    ("${TEST_PATH}" "$@" 2> >(tee -a "${XML_OUTPUT_FILE}.log" >&2) 1> >(tee -a "${XML_OUTPUT_FILE}.log") 2>&1) <&0 &
+    ("${TEST_PATH}" "$@" 2>&1 | tee -a "${XML_OUTPUT_FILE}.log") <&0 &
   else
-    ("$1" "$TEST_PATH" "${@:3}" 2> >(tee -a "${XML_OUTPUT_FILE}.log" >&2) 1> >(tee -a "${XML_OUTPUT_FILE}.log") 2>&1) <&0 &
+    ("$1" "$TEST_PATH" "${@:3}" 2>&1 | tee -a "${XML_OUTPUT_FILE}.log") <&0 &
   fi
 fi
 childPid=$!