[PATCH] tests: handle "funny" exit code 127 produced by MSVC-compiled exes

From: Johannes Schindelin via GitGitGadget <gitgitgadget@gmail.com>
Date: Oct 30, 2023, 15:45 UTC
Message-ID: <pull.1604.git.1698680732691.gitgitgadget@gmail.com>

From: Johannes Schindelin <johannes.schindelin@gmx.de>

The exit code 127 is well-documented to mean: command not found.

Unfortunately, it is also used as fall-back in Cygwin's `pinfo::status_exit()` method (which maps things like Windows' `STATUS_ACCESS_VIOLATION` to `128 | SIGSEGV`).

This is particularly unfortunate because there is no explicit mapping for `STATUS_STACK_OVERFLOW`. Meaning: when MSVC-compiled executables produce a stack overflow the exit code in the Cygwin Bash will be 127. Consequently, the same will be true for the MSYS2 Bash that is used by Git for Windows.

Now, `jk/tree-name-and-depth-limit` introduces a pair of test cases that expect a command that produces a stack overflow to fail, which it typically does with exit code 139 (which means SIGSEGV).

But since MSVC-compiled `git.exe` exits with `STATUS_STACK_OVERFLOW` which the MSYS2 runtime maps to 127, and since 127 is taken to mean "command not found" by `test_must_fail`, even though everything works as planned the two new test cases fail when run in `win+VS test`.

Let's work around this by:

1) recording which C compiler was used, and

2) adding an MSVC-only exception to `test_must_fail` to treat 127 as a
   regular failure.

There is a slight downside of this approach in that a real missing command could be mistaken for a failure. However, this would be caught on other platforms, and besides, we use `test_must_fail` only for `git` and `scalar` anymore, and we can be pretty certain that both are there.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
---
    Fix t6700.[45] in win+VS test
    
    These two test cases have been failing for a while in Git for Windows'
    shears/* branches. Took a good while to figure out, too.

Published-As: https://github.com/gitgitgadget/git/releases/tag/pr-1604%2Fdscho%2Ffix-vs-win-test-with-new-depth-limit-test-cases-v1
Fetch-It-Via: git fetch https://github.com/gitgitgadget/git pr-1604/dscho/fix-vs-win-test-with-new-depth-limit-test-cases-v1
Pull-Request: https://github.com/gitgitgadget/git/pull/1604

 contrib/buildsystems/CMakeLists.txt | 3 ++-
 t/test-lib-functions.sh             | 3 +++
 2 files changed, 5 insertions(+), 1 deletion(-)

diff --git a/contrib/buildsystems/CMakeLists.txt b/contrib/buildsystems/CMakeLists.txt
index 6b819e2fbdf..e164484be98 100644
--- a/contrib/buildsystems/CMakeLists.txt
+++ b/contrib/buildsystems/CMakeLists.txt
@@ -1057,7 +1057,8 @@ if(NOT PYTHON_TESTS)
 	set(NO_PYTHON 1)
 endif()
 
-file(WRITE ${CMAKE_BINARY_DIR}/GIT-BUILD-OPTIONS "SHELL_PATH='${SHELL_PATH}'\n")
+file(WRITE ${CMAKE_BINARY_DIR}/GIT-BUILD-OPTIONS "CMAKE_C_COMPILER='${CMAKE_C_COMPILER}'\n")
+file(APPEND ${CMAKE_BINARY_DIR}/GIT-BUILD-OPTIONS "SHELL_PATH='${SHELL_PATH}'\n")
 file(APPEND ${CMAKE_BINARY_DIR}/GIT-BUILD-OPTIONS "TEST_SHELL_PATH='${TEST_SHELL_PATH}'\n")
 file(APPEND ${CMAKE_BINARY_DIR}/GIT-BUILD-OPTIONS "PERL_PATH='${PERL_PATH}'\n")
 file(APPEND ${CMAKE_BINARY_DIR}/GIT-BUILD-OPTIONS "DIFF='${DIFF}'\n")
diff --git a/t/test-lib-functions.sh b/t/test-lib-functions.sh
index 2f8868caa17..ee19c748973 100644
--- a/t/test-lib-functions.sh
+++ b/t/test-lib-functions.sh
@@ -1112,6 +1112,9 @@ test_must_fail () {
 		return 1
 	elif test $exit_code -eq 127
 	then
+		# Work-around for MSVC-compiled executables
+		case "$CMAKE_C_COMPILER" in *MSVC*) return 0;; esac
+
 		echo >&4 "test_must_fail: command not found: $*"
 		return 1
 	elif test $exit_code -eq 126

base-commit: 3130c155df9a65ebccf128b4af5a19af49532580

-- 
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