Re: [PATCH 5/5] cmake: avoid editing t/test-lib.sh

[Phillip Wood <phillip.wood123@gmail.com>]

Hi Dscho

On 10/08/2022 16:02, Johannes Schindelin via GitGitGadget wrote:
> From: Johannes Schindelin <johannes.schindelin@gmx.de>
> 
> In 7f5397a07c6c (cmake: support for testing git when building out of the
> source tree, 2020-06-26), we implemented support for running Git's test
> scripts even after building Git in a different directory than the source
> directory.
> 
> The way we did this was to edit the file `t/test-lib.sh` to override
> `GIT_BUILD_DIR` to point somewhere else than the parent of the `t/`
> directory.
> 
> This is unideal because it always leaves a tracked file marked as
> modified, and it is all too easy to commit that change by mistake.
> 
> Let's change the strategy by teaching `t/test-lib.sh` to detect the
> presence of a file called `GIT-BUILD-DIR` in the source directory. If it
> exists, the contents are interpreted as the location to the _actual_
> build directory. We then write this file as part of the CTest
> definition.

I think it is really good to get away from editing the test files, but 
one of the nice things about CMake's out of tree builds is that you can 
have several build directories with different build configurations and 
this change does not support that. Could we pass the build directory to 
the test scripts as a commandline option or environment variable 
instead? e.g.

   foreach(tsh ${test_scipts})
    	add_test(NAME ${tsh}
-		COMMAND ${SH_EXE} ${tsh} --no-bin-wrappers --no-chain-lint -vx
+		COMMAND ${SH_EXE} ${tsh} --no-bin-wrappers --no-chain-lint 
--build-dir=${CMAKE_BINARY_DIR} -vx

   		WORKING_DIRECTORY ${CMAKE_SOURCE_DIR}/t)
   endforeach()

Doing that would avoid changing the main Makefile to remove a file which 
almost certainly does not exist every time make is invoked as well.

Best Wishes

Phillip

> To support building Git via a regular `make` invocation after building
> it using CMake, we ensure that the `GIT-BUILD-DIR` file is deleted (for
> convenience, this is done as part of the Makefile rule that is already
> run with every `make` invocation to ensure that `GIT-BUILD-OPTIONS` is
> up to date).
> 
> Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
> ---
>   .gitignore                          |  1 +
>   Makefile                            |  1 +
>   contrib/buildsystems/CMakeLists.txt |  7 +------
>   t/test-lib.sh                       | 11 ++++++++++-
>   4 files changed, 13 insertions(+), 7 deletions(-)
> 
> diff --git a/.gitignore b/.gitignore
> index a4522157641..b72ddf09346 100644
> --- a/.gitignore
> +++ b/.gitignore
> @@ -2,6 +2,7 @@
>   /fuzz_corpora
>   /fuzz-pack-headers
>   /fuzz-pack-idx
> +/GIT-BUILD-DIR
>   /GIT-BUILD-OPTIONS
>   /GIT-CFLAGS
>   /GIT-LDFLAGS
> diff --git a/Makefile b/Makefile
> index 04d0fd1fe60..9347ed90da7 100644
> --- a/Makefile
> +++ b/Makefile
> @@ -3028,6 +3028,7 @@ else
>   	@echo RUNTIME_PREFIX=\'false\' >>$@+
>   endif
>   	@if cmp $@+ $@ >/dev/null 2>&1; then $(RM) $@+; else mv $@+ $@; fi
> +	@if test -f GIT-BUILD-DIR; then rm GIT-BUILD-DIR; fi
>   
>   ### Detect Python interpreter path changes
>   ifndef NO_PYTHON
> diff --git a/contrib/buildsystems/CMakeLists.txt b/contrib/buildsystems/CMakeLists.txt
> index fe606c179f7..29d7e236ae1 100644
> --- a/contrib/buildsystems/CMakeLists.txt
> +++ b/contrib/buildsystems/CMakeLists.txt
> @@ -1067,14 +1067,9 @@ endif()
>   #Make the tests work when building out of the source tree
>   get_filename_component(CACHE_PATH ${CMAKE_CURRENT_LIST_DIR}/../../CMakeCache.txt ABSOLUTE)
>   if(NOT ${CMAKE_BINARY_DIR}/CMakeCache.txt STREQUAL ${CACHE_PATH})
> -	file(RELATIVE_PATH BUILD_DIR_RELATIVE ${CMAKE_SOURCE_DIR} ${CMAKE_BINARY_DIR}/CMakeCache.txt)
> -	string(REPLACE "/CMakeCache.txt" "" BUILD_DIR_RELATIVE ${BUILD_DIR_RELATIVE})
>   	#Setting the build directory in test-lib.sh before running tests
>   	file(WRITE ${CMAKE_BINARY_DIR}/CTestCustom.cmake
> -		"file(STRINGS ${CMAKE_SOURCE_DIR}/t/test-lib.sh GIT_BUILD_DIR_REPL REGEX \"GIT_BUILD_DIR=(.*)\")\n"
> -		"file(STRINGS ${CMAKE_SOURCE_DIR}/t/test-lib.sh content NEWLINE_CONSUME)\n"
> -		"string(REPLACE \"\${GIT_BUILD_DIR_REPL}\" \"GIT_BUILD_DIR=\\\"$TEST_DIRECTORY/../${BUILD_DIR_RELATIVE}\\\"\" content \"\${content}\")\n"
> -		"file(WRITE ${CMAKE_SOURCE_DIR}/t/test-lib.sh \${content})")
> +		"file(WRITE ${CMAKE_SOURCE_DIR}/GIT-BUILD-DIR \"${CMAKE_BINARY_DIR}\")")
>   	#misc copies
>   	file(COPY ${CMAKE_SOURCE_DIR}/t/chainlint.sed DESTINATION ${CMAKE_BINARY_DIR}/t/)
>   	file(COPY ${CMAKE_SOURCE_DIR}/po/is.po DESTINATION ${CMAKE_BINARY_DIR}/po/)
> diff --git a/t/test-lib.sh b/t/test-lib.sh
> index 55857af601b..4468ac51f25 100644
> --- a/t/test-lib.sh
> +++ b/t/test-lib.sh
> @@ -42,7 +42,16 @@ then
>   	TEST_OUTPUT_DIRECTORY=$TEST_DIRECTORY
>   fi
>   GIT_BUILD_DIR="${TEST_DIRECTORY%/t}"
> -if test "$TEST_DIRECTORY" = "$GIT_BUILD_DIR"
> +if test -f "$GIT_BUILD_DIR/GIT-BUILD-DIR"
> +then
> +	GIT_BUILD_DIR="$(cat "$GIT_BUILD_DIR/GIT-BUILD-DIR")" || exit 1
> +	# On Windows, we must convert Windows paths lest they contain a colon
> +	case "$(uname -s)" in
> +	*MINGW*)
> +		GIT_BUILD_DIR="$(cygpath -au "$GIT_BUILD_DIR")"
> +		;;
> +	esac
> +elif test "$TEST_DIRECTORY" = "$GIT_BUILD_DIR"
>   then
>   	echo "PANIC: Running in a $TEST_DIRECTORY that doesn't end in '/t'?" >&2
>   	exit 1