Re: [PATCH v2 02/10] cmake: do find Git for Windows' shell interpreter
- From
Johannes Schindelin <johannes.schindelin@gmx.de>
- Date
- Sep 28, 2020, 19:39 UTC
- Message-ID
- <nycvar.QRO.7.76.6.2009281557390.50@tvgsbejvaqbjf.bet>
- In-Reply-To
- <20200928111748.4122-1-oystwa@gmail.com>
Hi Øystein,
On Mon, 28 Sep 2020, Øystein Walle wrote:
Show 17 quoted lines
> > find_program(SH_EXE sh)
> > if(NOT SH_EXE)
> > - message(FATAL_ERROR "sh: shell interpreter was not found in your path, please install one."
> > - "On Windows, you can get it as part of 'Git for Windows' install at https://gitforwindows.org/")
> > + set(SH_EXE "C:/Program Files/Git/bin/sh.exe")
> > + if(NOT EXISTS ${SH_EXE})
> > + message(FATAL_ERROR "sh: shell interpreter was not found in your path, please install one."
> > + "On Windows, you can get it as part of 'Git for Windows' install at https://gitforwindows.org/")
> > + endif()
> > endif()
>
> You can write the find_program() command more succinctly as:
>
> find_program(SH_EXE sh PATHS "C:/Program Files/Git/bin")
>
> PATHS is is a list of extra directories to search, which are usually hard-coded
> guesses[1]. This way we avoid an extra check and indentation level.Thank you, I was not aware of this neat feature.
Show 11 quoted lines
> I found my Visual Studio installation already contains a sh.exe. I think it > ships with VS by default; I can't even find a way to remove it. It's located > at: > > C:\Program Files (x86)\Microsoft Visual Studio\2019\Community\Common7\IDE\CommonExtensions\Microsoft\TeamFoundation\Team Explorer\Git\usr\bin\sh.exe > > When I started writing this up I figured that could serve as an additional > fallback. However, if I use that shell I have to add (...)/usr/bin to PATH as > the various scripts need expr and sed among other things. I get the same result > if I search "C:/Program Files/Git/usr/bin", but there is no equivalent > (...)/bin in the Git included with VS for some reason.
Indeed. This is what I get in that case:
-- snip -- 1> [CMake] Generating GIT-VERSION-FILE 1> [CMake] C:/git-sdk-64/usr/src/vs2017-test/contrib/buildsystems/../../GIT-VERSION-GEN: line 24: sed: command not found 1> [CMake] C:/git-sdk-64/usr/src/vs2017-test/contrib/buildsystems/../../GIT-VERSION-GEN: line 29: expr: command not found 1> [CMake] GIT_VERSION = 1> [CMake] CMake Error at C:\git-sdk-64\usr\src\vs2017-test\contrib\buildsystems\CMakeLists.txt:79 (string): 1> [CMake] string sub-command FIND requires 3 or 4 parameters. 1> [CMake] 1> [CMake] 1> [CMake] CMake Error at C:\git-sdk-64\usr\src\vs2017-test\contrib\buildsystems\CMakeLists.txt:83 (string): 1> [CMake] string sub-command REGEX, mode MATCH needs at least 5 arguments total to 1> [CMake] command. 1> [CMake] 1> [CMake] 1> [CMake] CMake Error at C:\git-sdk-64\usr\src\vs2017-test\contrib\buildsystems\CMakeLists.txt:87 (project): 1> [CMake] VERSION ".0" format invalid. -- snap --
The explanation is pretty simple: you cannot just call into `sh.exe` via an absolute path and expect it to add its containing directory to the `PATH`. It does not, and the symptom is that neither `sed` nor `expr` are found.
One solution is to add it to the `PATH` manually, which is the original expectation in our `CMakeLists.txt` version.
Another solution is to point it to `C:\Program Files\Git\bin\sh.exe` which is not, in fact, a shell, but a small wrapper executable whose job it is to set up a couple environment variables (`PATH` being one of them) and then spawning the _actual_ `sh.exe`. The source code for that wrapper: https://github.com/git-for-windows/MINGW-packages/blob/main/mingw-w64-git/git-wrapper.c
As you figured out, it is _not_ enough to use `...\usr\bin\sh.exe` directly without adjusting the `PATH`.
Ciao, Dscho