[package] icu/74.2: won't build with msvc17 from within msys2, without MSVC paths pre-setup

[paulharris]

Description

I use msys2 as my shell (git-sdk-64), on my M:
I set up a python devenv with a dos prompt first, using Windows python (not msys),

Then in msys terminal, I run . /m/conan4/devenv/Scripts/activate
This works with most things - let me know if I should be doing things differently.
(I want to build with msvc17 and (in future) clang+msvc)

Now, I have 2 options when running my terminal. I'll just talk about DOS prompts, but I actually use Windows Terminal.

1. I start a plain DOS prompt. Enter bash. ie standard msys startup.
2. I run the MSVC command prompt setup first, and THEN enter bash.

The ICU build works with approach #2, which means the recipe DEPENDS ON the environment of the calling conan command. It SHOULD be using the conan environment setup, like all the other recipes!

So, anyway, without the initial MSVC environment setup,
I then run my big conan install for my recipe, and this is what happens when it comes to ICU's build:

see log below

NOTE that it complains, and then asks me to check config.log
I checked, the difference is there are MSVC bin paths in the PATH variable in the working example.

Package and Environment Details

• Package Name/Version: icu/74.2
• Operating System+version: Windows 10
• Compiler+version: msvc17
• Conan version: conan 2.2.3
• Python version: Python 3.11.2

Conan profile

======== Input profiles ========
Profile host:
[settings]
arch=x86_64
build_type=Debug
compiler=msvc
compiler.cppstd=20
compiler.runtime=dynamic
compiler.runtime_type=Debug
compiler.version=193
os=Windows
[options]
libcurl/:with_ssl=schannel
mxrap/:shared=True
qt/*:openssl=False
[conf]
tools.cmake.cmaketoolchain:generator=Ninja

Profile build:
[settings]
arch=x86_64
build_type=Release
compiler=msvc
compiler.cppstd=20
compiler.runtime=dynamic
compiler.runtime_type=Release
compiler.version=193
os=Windows
[options]
libcurl/:with_ssl=schannel
qt/:openssl=False
[conf]
tools.cmake.cmaketoolchain:generator=Ninja

Steps to reproduce

Open MSYS

conan create . --version 74.2 --user test --channel test1 -pr:h theprofileh -pr:b theprofileb

Logs

Click to expand log

-------- Installing package icu/74.2 (40 of 68) --------
icu/74.2: Building from source
icu/74.2: Package icu/74.2:08facffd46140036be35c6dc82940b177605cc13
icu/74.2: Copying sources to build folder
icu/74.2: Building your package in M:\cocache4\cache\b\icuf12bbba6c97ae\b
icu/74.2: Calling generate()
icu/74.2: Generators folder: M:\cocache4\cache\b\icuf12bbba6c97ae\b\build-debug\conan
icu/74.2: Generating aggregated env files
icu/74.2: Generated aggregated env files: ['conanbuild.sh', 'conanbuild.bat', 'conanrun.bat']
icu/74.2: Calling build()
icu/74.2: Apply patch (file): patches/0001-69.1-fix-mingw.patch
icu/74.2: Calling:
 > "/m/cocache4/cache/b/icuf12bbba6c97ae/b/src/source/configure" --disable-shared --enable-static --prefix=/ --bindir=${prefix}/bin --sbindir=${prefix}/bin --libdir=${prefix}/lib --includedir=${prefix}/include --oldincludedir=${prefix}/include --datarootdir=${prefix}/lib --enable-release=no --enable-debug=yes --enable-dyload=yes --enable-extras=no --enable-icuio=yes --disable-layoutex --disable-layout --enable-tools=yes --enable-tests=no --disable-samples --with-library-bits=64
icu/74.2: RUN: "/m/cocache4/cache/b/icuf12bbba6c97ae/b/src/source/configure" --disable-shared --enable-static --prefix=/ --bindir=${prefix}/bin --sbindir=${prefix}/bin --libdir=${prefix}/lib --includedir=${prefix}/include --oldincludedir=${prefix}/include --datarootdir=${prefix}/lib --enable-release=no --enable-debug=yes --enable-dyload=yes --enable-extras=no --enable-icuio=yes --disable-layoutex --disable-layout --enable-tools=yes --enable-tests=no --disable-samples --with-library-bits=64
conanvcvars.bat: Activating environment Visual Studio 17 - amd64 - winsdk_version=None - vcvars_ver=14.3
[vcvarsall.bat] Environment initialized for: 'x64'
mkdir: cannot create directory ‘/dev/shm’: Read-only file system

Creating /dev/shm directory failed.
POSIX semaphores and POSIX shared memory will not work

mkdir: cannot create directory ‘/dev/mqueue’: Read-only file system

Creating /dev/mqueue directory failed.
POSIX message queues will not work

configure: loading site script /etc/config.site
checking for ICU version numbers... release 74.2, library 74.2, unicode version 15.1
checking build system type... x86_64-w64-mingw32
checking host system type... x86_64-w64-mingw32
checking whether to build debug libraries... yes
checking whether to build release libraries... no
checking whether the C compiler works... no
configure: error: in `/m/cocache4/cache/b/icuf12bbba6c97ae/b/build-debug':
configure: error: C compiler cannot create executables
See `config.log' for more details

icu/74.2: ERROR:
Package '08facffd46140036be35c6dc82940b177605cc13' build failed
icu/74.2: WARN: Build folder M:\cocache4\cache\b\icuf12bbba6c97ae\b\build-debug
ERROR: icu/74.2: Error in build() method, line 204
        autotools.configure(build_script_folder=os.path.join(self.source_folder, "source"))
        ConanException: Error 77 while executing

[paulharris]

I guess the base question is:
Must I always run conan builds from within a terminal with MS vcvars already executed?
Or is this something I should expect conan to initialise with each package build step?

[paulharris]

I have managed to get this to build with some changes to the conan source code.
I'm making a PR.