fix(windows): pin Conan's CMake generator to match the project's

[fzipi]

Summary

Fixes #3604.

conan install (in vcbuild.bat) let Conan auto-detect its own CMake generator for dependencies built from source (--build=missing, e.g. yajl), based on whatever Visual Studio version its auto-detected profile picks up. On a machine with more than one VS version installed, that can differ from the "Visual Studio 17 2022" generator this script explicitly requests for the main project two lines later via cmake --fresh .. -G "Visual Studio 17 2022".

yajl/2.1.0's own CMakeLists.txt still does cmake_policy(SET CMP0026 OLD), a policy newer CMake versions have dropped OLD-behavior support for entirely. Under a newer, auto-detected generator/CMake (observed: "Visual Studio 18 2026" on a GitHub-hosted windows-2025 runner that had more than one VS install), yajl's configure step hard-errors on that unsupported policy before it ever gets to build. Under the generator this project actually targets, it configures fine.

• Explicitly pass the same generator to conan install via -c tools.cmake.cmaketoolchain:generator, so dependency builds use the identical toolchain as the main project rather than whatever a given machine's Conan profile auto-detection happens to prefer.
• Deduped the generator string into a single VS_GENERATOR variable referenced by both the Conan and CMake invocations, so a future VS-version bump only needs to change one line instead of two that must be kept in sync.

Reported downstream via ModSecurity-nginx's Windows CI (owasp-modsecurity/ModSecurity-nginx#388 built this via vcbuild.bat and hit this exact failure).

Note on validation

This repo's own PR-triggered Windows CI (ci.yml/ci_new.yml) runs on windows-2022, which — as far as I can tell — only has one Visual Studio version installed, so it's unlikely to reproduce the generator-mismatch this fixes even without the fix. The pin is a no-op when only one matching VS version is present either way, so it shouldn't regress that CI; real confirmation that this resolves the original failure will need a windows-2025-class runner (or a maintainer's machine with more than one VS version installed).

Test plan

• Reviewed the -c tools.cmake.cmaketoolchain:generator conf key against Conan's CMakeToolchain._get_generator() source to confirm it's the correct override point.
• CI: confirm ci.yml/ci_new.yml (windows-2022) still pass — expected to be a no-op there.
• Confirm on a windows-2025-class runner (or a machine with multiple VS installs) that this resolves the original CMP0026 failure.

[Copilot]

Pull request overview

This PR makes the Windows build script (vcbuild.bat) use a single, consistent CMake generator for both Conan-built dependencies (built from source under --build=missing) and the main CMake configure step, preventing generator/toolchain mismatches on machines with multiple Visual Studio installations.

Changes:

• Introduces a VS_GENERATOR variable as the single source of truth for the targeted Visual Studio/CMake generator.
• Pins Conan’s CMakeToolchain generator via -c tools.cmake.cmaketoolchain:generator=... to match the project’s CMake -G generator selection.

---

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[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[Zorono]

still same problem...

**********************************************************************
** Visual Studio 2026 Developer PowerShell v18.2.0
** Copyright (c) 2025 Microsoft Corporation
**********************************************************************
PS C:\Users\JohnMagdy> cd  ./zLanding\nginx\~.tst\ModSecurity"
PS ./zLanding\nginx\~.tst\ModSecurity> ./vcbuild.bat RelWithDebInfo
Build type: RelWithDebInfo
Arch: x86_64
Address Sanitizer: Disabled

======== Input profiles ========
Profile host:
[settings]
arch=x86_64
build_type=RelWithDebInfo
compiler=msvc
compiler.cppstd=17
compiler.runtime=dynamic
compiler.runtime_type=Release
compiler.version=195
os=Windows
[conf]
tools.cmake.cmaketoolchain:generator=Visual Studio 18 2026

Profile build:
[settings]
arch=x86_64
build_type=Release
compiler=msvc
compiler.cppstd=14
compiler.runtime=dynamic
compiler.runtime_type=Release
compiler.version=195
os=Windows


======== Computing dependency graph ========
Graph root
    conanfile.txt: ./zLanding\nginx\~.tst\ModSecurity\build\win32\conanfile.txt
Requirements
    bzip2/1.0.8#c470882369c2d95c5c77e970c0c7e321 - Cache
    dirent/1.24#697499506c82b54dd3eb2a764241b3a1 - Cache
    expat/2.8.3#625b7dbfb3a1ee8b8b5adbb68bfe6f29 - Cache
    libcurl/8.19.0#2b593de2a7f92cb5cc089ac471e5e8b4 - Cache
    libiconv/1.17#9923bc6dc6f106646d6967e0039a5ada - Cache
    libmaxminddb/1.12.2#d74b327eedee17498ed920654f9c3ad8 - Cache
    libmysqlclient/8.1.0#8fdde7579e52947972d1079e9381a595 - Cache
    libpq/17.7#d1ff57ca38fa1cd2c9368643dcc6ac7a - Cache
    libxml2/2.15.2#41c66d168eb3ddbc0de5aacd0f9bf97a - Cache
    lmdb/0.9.32#062e23b9624da8798d818cf697a2d6ba - Cache
    lua/5.5.0#2bac82d0b9a1744cfaf436c5c1d01bee - Cache
    lz4/1.9.4#a2f02ad3908618757c68d3618256a196 - Cache
    openssl/3.6.3#a81313131c78c6414f25b5fe0a83204b - Cache
    pcre2/10.44#e315fa6ae66a4bf3661c7aefd2e130af - Cache
    poco/1.14.2#2b3c3bd8b048fea9df2e6529539cb762 - Cache
    sqlite3/3.53.4#89fcf5cda598966acb7f3e185b19c58d - Cache
    utf8proc/2.9.0#eec4294dc0d40a25970f1cff540f1ab7 - Cache
    yajl/2.1.0#393bfcd6566fd70c7e777bdb1d063b2d - Cache
    zlib/1.3.2#1cb806da49011867778ffb6ac7190fcb - Cache
    zstd/1.5.7#b68ca8e3de04ba5957761751d1d661f4 - Cache
Build requirements
    cmake/4.4.2#8a0d360635c870b1d5c675489ee25074 - Cache
    meson/1.10.2#9d2d10681fe7fe61c788c58626c89b25 - Cache
    msys2/cci.latest#d22fe7b2808f5fd34d0a7923ace9c54f - Cache
    nasm/2.16.01#31e26f2ee3c4346ecd347911bd126904 - Cache
    ninja/1.13.2#c8c5dc2a52ed6e4e42a66d75b4717ceb - Cache
    pkgconf/2.5.1#93c2051284cba1279494a43a4fcfeae2 - Cache
    strawberryperl/5.32.1.1#8d114504d172cfea8ea1662d09b6333e - Cache
    winflexbison/2.5.25#c61164028f2b2a92ac8fe3e70d008a57 - Cache
Resolved version ranges
    cmake/[>=3.17]: cmake/4.4.2
    cmake/[>=3.18]: cmake/4.4.2
    expat/[>=2.6.2 <3]: expat/2.8.3
    libpq/[>=15.4 <18]: libpq/17.7
    meson/[>=1.2.2 <2]: meson/1.10.2
    meson/[>=1.2.3 <2]: meson/1.10.2
    ninja/[>=1.10.2 <2]: ninja/1.13.2
    openssl/[>=3 <4]: openssl/3.6.3
    pkgconf/[>=2.2 <3]: pkgconf/2.5.1
    sqlite3/[>=3.45.0 <4]: sqlite3/3.53.4
    utf8proc/[>=2.8.0 <3]: utf8proc/2.9.0
    zlib/[>=1.2.11 <2]: zlib/1.3.2
    zstd/[~1.5]: zstd/1.5.7

======== Computing necessary packages ========
Connecting to remote 'conancenter' anonymously
libmysqlclient/8.1.0: Main binary package '6b230489017e7643f98b866c079d05f0c2c37043' missing
libmysqlclient/8.1.0: Checking 3 compatible configurations
libmysqlclient/8.1.0: Compatible configurations not found in cache, checking servers
libmysqlclient/8.1.0: 'd88110b9d5a8b049a77437e5bba71e0a2bda2e0b': compiler.cppstd=14
libmysqlclient/8.1.0: '2ac8daecd6ec15acbfe4d14a95d17a192cffe420': compiler.cppstd=20
libmysqlclient/8.1.0: 'e1cc7dded2bbfb2e9e72f5af2c789f77acd00208': compiler.cppstd=23
libmysqlclient/8.1.0: No compatible configuration found
poco/1.14.2: WARN: risk: Transitive dependencies with 'headers=False' effect in 'package_id' is not necessary and suboptimal. Use required_conan_version='>=2.28' to activate it
poco/1.14.2: Main binary package 'c368f93a4b93197e6265293e261dbb693eedad17' missing
poco/1.14.2: Checking 3 compatible configurations
poco/1.14.2: Compatible configurations not found in cache, checking servers
poco/1.14.2: '0f033199d1b6a6cc3e3a3c104d300b1c80efb818': compiler.cppstd=14
poco/1.14.2: 'dd4924bc63327bb9df41f5d02af1226f0ca18758': compiler.cppstd=20
poco/1.14.2: '3fbe916167b07a1d0952350662b856b63b920db6': compiler.cppstd=23
poco/1.14.2: No compatible configuration found

A new experimental approach for binary compatibility detection is available.
    Enable it by setting the core.graph:compatibility_mode=optimized conf
    and get improved performance when querying multiple compatible binaries in remotes.

Requirements
    bzip2/1.0.8#c470882369c2d95c5c77e970c0c7e321:f185f562f9f72635db0825822e1f81d0ce42f0b6#f71c88a857bb9d133e61d4bb8b7e208e - Cache
    dirent/1.24#697499506c82b54dd3eb2a764241b3a1:da39a3ee5e6b4b0d3255bfef95601890afd80709#4050a6e20503e2662d7f3a866866a542 - Cache
    expat/2.8.3#625b7dbfb3a1ee8b8b5adbb68bfe6f29:884a2517fa00dbbbd61e0b114178aa1286db701d - Build
    libcurl/8.19.0#2b593de2a7f92cb5cc089ac471e5e8b4:ab9084e7bb47fae4a82c2c38146fca1b8dfd93ec - Build
    libiconv/1.17#9923bc6dc6f106646d6967e0039a5ada:e27dca2d924572607692bdcbe27560156a2d7dbe - Build
    libmaxminddb/1.12.2#d74b327eedee17498ed920654f9c3ad8:7afe8fa610a095d4ff321da05836cbb79e4dac20#9607871b7e48e43539b8a7ff8d13715c - Cache
    libmysqlclient/8.1.0#8fdde7579e52947972d1079e9381a595:6b230489017e7643f98b866c079d05f0c2c37043 - Build
    libpq/17.7#d1ff57ca38fa1cd2c9368643dcc6ac7a:77f6d8ee8a8ccb30adf2b9a433eec3337f81a01a - Build
    libxml2/2.15.2#41c66d168eb3ddbc0de5aacd0f9bf97a:967dd8a4a8734faad8ba6c3e5cab2f8fb3190382 - Build
    lmdb/0.9.32#062e23b9624da8798d818cf697a2d6ba:8230c32b385382a43a1a61288021f3c4620d2526#baa3936cd05db1041345c909622573da - Cache
    lua/5.5.0#2bac82d0b9a1744cfaf436c5c1d01bee:81c9a85bda35783c501740e7e60a3ccf4e7e92e7#f79214ba2742acdc19ff7e709a35bd16 - Cache
    lz4/1.9.4#a2f02ad3908618757c68d3618256a196:e27dca2d924572607692bdcbe27560156a2d7dbe#9f992fd015ca661133f1b39e1e5b44ef - Cache
    openssl/3.6.3#a81313131c78c6414f25b5fe0a83204b:a6a05662f7764830d863835a0d25ca80facccde2 - Build
    pcre2/10.44#e315fa6ae66a4bf3661c7aefd2e130af:dc1fd925eab650420740c518e8a2d46dadc6a13b - Build
    poco/1.14.2#2b3c3bd8b048fea9df2e6529539cb762:c368f93a4b93197e6265293e261dbb693eedad17 - Build
    sqlite3/3.53.4#89fcf5cda598966acb7f3e185b19c58d:7194ada3eaa23273aadf07abded728c6494363ce#e8f9d96189456d2d13be8592ac6ebcbc - Cache
    utf8proc/2.9.0#eec4294dc0d40a25970f1cff540f1ab7:e27dca2d924572607692bdcbe27560156a2d7dbe#b3a97132511f89ee99e2e7bcce6b2759 - Cache
    yajl/2.1.0#393bfcd6566fd70c7e777bdb1d063b2d:e27dca2d924572607692bdcbe27560156a2d7dbe - Build
    zlib/1.3.2#1cb806da49011867778ffb6ac7190fcb:e27dca2d924572607692bdcbe27560156a2d7dbe - Build
    zstd/1.5.7#b68ca8e3de04ba5957761751d1d661f4:e7aedec99a2924d7bc741ea32a7bb1c4f3226199 - Build
Build requirements
    cmake/4.4.2#8a0d360635c870b1d5c675489ee25074:522dcea5982a3f8a5b624c16477e47195da2f84f#a47bdc3f19a0641b0c4e86f127db70cd - Cache
    meson/1.10.2#9d2d10681fe7fe61c788c58626c89b25:da39a3ee5e6b4b0d3255bfef95601890afd80709#f54fda458a6ea9fa57bcbb5f76c05bd7 - Cache
    msys2/cci.latest#d22fe7b2808f5fd34d0a7923ace9c54f:956a88975bda9dfcc485e2861d71e74bd7e2b9a5#13a1f739fca1c2de0517ce2f6ccd5f8f - Cache
    nasm/2.16.01#31e26f2ee3c4346ecd347911bd126904:723257509aee8a72faf021920c2874abc738e029#cfe619d6bb82b0997c21183fa9b7183d - Cache
    ninja/1.13.2#c8c5dc2a52ed6e4e42a66d75b4717ceb:723257509aee8a72faf021920c2874abc738e029#5f167024cd4b823987d6721464aef35b - Cache
    pkgconf/2.5.1#93c2051284cba1279494a43a4fcfeae2:43771b8671ac44479c188dd72670e2eb2d7918a6#0caa2aa4311b92e62664e58b821a22e5 - Cache
    strawberryperl/5.32.1.1#8d114504d172cfea8ea1662d09b6333e:522dcea5982a3f8a5b624c16477e47195da2f84f#a365b3810f698e2f0a00fbeece022903 - Cache
    winflexbison/2.5.25#c61164028f2b2a92ac8fe3e70d008a57:723257509aee8a72faf021920c2874abc738e029#5c0ad8fd9487521c47d82e39e3686333 - Cache

======== Installing packages ========
bzip2/1.0.8: Already installed! (1 of 28)
cmake/4.4.2: Already installed! (2 of 28)
dirent/1.24: Already installed! (3 of 28)
libmaxminddb/1.12.2: Already installed! (4 of 28)
lmdb/0.9.32: Already installed! (5 of 28)
lmdb/0.9.32: Appending PATH environment variable: C:\Users\JohnMagdy\.conan2\p\b\lmdb718f858ecf59a\p\bin
lua/5.5.0: Already installed! (6 of 28)
lz4/1.9.4: Already installed! (7 of 28)
msys2/cci.latest: Already installed! (8 of 28)
ninja/1.13.2: Already installed! (9 of 28)
sqlite3/3.53.4: Already installed! (10 of 28)
strawberryperl/5.32.1.1: Already installed! (11 of 28)
utf8proc/2.9.0: Already installed! (12 of 28)
winflexbison/2.5.25: Already installed! (13 of 28)
winflexbison/2.5.25: Setting LEX environment variable: C:/Users/JohnMagdy/.conan2/p/winfl7a918feb93fcf/p/bin/win_flex
winflexbison/2.5.25: Setting YACC environment variable: C:/Users/JohnMagdy/.conan2/p/winfl7a918feb93fcf/p/bin/win_bison -y

-------- Installing package yajl/2.1.0 (14 of 28) --------
yajl/2.1.0: Building from source
yajl/2.1.0: Package yajl/2.1.0:e27dca2d924572607692bdcbe27560156a2d7dbe
yajl/2.1.0: settings: os=Windows arch=x86_64 compiler=msvc compiler.runtime=dynamic compiler.runtime_type=Release compiler.version=195 build_type=RelWithDebInfo
yajl/2.1.0: options: shared=False
>>> Source step
yajl/2.1.0: Copying sources to build folder
yajl/2.1.0: Building your package in C:\Users\JohnMagdy\.conan2\p\b\yajl693600081cddb\b
>>> Generate step
Generating files for yajl/2.1.0
Generators folder: C:\Users\JohnMagdy\.conan2\p\b\yajl693600081cddb\b\build\generators
Calling generate() method in recipe
CMakeToolchain generated: conan_toolchain.cmake
CMakeToolchain generated: C:\Users\JohnMagdy\.conan2\p\b\yajl693600081cddb\b\build\generators\CMakePresets.json
CMakeToolchain generated: C:\Users\JohnMagdy\.conan2\p\b\yajl693600081cddb\b\src\CMakeUserPresets.json
Generating aggregated env files
Generated aggregated env files: ['conanbuild.bat', 'conanrun.bat']
>>> Build step
Building yajl/2.1.0
yajl/2.1.0: Calling build()
yajl/2.1.0: Apply patch (conan): CMake: fix mingw, disable build of doc/test/perf/example, relocatable shared lib for macos, install DLL into bin folder
yajl/2.1.0: Running CMake.configure()
yajl/2.1.0: RUN: cmake -G "Visual Studio 18 2026" -DCMAKE_TOOLCHAIN_FILE="generators/conan_toolchain.cmake" -DCMAKE_INSTALL_PREFIX="C:/Users/JohnMagdy/.conan2/p/b/yajl693600081cddb/p" -DCMAKE_POLICY_DEFAULT_CMP0091="NEW" "C:/Users/JohnMagdy/.conan2/p/b/yajl693600081cddb/b/src"
CMake Error at CMakeLists.txt:17 (cmake_policy):
  Policy CMP0026 may not be set to OLD behavior because this version of CMake
  no longer supports it.  The policy was introduced in CMake version 3.0.0,
  and use of NEW behavior is now required.

  Please either update your CMakeLists.txt files to conform to the new
  behavior or use an older version of CMake that still supports the old
  behavior.  Run cmake --help-policy CMP0026 for more information.


-- Using Conan toolchain: C:/Users/JohnMagdy/.conan2/p/b/yajl693600081cddb/b/build/generators/conan_toolchain.cmake
-- Conan toolchain: CMAKE_GENERATOR_TOOLSET=v145
-- Conan toolchain: Setting CMAKE_MSVC_RUNTIME_LIBRARY=$<$<CONFIG:RelWithDebInfo>:MultiThreadedDLL>
-- Conan toolchain: Setting BUILD_SHARED_LIBS = OFF
-- Selecting Windows SDK version 10.0.26100.0 to target Windows 10.0.26200.
-- The C compiler identification is MSVC 19.50.35722.0
-- Detecting C compiler ABI info
-- Detecting C compiler ABI info - done
-- Check for working C compiler: M:/Installations/Visual Studio 2026 Build Tools/VC/Tools/MSVC/14.50.35717/bin/Hostx64/x64/cl.exe - skipped
-- Detecting C compile features
-- Detecting C compile features - done
CMake Warning (dev) at src/CMakeLists.txt:68 (EXEC_PROGRAM):
  Policy CMP0153 is not set: The exec_program command should not be called.
  Run "cmake --help-policy CMP0153" for policy details.  Use the cmake_policy
  command to set the policy and suppress this warning.

  Use execute_process() instead.
This warning is for project developers.  Use -Wno-dev to suppress it.

CMake Warning (dev) at src/CMakeLists.txt:68 (EXEC_PROGRAM):
  Policy CMP0153 is not set: The exec_program command should not be called.
  Run "cmake --help-policy CMP0153" for policy details.  Use the cmake_policy
  command to set the policy and suppress this warning.

  Use execute_process() instead.
This warning is for project developers.  Use -Wno-dev to suppress it.

CMake Warning (dev) at src/CMakeLists.txt:68 (EXEC_PROGRAM):
  Policy CMP0153 is not set: The exec_program command should not be called.
  Run "cmake --help-policy CMP0153" for policy details.  Use the cmake_policy
  command to set the policy and suppress this warning.

  Use execute_process() instead.
This warning is for project developers.  Use -Wno-dev to suppress it.

CMake Warning (dev) at src/CMakeLists.txt:68 (EXEC_PROGRAM):
  Policy CMP0153 is not set: The exec_program command should not be called.
  Run "cmake --help-policy CMP0153" for policy details.  Use the cmake_policy
  command to set the policy and suppress this warning.

  Use execute_process() instead.
This warning is for project developers.  Use -Wno-dev to suppress it.

CMake Error at reformatter/CMakeLists.txt:38 (GET_TARGET_PROPERTY):
  The LOCATION property may not be read from target "json_reformat".  Use the
  target name directly with add_custom_command, or use the generator
  expression $<TARGET_FILE>, as appropriate.



CMake Error at verify/CMakeLists.txt:32 (GET_TARGET_PROPERTY):
  The LOCATION property may not be read from target "json_verify".  Use the
  target name directly with add_custom_command, or use the generator
  expression $<TARGET_FILE>, as appropriate.



-- Configuring incomplete, errors occurred!

yajl/2.1.0: ERROR:
Package 'e27dca2d924572607692bdcbe27560156a2d7dbe' build failed
yajl/2.1.0: WARN: Build folder C:\Users\JohnMagdy\.conan2\p\b\yajl693600081cddb\b\build
ERROR: yajl/2.1.0: Error in build() method, line 53
        cmake.configure()
        ConanException: Error 1 while executing
The system cannot find the path specified.
CMake Warning:
  Ignoring extra path from command line:

   ".."


CMake Error: The source directory "./zLanding/nginx/~.tst/ModSecurity/build" does not appear to contain CMakeLists.txt.
Specify --help for usage, or press the help button on the CMake GUI.
Error: not a CMake build directory (missing CMakeCache.txt)