[Bug] ${buildKitTargetArch} is 'unknown' for Visual Studio Kits

[gerardcarbo]

Brief Issue Summary

When using ${buildKitTargetArch} as Variable substitution in Build Directory (${workspaceFolder}/build/${buildKitTargetArch}) for Visual Studio Kits (tested in Visual Studio Professional 2019 and 2022 Release) the created folder is 'build/unknown' for all target architectures:

CMake Tools Diagnostics

{
  "os": "win32",
  "vscodeVersion": "1.103.1",
  "cmtVersion": "1.22.7",
  "configurations": [
    {
      "folder": "e:\\DeltaIdPlus\\OCR\\cpp",
      "cmakeVersion": "4.1.1",
      "configured": false,
      "generator": "Visual Studio 17 2022",
      "usesPresets": false,
      "compilers": {}
    }
  ],
  "cpptoolsIntegration": {
    "isReady": false,
    "hasCodeModel": false,
    "activeBuildType": "",
    "buildTypesSeen": [],
    "requests": [],
    "responses": [],
    "partialMatches": [],
    "targetCount": 0,
    "executablesCount": 0,
    "librariesCount": 0,
    "targets": []
  },
  "settings": [
    {
      "communicationMode": "automatic",
      "useCMakePresets": "auto",
      "configureOnOpen": true
    }
  ]
}

Debug Log

[main] Configuring project: cmaketest 
[main] Saving open files before configure/build
[expand] expanded ${workspaceFolder}/build/${buildKitTargetArch}
[driver] Start configure 
[driver] Running pre-configure checks and steps
[expand] expanded ${workspaceFolder}/build/${buildKitTargetArch}
[cmakefileapi-driver] Configuring using kit
[cmakefileapi-driver] Invoking CMake C:\Program Files\CMake\bin\cmake.exe with arguments ["-DCMAKE_EXPORT_COMPILE_COMMANDS:BOOL=TRUE","--no-warn-unused-cli","-S","E:/cmaketest","-B","e:/cmaketest/build/unknown","-G","Visual Studio 17 2022","-T","host=x64","-A","x64"]
[proc] Executing command: "C:\Program Files\CMake\bin\cmake.exe" -DCMAKE_EXPORT_COMPILE_COMMANDS:BOOL=TRUE --no-warn-unused-cli -S E:/cmaketest -B e:/cmaketest/build/unknown -G "Visual Studio 17 2022" -T host=x64 -A x64
[proc]   with environment: {"windir":"C:\\WINDOWS"}
[cmake] CMake Warning (dev) in CMakeLists.txt:
[cmake]   No project() command is present.  The top-level CMakeLists.txt file must
[cmake]   contain a literal, direct call to the project() command.  Add a line of
[cmake]   code such as
[cmake] 
[cmake]     project(ProjectName)
[cmake] 
[cmake]   near the top of the file, but after cmake_minimum_required().
[cmake] 
[cmake]   CMake is pretending there is a "project(Project)" command on the first
[cmake]   line.
[cmake] This warning is for project developers.  Use -Wno-dev to suppress it.
[cmake] 
[cmake] CMake Warning (dev) in CMakeLists.txt:
[cmake]   cmake_minimum_required() should be called prior to this top-level project()
[cmake]   call.  Please see the cmake-commands(7) manual for usage documentation of
[cmake]   both commands.
[cmake] This warning is for project developers.  Use -Wno-dev to suppress it.
[cmake] 
[cmake] Not searching for unused variables given on the command line.
[cmake] -- Configuring done (0.0s)
[cmake] -- Generating done (0.0s)
[cmake] -- Build files have been written to: E:/cmaketest/build/unknown
[cmakefileapi-parser] Read reply folder: e:\cmaketest\build\unknown\.cmake\api\v1\reply
[cmakefileapi-parser] Found index files: ["cache-v2-601efeae2835cb0cd94f.json","cmakeFiles-v1-7c2c6f222de125540abf.json","codemodel-v2-abef0fa53ac10be45b2d.json","directory-.-Debug-d0094a50bb2071803777.json","directory-.-MinSizeRel-d0094a50bb2071803777.json","directory-.-Release-d0094a50bb2071803777.json","directory-.-RelWithDebInfo-d0094a50bb2071803777.json","index-2025-08-29T08-35-50-0185.json","target-ALL_BUILD-Debug-21b93cdebeda8b7eaff2.json","target-ALL_BUILD-MinSizeRel-21b93cdebeda8b7eaff2.json","target-ALL_BUILD-Release-21b93cdebeda8b7eaff2.json","target-ALL_BUILD-RelWithDebInfo-21b93cdebeda8b7eaff2.json","target-ZERO_CHECK-Debug-a51371a7c25be58acdcf.json","target-ZERO_CHECK-MinSizeRel-a51371a7c25be58acdcf.json","target-ZERO_CHECK-Release-a51371a7c25be58acdcf.json","target-ZERO_CHECK-RelWithDebInfo-a51371a7c25be58acdcf.json","toolchains-v1-07df8119f147e128ca2e.json"]
[kit] VS installation instance not found for kit "Visual Studio Professional 2022 Release - amd64" - (7649b17b). It is recommended you re-scan the kits and also remove any user-local entries that are not present anymore on the system.
[cache] Reading CMake cache file e:/cmaketest/build/unknown/CMakeCache.txt
[cache] Parsing CMake cache string

Additional Information

No response

[yanghhhhhhh]

Hi @gerardcarbo , thank you for reporting this issue. We tried to check this issue in Visual Studio Code v1.103.2 + CMake Tools v1.22.2. But we can't reproduce this issue. Could you help to take a look at it? If we missed something, please let us know. In order for us to investigate this further, could you please provide a sample project to us that can reproduce this issue? Thanks.

[gerardcarbo]

Hi @yanghhhhhhh, the problem is with ${buildKitTargetArch} (x86, x64, ...). With ${buildKit} works properly.

The output forder should be: build/x86, build/x64, ... as indicated in vscode-cmake-tools doc

Not buid/Visual Studio Professional 2022 Release - amd64 as you are getting

Now with ${buildKitTargetArch} it generates the folder 'unknown':

[yanghhhhhhh]

Hi @gerardcarbo , thanks for reporting issue here! Reproduced this issue on VS Code v1.103.2 + CMake Tools v1.22.8 release version. Repro Steps:

1. Launch VS Code and open a test folder.
2. Add a CMakeLists.txt and add the following code.

cmake_minimum_required(VERSION 3.10.0)
project(test VERSION 0.1.0 LANGUAGES C CXX)

3. Open the command palette (F1 or Ctrl+Shift+P) run command: "Preferences: Open Settings (UI)".
4. Set the "Cmake: Build Directory" option to "${workspaceFolder}/build/${buildKitTargetArch}".
5. Open the command palette (F1 or Ctrl+Shift+P) run command: "CMake:configure".
6. Observe the build output folder.

Details please see following video:

FYI: @gcampbell-msft