Language server does not report path to SDK when using Xcode generator

[alexbatalov]

Environment

• OS and Version: macOS 14.5
• VS Code Version: 1.96.4 (Universal)
• C/C++ Extension Version: 1.23.5.0

Bug Summary and Steps to Reproduce

Minimal repo to reproduce: https://gist.github.com/alexbatalov/d364a78251d0c0d887a221a2cc0cf41f
Select unix makefiles preset, observe there is no include error in the main.c. Select xcode preset, observe include error.

Configuration and Logs

All defaults (implying cmake-tools configuration provider).

Other Extensions

ms-vscode.cmake-tools (1.19.52)

Additional context

Here is diagnostics log from unix makefiles preset:

Version: 1.23.5
Current Configuration:
{
    "name": "Mac",
    "includePath": [
        "/Users/alex/dev/sample/**"
    ],
    "defines": [],
    "macFrameworkPath": [
        "/Library/Developer/CommandLineTools/SDKs/MacOSX14.5.sdk/System/Library/Frameworks"
    ],
    "compilerPath": "/usr/bin/clang",
    "cStandard": "c17",
    "cppStandard": "c++17",
    "intelliSenseMode": "macos-clang-x64",
    "compilerPathInCppPropertiesJson": "/usr/bin/clang",
    "intelliSenseModeIsExplicit": false,
    "cStandardIsExplicit": false,
    "cppStandardIsExplicit": false,
    "mergeConfigurations": false,
    "compilerPathIsExplicit": false,
    "configurationProvider": "ms-vscode.cmake-tools",
    "browse": {
        "path": [
            "/Users/alex/dev/sample/**",
            "${workspaceFolder}"
        ],
        "limitSymbolsToIncludedHeaders": true
    }
}
Additional Tracked Settings:
{
    "editorTabSize": 4,
    "editorInsertSpaces": true,
    "editorAutoClosingBrackets": "languageDefined",
    "filesEncoding": "utf8",
    "filesAssociations": {
        "stdio.h": "c"
    },
    "filesExclude": {
        "**/.git": true,
        "**/.svn": true,
        "**/.hg": true,
        "**/CVS": true,
        "**/.DS_Store": true,
        "**/Thumbs.db": true
    },
    "filesAutoSaveAfterDelay": false,
    "editorInlayHintsEnabled": true,
    "editorParameterHintsEnabled": true,
    "searchExclude": {
        "**/node_modules": true,
        "**/bower_components": true,
        "**/*.code-search": true
    },
    "workbenchSettingsEditor": "ui"
}
Custom browse configuration: 
{
    "browsePath": [
        "/users/alex/dev/sample"
    ],
    "compilerPath": "/applications/xcode.app/contents/developer/toolchains/xcodedefault.xctoolchain/usr/bin/cc",
    "compilerArgs": [],
    "compilerFragments": [
        " -isysroot /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX15.1.sdk -mmacosx-version-min=14.5"
    ]
}
cpptools version (native): 1.23.5.0
Current database path: /Users/alex/Library/Caches/vscode-cpptools/574f383c91e984d4b69b86e95ab00552/.browse.VC.db
Translation Unit Mappings:
[ /Users/alex/dev/sample/main.c - source TU]:
Translation Unit Configurations:
[ /Users/alex/dev/sample/main.c ]
    Process ID: 4728
    Memory Usage: 15 MB
    Compiler Path: /applications/xcode.app/contents/developer/toolchains/xcodedefault.xctoolchain/usr/bin/cc
    Includes:
    System Includes:
        /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/lib/clang/16/include
        /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX15.1.sdk/usr/include
        /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/include
    Frameworks:
        /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX15.1.sdk/System/Library/Frameworks
    Standard Version: c17
    IntelliSense Mode: macos-clang-x64
    Other Flags:
        --clang
        --clang_version=170006
Total Memory Usage: 15 MB

------- Workspace parsing diagnostics -------
Number of files discovered (not excluded): 3283

And here are for the xcode preset:

Version: 1.23.5
Current Configuration:
{
    "name": "Mac",
    "includePath": [
        "/Users/alex/dev/sample/**"
    ],
    "defines": [],
    "macFrameworkPath": [
        "/Library/Developer/CommandLineTools/SDKs/MacOSX14.5.sdk/System/Library/Frameworks"
    ],
    "compilerPath": "/usr/bin/clang",
    "cStandard": "c17",
    "cppStandard": "c++17",
    "intelliSenseMode": "macos-clang-x64",
    "compilerPathInCppPropertiesJson": "/usr/bin/clang",
    "intelliSenseModeIsExplicit": false,
    "cStandardIsExplicit": false,
    "cppStandardIsExplicit": false,
    "mergeConfigurations": false,
    "compilerPathIsExplicit": false,
    "configurationProvider": "ms-vscode.cmake-tools",
    "browse": {
        "path": [
            "/Users/alex/dev/sample/**",
            "${workspaceFolder}"
        ],
        "limitSymbolsToIncludedHeaders": true
    }
}
Additional Tracked Settings:
{
    "editorTabSize": 4,
    "editorInsertSpaces": true,
    "editorAutoClosingBrackets": "languageDefined",
    "filesEncoding": "utf8",
    "filesAssociations": {
        "stdio.h": "c"
    },
    "filesExclude": {
        "**/.git": true,
        "**/.svn": true,
        "**/.hg": true,
        "**/CVS": true,
        "**/.DS_Store": true,
        "**/Thumbs.db": true
    },
    "filesAutoSaveAfterDelay": false,
    "editorInlayHintsEnabled": true,
    "editorParameterHintsEnabled": true,
    "searchExclude": {
        "**/node_modules": true,
        "**/bower_components": true,
        "**/*.code-search": true
    },
    "workbenchSettingsEditor": "ui"
}
Custom browse configuration: 
{
    "browsePath": [
        "/users/alex/dev/sample/out/build/xcode/cmakefiles",
        "/users/alex/dev/sample"
    ],
    "compilerPath": "/applications/xcode.app/contents/developer/toolchains/xcodedefault.xctoolchain/usr/bin/clang",
    "compilerArgs": [],
    "compilerFragments": [
        "-g"
    ]
}
cpptools version (native): 1.23.5.0
Current database path: /Users/alex/Library/Caches/vscode-cpptools/574f383c91e984d4b69b86e95ab00552/.browse.VC.db
Translation Unit Mappings:
[ /Users/alex/dev/sample/main.c - source TU]:
Translation Unit Configurations:
[ /Users/alex/dev/sample/main.c ]
    Process ID: 4774
    Memory Usage: 13 MB
    Compiler Path: /applications/xcode.app/contents/developer/toolchains/xcodedefault.xctoolchain/usr/bin/clang
    Includes:
    System Includes:
        /usr/local/include
        /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/lib/clang/16/include
        /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/include
    Frameworks:
        /System/Library/Frameworks
        /Library/Frameworks
    Standard Version: c17
    IntelliSense Mode: macos-clang-x64
    Other Flags:
        --clang
        --clang_version=170006
Total Memory Usage: 13 MB

------- Workspace parsing diagnostics -------
Number of files discovered (not excluded): 16640

Path to SDK (/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX15.1.sdk/) is missing, hence include error. I'm not sure if that's vscode-cpptools or vscode-cmake-tools fault.