How do I modify sources of ports before installing?

[BullyWiiPlaza]

I'm trying to track down a Dear ImGui bug, my operating system is Windows 11 Pro. For the bug research I need to install imgui v1.88 (the latest) and comment out 1 - 2 lines of code. When installing the imgui package, I see output as follows:

C:\vcpkg>vcpkg install imgui:x64-windows-static --no-binarycaching
Computing installation plan...
The following packages will be built and installed:
    imgui[core]:x64-windows-static -> 1.88#1
Detecting compiler hash for triplet x64-windows-static...
Installing 1/1 imgui:x64-windows-static...
Building imgui[core]:x64-windows-static...
-- Using cached ocornut-imgui-v1.88.tar.gz.
-- Cleaning sources at C:/vcpkg/buildtrees/imgui/src/v1.88-34c93572a3.clean. Use --editable to skip cleaning for the packages you specify.
-- Extracting source C:/vcpkg/downloads/ocornut-imgui-v1.88.tar.gz
-- Using source at C:/vcpkg/buildtrees/imgui/src/v1.88-34c93572a3.clean
-- Found external ninja('1.10.2').
-- Configuring x64-windows-static
-- Building x64-windows-static-dbg
-- Building x64-windows-static-rel
-- Installing: C:/vcpkg/packages/imgui_x64-windows-static/share/imgui/copyright
-- Performing post-build validation
-- Performing post-build validation done
Elapsed time to handle imgui:x64-windows-static: 13.11 s

Total elapsed time: 16.09 s

imgui provides CMake targets:
    # this is heuristically generated, and may not be correct
    find_package(imgui CONFIG REQUIRED)
    target_link_libraries(main PRIVATE imgui::imgui)

I already found the --no-binarycaching which helps me avoid using cached binaries instead of rebuilding. I tried modifying the archive under C:/vcpkg/downloads/ocornut-imgui-v1.88.tar.gz but it seems to cause vcpkg to fail afterwards:

-- Extracting source C:/vcpkg/downloads/ocornut-imgui-v1-bfb73813.88.tar.gz
CMake Error at scripts/cmake/vcpkg_extract_source_archive.cmake:159 (file):
  file RENAME failed to rename

    C:/vcpkg/buildtrees/imgui/src/v1.88-34c93572a3.clean.tmp/imgui-1.88

  to

    C:/vcpkg/buildtrees/imgui/src/v1.88-34c93572a3.clean

  because: Access is denied.



Call Stack (most recent call first):
  scripts/cmake/vcpkg_extract_source_archive_ex.cmake:8 (vcpkg_extract_source_archive)
  scripts/cmake/vcpkg_from_github.cmake:113 (vcpkg_extract_source_archive_ex)
  ports/imgui/portfile.cmake:12 (vcpkg_from_github)
  scripts/ports.cmake:147 (include)


error: building imgui:x64-windows-static failed with: BUILD_FAILED
Please ensure you're using the latest port files with `git pull` and `vcpkg update`.
Then check for known issues at:
    https://github.com/microsoft/vcpkg/issues?q=is%3Aissue+is%3Aopen+in%3Atitle+imgui
You can submit a new issue at:
    https://github.com/microsoft/vcpkg/issues/new?template=report-package-build-failure.md&title=[imgui]+Build+error
Include '[imgui] Build error' in your bug report title, the following version information in your bug description, and attach any relevant failure logs from above.
    vcpkg-tool version: 2022-07-21-a0e87e227afb536c62188c11ad029954f28fdb22
    vcpkg-scripts version: 48369f2a2 2022-08-01 (18 hours ago)

You can also use the prefilled template from C:\vcpkg\installed\vcpkg\issue_body.md.

I used 7-zip for modifying the ocornut-imgui-v1.88.tar.gz file. I'm not sure if that's a viable way to do it. If I delete the ocornut-imgui-v1-bfb73813.88.tar.gz it will redownload from GitHub: -- Downloading https://github.com/ocornut/imgui/archive/v1.88.tar.gz -> ocornut-imgui-v1-bfb73813.88.tar.gz.... This wipes out my edit.

Or if I modify the ocornut-imgui-v1-bfb73813.88.tar.gz I get:

CMake Error at scripts/cmake/vcpkg_download_distfile.cmake:22 (message):


  File does not have expected hash:

          File path: [ C:/vcpkg/downloads/ocornut-imgui-v1-bfb73813.88.tar.gz ]
      Expected hash: [ bfb7381334f1493d64386321401086e4136129b3cc57bf57505ec6183008dddab1a2056b0af2610bc3286c606bafdf9b6e3ebc103131e0504bab2336662bc2c1 ]
        Actual hash: [  ]

  The cached file SHA512 doesn't match.  The file may have been corrupted.
  To re-download this file please delete cached file at path
  C:/vcpkg/downloads/ocornut-imgui-v1-bfb73813.88.tar.gz and retry.

Is there another straightforward way of modifying a *.cpp of a port and recompiling with it?

[Osyotr]

vcpkg install imgui:x64-windows-static --editable
This will prevent vcpkg from clearing extracted source files directory.

[JackBoosY]

The another way is make a patch and apply it in ports/PORT_NAME/portfile.cmake.

[Osyotr]

Yes, this is usually done in combination. See https://stackoverflow.com/a/72778459/5802715

[BullyWiiPlaza]

Yes, this is usually done in combination. See https://stackoverflow.com/a/72778459/5802715

Thanks, this was very helpful. That's all I needed.