Capture git diff when building#3415
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- Generates a git diff on build, so the diff used when compiling is stored, not the diff when configuring. Handles out-of-source builds and cases where the source is not under git e.g. release tarballs. - Stores the diff as a string in a compilation unit git_metadata.cxx - Saves to output, along with flags indicating whether the diff was available, and whether the build had uncommitted changes.
dschwoerer
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dschwoerer
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If we want to test this in CI, it would not be that hard. We already have some post ctest tests: https://github.com/boutproject/BOUT-dev/blob/next/.ci_with_cmake.sh#L18
We could it there. Modify a source file, adding some white space to a file, and then build a test executable, and check the output. Certainly not a nice implementation, and I am not sure it is worth to have the extra time spent in CI.
| ERROR_QUIET | ||
| ) | ||
| if(NOT git_cached_diff_result EQUAL 0) | ||
| set(git_cached_diff "") |
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| set(git_cached_diff "") | |
| set(git_cached_diff "git diff unavailable") |
We could store also that the git diff is not available in the string.
If it is used programmatically, it would fail to apply the diff, which would be fine, I think. If it is used by humans, it is easy enough to see that this is not actually a diff.
| set(output_tmp "${OUTPUT_FILE}.tmp") | ||
| file(WRITE "${output_tmp}" "#include \"bout/git_metadata.hxx\"\n\n") | ||
| file(APPEND "${output_tmp}" "namespace bout {\n") | ||
| file(APPEND "${output_tmp}" "namespace version {\n") | ||
| file(APPEND "${output_tmp}" "namespace {\n") | ||
| file( | ||
| APPEND "${output_tmp}" | ||
| "constexpr bool git_metadata_available_value = ${git_metadata_available};\n" | ||
| ) | ||
| file(APPEND "${output_tmp}" "constexpr bool git_dirty_value = ${git_dirty};\n") | ||
| file(APPEND "${output_tmp}" "constexpr char git_diff_value[] =\n") | ||
| file(APPEND "${output_tmp}" "\"${git_diff_escaped}\";\n") | ||
| file(APPEND "${output_tmp}" "} // namespace\n\n") | ||
| file( | ||
| APPEND "${output_tmp}" | ||
| "auto git_metadata_available() -> bool { return git_metadata_available_value; }\n" | ||
| ) | ||
| file(APPEND "${output_tmp}" | ||
| "auto git_dirty() -> bool { return git_dirty_value; }\n" | ||
| ) | ||
| file(APPEND "${output_tmp}" | ||
| "auto git_diff() -> std::string_view { return git_diff_value; }\n" | ||
| ) | ||
| file(APPEND "${output_tmp}" "} // namespace version\n") | ||
| file(APPEND "${output_tmp}" "} // namespace bout\n") |
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For other cases we have a file, that we configure. I think that is easier to read and maintain.
| COMMAND "${CMAKE_COMMAND}" -E copy_if_different "${output_tmp}" | ||
| "${OUTPUT_FILE}" | ||
| ) | ||
| execute_process(COMMAND "${CMAKE_COMMAND}" -E rm -f "${output_tmp}") |
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I think cmake should be able to move?
| set_source_files_properties( | ||
| ${BOUT_GIT_METADATA_SOURCE} PROPERTIES GENERATED TRUE | ||
| ) | ||
| add_custom_target( |
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I would prefer add_custom_command - like we use for the timestamp above.
Although, it makes me wonder - could / should they be in the same file? Having to compile just one file should be faster, and both contain dynamic, generated content. They both get modified at the same time.
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| add_library( | ||
| bout++ ${BOUT_SOURCES} ${CMAKE_CURRENT_BINARY_DIR}/bout++-time.cxx | ||
| ${BOUT_GIT_METADATA_SOURCE} |
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I think we can just write the name here (and above), that makes it easier to read.
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Stores code changes from the current commit into the output dump files. This is to help in reproducing results when code was not committed before building.
Generates a git diff on build, so the diff used when compiling is stored, not the diff when configuring. Handles out-of-source builds and cases where the source is not under git e.g. release tarballs.
Stores the diff as a string in a compilation unit git_metadata.cxx
Saves to output, along with flags indicating whether the diff was available, and whether the build had uncommitted changes.
Not sure how to test this in CI, so I just verified manually that changes in source get stored in the output files (
conductionexample). GPT-5.4 wrote most of the code; I reviewed and modified slightly.Fixes #2217