[PATCH] D31985: Support: Add a VCSRevision.h header file.

[Quentin Neill via Phabricator via llvm-commits]

qneill2014 added a comment.

In https://reviews.llvm.org/D31985#734032, @pcc wrote:

> Actually, I think that won't work because it looks like `.git/HEAD` does not get updated if a commit is made on a branch.


Hmm, you are right, because .git/HEAD holds a ref

> An alternative solution would be to touch `.git/logs/HEAD` if it does not exist.

I checked and this seems to work, it doesn't seem to affect our typical usage ('repo init' ... 'repo sync').

To answer your other question, I haven't committed anything for a couple of years, so practically I don't have commit access; please submit a patch

FWIW I am testing this locally to see if anything else pops up:

  diff --git a/include/llvm/Support/CMakeLists.txt b/include/llvm/Support/CMakeLists.txt
  index b4b9937..41e2668 100644
  --- a/include/llvm/Support/CMakeLists.txt
  +++ b/include/llvm/Support/CMakeLists.txt
  @@ -18,6 +18,10 @@ macro(find_first_existing_vc_file out_var path)
     if(git_result EQUAL 0)
       string(STRIP "${git_dir}" git_dir)
       set(${out_var} "${git_dir}/logs/HEAD")
  +    # some branchless cases (e.g. 'repo') may not yet have .git/logs/HEAD
  +    if (not EXISTS "${git_dir}/logs/HEAD") 
  +      file(WRITE "${git_dir}/logs/HEAD" "")
  +    endif()
     else()
       find_first_existing_file(${out_var}
         "${path}/.svn/wc.db"   # SVN 1.7


Repository:
  rL LLVM

https://reviews.llvm.org/D31985