llvm dev - Sep 2013 - [LLVMdev] [PATCH] Detect SVN revision and path on Git working copy

Currently when building from Git `clang --version` shows Git hash and repo URL
instead of SVN revision. However SVN is master for LLVM, so it is better to
show exactly the same as if built from SVN, if we build using clean master.

Therefore we check if last commit contains git-svn-id: and if so we extract SVN
revision and repo URL. Otherwise we fallback to Git hash and URL.

Calls to sed and grep conform to POSIX standard (no extended RE).
---
utils/GetRepositoryPath | 2 ++
utils/GetSourceVersion  | 2 ++
2 files changed, 4 insertions(+)

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On Sep 17, 2013, at 6:16 AM, Adam Strzelecki <ono at java.pl> wrote:
> Currently when building from Git `clang --version` shows Git hash and repo
URL
> instead of SVN revision. However SVN is master for LLVM, so it is better to
> show exactly the same as if built from SVN, if we build using clean master.
I’m not sure I follow why that is better. If I’m building from a clone of a git
repo why wouldn’t I want the git hash?
> 
> Therefore we check if last commit contains git-svn-id: and if so we extract
SVN
> revision and repo URL. Otherwise we fallback to Git hash and URL.
This means that from build to build, depending on whether a Git change or SVN
change is the most recent on my branch, I will get different results. That seems
problematic.
> 
> Calls to sed and grep conform to POSIX standard (no extended RE).
> ---
> utils/GetRepositoryPath | 2 ++
> utils/GetSourceVersion  | 2 ++
> 2 files changed, 4 insertions(+)
> 
>
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On 17 Sep 2013, at 18:18, Mark Lacey <mark.lacey at apple.com> wrote:
> This means that from build to build, depending on whether a Git change or
SVN change is the most recent on my branch, I will get different results. That
seems problematic.
If you're not rebasing after pulling in changes from LLVM svn, then
you're going to be in for a world of pain later (I, unfortunately, speak
from experience here).  If you're following a git tree that has any patches
on top of svn ToT then you will see a git commit as the most recent one.  If
you're following svn via git but don't have any local patches, then
you'll get the same build if you did an svn checkout.  If you do git pull
from the git svn mirrors without --rebase then you're already setting
yourself up for so many problems that nothing we do can really help you...

David