[llvm-dev] Distinguishing trunk version number from release

Hal Finkel via llvm-dev
Wed, 03 Jan 2018 21:22:53 -0000

On 01/03/2018 02:55 PM, Tom Stellard via llvm-dev wrote:
> On 01/03/2018 09:24 AM, James Y Knight via llvm-dev wrote:
>> I'd like to propose that trunk always have a version number which
is in between versions used by the previous release branch, and before the
versions used in the next release branch.
>>
>> Right now, trunk is sharing the 7.0.0 number, which will also be used
by the next release 4 months from now. Since some people use and release
snapshots of clang from trunk (e.g. the Android NDK), it'd be helpful to be
able to more reliably distinguish this.
>>
>> This is both confusing in general, and means that if you're writing
an #if checking the version (which of course ought to be avoided when possible,
but is sometimes the best answer), it is more difficult than it needs to be to
do the right thing.
>>
>> E.g., a check like this will erroneously think that trunk, now, is
Clang 7, and has fixed this hypothetical bug.
>> #if __clang_major__ >= 7
>> // Do something which was buggy before Clang 7.
>> #endif
>>
>
>
>> I see a couple alternatives for improving this:
>>
>> 1. Change the way we version trunk.
>>
>> After creating release branch for X.0, change trunk to version X.99
instead of (X+1).0. Thus, trunk would always have a .99 minor release. The
release branch would be incremented from X.99 to (X+1).0 upon creation.
>>
>> 6.99.0-------7.99.0----------------8.99.0------...
>>             \-7.0.0----7.0.1      \-8.0.0----8.0.1
>>
>> 2. Change the minor version of the first release.
>>
>> Leave trunk as X.0 as now, but on the release branch, increment the
version to X.1.
>>
>> 7.0.0--------8.0.0-----------------9.0.0------...
>>             \-7.1.0----7.1.1      \-8.1.0----8.1.1
>>
>> I'd marginally favor #2, because that's similar to how GCC is
doing it now, but what do others think?
>>
>
> These proposed solutions only help distinguish between clang trunk and
> a clang release branch, but does not help to distinguish between
today's
> trunk and a month from now trunk, which people using snapshots might
> care more about.
>
>
> What about adding a define like __clang_svn_revision__ instead?

I think that the best we can do is give people some of idea of "this is
based on a release" vs. "this is based on some other intermediate
version." Testing revision numbers is probably not meaningful because
you never know what other commits have been reverted or back-ported for
a particular build.

  -Hal

>
> -Tom
>
>>
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--
Hal Finkel
Lead, Compiler Technology and Programming Languages
Leadership Computing Facility
Argonne National Laboratory