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Re: [Question] .git folder file updates for changing head commit

From
JGJohn Garry <john.garry@huawei.com>
Date
Mar 24, 2022, 12:56 UTC
Message-ID
<f80bac33-7864-8f31-d81f-78cf7cb2987d@huawei.com>
In-Reply-To
<YjuCSpAHD6xHkb5G@nand.local>
On 23/03/2022 20:25, Taylor Blau wrote:
Show 9 quoted lines
> On Wed, Mar 23, 2022 at 03:19:06PM +0000, John Garry wrote:
>> For building the linux perf tool we use the git head commit id as part of
>> the tool version sting. To save time in re-building, the Makefile rule has a
>> dependency on .git/HEAD for rebuilding. An alternative approach would be to
>> compare git log output to check current versus previous build head commit,
>> but that is seen as inefficient time-wise.
> Having a Makefile recipe that depends on $GIT_DIR/HEAD seems strange to
> me.
>

Yeah, as mentioned, the idea was the we can check a rebuild on this rather than running a relatively time-consuming command like "git describe". Wasn't my idea :)

> Presumably your Makefile rules would map out which parts of your program
> depend on each other, and would get invalidated when the source itself
> changes, no?

Correct, they do. It's just the part which constructs the app version tag which depends on this.

Show 6 quoted lines
> 
> Perhaps you also care about the commit you're building from in order to
> embed something into your program. But it seems like you could inject
> the output of "git rev-parse HEAD" when you construct the version
> identifier whenever you do need to rebuild.
>

ok, so I think that we may need to run a git command always one way or another.

Thanks, John

Previous: Taylor BlauNext: Ævar Arnfjörð Bjarmason
Message 3 of 9 in “[Question] .git folder file updates for changing head commit”
  1. John GarryMar 23, 2022
  2. Taylor BlauMar 23, 2022
  3. John GarryMar 24, 2022
  4. Ævar Arnfjörð BjarmasonMar 27, 2022
  5. John GarryMar 30, 2022
  6. Glen ChooMar 23, 2022
  7. John GarryMar 24, 2022
  8. Andreas SchwabMar 23, 2022
  9. John GarryMar 24, 2022

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