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Message-ID: <2a4a15a4-55cd-f98b-4b14-474f24e2c308@huawei.com>
Date:   Thu, 29 Sep 2022 11:09:12 +0100
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Subject: Re: [PATCH] perf tools: Fix empty version number when building
 outside of a git repo
To:     Will Chandler <wfc@wfchandler.org>
CC:     <peterz@infradead.org>, <mingo@redhat.com>, <acme@kernel.org>,
        <mark.rutland@arm.com>, <alexander.shishkin@linux.intel.com>,
        <jolsa@kernel.org>, <namhyung@kernel.org>,
        <linux-perf-users@vger.kernel.org>, <linux-kernel@vger.kernel.org>
References: <20220927195228.47304-1-wfc@wfchandler.org>
 <c5181877-2998-b952-abe6-26d733ae2aeb@huawei.com>
 <87A1F5B6-3F60-4988-8BA6-A993E5789C80@wfchandler.org>
From:   John Garry <john.garry@huawei.com>
In-Reply-To: <87A1F5B6-3F60-4988-8BA6-A993E5789C80@wfchandler.org>
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On 28/09/2022 18:26, Will Chandler wrote:
> On 28 Sep 2022, at 5:21, John Garry wrote:
> 
>> This looks ok. But did you consider going back to same flow as pre-7572733b8499 to avoid a Makefile check, like:
>>
>> ---8<----
>>
>> CID=
>> TAG=
>> if test -d ../../.git -o -f ../../.git
>> then
>> TAG=$(MAKEFLAGS= make -sC ../.. kernelversion)
>> CID=$(git log -1 --abbrev=12 --pretty=format:"%h" 2>/dev/null) && CID="-g$CID"
>> elif test -f ../../PERF-VERSION-FILE
>> then
>> TAG=$(cut -d' ' -f3 ../../PERF-VERSION-FILE | sed -e 's/\"//g')
>> fi
>> if test -z "$TAG"
>> then
>> TAG=$(MAKEFLAGS= make -sC ../.. kernelversion)
>> fi
>>
>> --->8---
>>
>> The evaluation for $TAG is not really needed in the first leg since the fallback does the same thing, but just added for clarity.
> 
> I think that would be fine as well. I don't have a strong opinion on which one
> is easier to follow.
> 
> Looking at this more closely, there is a slight difference between the two
> approaches. In the problem scenario my patch will always use `make kernelversion`,
> while pre-7572733b8499 starts with PERF-VERSION-FILE if available, falling
> back to the Makefile.
> 
> With the old approach PERF-VERSION-FILE could be used to manually
> override the version, but this is inconsistent with how the version is
> generated when building in a git repo. Is this relevant?

Hmmm... maybe someone would want to customise PERF-VERSION-FILE for 
their own distro. Not sure. But then fiddling with PERF-VERSION-FILE 
might break the parsing so...I guess not.

BTW, is there any other method of building the perf code not considered? 
So far I know:
a. in git tree
b. perf-tar-src-pkg
c. tarball

Thanks,
John