Re: [PATCH v5 09/11] commit-graph: use generation v2 only if entire chain does

> On Tue, Dec 29, 2020 at 10:23:54PM -0500, Derrick Stolee wrote:
>> Your tests in this patch seem very thorough, covering all the cases
>> I could think to create this strange situation. I even tried creating
>> cases where the overflow would be necessary. The following test actually
>> fails on the "graph_read_expect 6" due to the extra chunk, not the 'write'
>> process I was trying to trick into failure.
>>
>> diff --git a/t/t5324-split-commit-graph.sh b/t/t5324-split-commit-graph.sh
>> index 8e90f3423b..cfef8e52b9 100755
>> --- a/t/t5324-split-commit-graph.sh
>> +++ b/t/t5324-split-commit-graph.sh
>> @@ -453,6 +453,20 @@ test_expect_success 'prevent regression for duplicate commits across layers' '
>>         git -C dup commit-graph verify
>>  '
>>  
>> +test_expect_success 'upgrade to generation data succeeds when there was none' '
>> +	(
>> +		cd dup &&
>> +		rm -rf .git/objects/info/commit-graph* &&
>> +		GIT_TEST_COMMIT_GRAPH_NO_GDAT=1 git commit-graph \
>> +			write --reachable &&
>> +		GIT_COMMITTER_DATE="1980-01-01 00:00" git commit --allow-empty -m one &&
>> +		GIT_COMMITTER_DATE="2090-01-01 00:00" git commit --allow-empty -m two &&
>> +		GIT_COMMITTER_DATE="2000-01-01 00:00" git commit --allow-empty -m three &&
>> +		git commit-graph write --reachable &&
>> +		graph_read_expect 6
>> +	)
>> +'
> 
> I am not sure what this test adds over the existing generation data
> overflow related tests added in t5318-commit-graph.sh