Re: [PATCH v2 2/2] revision: allow --ancestry-path to take an argument

[Derrick Stolee <derrickstolee@github.com>]

On 8/18/2022 11:50 AM, Ævar Arnfjörð Bjarmason wrote:
> 
> On Thu, Aug 18 2022, Derrick Stolee wrote:
> 
>> On 8/18/2022 2:17 AM, Elijah Newren via GitGitGadget wrote:
>>> +test_expect_success 'rev-list --ancestry-path=F D..M' '
>>> +	test_write_lines E F J L M >expect &&
>>> +	git rev-list --ancestry-path=F --format=%s D..M |
>>> +	sed -e "/^commit /d" |
>>> +	sort >actual &&
>>> +	test_cmp expect actual
>>> +'
>>
>> These tests follow the patterns from other tests in this file, but
>> it also has bad patterns. Specifically, the 'git rev-list' command
>> is fed directly into a pipe. I include a patch below that applies
>> directly on this one to rewrite these tests. If you want, you could
>> rebase to have that test refactor happen before you add your new
>> --ancestry-path=<X> option tests.
> 
> Thanks, I was going to comment on the same, but your solution is much
> better (I was just going to suggest using intermediate files).
> 
>> [...]
>> -test_expect_success 'rev-list --ancestry-path D..M -- M.t' '
>> -	echo M >expect &&
>> -	git rev-list --ancestry-path --format=%s D..M -- M.t |
>> -	sed -e "/^commit /d" >actual &&
>> -	test_cmp expect actual
>> -'
>> +test_ancestry () {
>> +	args=$1
>> +	expected=$2
> 
> Maybe add &&-chaining here (we do it in some cases, but I'm not sure
> when such assignments would ever fail).

These are outside of a test_expect_success, so they are not important.
 
>> +	test_expect_success "rev-list $args" "
>> +		test_write_lines $expected >expect &&
>> +		git rev-list --format=%s $args >raw &&
>> +
>> +		if test -n \"$expected\"
> 
> Aren't you making things harder for yourself here than required by using
> ""-quoting for the body of the test.
> 
> We eval it into existence, so you can use ''-quotes, and then you don't
> need to escape e.g. the "" quotes here for expected, no?

Are "args" and "expected" in-scope if I use single quotes? I don't think
they are unless we export them. I could be wrong.

>> +		then
>> +			sed -e \"/^commit /d\" raw | sort >actual &&
> 
> nit for debuggability (and not correctness), maybe using intermediate
> files here would be nicer? And then perhaps call them "actual" and
> "actual.sorted".

I don't think that level of debuggability is important. We have the
raw file if we want to see what the Git output was.

> 
>> +			test_cmp expect actual || return 1
> 
> No need for a "return 1" here when we're not in a loop. It's redundant,
> and makes the -x output on failure confusing ("why didn't I fail on the
> test_cmp, but on this stray return?...").

Sure. I did this more out of habit, but it makes sense that we don't
need it for an if block.

> ...
> 
>> +		else
>> +			test_must_be_empty raw
> 
> ...which would also allow you to extract much of this if/else at the
> cost of not using test_must_be_empty, i.e. just make the "expected"
> empty unless "$expected" is provided. Just a thought/nit, we could also
> leave this as-is :)

*shrug* either way is fine by me.

> Also does the "compare rev" part of this want test_cmp_rev instead?

I don't know what you mean here. We are not comparing revisions anywhere,
but we are using the commit messages to create an easy comparison for the
output.

Thanks,
-Stolee