Subject: Re: [PATCH v3] [GSOC] cherry-pick: use better advice message

From: Junio C Hamano <[email-masked]>
Date: Fri, 13 Aug 2021 13:14:44 -0700

Phillip Wood <[email-masked]> writes:

>> +++ b/t/t3507-cherry-pick-conflict.sh
>> @@ -53,9 +53,12 @@ test_expect_success 'advice from failed cherry-pick' "
>>   	picked=\$(git rev-parse --short picked) &&
>>   	cat <<-EOF >expected &&
>
> If you quote the here doc end marker then there is no substitution in
> the here doc so writing
>
> 	cat <<-\EOF >expected &&
>
>>   	error: could not apply \$picked... picked
>> -	hint: after resolving the conflicts, mark the corrected paths
>> -	hint: with 'git add <paths>' or 'git rm <paths>'
>> -	hint: and commit the result with 'git commit'
>> +	hint: Resolve all conflicts manually, mark them as resolved with
>> +	hint: \"git add/rm <conflicted_files>\", then run
>
> means you can replace \" with " here

Hmph, actually the double-quote that opens the body of
test_expect_success should be stared at with a very cautious eyes,
as they often do not mean what the author of the patch thought they
do.  I can see that it already fooled your eyes into thinking that
there is no substitution, but $picked needs to be substituted into
its value.  The backslash before it is *not* about guarding it from
substitution inside here-doc; it is to pass literal "$" into the
string, which is the last parameter to test_expect_success, that
gets eval'ed.

The original of this one, for example, would probably have been
better if written like so:

test_expect_success 'advice from failed cherry-pick' '
	pristine_detach initial &&
	SQ='\'' &&

	picked=$(git rev-parse --short picked) &&
	cat <<-EOF >expected &&
	error: could not apply $picked... picked
	hint: after resolving the conflicts, mark the corrected paths
	hint: with ${SQ}git add <paths>${SQ} or ${SQ}git rm <paths>${SQ}
	hint: and commit the result with ${SQ}git commit${SQ}
	EOF
	test_must_fail git cherry-pick picked 2>actual &&

	test_cmp expected actual
'

And because there is no single quote in the updated text, it would
become:

test_expect_success 'advice from failed cherry-pick' '
	pristine_detach initial &&

	picked=$(git rev-parse --short picked) &&
	cat <<-EOF >expected &&
	error: could not apply $picked... picked
	hint: Resolve all conflicts manually, mark them as resolved with
	hint: "git add/rm <conflicted_files>", then run
	EOF
	test_must_fail git cherry-pick picked 2>actual &&

	test_cmp expected actual
'

which makes it far easier to see that $picked needs to be
substituted, and the "git add/rm" are to be enclosed in dq pair.