merge-base: add tests for --is-ancestor

[nikolauspschuetz]

Changes since v1, per review:

• Reuse the E---D---C---B---A history and the G/H merges from the
  "set up G and H" test instead of creating a separate repository.
• Add a test that --is-ancestor requires exactly two commits: too few
  is a usage error (exit 129), while more than two is rejected with
  "--is-ancestor takes exactly two commits" (exit 128).

cc: Phillip Wood phillip.wood123@gmail.com

[gitgitgadget]

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[nikolauspschuetz]

/preview

[gitgitgadget]

Error: User nikolauspschuetz is not yet permitted to use GitGitGadget

[Ikke]

/allow

[gitgitgadget]

User nikolauspschuetz is now allowed to use GitGitGadget.

[nikolauspschuetz]

/preview

[gitgitgadget]

Preview email sent as pull.2186.git.1784958204570.gitgitgadget@gmail.com

[nikolauspschuetz]

/submit

[gitgitgadget]

Submitted as pull.2186.git.1784998828879.gitgitgadget@gmail.com

To fetch this version into FETCH_HEAD:

git fetch https://github.com/gitgitgadget/git/ pr-2186/nikolauspschuetz/t6010-test-is-ancestor-v1

To fetch this version to local tag pr-2186/nikolauspschuetz/t6010-test-is-ancestor-v1:

git fetch --no-tags https://github.com/gitgitgadget/git/ tag pr-2186/nikolauspschuetz/t6010-test-is-ancestor-v1

[gitgitgadget]

Junio C Hamano wrote on the Git mailing list (how to reply to this email):

"Nikolaus Schuetz via GitGitGadget" <gitgitgadget@gmail.com> writes:

> From: Nikolaus Schuetz <nikolauspschuetz@gmail.com>
>
> `git merge-base --is-ancestor A B` is used a lot in scripts but has no
> tests. Add some to t6010 covering its exit codes: 0 when A is an
> ancestor of B, 1 when it is not, and 128 (not 1) when given a bad
> argument. Also check that --is-ancestor and --all can't be combined,
> and that the resulting error names both options.
>
> Signed-off-by: Nikolaus Schuetz <nikolauspschuetz@gmail.com>
> ---
>     merge-base: add tests for --is-ancestor
>
> Published-As: https://github.com/gitgitgadget/git/releases/tag/pr-2186%2Fnikolauspschuetz%2Ft6010-test-is-ancestor-v1
> Fetch-It-Via: git fetch https://github.com/gitgitgadget/git pr-2186/nikolauspschuetz/t6010-test-is-ancestor-v1
> Pull-Request: https://github.com/gitgitgadget/git/pull/2186
>
>  t/t6010-merge-base.sh | 34 ++++++++++++++++++++++++++++++++++
>  1 file changed, 34 insertions(+)

Thanks, will queue.

>
> diff --git a/t/t6010-merge-base.sh b/t/t6010-merge-base.sh
> index 44c726ea39..d28d9dab2c 100755
> --- a/t/t6010-merge-base.sh
> +++ b/t/t6010-merge-base.sh
> @@ -305,4 +305,38 @@ test_expect_success 'merge-base --octopus --all for complex tree' '
>  	test_cmp expected actual
>  '
>  
> +test_expect_success 'setup --is-ancestor' '
> +	git init is-ancestor &&
> +	(
> +		cd is-ancestor &&
> +		test_commit one &&
> +		test_commit two &&
> +		git checkout -b side one &&
> +		test_commit three
> +	)
> +'
> +
> +test_expect_success '--is-ancestor parent and child' '
> +	git -C is-ancestor merge-base --is-ancestor one two &&
> +	test_expect_code 1 git -C is-ancestor merge-base --is-ancestor two one
> +'
> +
> +test_expect_success '--is-ancestor self' '
> +	git -C is-ancestor merge-base --is-ancestor two two
> +'
> +
> +test_expect_success '--is-ancestor diverged commits' '
> +	test_expect_code 1 git -C is-ancestor merge-base --is-ancestor three two
> +'
> +
> +test_expect_success '--is-ancestor exit 128 non-existent commit' '
> +	test_expect_code 128 git -C is-ancestor merge-base --is-ancestor one no-such-commit &&
> +	test_expect_code 128 git -C is-ancestor merge-base --is-ancestor no-such-commit one
> +'
> +
> +test_expect_success '--is-ancestor and --all cannot be used together' '
> +	test_expect_code 128 git -C is-ancestor merge-base --is-ancestor --all one two 2>err &&
> +	test_grep "options .--is-ancestor. and .--all. cannot be used together" err
> +'
> +
>  test_done
>
> base-commit: f60db8d575adb79761d363e026fb49bddf330c73

[gitgitgadget]

Phillip Wood wrote on the Git mailing list (how to reply to this email):

Hi Nikolaus

On 25/07/2026 18:00, Nikolaus Schuetz via GitGitGadget wrote:
> From: Nikolaus Schuetz <nikolauspschuetz@gmail.com>
> > `git merge-base --is-ancestor A B` is used a lot in scripts but has no
> tests. Add some to t6010 covering its exit codes: 0 when A is an
> ancestor of B, 1 when it is not, and 128 (not 1) when given a bad
> argument. Also check that --is-ancestor and --all can't be combined,
> and that the resulting error names both options.

Thanks for adding some tests for this option

> diff --git a/t/t6010-merge-base.sh b/t/t6010-merge-base.sh
> index 44c726ea39..d28d9dab2c 100755
> --- a/t/t6010-merge-base.sh
> +++ b/t/t6010-merge-base.sh
> @@ -305,4 +305,38 @@ test_expect_success 'merge-base --octopus --all for complex tree' '
>   	test_cmp expected actual
>   '
>   > +test_expect_success 'setup --is-ancestor' '
> +	git init is-ancestor &&
> +	(
> +		cd is-ancestor &&
> +		test_commit one &&
> +		test_commit two &&
> +		git checkout -b side one &&
> +		test_commit three
> +	)
> +'

Do we really need to create a new repository? None of the existing tests do that - can't we just use the commits created by the first test? Having said that, the tests below look good. We could perhaps have a test to check that it fails with one commit or three commits but what you have here is clearly a very useful improvement in our test coverage.

Thanks

Phillip

> +test_expect_success '--is-ancestor parent and child' '
> +	git -C is-ancestor merge-base --is-ancestor one two &&
> +	test_expect_code 1 git -C is-ancestor merge-base --is-ancestor two one
> +'
> +
> +test_expect_success '--is-ancestor self' '
> +	git -C is-ancestor merge-base --is-ancestor two two
> +'
> +
> +test_expect_success '--is-ancestor diverged commits' '
> +	test_expect_code 1 git -C is-ancestor merge-base --is-ancestor three two
> +'
> +
> +test_expect_success '--is-ancestor exit 128 non-existent commit' '
> +	test_expect_code 128 git -C is-ancestor merge-base --is-ancestor one no-such-commit &&
> +	test_expect_code 128 git -C is-ancestor merge-base --is-ancestor no-such-commit one
> +'
> +
> +test_expect_success '--is-ancestor and --all cannot be used together' '
> +	test_expect_code 128 git -C is-ancestor merge-base --is-ancestor --all one two 2>err &&
> +	test_grep "options .--is-ancestor. and .--all. cannot be used together" err
> +'
> +
>   test_done
> > base-commit: f60db8d575adb79761d363e026fb49bddf330c73

[gitgitgadget]

User Phillip Wood <phillip.wood123@gmail.com> has been added to the cc: list.

[gitgitgadget]

Junio C Hamano wrote on the Git mailing list (how to reply to this email):

Phillip Wood <phillip.wood123@gmail.com> writes:

> Thanks for adding some tests for this option
>
>> diff --git a/t/t6010-merge-base.sh b/t/t6010-merge-base.sh
>> index 44c726ea39..d28d9dab2c 100755
>> --- a/t/t6010-merge-base.sh
>> +++ b/t/t6010-merge-base.sh
>> @@ -305,4 +305,38 @@ test_expect_success 'merge-base --octopus --all for complex tree' '
>>   	test_cmp expected actual
>>   '
>>   
>> +test_expect_success 'setup --is-ancestor' '
>> +	git init is-ancestor &&
>> +	(
>> +		cd is-ancestor &&
>> +		test_commit one &&
>> +		test_commit two &&
>> +		git checkout -b side one &&
>> +		test_commit three
>> +	)
>> +'
>
> Do we really need to create a new repository? None of the existing tests 
> do that - can't we just use the commits created by the first test? 

Good point.  It is often a lot more work to do so when writing these
new tests, and I suspect that is the reason why this new repository
was created, but I do not know whether, in the long run, it is
cheaper and more maintainable to reuse the test history that has been
used by all existing tests above.  The next developer who needs to
tweak the first test has 5 (the number of tests below) extra
constraints if we go that route, but a separate setup means the two
sets of tests are more isolated.

> Having said that, the tests below look good. We could perhaps have a 
> test to check that it fails with one commit or three commits but what 
> you have here is clearly a very useful improvement in our test coverage.

Thanks.

[gitgitgadget]

This patch series was integrated into seen via git@5d1d3ed.

[nikolauspschuetz]

/submit

[gitgitgadget]

Submitted as pull.2186.v2.git.1785392350660.gitgitgadget@gmail.com

To fetch this version into FETCH_HEAD:

git fetch https://github.com/gitgitgadget/git/ pr-2186/nikolauspschuetz/t6010-test-is-ancestor-v2

To fetch this version to local tag pr-2186/nikolauspschuetz/t6010-test-is-ancestor-v2:

git fetch --no-tags https://github.com/gitgitgadget/git/ tag pr-2186/nikolauspschuetz/t6010-test-is-ancestor-v2

[gitgitgadget]

Junio C Hamano wrote on the Git mailing list (how to reply to this email):

"Nikolaus Schuetz via GitGitGadget" <gitgitgadget@gmail.com> writes:

>     Changes since v1, per review:
>     
>      * Reuse the E---D---C---B---A history and the G/H merges from the "set
>        up G and H" test instead of creating a separate repository.

Looks good.

>      * Add a test that --is-ancestor requires exactly two commits: too few
>        is a usage error (exit 129), while more than two is rejected with
>        "--is-ancestor takes exactly two commits" (exit 128).

OK.

Will queue.  Thanks.

[gitgitgadget]

This branch is now known as ns/merge-base-is-ancestor-tests.