diff mbox series

[v2] merge-ll: expose revision names to custom drivers

Message ID pull.1648.v2.git.git.1705592581272.gitgitgadget@gmail.com (mailing list archive)
State Superseded
Headers show
Series [v2] merge-ll: expose revision names to custom drivers | expand

Commit Message

Antonin Delpeuch Jan. 18, 2024, 3:43 p.m. UTC
From: Antonin Delpeuch <antonin@delpeuch.eu>

Custom merge drivers need access to the names of the revisions they
are working on, so that the merge conflict markers they introduce
can refer to those revisions. The placeholders '%S', '%X' and '%Y'
are introduced to this end.

Signed-off-by: Antonin Delpeuch <antonin@delpeuch.eu>
---
    merge-ll: expose revision names to custom drivers

Published-As: https://github.com/gitgitgadget/git/releases/tag/pr-git-1648%2Fwetneb%2Fmerge_driver_pathnames-v2
Fetch-It-Via: git fetch https://github.com/gitgitgadget/git pr-git-1648/wetneb/merge_driver_pathnames-v2
Pull-Request: https://github.com/git/git/pull/1648

Range-diff vs v1:

 1:  e648f9f0696 ! 1:  6dec70529c0 merge-ll: expose revision names to custom drivers
     @@ Commit message
          can refer to those revisions. The placeholders '%S', '%X' and '%Y'
          are introduced to this end.
      
     -    CC: Junio C Hamano <gitster@pobox.com>
     -
          Signed-off-by: Antonin Delpeuch <antonin@delpeuch.eu>
      
       ## Documentation/gitattributes.txt ##


 Documentation/gitattributes.txt | 10 +++++++---
 merge-ll.c                      | 17 ++++++++++++++---
 t/t6406-merge-attr.sh           | 16 +++++++++++-----
 3 files changed, 32 insertions(+), 11 deletions(-)


base-commit: 186b115d3062e6230ee296d1ddaa0c4b72a464b5

Comments

Junio C Hamano Jan. 18, 2024, 8:16 p.m. UTC | #1
"Antonin Delpeuch via GitGitGadget" <gitgitgadget@gmail.com> writes:

> From: Antonin Delpeuch <antonin@delpeuch.eu>
>
> Custom merge drivers need access to the names of the revisions they
> are working on, so that the merge conflict markers they introduce
> can refer to those revisions. The placeholders '%S', '%X' and '%Y'
> are introduced to this end.
>
> Signed-off-by: Antonin Delpeuch <antonin@delpeuch.eu>
> ---
>     merge-ll: expose revision names to custom drivers
>
>  Documentation/gitattributes.txt | 10 +++++++---
>  merge-ll.c                      | 17 ++++++++++++++---
>  t/t6406-merge-attr.sh           | 16 +++++++++++-----
>  3 files changed, 32 insertions(+), 11 deletions(-)
>
> diff --git a/Documentation/gitattributes.txt b/Documentation/gitattributes.txt
> index 201bdf5edbd..108c2e23baa 100644
> --- a/Documentation/gitattributes.txt
> +++ b/Documentation/gitattributes.txt
> @@ -1141,7 +1141,7 @@ command to run to merge ancestor's version (`%O`), current
>  version (`%A`) and the other branches' version (`%B`).  These
>  three tokens are replaced with the names of temporary files that
>  hold the contents of these versions when the command line is
> -built. Additionally, %L will be replaced with the conflict marker
> +built. Additionally, `%L` will be replaced with the conflict marker
>  size (see below).

Good eyes.  Nice to fix it while we are in the vicinity.

> @@ -1159,8 +1159,12 @@ When left unspecified, the driver itself is used for both
>  internal merge and the final merge.
>  
>  The merge driver can learn the pathname in which the merged result
> -will be stored via placeholder `%P`.
> -
> +will be stored via placeholder `%P`. Additionally, the names of the
> +merge ancestor revision (`%S`), of the current revision (`%X`) and

The phrase already existsin the description of '%O', but the correct
word for that is "the common ancestor", not "the merge ancestor".
At least this one is consistent with the existing error, so we can
fix them together in a clean-up patch after the dust settles.  

Or you could fix %O's description "while at it" and use the right
term from the get-go for %S.

> diff --git a/merge-ll.c b/merge-ll.c
> index 1df58ebaac0..ae9eb69be14 100644
> --- a/merge-ll.c
> +++ b/merge-ll.c
> @@ -185,9 +185,9 @@ static void create_temp(mmfile_t *src, char *path, size_t len)
>  static enum ll_merge_result ll_ext_merge(const struct ll_merge_driver *fn,
>  			mmbuffer_t *result,
>  			const char *path,
> -			mmfile_t *orig, const char *orig_name UNUSED,
> -			mmfile_t *src1, const char *name1 UNUSED,
> -			mmfile_t *src2, const char *name2 UNUSED,
> +			mmfile_t *orig, const char *orig_name,
> +			mmfile_t *src1, const char *name1,
> +			mmfile_t *src2, const char *name2,
>  			const struct ll_merge_options *opts,
>  			int marker_size)
>  {
> @@ -222,6 +222,12 @@ static enum ll_merge_result ll_ext_merge(const struct ll_merge_driver *fn,
>  			strbuf_addf(&cmd, "%d", marker_size);
>  		else if (skip_prefix(format, "P", &format))
>  			sq_quote_buf(&cmd, path);
> +		else if (skip_prefix(format, "S", &format))
> +		    sq_quote_buf(&cmd, orig_name);
> +		else if (skip_prefix(format, "X", &format))
> +			sq_quote_buf(&cmd, name1);
> +		else if (skip_prefix(format, "Y", &format))
> +			sq_quote_buf(&cmd, name2);
>  		else
>  			strbuf_addch(&cmd, '%');
>  	}

I see some funny indentation for "S" here.

> diff --git a/t/t6406-merge-attr.sh b/t/t6406-merge-attr.sh
> index 72f8c1722ff..156a1efacfe 100755
> --- a/t/t6406-merge-attr.sh
> +++ b/t/t6406-merge-attr.sh
> @@ -42,11 +42,15 @@ test_expect_success setup '
>  	#!/bin/sh
>  
>  	orig="$1" ours="$2" theirs="$3" exit="$4" path=$5
> +	orig_name="$6" our_name="$7" their_name="$8"
>  	(
>  		echo "orig is $orig"
>  		echo "ours is $ours"
>  		echo "theirs is $theirs"
>  		echo "path is $path"
> +		echo "orig_name is $orig_name"
> +		echo "our_name is $our_name"
> +		echo "their_name is $their_name"
>  		echo "=== orig ==="
>  		cat "$orig"
>  		echo "=== ours ==="
> @@ -121,7 +125,7 @@ test_expect_success 'custom merge backend' '
>  
>  	git reset --hard anchor &&
>  	git config --replace-all \
> -	merge.custom.driver "./custom-merge %O %A %B 0 %P" &&
> +	merge.custom.driver "./custom-merge %O %A %B 0 %P %S %X %Y" &&
>  	git config --replace-all \
>  	merge.custom.name "custom merge driver for testing" &&
>  
> @@ -132,7 +136,8 @@ test_expect_success 'custom merge backend' '
>  	o=$(git unpack-file main^:text) &&
>  	a=$(git unpack-file side^:text) &&
>  	b=$(git unpack-file main:text) &&
> -	sh -c "./custom-merge $o $a $b 0 text" &&
> +	base_revid=$(git rev-parse --short main^) &&
> +	sh -c "./custom-merge $o $a $b 0 text $base_revid HEAD main" &&
>  	sed -e 1,3d $a >check-2 &&
>  	cmp check-1 check-2 &&
>  	rm -f $o $a $b

OK.

> @@ -142,7 +147,7 @@ test_expect_success 'custom merge backend' '
>  
>  	git reset --hard anchor &&
>  	git config --replace-all \
> -	merge.custom.driver "./custom-merge %O %A %B 1 %P" &&
> +	merge.custom.driver "./custom-merge %O %A %B 1 %P %S %X %Y" &&
>  	git config --replace-all \
>  	merge.custom.name "custom merge driver for testing" &&
>  
> @@ -159,7 +164,8 @@ test_expect_success 'custom merge backend' '
>  	o=$(git unpack-file main^:text) &&
>  	a=$(git unpack-file anchor:text) &&
>  	b=$(git unpack-file main:text) &&
> -	sh -c "./custom-merge $o $a $b 0 text" &&
> +	base_revid=$(git rev-parse --short main^) &&
> +	sh -c "./custom-merge $o $a $b 0 text $base_revid HEAD main" &&
>  	sed -e 1,3d $a >check-2 &&
>  	cmp check-1 check-2 &&
>  	sed -e 1,3d -e 4q $a >check-3 &&

OK.

> @@ -173,7 +179,7 @@ test_expect_success !WINDOWS 'custom merge driver that is killed with a signal'
>  
>  	git reset --hard anchor &&
>  	git config --replace-all \
> -	merge.custom.driver "./custom-merge %O %A %B 0 %P" &&
> +	merge.custom.driver "./custom-merge %O %A %B 0 %P %S %X %Y" &&
>  	git config --replace-all \
>  	merge.custom.name "custom merge driver for testing" &&

;-)

This one is expected to die and not produce meaningful output;
I was wondering why this does not need to make corresponding changes
to the expected output pattern like the earlier tests.
Antonin Delpeuch Jan. 18, 2024, 8:56 p.m. UTC | #2
Hi Junio,

Thanks a lot for your review! (and many apologies for the double sending 
as HTML…)

On 18/01/2024 21:16, Junio C Hamano wrote:
> Or you could fix %O's description "while at it" and use the right
> term from the get-go for %S.
Agreed, I'll do that, it also feels more fitting to me.
> I see some funny indentation for "S" here.
Oops, sorry about that.
>> @@ -173,7 +179,7 @@ test_expect_success !WINDOWS 'custom merge driver that is killed with a signal'
>>   
>>   	git reset --hard anchor &&
>>   	git config --replace-all \
>> -	merge.custom.driver "./custom-merge %O %A %B 0 %P" &&
>> +	merge.custom.driver "./custom-merge %O %A %B 0 %P %S %X %Y" &&
>>   	git config --replace-all \
>>   	merge.custom.name "custom merge driver for testing" &&
> ;-)
>
> This one is expected to die and not produce meaningful output;
> I was wondering why this does not need to make corresponding changes
> to the expected output pattern like the earlier tests.

As far as I can tell, this test does not compare the result of the merge 
to the expected merge driver output, because that output is expected to 
be disregarded by git given that the merge driver died (see the last two 
lines). So it seems normal to me that we don't need to adapt the 
expected output: the repository files are still left unchanged.

I'll submit a new version of the patch with the two changes above.

Antonin
diff mbox series

Patch

diff --git a/Documentation/gitattributes.txt b/Documentation/gitattributes.txt
index 201bdf5edbd..108c2e23baa 100644
--- a/Documentation/gitattributes.txt
+++ b/Documentation/gitattributes.txt
@@ -1141,7 +1141,7 @@  command to run to merge ancestor's version (`%O`), current
 version (`%A`) and the other branches' version (`%B`).  These
 three tokens are replaced with the names of temporary files that
 hold the contents of these versions when the command line is
-built. Additionally, %L will be replaced with the conflict marker
+built. Additionally, `%L` will be replaced with the conflict marker
 size (see below).
 
 The merge driver is expected to leave the result of the merge in
@@ -1159,8 +1159,12 @@  When left unspecified, the driver itself is used for both
 internal merge and the final merge.
 
 The merge driver can learn the pathname in which the merged result
-will be stored via placeholder `%P`.
-
+will be stored via placeholder `%P`. Additionally, the names of the
+merge ancestor revision (`%S`), of the current revision (`%X`) and
+of the other branch (`%Y`) can also be supplied. Those are short
+revision names, optionally joined with the paths of the file in each
+revision. Those paths are only present if they differ and are separated
+from the revision by a colon.
 
 `conflict-marker-size`
 ^^^^^^^^^^^^^^^^^^^^^^
diff --git a/merge-ll.c b/merge-ll.c
index 1df58ebaac0..ae9eb69be14 100644
--- a/merge-ll.c
+++ b/merge-ll.c
@@ -185,9 +185,9 @@  static void create_temp(mmfile_t *src, char *path, size_t len)
 static enum ll_merge_result ll_ext_merge(const struct ll_merge_driver *fn,
 			mmbuffer_t *result,
 			const char *path,
-			mmfile_t *orig, const char *orig_name UNUSED,
-			mmfile_t *src1, const char *name1 UNUSED,
-			mmfile_t *src2, const char *name2 UNUSED,
+			mmfile_t *orig, const char *orig_name,
+			mmfile_t *src1, const char *name1,
+			mmfile_t *src2, const char *name2,
 			const struct ll_merge_options *opts,
 			int marker_size)
 {
@@ -222,6 +222,12 @@  static enum ll_merge_result ll_ext_merge(const struct ll_merge_driver *fn,
 			strbuf_addf(&cmd, "%d", marker_size);
 		else if (skip_prefix(format, "P", &format))
 			sq_quote_buf(&cmd, path);
+		else if (skip_prefix(format, "S", &format))
+		    sq_quote_buf(&cmd, orig_name);
+		else if (skip_prefix(format, "X", &format))
+			sq_quote_buf(&cmd, name1);
+		else if (skip_prefix(format, "Y", &format))
+			sq_quote_buf(&cmd, name2);
 		else
 			strbuf_addch(&cmd, '%');
 	}
@@ -315,7 +321,12 @@  static int read_merge_config(const char *var, const char *value,
 		 *    %B - temporary file name for the other branches' version.
 		 *    %L - conflict marker length
 		 *    %P - the original path (safely quoted for the shell)
+		 *    %S - the revision for the merge base
+		 *    %X - the revision for our version
+		 *    %Y - the revision for their version
 		 *
+		 * If the file is not named indentically in all versions, then each
+		 * revision is joined with the corresponding path, separated by a colon.
 		 * The external merge driver should write the results in the
 		 * file named by %A, and signal that it has done with zero exit
 		 * status.
diff --git a/t/t6406-merge-attr.sh b/t/t6406-merge-attr.sh
index 72f8c1722ff..156a1efacfe 100755
--- a/t/t6406-merge-attr.sh
+++ b/t/t6406-merge-attr.sh
@@ -42,11 +42,15 @@  test_expect_success setup '
 	#!/bin/sh
 
 	orig="$1" ours="$2" theirs="$3" exit="$4" path=$5
+	orig_name="$6" our_name="$7" their_name="$8"
 	(
 		echo "orig is $orig"
 		echo "ours is $ours"
 		echo "theirs is $theirs"
 		echo "path is $path"
+		echo "orig_name is $orig_name"
+		echo "our_name is $our_name"
+		echo "their_name is $their_name"
 		echo "=== orig ==="
 		cat "$orig"
 		echo "=== ours ==="
@@ -121,7 +125,7 @@  test_expect_success 'custom merge backend' '
 
 	git reset --hard anchor &&
 	git config --replace-all \
-	merge.custom.driver "./custom-merge %O %A %B 0 %P" &&
+	merge.custom.driver "./custom-merge %O %A %B 0 %P %S %X %Y" &&
 	git config --replace-all \
 	merge.custom.name "custom merge driver for testing" &&
 
@@ -132,7 +136,8 @@  test_expect_success 'custom merge backend' '
 	o=$(git unpack-file main^:text) &&
 	a=$(git unpack-file side^:text) &&
 	b=$(git unpack-file main:text) &&
-	sh -c "./custom-merge $o $a $b 0 text" &&
+	base_revid=$(git rev-parse --short main^) &&
+	sh -c "./custom-merge $o $a $b 0 text $base_revid HEAD main" &&
 	sed -e 1,3d $a >check-2 &&
 	cmp check-1 check-2 &&
 	rm -f $o $a $b
@@ -142,7 +147,7 @@  test_expect_success 'custom merge backend' '
 
 	git reset --hard anchor &&
 	git config --replace-all \
-	merge.custom.driver "./custom-merge %O %A %B 1 %P" &&
+	merge.custom.driver "./custom-merge %O %A %B 1 %P %S %X %Y" &&
 	git config --replace-all \
 	merge.custom.name "custom merge driver for testing" &&
 
@@ -159,7 +164,8 @@  test_expect_success 'custom merge backend' '
 	o=$(git unpack-file main^:text) &&
 	a=$(git unpack-file anchor:text) &&
 	b=$(git unpack-file main:text) &&
-	sh -c "./custom-merge $o $a $b 0 text" &&
+	base_revid=$(git rev-parse --short main^) &&
+	sh -c "./custom-merge $o $a $b 0 text $base_revid HEAD main" &&
 	sed -e 1,3d $a >check-2 &&
 	cmp check-1 check-2 &&
 	sed -e 1,3d -e 4q $a >check-3 &&
@@ -173,7 +179,7 @@  test_expect_success !WINDOWS 'custom merge driver that is killed with a signal'
 
 	git reset --hard anchor &&
 	git config --replace-all \
-	merge.custom.driver "./custom-merge %O %A %B 0 %P" &&
+	merge.custom.driver "./custom-merge %O %A %B 0 %P %S %X %Y" &&
 	git config --replace-all \
 	merge.custom.name "custom merge driver for testing" &&