[PATCH] git-am: teach git-am to apply a patch to an unborn branch

[PATCH] git-am: teach git-am to apply a patch to an unborn branch

[Nanako Shiraishi]

People sometimes wonder why they cannot apply a patch that only
creates new files to an unborn branch.

Signed-off-by: Nanako Shiraishi <nanako3@lavabit.com>
---
 git-am.sh     |   29 ++++++++++++++++++++++++-----
 t/t4150-am.sh |   15 +++++++++++++++
 2 files changed, 39 insertions(+), 5 deletions(-)

diff --git a/git-am.sh b/git-am.sh
index d339075..774383f 100755
--- a/git-am.sh
+++ b/git-am.sh
@@ -36,6 +36,13 @@ cd_to_toplevel
 git var GIT_COMMITTER_IDENT >/dev/null ||
 	die "You need to set your committer info first"
 
+if git rev-parse --verify -q HEAD >/dev/null
+then
+	HAS_HEAD=yes
+else
+	HAS_HEAD=
+fi
+
 sq () {
 	for sqarg
 	do
@@ -290,16 +297,26 @@ else
 		: >"$dotest/rebasing"
 	else
 		: >"$dotest/applying"
-		git update-ref ORIG_HEAD HEAD
+		if test -n "$HAS_HEAD"
+		then
+			git update-ref ORIG_HEAD HEAD
+		else
+			git update-ref -d ORIG_HEAD >/dev/null 2>&1
+		fi
 	fi
 fi
 
 case "$resolved" in
 '')
-	files=$(git diff-index --cached --name-only HEAD --) || exit
+	case "$HAS_HEAD" in
+	'')
+		files=$(git ls-files) ;;
+	?*)
+		files=$(git diff-index --cached --name-only HEAD --) ;;
+	esac || exit
 	if test "$files"
 	then
-		: >"$dotest/dirtyindex"
+		test -n "$HAS_HEAD" && : >"$dotest/dirtyindex"
 		die "Dirty index: cannot apply patches (dirty: $files)"
 	fi
 esac
@@ -541,18 +558,20 @@ do
 	fi
 
 	tree=$(git write-tree) &&
-	parent=$(git rev-parse --verify HEAD) &&
 	commit=$(
 		if test -n "$ignore_date"
 		then
 			GIT_AUTHOR_DATE=
 		fi
+		parent=$(git rev-parse --verify -q HEAD) ||
+		echo >&2 "applying to an empty history"
+
 		if test -n "$committer_date_is_author_date"
 		then
 			GIT_COMMITTER_DATE="$GIT_AUTHOR_DATE"
 			export GIT_COMMITTER_DATE
 		fi &&
-		git commit-tree $tree -p $parent <"$dotest/final-commit"
+		git commit-tree $tree ${parent:+-p $parent} <"$dotest/final-commit"
 	) &&
 	git update-ref -m "$GIT_REFLOG_ACTION: $FIRSTLINE" HEAD $commit $parent ||
 	stop_here $this
diff --git a/t/t4150-am.sh b/t/t4150-am.sh
index 5e65afa..b97d102 100755
--- a/t/t4150-am.sh
+++ b/t/t4150-am.sh
@@ -290,4 +290,19 @@ test_expect_success 'am --ignore-date' '
 	echo "$at" | grep "+0000"
 '
 
+test_expect_success 'am into an unborn branch' '
+	rm -fr subdir &&
+	mkdir -p subdir &&
+	git format-patch --numbered-files -o subdir -1 first &&
+	(
+		cd subdir &&
+		git init &&
+		git am 1
+	) &&
+	result=$(
+		cd subdir && git rev-parse HEAD^{tree}
+	) &&
+	test "z$result" = "z$(git rev-parse first^{tree})"
+'
+
 test_done
-- 
1.6.2.2

-- 
Nanako Shiraishi
http://ivory.ap.teacup.com/nanako3/

Re: [PATCH] git-am: teach git-am to apply a patch to an unborn branch

[Junio C Hamano]

Thanks.

[PATCH] git-am: teach git-am to apply a patch to an unborn branch

[Nanako Shiraishi]

Signed-off-by: Nanako Shiraishi <nanako3@lavabit.com>
---
 git-am.sh     |   33 ++++++++++++++++++++++++++++-----
 t/t4150-am.sh |   15 +++++++++++++++
 2 files changed, 43 insertions(+), 5 deletions(-)

diff --git a/git-am.sh b/git-am.sh
index d339075..c21642b 100755
--- a/git-am.sh
+++ b/git-am.sh
@@ -36,6 +36,13 @@ cd_to_toplevel
 git var GIT_COMMITTER_IDENT >/dev/null ||
 	die "You need to set your committer info first"
 
+if git rev-parse --verify -q HEAD >/dev/null
+then
+	HAS_HEAD=yes
+else
+	HAS_HEAD=
+fi
+
 sq () {
 	for sqarg
 	do
@@ -290,16 +297,26 @@ else
 		: >"$dotest/rebasing"
 	else
 		: >"$dotest/applying"
-		git update-ref ORIG_HEAD HEAD
+		if test -n "$HAS_HEAD"
+		then
+			git update-ref ORIG_HEAD HEAD
+		else
+			git update-ref -d ORIG_HEAD >/dev/null 2>&1
+		fi
 	fi
 fi
 
 case "$resolved" in
 '')
-	files=$(git diff-index --cached --name-only HEAD --) || exit
+	if test -n "$HAS_HEAD"
+	then
+		files=$(git diff-index --cached --name-only HEAD --)
+	else
+		files=$(git ls-files)
+	fi || exit
 	if test "$files"
 	then
-		: >"$dotest/dirtyindex"
+		test -n "$HAS_HEAD" && : >"$dotest/dirtyindex"
 		die "Dirty index: cannot apply patches (dirty: $files)"
 	fi
 esac
@@ -541,7 +558,13 @@ do
 	fi
 
 	tree=$(git write-tree) &&
-	parent=$(git rev-parse --verify HEAD) &&
+	if parent=$(git rev-parse --verify -q HEAD)
+	then
+		pparent="-p $parent"
+	else
+		echo >&2 "applying to an empty history"
+		parent= pparent=
+	fi &&
 	commit=$(
 		if test -n "$ignore_date"
 		then
@@ -552,7 +575,7 @@ do
 			GIT_COMMITTER_DATE="$GIT_AUTHOR_DATE"
 			export GIT_COMMITTER_DATE
 		fi &&
-		git commit-tree $tree -p $parent <"$dotest/final-commit"
+		git commit-tree $tree $pparent <"$dotest/final-commit"
 	) &&
 	git update-ref -m "$GIT_REFLOG_ACTION: $FIRSTLINE" HEAD $commit $parent ||
 	stop_here $this
diff --git a/t/t4150-am.sh b/t/t4150-am.sh
index 5e65afa..b97d102 100755
--- a/t/t4150-am.sh
+++ b/t/t4150-am.sh
@@ -290,4 +290,19 @@ test_expect_success 'am --ignore-date' '
 	echo "$at" | grep "+0000"
 '
 
+test_expect_success 'am in an unborn branch' '
+	rm -fr subdir &&
+	mkdir -p subdir &&
+	git format-patch --numbered-files -o subdir -1 first &&
+	(
+		cd subdir &&
+		git init &&
+		git am 1
+	) &&
+	result=$(
+		cd subdir && git rev-parse HEAD^{tree}
+	) &&
+	test "z$result" = "z$(git rev-parse first^{tree})"
+'
+
 test_done
-- 
1.6.2.1

-- 
Nanako Shiraishi
http://ivory.ap.teacup.com/nanako3/

Re: [PATCH] git-am: teach git-am to apply a patch to an unborn branch

[Junio C Hamano]

Nanako Shiraishi <nanako3@lavabit.com> writes:

> Signed-off-by: Nanako Shiraishi <nanako3@lavabit.com>
> ---
>  git-am.sh     |   33 ++++++++++++++++++++++++++++-----
>  t/t4150-am.sh |   15 +++++++++++++++
>  2 files changed, 43 insertions(+), 5 deletions(-)
>
> diff --git a/git-am.sh b/git-am.sh
> index d339075..c21642b 100755
> --- a/git-am.sh
> +++ b/git-am.sh
> @@ -36,6 +36,13 @@ cd_to_toplevel
>  git var GIT_COMMITTER_IDENT >/dev/null ||
>  	die "You need to set your committer info first"
>  
> +if git rev-parse --verify -q HEAD >/dev/null
> +then
> +	HAS_HEAD=yes
> +else
> +	HAS_HEAD=
> +fi
> +

Probably nicer this way than Peff's as I suspect we would need to special
case the unborn-branch case a lot more.  Have you tried --skip and --abort
codepaths with your patch?

>  sq () {
>  	for sqarg
>  	do
> @@ -290,16 +297,26 @@ else
>  		: >"$dotest/rebasing"
>  	else
>  		: >"$dotest/applying"
> -		git update-ref ORIG_HEAD HEAD
> +		if test -n "$HAS_HEAD"
> +		then
> +			git update-ref ORIG_HEAD HEAD
> +		else
> +			git update-ref -d ORIG_HEAD >/dev/null 2>&1
> +		fi

So is this part.

>  	fi
>  fi
>  
>  case "$resolved" in
>  '')
> -	files=$(git diff-index --cached --name-only HEAD --) || exit
> +	if test -n "$HAS_HEAD"
> +	then
> +		files=$(git diff-index --cached --name-only HEAD --)
> +	else
> +		files=$(git ls-files)
> +	fi || exit
>  	if test "$files"
>  	then
> -		: >"$dotest/dirtyindex"
> +		test -n "$HAS_HEAD" && : >"$dotest/dirtyindex"
>  		die "Dirty index: cannot apply patches (dirty: $files)"
>  	fi
>  esac

And here...

> @@ -541,7 +558,13 @@ do
>  	fi
>  
>  	tree=$(git write-tree) &&
> -	parent=$(git rev-parse --verify HEAD) &&
> +	if parent=$(git rev-parse --verify -q HEAD)
> +	then
> +		pparent="-p $parent"
> +	else
> +		echo >&2 "applying to an empty history"
> +		parent= pparent=
> +	fi &&
>  	commit=$(
>  		if test -n "$ignore_date"
>  		then
> @@ -552,7 +575,7 @@ do
>  			GIT_COMMITTER_DATE="$GIT_AUTHOR_DATE"
>  			export GIT_COMMITTER_DATE
>  		fi &&
> -		git commit-tree $tree -p $parent <"$dotest/final-commit"
> +		git commit-tree $tree $pparent <"$dotest/final-commit"

Peff's ${a+something $a} trick looks more "expert" here ;-).

> diff --git a/t/t4150-am.sh b/t/t4150-am.sh
> index 5e65afa..b97d102 100755
> --- a/t/t4150-am.sh
> +++ b/t/t4150-am.sh
> @@ -290,4 +290,19 @@ test_expect_success 'am --ignore-date' '
>  	echo "$at" | grep "+0000"
>  '
>  
> +test_expect_success 'am in an unborn branch' '
> +	rm -fr subdir &&
> +	mkdir -p subdir &&
> +	git format-patch --numbered-files -o subdir -1 first &&
> +	(
> +		cd subdir &&
> +		git init &&
> +		git am 1
> +	) &&
> +	result=$(
> +		cd subdir && git rev-parse HEAD^{tree}
> +	) &&
> +	test "z$result" = "z$(git rev-parse first^{tree})"
> +'
> +

Looks good.

Re: [PATCH] git-am: teach git-am to apply a patch to an unborn branch

[Jeff King]

On Fri, Mar 20, 2009 at 07:12:31AM +0900, Nanako Shiraishi wrote:

> Signed-off-by: Nanako Shiraishi <nanako3@lavabit.com>

Thanks for picking up this topic. It looks sane overall.

> -	parent=$(git rev-parse --verify HEAD) &&
> +	if parent=$(git rev-parse --verify -q HEAD)
> +	then
> +		pparent="-p $parent"
> +	else
> +		echo >&2 "applying to an empty history"
> +		parent= pparent=
> +	fi &&

Note that the '&&' here is now pointless, since one side of the
conditional will always be true. We are losing the ability to detect
errors besides "HEAD does not point to a valid object", but I don't
think there is a way to tell the difference from the exit code of
rev-parse.

-Peff