[PATCH] git-quiltimport.sh: disallow fuzz

[Jörn Engel]

git-quiltimport passed "-C1" to git-apply, supposedly to roughly match
the quilt default of --fuzz 2. This is against the spirit of git.
Quoting Linus:
Except unlike the standard "patch" program, "git apply" doesn't accept
fuzz by default (which to me is a huge deal - I hate how "patch" tries
to apply stuff that clearly isn't valid any more)

It also causes active harm when combining git-quiltimport with regular
quilt and quilt is used with --fuzz=0, as it should be by any prudent
person.

Signed-off-by: Joern Engel <***@logfs.org>
---
git-quiltimport.sh | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/git-quiltimport.sh b/git-quiltimport.sh
index 167d79fea809..3eb2e2fd3648 100755
--- a/git-quiltimport.sh
+++ b/git-quiltimport.sh
@@ -130,7 +130,7 @@ do
fi

if [ -z "$dry_run" ] ; then
- git apply --index -C1 ${level:+"$level"} "$tmp_patch" &&
+ git apply --index ${level:+"$level"} "$tmp_patch" &&
tree=$(git write-tree) &&
commit=$( (echo "$SUBJECT"; echo; cat "$tmp_msg") | git commit-tree $tree -p $commit) &&
git update-ref -m "quiltimport: $patch_name" HEAD $commit || exit 4

[Junio C Hamano]

git-quiltimport passed "-C1" to git-apply, supposedly to roughly matc=

h

the quilt default of --fuzz 2. This is against the spirit of git.
Except unlike the standard "patch" program, "git apply" doesn't acc=

ept

fuzz by default (which to me is a huge deal - I hate how "patch" tr=

ies

to apply stuff that clearly isn't valid any more)
It also causes active harm when combining git-quiltimport with regula=

r

quilt and quilt is used with --fuzz=3D0,...

This is fine for those who use quilt with --fuzz=3D0, but how are you
helping those who use quilt without --fuzz=3D0?

I agree that unconditionally passing -C1 is a bad thing, but
unconditionally passing -C2 is not that better. Shouldn't this be
done by introducing a new --fuzz=3D<number> option to quiltimport?

---
git-quiltimport.sh | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/git-quiltimport.sh b/git-quiltimport.sh
index 167d79fea809..3eb2e2fd3648 100755
--- a/git-quiltimport.sh
+++ b/git-quiltimport.sh
@@ -130,7 +130,7 @@ do
fi
=20
if [ -z "$dry_run" ] ; then
- git apply --index -C1 ${level:+"$level"} "$tmp_patch" &&
+ git apply --index ${level:+"$level"} "$tmp_patch" &&
tree=3D$(git write-tree) &&
commit=3D$( (echo "$SUBJECT"; echo; cat "$tmp_msg") | git commit-t=

ree $tree -p $commit) &&

git update-ref -m "quiltimport: $patch_name" HEAD $commit || exit =

4

[Jörn Engel]

Post by Junio C Hamano
=20
This is fine for those who use quilt with --fuzz=3D0, but how are you
helping those who use quilt without --fuzz=3D0?
=20
I agree that unconditionally passing -C1 is a bad thing, but
unconditionally passing -C2 is not that better. Shouldn't this be
done by introducing a new --fuzz=3D<number> option to quiltimport?

Maybe the patch below then? Defaulting to no fuzz is both me
enforcing my (and Linus') preference and that alternatives are hard
and messy. How would one specify fuzz=3D0? -C3 would work for standar=
d
patches, but be wrong for patches with more context. -C0 would
arguably also be wrong. There really is no good choice. And I won't
add a fuzz parameter until git-apply has one, as it can only be
transformed to -C by either making assumptions about the context or
parsing the patches - ick!

J=C3=B6rn

--
When I am working on a problem I never think about beauty. I think
only how to solve the problem. But when I have finished, if the
solution is not beautiful, I know it is wrong.
-- R. Buckminster Fuller

Subject: [PATCH] git-quiltimport.sh: disallow fuzz by default

git-quiltimport passed "-C1" to git-apply, supposedly to roughly match
the quilt default of --fuzz 2. This is against the spirit of git.
Quoting Linus:
Except unlike the standard "patch" program, "git apply" doesn't accep=
t
fuzz by default (which to me is a huge deal - I hate how "patch" trie=
s
to apply stuff that clearly isn't valid any more)

Users that want to want to emulate quilt defaults can pass "-C 1" to
git-quiltimport now.

Also note that -C1 and fuzz=3D2 is not identical. Most patches have th=
ree
lines of context, so fuzz=3D2 leaves one relevant line of context. But
for any patches with more or less context this is not true. git-apply
has no option for fuzz, so any emulation will always be best-effort.

Signed-off-by: Joern Engel <***@logfs.org>
---
git-quiltimport.sh | 15 +++++++++++++--
1 file changed, 13 insertions(+), 2 deletions(-)

diff --git a/git-quiltimport.sh b/git-quiltimport.sh
index 167d79fea809..f45ee5ff6599 100755
--- a/git-quiltimport.sh
+++ b/git-quiltimport.sh
@@ -4,8 +4,9 @@ OPTIONS_STUCKLONG=3D
OPTIONS_SPEC=3D"\
git quiltimport [options]
--
-n,dry-run dry run
author=3D author name and email address for patches without any
+C=3D minimum context (see git apply)
+n,dry-run dry run
patches=3D path to the quilt series and patches
"
SUBDIRECTORY_ON=3DYes
@@ -13,6 +14,7 @@ SUBDIRECTORY_ON=3DYes
=20
dry_run=3D""
quilt_author=3D""
+cflag=3D""
while test $# !=3D 0
do
case "$1" in
@@ -20,6 +22,15 @@ do
shift
quilt_author=3D"$1"
;;
+ -C)
+ shift
+ # ensure numerical parameter
+ case $1 in
+ ''|*[!0-9]*) usage;;
+ *) ;;
+ esac
+ cflag=3D"-C$1"
+ ;;
-n|--dry-run)
dry_run=3D1
;;
@@ -130,7 +141,7 @@ do
fi
=20
if [ -z "$dry_run" ] ; then
- git apply --index -C1 ${level:+"$level"} "$tmp_patch" &&
+ git apply --index $cflag ${level:+"$level"} "$tmp_patch" &&
tree=3D$(git write-tree) &&
commit=3D$( (echo "$SUBJECT"; echo; cat "$tmp_msg") | git commit-tre=
e $tree -p $commit) &&
git update-ref -m "quiltimport: $patch_name" HEAD $commit || exit 4
--=20
2.1.0

[Junio C Hamano]

Post by Jörn Engel
When I am working on a problem I never think about beauty. I think
only how to solve the problem. But when I have finished, if the
solution is not beautiful, I know it is wrong.
-- R. Buckminster Fuller

Nice quote, but does not belong to above --- lines, unless you have
a -- >8 -- line below or something.

Now is the patch beautiful? ;-)

Post by Jörn Engel
Subject: [PATCH] git-quiltimport.sh: disallow fuzz by default
git-quiltimport passed "-C1" to git-apply, supposedly to roughly matc=

h

Post by Jörn Engel
the quilt default of --fuzz 2. This is against the spirit of git.
Except unlike the standard "patch" program, "git apply" doesn't acc=

ept

Post by Jörn Engel
fuzz by default (which to me is a huge deal - I hate how "patch" tr=

ies

Post by Jörn Engel
to apply stuff that clearly isn't valid any more)
Users that want to want to emulate quilt defaults can pass "-C 1" to
git-quiltimport now.

Things might have been different if this were mid 2006 or early
2007, but I am afraid that "the spirit of git" with a quote from
Linus no longer carries much weight on this particular issue. A
backward incompatible change is backward incompatible change that
breaks existing users no matter how loudly you (and I) shout that it
is the right thing to do in the long run.

Let's have it the other way around, keep the same behaviour for
those who run the command without the new option, while allowing
people who know better and are aligned with the spirit of git to
pass the parameter, at least for now, with a note in the
documentation to warn that the default may change in the future to
allow no fuzz, or something.

Post by Jörn Engel
Also note that -C1 and fuzz=3D2 is not identical. Most patches have =

three

Post by Jörn Engel
lines of context, so fuzz=3D2 leaves one relevant line of context. B=

ut

Post by Jörn Engel
for any patches with more or less context this is not true. git-appl=

y

Post by Jörn Engel
has no option for fuzz, so any emulation will always be best-effort.
---
git-quiltimport.sh | 15 +++++++++++++--
1 file changed, 13 insertions(+), 2 deletions(-)
diff --git a/git-quiltimport.sh b/git-quiltimport.sh
index 167d79fea809..f45ee5ff6599 100755
--- a/git-quiltimport.sh
+++ b/git-quiltimport.sh
@@ -4,8 +4,9 @@ OPTIONS_STUCKLONG=3D
OPTIONS_SPEC=3D"\
git quiltimport [options]
--
-n,dry-run dry run
author=3D author name and email address for patches without an=

y

Post by Jörn Engel
+C=3D minimum context (see git apply)
+n,dry-run dry run
patches=3D path to the quilt series and patches
"
SUBDIRECTORY_ON=3DYes
@@ -13,6 +14,7 @@ SUBDIRECTORY_ON=3DYes
=20
dry_run=3D""
quilt_author=3D""
+cflag=3D""
while test $# !=3D 0
do
case "$1" in
@@ -20,6 +22,15 @@ do
shift
quilt_author=3D"$1"
;;
+ -C)
+ shift
+ # ensure numerical parameter
+ case $1 in
+ ''|*[!0-9]*) usage;;
+ *) ;;
+ esac
+ cflag=3D"-C$1"
+ ;;
-n|--dry-run)
dry_run=3D1
;;
@@ -130,7 +141,7 @@ do
fi
=20
if [ -z "$dry_run" ] ; then
- git apply --index -C1 ${level:+"$level"} "$tmp_patch" &&
+ git apply --index $cflag ${level:+"$level"} "$tmp_patch" &&
tree=3D$(git write-tree) &&
commit=3D$( (echo "$SUBJECT"; echo; cat "$tmp_msg") | git commit-t=

ree $tree -p $commit) &&

Post by Jörn Engel
git update-ref -m "quiltimport: $patch_name" HEAD $commit || exit =

4

[Junio C Hamano]

Post by Junio C Hamano
Let's have it the other way around, keep the same behaviour for
those who run the command without the new option, while allowing
people who know better and are aligned with the spirit of git to
pass the parameter, at least for now, with a note in the
documentation to warn that the default may change in the future to
allow no fuzz, or something.

Perhaps like this, with some documentation added (do we have/need
any test???).

-- >8 --
To: J=C3=B6rn Engel <***@logfs.org>
Date: Thu, 25 Sep 2014 18:08:31 -0400
Subject: [PATCH] git-quiltimport.sh: allow declining fuzz with --exact =
option

git-quiltimport unconditionally passes "-C1" to "git apply",
supposedly to roughly match the quilt default of --fuzz 2. Allow
users to pass --exact option to disable it, requiring the patch to
apply without any fuzz.

Also note that -C1 and fuzz=3D2 is not identical. Most patches have
three lines of context, so fuzz=3D2 leaves one relevant line of
context. But for any patches with more or less context this is not
true. git-apply has no option for fuzz, so any emulation will
always be best-effort.

Signed-off-by: Joern Engel <***@logfs.org>
Signed-off-by: Junio C Hamano <***@pobox.com>
---
Documentation/git-quiltimport.txt | 12 ++++++++++++
git-quiltimport.sh | 17 ++++++++++++++++-
2 files changed, 28 insertions(+), 1 deletion(-)

diff --git a/Documentation/git-quiltimport.txt b/Documentation/git-quil=
timport.txt
index a356196..109918d 100644
--- a/Documentation/git-quiltimport.txt
+++ b/Documentation/git-quiltimport.txt
@@ -49,6 +49,18 @@ The default for the patch directory is patches
or the value of the $QUILT_PATCHES environment
variable.
=20
+-C <number>::
+ Pass `-C<number>` to underlying `git apply` when applying
+ the patch, to reduce number of context lines to be matched.
+ By default, `-C1` is passed to `git apply` to emulate the
+ `--fuzz=3D2` behaviour of quilt (assuming the standard 3
+ context lines).
+
+--exact::
+ Do not pass any `-C<number>` option to `git apply` when
+ applying the patch, to require context lines to fully match.
+
+
GIT
---
Part of the linkgit:git[1] suite
diff --git a/git-quiltimport.sh b/git-quiltimport.sh
index 167d79f..2d2c377 100755
--- a/git-quiltimport.sh
+++ b/git-quiltimport.sh
@@ -6,6 +6,8 @@ git quiltimport [options]
--
n,dry-run dry run
author=3D author name and email address for patches without any
+C=3D minimum context (see git apply)
+exact allow no-fuzz
patches=3D path to the quilt series and patches
"
SUBDIRECTORY_ON=3DYes
@@ -13,6 +15,7 @@ SUBDIRECTORY_ON=3DYes
=20
dry_run=3D""
quilt_author=3D""
+cflag=3D-C1
while test $# !=3D 0
do
case "$1" in
@@ -20,6 +23,18 @@ do
shift
quilt_author=3D"$1"
;;
+ -C)
+ shift
+ # ensure numerical parameter
+ case "$1" in
+ ''|*[!0-9]*) usage;;
+ *) ;;
+ esac
+ cflag=3D"-C$1"
+ ;;
+ --exact)
+ cflag=3D
+ ;;
-n|--dry-run)
dry_run=3D1
;;
@@ -130,7 +145,7 @@ do
fi
=20
if [ -z "$dry_run" ] ; then
- git apply --index -C1 ${level:+"$level"} "$tmp_patch" &&
+ git apply --index $cflag ${level:+"$level"} "$tmp_patch" &&
tree=3D$(git write-tree) &&
commit=3D$( (echo "$SUBJECT"; echo; cat "$tmp_msg") | git commit-tre=
e $tree -p $commit) &&
git update-ref -m "quiltimport: $patch_name" HEAD $commit || exit 4
--=20
2.1.1-394-g5293c25

[Junio C Hamano]

Post by Junio C Hamano
Perhaps like this, with some documentation added (do we have/need
any test???).
-- >8 --
Date: Thu, 25 Sep 2014 18:08:31 -0400
Subject: [PATCH] git-quiltimport.sh: allow declining fuzz with --exact option

And on top of that change, if somebody really wants to enforce
stricter check by default, I think we could do something like this.

Obviously not tested at all, as I do not care too deeply myself ;-)

-- >8 --
Subject: [PATCH] git-quiltimport: flip the default not to allow fuzz

Trying to be as strict as possible when applying the patch may be a
good discipline, so let's flip the default but we can be helpful to
those who do rely on the original behaviour thanks to the previous
change to add -C$n option.

Suggest using -C1 when:

- "git apply" without fuzz fails to apply; and
- the user did not specify a -C$n or --exact option; and
- "git apply -C1" (old behaviour) would have succeeded.

Signed-off-by: Junio C Hamano <***@pobox.com>
---
git-quiltimport.sh | 26 ++++++++++++++++++++++++--
1 file changed, 24 insertions(+), 2 deletions(-)

diff --git a/git-quiltimport.sh b/git-quiltimport.sh
index 929365f..01de26d 100755
--- a/git-quiltimport.sh
+++ b/git-quiltimport.sh
@@ -15,7 +15,8 @@ SUBDIRECTORY_ON=Yes

dry_run=""
quilt_author=""
-cflag=-C1
+cflag=
+fuzz_specified=
while test $# != 0
do
case "$1" in
@@ -31,9 +32,11 @@ do
*) ;;
esac
cflag="-C$1"
+ fuzz_specified=yes
;;
--exact)
cflag=
+ fuzz_specified=yes
;;
-n|--dry-run)
dry_run=1
@@ -74,6 +77,25 @@ tmp_msg="$tmp_dir/msg"
tmp_patch="$tmp_dir/patch"
tmp_info="$tmp_dir/info"

+# Helper to warn about -C$n option
+do_apply () {
+ if git apply --index $cflag "$@"
+ then
+ return
+ fi
+ if test -z "$fuzz_specified" &&
+ git apply --check --index -C1 "$@" >/dev/null 2>&1
+ then
+ cat >&2 <<-\EOM
+ 'git quiltimport' by default no longer attempts to apply
+ patches with reduced context lines to allow fuzz; if you
+ want the old 'unsafe' behaviour, run the command with -C1
+ option.
+ EOM
+
+ fi
+ return 1
+}

# Find the initial commit
commit=$(git rev-parse HEAD)
@@ -145,7 +167,7 @@ do
fi

if [ -z "$dry_run" ] ; then
- git apply --index $cflag ${level:+"$level"} "$tmp_patch" &&
+ do_apply ${level:+"$level"} "$tmp_patch" &&
tree=$(git write-tree) &&
commit=$( (echo "$SUBJECT"; echo; cat "$tmp_msg") | git commit-tree $tree -p $commit) &&
git update-ref -m "quiltimport: $patch_name" HEAD $commit || exit 4

[Junio C Hamano]

Post by Junio C Hamano
Things might have been different if this were mid 2006 or early
2007, but I am afraid that "the spirit of git" with a quote from
Linus no longer carries much weight on this particular issue. A
backward incompatible change is backward incompatible change that
breaks existing users no matter how loudly you (and I) shout that it
is the right thing to do in the long run.
Let's have it the other way around, keep the same behaviour for
those who run the command without the new option, while allowing
people who know better and are aligned with the spirit of git to
pass the parameter, at least for now, with a note in the
documentation to warn that the default may change in the future to
allow no fuzz, or something.

I was waiting to hear an Ack or some comments and then forgot about
this topic.

I'll send two patches, one is essentially yours *but* does not
flip the default (i.e. those who want to be safe have to be explicit
about it), and then the other is to flip the default but more gently.

Here is the first one. I'll send the "default flipping" as a reply
to this message.

-- >8 --
From: Joern Engel <***@logfs.org>
Date: Thu, 25 Sep 2014 18:08:31 -0400
Subject: [PATCH 1/2] git-quiltimport.sh: allow declining fuzz with --exact option

git-quiltimport unconditionally passes "-C1" to "git apply",
supposedly to roughly match the quilt default of --fuzz 2. Allow
users to pass --exact option to disable it, requiring the patch to
apply without any fuzz.

Also note that -C1 and fuzz=2 is not identical. Most patches have
three lines of context, so fuzz=2 leaves one relevant line of
context. But for any patches with more or less context this is not
true. git-apply has no option for fuzz, so any emulation will
always be best-effort.

Signed-off-by: Joern Engel <***@logfs.org>
Signed-off-by: Junio C Hamano <***@pobox.com>
---
Documentation/git-quiltimport.txt | 12 ++++++++++++
git-quiltimport.sh | 17 ++++++++++++++++-
2 files changed, 28 insertions(+), 1 deletion(-)

diff --git a/Documentation/git-quiltimport.txt b/Documentation/git-quiltimport.txt
index a356196..109918d 100644
--- a/Documentation/git-quiltimport.txt
+++ b/Documentation/git-quiltimport.txt
@@ -49,6 +49,18 @@ The default for the patch directory is patches
or the value of the $QUILT_PATCHES environment
variable.

+-C <number>::
+ Pass `-C<number>` to underlying `git apply` when applying
+ the patch, to reduce number of context lines to be matched.
+ By default, `-C1` is passed to `git apply` to emulate the
+ `--fuzz=2` behaviour of quilt (assuming the standard 3
+ context lines).
+
+--exact::
+ Do not pass any `-C<number>` option to `git apply` when
+ applying the patch, to require context lines to fully match.
+
+
GIT
---
Part of the linkgit:git[1] suite
diff --git a/git-quiltimport.sh b/git-quiltimport.sh
index 167d79f..929365f 100755
--- a/git-quiltimport.sh
+++ b/git-quiltimport.sh
@@ -6,6 +6,8 @@ git quiltimport [options]
--
n,dry-run dry run
author= author name and email address for patches without any
+C= minimum context (see git apply)
+exact allow no-fuzz
patches= path to the quilt series and patches
"
SUBDIRECTORY_ON=Yes
@@ -13,6 +15,7 @@ SUBDIRECTORY_ON=Yes

dry_run=""
quilt_author=""
+cflag=-C1
while test $# != 0
do
case "$1" in
@@ -20,6 +23,18 @@ do
shift
quilt_author="$1"
;;
+ -C)
+ shift
+ # ensure numerical parameter
+ case "$1" in
+ ''|*[!0-9]*) usage;;
+ *) ;;
+ esac
+ cflag="-C$1"
+ ;;
+ --exact)
+ cflag=
+ ;;
-n|--dry-run)
dry_run=1
;;
@@ -130,7 +145,7 @@ do
fi

if [ -z "$dry_run" ] ; then
- git apply --index -C1 ${level:+"$level"} "$tmp_patch" &&
+ git apply --index $cflag ${level:+"$level"} "$tmp_patch" &&
tree=$(git write-tree) &&
commit=$( (echo "$SUBJECT"; echo; cat "$tmp_msg") | git commit-tree $tree -p $commit) &&
git update-ref -m "quiltimport: $patch_name" HEAD $commit || exit 4

[Junio C Hamano]

Trying to be as strict as possible when applying the patch may be a
good discipline, so let's flip the default but we can be helpful to
those who do rely on the original behaviour thanks to the previous
change to add -C$n option.

Suggest using -C1 when (and only when):

- "git apply" without fuzz fails to apply; and
- the user did not specify a -C$n or --exact option; and
- "git apply -C1" (old behaviour) would have succeeded.

Signed-off-by: Junio C Hamano <***@pobox.com>
---

* And this is the "flipping of the default"

git-quiltimport.sh | 26 ++++++++++++++++++++++++--
1 file changed, 24 insertions(+), 2 deletions(-)

diff --git a/git-quiltimport.sh b/git-quiltimport.sh
index 929365f..1190eb9 100755
--- a/git-quiltimport.sh
+++ b/git-quiltimport.sh
@@ -15,7 +15,8 @@ SUBDIRECTORY_ON=Yes

dry_run=""
quilt_author=""
-cflag=-C1
+cflag=
+fuzz_specified=
while test $# != 0
do
case "$1" in
@@ -31,9 +32,11 @@ do
*) ;;
esac
cflag="-C$1"
+ fuzz_specified=yes
;;
--exact)
cflag=
+ fuzz_specified=yes
;;
-n|--dry-run)
dry_run=1
@@ -74,6 +77,25 @@ tmp_msg="$tmp_dir/msg"
tmp_patch="$tmp_dir/patch"
tmp_info="$tmp_dir/info"

+# Helper to warn about -C$n option
+do_apply () {
+ if git apply --index ${cflag+"$cflag"} "$@"
+ then
+ return
+ fi
+ if test -z "$fuzz_specified" &&
+ git apply --check --index -C1 "$@" >/dev/null 2>&1
+ then
+ cat >&2 <<-\EOM
+ 'git quiltimport' by default no longer attempts to apply
+ patches with reduced context lines to allow fuzz; if you
+ want the old 'unsafe' behaviour, run the command with -C1
+ option.
+ EOM
+
+ fi
+ return 1
+}

# Find the initial commit
commit=$(git rev-parse HEAD)
@@ -145,7 +167,7 @@ do
fi

if [ -z "$dry_run" ] ; then
- git apply --index $cflag ${level:+"$level"} "$tmp_patch" &&
+ do_apply ${level:+"$level"} "$tmp_patch" &&
tree=$(git write-tree) &&
commit=$( (echo "$SUBJECT"; echo; cat "$tmp_msg") | git commit-tree $tree -p $commit) &&
git update-ref -m "quiltimport: $patch_name" HEAD $commit || exit 4