* bug in git diff --unified=0 ?
@ 2009-05-02 23:47 Shawn O. Pearce
2009-05-03 0:17 ` Junio C Hamano
0 siblings, 1 reply; 4+ messages in thread
From: Shawn O. Pearce @ 2009-05-02 23:47 UTC (permalink / raw)
To: git
I can't decide if this is a bug in JGit, or a bug in CGit, or just
an area where the patch format is very unclear.
The following 2 patches are identical, but use different context:
git diff --unified=1:
diff --git a/X b/X
index a3648a1..2d44096 100644
--- a/X
+++ b/X
@@ -2,2 +2,3 @@
b
+c
d
@@ -16,4 +17,2 @@
q
-r
-s
t
git diff --unified=0:
diff --git a/X b/X
index a3648a1..2d44096 100644
--- a/X
+++ b/X
@@ -2,0 +3 @@
+c
@@ -17,2 +17,0 @@
-r
-s
Now lets look at JGit's output of that last patch, unified=0:
diff --git a/X b/X
index a3648a1..2d44096 100644
--- a/X
+++ b/X
@@ -3,0 +3,1 @@
+c
@@ -17,2 +18,0 @@
-r
-s
Notice that `git diff --unified=1` said the first hunk started on
line 2 of the pre-image, as the 2nd line of the file is the context
line "b\n". I call that correct.
However, `git diff --unified=0` said the first hunk started on line
2 of the pre-image, but there is no pre-image mentioned. JGit says
it starts on line 3 of the pre-image, because the script is adding
a "c\n" on line 3.
The exact opposite behavior can be seen in the 2nd hunk, where we
delete lines. Again, `git diff --unified=0` seems to behave as
though we had 1 line of context, but we don't.
--
Shawn.
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: bug in git diff --unified=0 ?
2009-05-02 23:47 bug in git diff --unified=0 ? Shawn O. Pearce
@ 2009-05-03 0:17 ` Junio C Hamano
2009-05-03 0:23 ` Shawn O. Pearce
2009-05-03 5:18 ` Junio C Hamano
0 siblings, 2 replies; 4+ messages in thread
From: Junio C Hamano @ 2009-05-03 0:17 UTC (permalink / raw)
To: Shawn O. Pearce; +Cc: git
"Shawn O. Pearce" <spearce@spearce.org> writes:
> I can't decide if this is a bug in JGit, or a bug in CGit, or just
> an area where the patch format is very unclear.
>
> The following 2 patches are identical, but use different context:
>
> git diff --unified=1:
>
> diff --git a/X b/X
> index a3648a1..2d44096 100644
> --- a/X
> +++ b/X
> @@ -2,2 +2,3 @@
> b
> +c
> d
> @@ -16,4 +17,2 @@
> q
> -r
> -s
> t
>
> git diff --unified=0:
>
> diff --git a/X b/X
> index a3648a1..2d44096 100644
> --- a/X
> +++ b/X
> @@ -2,0 +3 @@
> +c
> @@ -17,2 +17,0 @@
> -r
> -s
>
> Now lets look at JGit's output of that last patch, unified=0:
>
> diff --git a/X b/X
> index a3648a1..2d44096 100644
> --- a/X
> +++ b/X
> @@ -3,0 +3,1 @@
> +c
> @@ -17,2 +18,0 @@
> -r
> -s
I do not know what the current status of the POSIX draft for spliting
"context diff" format into "copied context" and "unified context", but
see http://www.opengroup.org/austin/aardvark/latest/xcubug2.txt for the
definition that was on track the last time I checked.
First the range of lines in each file shall be written in the
following format:
"@@^-%s^+%s^@@", <file1 range>, <file2 range>
Each <range> field shall be of the form:
"%1d", <beginning line number>
if the range contains exactly one line, and:
"%1d,%1d", <beginning line number>, <number of lines>
otherwise. If a range is empty, its beginning line number shall be
the number of the line just before the range, or 0 if the empty
range starts the file.
So, JGit is wrong.
^ permalink raw reply [flat|nested] 4+ messages in thread
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2009-05-02 23:47 bug in git diff --unified=0 ? Shawn O. Pearce
2009-05-03 0:17 ` Junio C Hamano
2009-05-03 0:23 ` Shawn O. Pearce
2009-05-03 5:18 ` Junio C Hamano
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