Why a _full_ diff? (was: [PATCH] Char: serial167, cleanup (fwd))

Why a _full_ diff? (was: [PATCH] Char: serial167, cleanup (fwd))

[Geert Uytterhoeven]

	Hi,

I received the email below, showing a _full_ (i.e. every single line) diff
between the old and the new version:

| Date: Sun, 11 Feb 2007 20:00:54 GMT
| From: Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
| To: git-commits-head@vger.kernel.org
| Subject: [PATCH] Char: serial167, cleanup
| 
| Gitweb:     http://git.kernel.org/git/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=44bafdf37b30234671d4e2fb595dea4c3717d089
| Commit:     44bafdf37b30234671d4e2fb595dea4c3717d089
| Parent:     30a063a900518926966f4d75333c1bfbde1658fa
| Author:     Jiri Slaby <jirislaby@gmail.com>
| AuthorDate: Sat Feb 10 01:45:08 2007 -0800
| Committer:  Linus Torvalds <torvalds@woody.linux-foundation.org>
| CommitDate: Sun Feb 11 10:51:28 2007 -0800
| 
|     [PATCH] Char: serial167, cleanup
|     
|     serial167, cleanup
|     
|     - Lindent the code
|     - remove 3 pointers from paranoia_check
|     
|     Signed-off-by: Jiri Slaby <jirislaby@gmail.com>
|     Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|     Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| ---
|  drivers/char/serial167.c | 5616 +++++++++++++++++++++++-----------------------
|  1 files changed, 2792 insertions(+), 2824 deletions(-)
| 
| diff --git a/drivers/char/serial167.c b/drivers/char/serial167.c
| dissimilarity index 67%
| index af50d32..5fd314a 100644
| --- a/drivers/char/serial167.c
| +++ b/drivers/char/serial167.c
| @@ -1,2824 +1,2792 @@
| -/*
| - * linux/drivers/char/serial167.c
| - *

    [...]

| -#endif
| -
| -MODULE_LICENSE("GPL");
| +/*
| + * linux/drivers/char/serial167.c
| + *

    [...]

| +#endif
| +
| +MODULE_LICENSE("GPL");
| -
| To unsubscribe from this list: send the line "unsubscribe git-commits-head" in
| the body of a message to majordomo@vger.kernel.org
| More majordomo info at  http://vger.kernel.org/majordomo-info.html

At first I thought the new version had CR/LF line endings or so, but that
isn't the case.

Just using

| anakin$ git show 44bafdf37b30234671d4e2fb595dea4c3717d089 | diffstat
|  serial167.c | 3322 +++++++++++++++++++++++++++++-------------------------------
|  1 file changed, 1645 insertions(+), 1677 deletions(-)
| anakin$

shows that far from all lines were changed.

Gr{oetje,eeting}s,

						Geert

P.S. I'm not subscribed to git@vger.kernel.org, please CC me on replies
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
							    -- Linus Torvalds

Re: Why a _full_ diff? (was: [PATCH] Char: serial167, cleanup (fwd))

[Jeff King]

On Mon, Feb 12, 2007 at 09:39:46AM +0100, Geert Uytterhoeven wrote:

> At first I thought the new version had CR/LF line endings or so, but that
> isn't the case.

Close. It looks like tabs/spaces changes. Try

  git show 44bafd | cat -A | less

-Peff

Re: Why a _full_ diff? (was: [PATCH] Char: serial167, cleanup (fwd))

[Jeff King]

On Mon, Feb 12, 2007 at 09:39:46AM +0100, Geert Uytterhoeven wrote:

> I received the email below, showing a _full_ (i.e. every single line) diff
> between the old and the new version:

Hmm. I'm not sure what is generating this, but the diffstat in the email
is wrong (anybody know where the mailing list feeder script lives?).

> | diff --git a/drivers/char/serial167.c b/drivers/char/serial167.c
> | dissimilarity index 67%
> | index af50d32..5fd314a 100644
> | --- a/drivers/char/serial167.c
> | +++ b/drivers/char/serial167.c
> | @@ -1,2824 +1,2792 @@
> | -/*
> | - * linux/drivers/char/serial167.c
> | - *

This may or may not be related to the diffstat issue; you can get a
similar effect by asking for a lot of context. For example:

  git show --unified=150 44bafd

> | anakin$ git show 44bafdf37b30234671d4e2fb595dea4c3717d089 | diffstat
> |  serial167.c | 3322 +++++++++++++++++++++++++++++-------------------------------
> |  1 file changed, 1645 insertions(+), 1677 deletions(-)

This is also what git produces, using

  git show --stat 44bafd

I think there is probably some erroneous magic going on in whatever
script generates the mail.

-Peff

Re: Why a _full_ diff? (was: [PATCH] Char: serial167, cleanup (fwd))

[Jeff King]

On Mon, Feb 12, 2007 at 04:20:30AM -0500, Jeff King wrote:

> > | diff --git a/drivers/char/serial167.c b/drivers/char/serial167.c
> > | dissimilarity index 67%
> > | index af50d32..5fd314a 100644

OK, I see now. This is triggered by using 'git show -B', which breaks
the diff apart into a big rewriting chunk. Unfortunately, I don't know
enough about how -B works to say whether this makes sense or not.

-Peff

Re: Why a _full_ diff? (was: [PATCH] Char: serial167, cleanup (fwd))

[Johannes Schindelin]

Hi,

On Mon, 12 Feb 2007, Jeff King wrote:

> On Mon, Feb 12, 2007 at 04:20:30AM -0500, Jeff King wrote:
> 
> > > | diff --git a/drivers/char/serial167.c b/drivers/char/serial167.c
> > > | dissimilarity index 67%
> > > | index af50d32..5fd314a 100644
> 
> OK, I see now. This is triggered by using 'git show -B', which breaks
> the diff apart into a big rewriting chunk. Unfortunately, I don't know
> enough about how -B works to say whether this makes sense or not.

AFAICT you can provide a minimum score with -B, just as with -M, i.e. if 
the diff score is larger than this value, it is interpreted as a complete 
rewrite.

Hth,
Dscho