Re: make git ignore the timestamp embedded in PDFs

From: Andreas Leha <andreas.leha@med.uni-goettingen.de>
Date: May 18, 2013, 07:42 UTC
Message-ID: <87ppwohgyd.fsf@med.uni-goettingen.de>
In-Reply-To: <51928FE8.2050804@kdbg.org>

Hi Hannes,

thanks for taking this up and sorry for the long delay in my answer.

Johannes Sixt <j6t@kdbg.org> writes:

Show 21 quoted lines

> Am 14.05.2013 15:17, schrieb Andreas Leha:
>> Hi all,
>> 
>> how can I make git ignore the time stamp(s) in a PDF.  Two PDFs that
>> differ only in these time stamps should be considered identical.
>> ...
>> What I tried is a filter:
>> ,----[ ~/.gitconfig ]
>> | [filter "pdfresetdate"]
>> |         clean = pdfresetdate
>> `----
>> 
>> This 'works' as far as the committed pdf indeed has the date reset to my
>> default value.
>> 
>> However, when I re-checkout the files, they are marked modified by git.
>
> I'm using cleaned files every now and then, but not on Linux. I have
> never observed this behavior recently.
>
> If you 'git add' the file, does it keep its modified state? Does 'git

yes.

> diff' tell a difference?

no.

Here is a complete 'session':
,----
| > mkdir test
| > cd test
| > git init
| > echo '*.pdf filter=pdfresetdate' > .gitattributes
| > cp ~/PDF/score_table.pdf .
| > pdfinfo score_table.pdf
| Title:          (score_table)
| Author:         (andreas)
| Creator:        GPL Ghostscript 905 (ps2write)
| Producer:       GPL Ghostscript 9.05
| CreationDate:   Fri Feb  8 15:44:47 2013
| ModDate:        Fri Feb  8 15:44:47 2013
| Tagged:         no
| Pages:          1
| Encrypted:      no
| Page size:      595 x 842 pts (A4)
| File size:      36989 bytes
| Optimized:      no
| PDF version:    1.4
| > git add score_table.pdf
| > pdfinfo score_table.pdf
| Title:          (score_table)
| Author:         (andreas)
| Creator:        GPL Ghostscript 905 (ps2write)
| Producer:       GPL Ghostscript 9.05
| CreationDate:   Fri Feb  8 15:44:47 2013
| ModDate:        Fri Feb  8 15:44:47 2013
| Tagged:         no
| Pages:          1
| Encrypted:      no
| Page size:      595 x 842 pts (A4)
| File size:      36989 bytes
| Optimized:      no
| PDF version:    1.4
| > git commit -m "test"
| > pdfinfo score_table.pdf
| Title:          (score_table)
| Author:         (andreas)
| Creator:        GPL Ghostscript 905 (ps2write)
| Producer:       GPL Ghostscript 9.05
| CreationDate:   Fri Feb  8 15:44:47 2013
| ModDate:        Fri Feb  8 15:44:47 2013
| Tagged:         no
| Pages:          1
| Encrypted:      no
| Page size:      595 x 842 pts (A4)
| File size:      36989 bytes
| Optimized:      no
| PDF version:    1.4
| > rm score_table.pdf
| > git checkout  score_table.pdf  
| > git status
| # On branch master
| # Changes not staged for commit:
| #   (use "git add <file>..." to update what will be committed)
| #   (use "git checkout -- <file>..." to discard changes in working directory)
| #
| #       modified:   score_table.pdf
| #
| # Untracked files:
| #   (use "git add <file>..." to include in what will be committed)
| #
| #       .gitattributes
| no changes added to commit (use "git add" and/or "git commit -a")
| > pdfinfo score_table.pdf 
| Title:          (score_table)
| Author:         (andreas)
| Creator:        GPL Ghostscript 905 (ps2write)
| Producer:       GPL Ghostscript 9.05
| CreationDate:   Mon Jan  1 07:26:19 1979
| ModDate:        Mon Jan  1 07:26:19 1979
| Tagged:         no
| Pages:          1
| Encrypted:      no
| Page size:      595 x 842 pts (A4)
| File size:      37126 bytes
| Optimized:      no
| PDF version:    1.4
| > git add score_table.pdf
| > git status
| # On branch master
| # Changes to be committed:
| #   (use "git reset HEAD <file>..." to unstage)
| #
| #       modified:   score_table.pdf
| #
| # Untracked files:
| #   (use "git add <file>..." to include in what will be committed)
| #
| #       .gitattributes
| > git diff score_table.pdf
| > 
`----

Regards, Andreas