Re: Un-paged commit messages in git filter-branch's commit-filter?

[Stefan Tauner <stefan.tauner@gmx.at>]

On Mon, 1 Aug 2016 17:36:31 -0400
Jeff King <peff@peff.net> wrote:

> On Sun, Jul 31, 2016 at 06:39:35PM +0200, Stefan Tauner wrote:
> 
> > > There are some output formats that will wrap lines, but by default,
> > > filter-branch should not be using them (and I could not reproduce the
> > > issue in a simple test). Can you show us what your commit-filter looks
> > > like?  
> > 
> > Thanks for your answer. I have tried to reproduce it in other (newly
> > created) repositories but failed. However, it seems to relate to some
> > kind of persistent paging setting, is that possible?
> > git config -l does not show anything suspicious.
> > 
> > The following commands produce paged output:
> > git show hash
> > git show --pretty=%B
> > git log hash^..hash
> > Commit message in gitk
> > 
> > 
> > These do NOT produce paged output:
> > git patch hash^..hash
> > Commit message in gitg 0.2.7  
> 
> What is "git patch"? An alias for "format-patch?".

Yes, sorry.
And this is the most amazing thing about this behavior... what's so
different between format-patch and log or show --pretty=%B. Shouldn't
these match 100%?

> 
> > This is the script I tried to use to reproduce the problem:
> > 
> > #!/bin/bash
> > export LC_ALL=C
> > input=$(cat)
> > echo "===========================
> > $input
> > ===========================" >> /tmp/paging_bug.txt
> > git commit-tree "$@" -m "$input"  
> 
> Can you be more specific about the input you're feeding to git and the
> output you're seeing?
> 
> For instance, if I do:
> 
>   git init
>   echo content >file
>   git add file
>   git commit -m "$(perl -e 'print join(" ", 1..100)')"
> 
> I get a commit message with one long unwrapped line, which I can view
> via git-log, etc.

That's approximately what I did in my tests as well. And like you, when
I do this in a fresh repository, it works like that..

> Now if I try to run filter-branch on that:
> 
>   git filter-branch --commit-filter '
> 	input=$(cat)
> 	{
> 		echo "===================="
> 		echo $input
> 		echo "===================="
> 	} >>/tmp/paging_bug.txt
> 	git commit-tree "$@" -m "$input"
>   '
> 
> then the commit remains unchanged, and paging_bug shows one long line.

as well as filter-branch. That's what I meant when I wrote I cannot
reproduce it with a new repository (to create a MWE). I wrote the first
mail under the presumption that filter-branch is somehow involved but
apparently it is not the only git command and receives the mangled
input already as the commands stated in the last email show.

> What am I missing?
> 
> (I wondered at first if the extra "cat" and "-m" could be messing up
> whitespace for you, but it should not, as the quoting around "$input"
> should preserve things like newlines. And anyway, the bug in that case
> would be the _opposite_; I'd expect it to stuff everything onto a single
> line rather than breaking lines).

The commit messages I try to process are nothing special really... just
very long and not subject-like (because SVN and not giving too much
thought to them sometimes). The only special thing I can think of is
that they have been processed by git-svn earlier.

-- 
Kind regards/Mit freundlichen Grüßen, Stefan Tauner