Re: Bug report: "Use of uninitialized value $_ in print"

From: Jonathan Nieder <jrnieder@gmail.com>
Date: Mar 2, 2018, 07:04 UTC
Message-ID: <20180302070434.GG238112@aiede.svl.corp.google.com>
In-Reply-To: <CAD-Jur+6m1SjqHVWBxW5HnTjutSVrkP+dEXdYmFHzoUf0FGdNA@mail.gmail.com>

Hi,

Sam Kuper wrote:

Show 18 quoted lines

> First, background. I encountered a bug on Debian Stretch, using this
> git version:
>
> $ git --version
> git version 2.11.0
>
> The bug is that in the midst of running
>
> git -c interactive.diffFilter="git diff --word-diff --color" add --patch
>
> and after having answered "y" to some patches and "n" to others, git
> suddenly spewed the following output:
>
> Use of uninitialized value $_ in print at
> /usr/lib/git-core/git-add--interactive line 1371, <STDIN> line 74.
> Stage this hunk [y,n,q,a,d,/,K,j,J,g,e,?]? n
> Use of uninitialized value $_ in print at
> /usr/lib/git-core/git-add--interactive line 1371, <STDIN> line 75.

[...]

Strange.  The relevant line, for reference:

$ dpkg-deb --fsys-tarfile git_2.11.0-3+deb9u2_amd64.deb |
  tar Oxf - ./usr/lib/git-core/git-add--interactive |
  sed -n '1370,1372 p'

		for (@{$hunk[$ix]{DISPLAY}}) {
			print; <---- this one
		}

This is a foreach loop, so it's supposed to have set $_ to each value in the list @{$hunk[$ix]{DISPLAY}). So why is Perl considering it uninitialized?

Is this reproducible for you? Do you have more details about how I can reproduce it?

What arch are you on? What perl version do you use? Can you report this using "reportbug git"?

Thanks, Jonathan