Re: [PATCH] git-svn: fix ls-tree usage with dash-prefixed paths

From: Björn Steinbrink <b.steinbrink@gmx.de>
Date: Mar 30, 2009, 05:28 UTC
Message-ID: <20090330052817.GB2681@atjola.homenet>
In-Reply-To: <7v8wmoqdc1.fsf@gitster.siamese.dyndns.org>

On 2009.03.29 13:33:02 -0700, Junio C Hamano wrote:

Show 48 quoted lines

> Eric Wong <normalperson@yhbt.net> writes:
> 
> > To find the blob object name given a tree and pathname, we were
> > incorrectly calling "git ls-tree" with a "--" argument followed
> > by the pathname of the file we wanted to get.
> >
> >   git ls-tree <TREE> -- --dashed/path/name.c
> >
> > Unlike many command-line interfaces, the "--" alone does not
> > symbolize the end of non-option arguments on the command-line.
> >
> > ls-tree interprets the "--" as a prefix to match against, thus
> > the entire contents of the --dashed/* hierarchy would be
> > returned because the "--" matches "--dashed" and every path
> > under it.
> 
> The above makes only half a sense to me.  In an empty directory:
> 
>     $ git init
>     Initialized empty Git repository in /tmp/empty/.git
>     $ mkdir -p ./--dashed/path
>     $ >./--dashed/path/name
>     $ git add .
>     $ git ls-files
>     --dashed/path/name
>     $ git commit -a -m initial
>     [master (root-commit) cd44284] initial
>      0 files changed, 0 insertions(+), 0 deletions(-)
>      create mode 100644 --dashed/path/name
>     $ git ls-tree HEAD^{tree} --
>     $ git ls-tree HEAD^{tree} -- --dashed/path/name
>     100644 blob e69de29bb2d1d6434b8b29ae775ad8c2e48c5391	--dashed/path/name
>     $ mkdir ./--
>     $ >./--/eman
>     $ git add .
>     $ git commit -m second
>     [master 80f8ef9] second
>      0 files changed, 0 insertions(+), 0 deletions(-)
>      create mode 100644 --/eman
>     $ git ls-tree HEAD^{tree} -- --dashed/path
>     100644 blob e69de29bb2d1d6434b8b29ae775ad8c2e48c5391	--/eman
>     040000 tree 23e59e0c91294c39ac7c5a2e39efb01d878de9a0	--dashed/path
>     $ exit
> 
> Perhaps the problem repository had a pathname that is exactly -- (in
> addition to --dashed/), and ls-tree emitted everything under --/
> hierarchy?  In other words, your fix to git-svn may be correct and I am
> reading your problem description above incorrectly?

Your test case is flawed, because you only have a single path in --dashed/

Initialized empty Git repository in /home/doener/test/.git/
$ mkdir ./--dashed
$ touch ./--dashed/{1,2}
$ git add .
$ git ls-files
--dashed/1
--dashed/2
$ git commit -m init
[master (root-commit) ae7cd83] init
 0 files changed, 0 insertions(+), 0 deletions(-)
 create mode 100644 --dashed/1
 create mode 100644 --dashed/2
$ git ls-tree HEAD^{tree}
040000 tree f353b342b53872c6a510229524f819c4fe0d5c1b	--dashed
$ git ls-tree HEAD^{tree} --
$ git ls-tree HEAD^{tree} -- --dashed
040000 tree f353b342b53872c6a510229524f819c4fe0d5c1b	--dashed
$ git ls-tree HEAD^{tree} -- --dashed/
100644 blob e69de29bb2d1d6434b8b29ae775ad8c2e48c5391	--dashed/1
100644 blob e69de29bb2d1d6434b8b29ae775ad8c2e48c5391	--dashed/2
$ git ls-tree HEAD^{tree} -- --dashed/1
100644 blob e69de29bb2d1d6434b8b29ae775ad8c2e48c5391	--dashed/1
100644 blob e69de29bb2d1d6434b8b29ae775ad8c2e48c5391	--dashed/2

Or even more weird (at least to me):

Initialized empty Git repository in /home/doener/test/.git/
$ mkdir foo fab
$ touch {foo,fab}/{1,2}
$ git add .
$ git commit -m init
[master (root-commit) fdb7bb3] init
 0 files changed, 0 insertions(+), 0 deletions(-)
 create mode 100644 fab/1
 create mode 100644 fab/2
 create mode 100644 foo/1
 create mode 100644 foo/2
$ git ls-files foo/1 fab/1
fab/1
foo/1
$ git ls-files foo/1 fab/1 f
fab/1
foo/1
$ git ls-tree HEAD^{tree} foo/1 fab/1
100644 blob e69de29bb2d1d6434b8b29ae775ad8c2e48c5391	fab/1
100644 blob e69de29bb2d1d6434b8b29ae775ad8c2e48c5391	foo/1
$ git ls-tree HEAD^{tree} foo/1 fab/1 f
100644 blob e69de29bb2d1d6434b8b29ae775ad8c2e48c5391	fab/1
100644 blob e69de29bb2d1d6434b8b29ae775ad8c2e48c5391	fab/2
100644 blob e69de29bb2d1d6434b8b29ae775ad8c2e48c5391	foo/1
100644 blob e69de29bb2d1d6434b8b29ae775ad8c2e48c5391	foo/2

So if you go into some tree, any additional pattern that is a prefix of the tree name will match the tree and its contents.

Björn