Re: Bug in git log

[Linus Torvalds <torvalds@osdl.org>]

On Tue, 2 May 2006, Matthias Kestenholz wrote:
> 
> The "double dash" problem is not a big deal since it only happens
> with the deprecated shellscript-version of whatchanged.

Simple enough to fix. Appended.

The problem was that "git-rev-parse --no-flags --no-revs" will show _just_ 
the filenames from the argument list. That means that it will also remove 
the "--" from the original. That's all well and proper, but 
git-whatchanged had a bug, and it wouldn't separate the filename arguments 
from the flags by adding its own "--".

That bug didn't matter back when we didn't check the parsing all that 
carefully. It does now.

> Does anyone get some output with the following command? That was the
> bug I tried to report (sorry for my bad/convoluted english)
> 
> $ git log -- unresolve.c

Now, this returns empty, and it actually does that for a reason.

Along the main path, "unresolve.c" has never existed. The modern 
"git-whatchanged" (and "git log") is a bit different from the old 
big-whatchanged.

The old git-whatchanged would go through _every_ commit, because it 
literally did

	git-rev-list | git-diff-tree --stdin -- <paths>

and thus the revision list was generated without _any_ regard for the 
paths - and every single commit shows up, whether it is relevant or not.

The new revision is based on the revision parsing thing, and the semantics 
are a bit different: it semantically does the equivalent of

	git-rev-list <paths> | git-diff-tree --stdin -- <paths>

which limits the revision list too on the paths.

And yes, "git log" does the same.

See the discussion a few weeks ago about "path limiting broken", and my 
patch that suggested a "--no-prune-merges" flag:

	http://www.gelato.unsw.edu.au/archives/git/0604/19180.html

which gives more of an explanation.

		Linus

--
diff --git a/git-whatchanged.sh b/git-whatchanged.sh
index 1fb9feb..bb73cff 100755
--- a/git-whatchanged.sh
+++ b/git-whatchanged.sh
@@ -24,5 +24,5 @@ rev_list_args=$(git-rev-parse --sq --def
 diff_tree_args=$(git-rev-parse --sq --no-revs --no-flags "$@") &&
 
 eval "git-rev-list $count $rev_list_args" |
-eval "git-diff-tree --stdin --pretty -r $diff_tree_flags $diff_tree_args" |
+eval "git-diff-tree --stdin --pretty -r $diff_tree_flags -- $diff_tree_args" |
 LESS="$LESS -S" ${PAGER:-less}