Re: [PATCH v5 1/2] filter-branch: stop special-casing $filter_subdir argument

Johannes Sixt wrote in the other reply:

I thought that the intention to give an extra path argument is to reduce
the number of commits that remain in the rewritten history. But by giving
--subdirectory-filter, the path filter actually loosened, and many more
commits are rewritten.

Right, I had a thinko there, the path filter adds up as an "or", so
filtering for paths outside the subdir loosens it (and filtering for
more paths inside doesn't make a difference).

Since your intention to write this patch is actually to implement
--remap-to-ancestor, I suggest that we defer the question whether the
above use-case makes sense, and only rewrite this particular paragraph in
the commit message to point out the real bug:

Agreed.

Johannes Sixt wrote:

Furthermore, --subdirectory-filter supplies its own '--', and if the user
provided one himself, such as in

  git filter-branch --subdirectory-filter subdir -- --all -- subdir/file

	an extra '--' was used as path filter in the call to git-rev-list that
determines the commits that shall be rewritten.

There's some stray space here that should probably also be removed.

Here it is. The interdiff to your version is merely

[...]

 # we need "--" only if there are no path arguments in $@
 nonrevs=$(git rev-parse --no-revs "$@") || exit
-dashdash=${nonrevs+"--"}
+test -z "$nonrevs" && dashdash=-- || dashdash=

Ack.

-- 
Thomas Rast
trast@{inf,student}.ethz.ch