Re: [PATCH 7/8] setup_tree_pathspec(): interpret '^' as negative pathspec

2010/9/8 Nguyễn Thái Ngọc Duy [off-list ref]:

This patch does preparation work for tree exclusion in
tree_entry_interesting(). '^' has similar meaning to '!' in
gitexcludes. '!' is not used because bash does not like arguments with
a leading '!'.

Eventually, "git diff -- foo ^foo/bar" should show differences in foo,
except foo/bar. If "git diff -- ^foo" is given, then it implies
everything except foo, which could surprise users that
"bar" in "git diff -- bar ^foo" has no effect at all.

I really like the work here.  There are just two things that I think
are missing:
  * It doesn't handle files with leading carats in their name
  * It handles some nested include/exclude cases (e.g. dir
^dir/subdir) but not more complicated ones.

You could add these three testcases (on top of your 8/8 patch) to see
what I mean:


test_expect_failure 'diff ^one one/two' '
	printf "file\none/two/file\n" >expected &&
	git diff --name-only HEAD^ HEAD -- ^one one/two >result &&
	test_cmp expected result
'

test_expect_failure 'diff ^funny-filename' '
	touch ^funny-filename &&
	git add ^funny-filename &&
	git commit -m "Add a filename with a leading carat" &&

	git ls-files >expected &&
	git diff --name-only HEAD^^ HEAD -- ^funny-filename >result &&
	test_cmp expected result &&

	echo ^funny-filename >expected &&
	git diff --name-only HEAD^^ HEAD -- ^^funny-filename >result &&
	test_cmp expected result &&

	git ls-files | grep -v funny-filename >expected &&
	git diff --name-only HEAD^^ HEAD -- ^^^funny-filename >result &&
	test_cmp expected result
'

test_expect_failure 'deeper nested exclude/include' '
	touch one/two/zoo &&
	for i in one/file one/zoo one/two/file; do echo 2 >>$i; done &&
	git add one &&
	git commit -m 4 &&

	printf "one/file\none/two/file\none/zoo\n" > expected &&
	git diff --name-only HEAD^ HEAD -- one ^one/two one/two/file >result &&
	test_cmp expected result &&

	printf "one/two/zoo\n" > expected &&
	git diff --name-only HEAD^ HEAD -- ^one one/two ^one/two/file >result &&
	test_cmp expected result
'

Note: In the second test, I used:
 * "^funny" to search for all files EXCEPT "funny"
 * "^^funny" to search for a file named "^funny"
 * "^^^funny" to search for all files EXCEPT "^funny"
I'm not sure if that's really the syntax we want to adopt, but it
should be easy to change if we decide on some other syntax.