Re: [PATCH] fetch-pack: test explicitly that --all can fetch tag references pointing to non-commits

[Jeff King <peff@peff.net>]

On Wed, Jun 13, 2018 at 05:05:09PM -0400, Jeff King wrote:

> > In order to be sure fetching funky tags will never break, let's
> > explicitly test all relevant cases with 4 tag objects pointing to 1) a
> > blob, 2) a tree, 3) a commit, and 4) another tag objects. The referenced
> > tag objects themselves are referenced from under regular refs/tags/*
> > namespace. Before e9502c0a7f `fetch-pack --all` was failing e.g. this way:
> > 
> >         .../git/t/trash directory.t5500-fetch-pack/fetchall$ git ls-remote ..
> >         44085874...        HEAD
> >         ...
> >         bc4e9e1f...        refs/tags/tag-to-blob
> >         038f48ad...        refs/tags/tag-to-blob^{}	# peeled
> >         520db1f5...        refs/tags/tag-to-tree
> >         7395c100...        refs/tags/tag-to-tree^{}	# peeled
> > 
> >         .../git/t/trash directory.t5500-fetch-pack/fetchall$ git fetch-pack --all ..
> >         fatal: A git upload-pack: not our ref 038f48ad...
> >         fatal: The remote end hung up unexpectedly
> 
> TBH, I do not find this snippet all that compelling. We know that
> e9502c0a7f already fixed the bug, and that it had nothing to do with
> non-commits at all.
> 
> The primary reason to add these tests is that in general we do not cover
> fetch-pack over tags to non-commits. And I think the reason to use
> otherwise unreferenced objects is that it they are more likely to have
> detectable symptoms if they tickle a bug.
> 
> So why don't we say that, instead of re-hashing output from the earlier
> fix?

Hmm, it looks like this already hit 'next', so it is too late to change
the commit message (although 'next' will get rewound after the release,
so we _could_ do it then).

I also was going to suggest these style fixes, which could be applied on
top (or squashed if we end up going that route). I actually wonder if
the final tag one could just use two invocations of "git tag -m", but
it's probably not worth spending too much time on polishing.

-- >8 --
Subject: [PATCH] t5500: prettify non-commit tag tests

We don't need to use backslash continuation, as the "&&"
already provides continuation (and happily soaks up empty
lines between commands).

We can also expand the multi-line printf into a
here-document, which lets us use line breaks more naturally
(and avoids another continuation that required us to break
the natural indentation).

Signed-off-by: Jeff King <peff@peff.net>
---
 t/t5500-fetch-pack.sh | 19 +++++++++++++------
 1 file changed, 13 insertions(+), 6 deletions(-)

diff --git a/t/t5500-fetch-pack.sh b/t/t5500-fetch-pack.sh
index ea6570e819..3d33ab3875 100755
--- a/t/t5500-fetch-pack.sh
+++ b/t/t5500-fetch-pack.sh
@@ -533,19 +533,26 @@ test_expect_success 'test --all wrt tag to non-commits' '
 	# are reachable only via created tag references.
 	blob=$(echo "hello blob" | git hash-object -t blob -w --stdin) &&
 	git tag -a -m "tag -> blob" tag-to-blob $blob &&
- \
+
 	tree=$(printf "100644 blob $blob\tfile" | git mktree) &&
 	git tag -a -m "tag -> tree" tag-to-tree $tree &&
- \
+
 	tree2=$(printf "100644 blob $blob\tfile2" | git mktree) &&
 	commit=$(git commit-tree -m "hello commit" $tree) &&
 	git tag -a -m "tag -> commit" tag-to-commit $commit &&
- \
+
 	blob2=$(echo "hello blob2" | git hash-object -t blob -w --stdin) &&
-	tag=$(printf "object $blob2\ntype blob\ntag tag-to-blob2\n\
-tagger author A U Thor <author@example.com> 0 +0000\n\nhello tag" | git mktag) &&
+	tag=$(git mktag <<-EOF
+		object $blob2
+		type blob
+		tag tag-to-blob2
+		tagger author A U Thor <author@example.com> 0 +0000
+
+		hello tag
+	EOF
+	) &&
 	git tag -a -m "tag -> tag" tag-to-tag $tag &&
- \
+
 	# `fetch-pack --all` should succeed fetching all those objects.
 	mkdir fetchall &&
 	(
-- 
2.18.0.rc2.519.gb87ed92113