Re: [PATCH] for-each-ref: add %(upstream:gone) to mark missing refs

On Fri, Aug 19, 2016 at 11:50:23PM +0200, Øystein Walle wrote:

git branch -vv will show "gone" next to a remote tracking branch if it
does not exist. for-each-ref is suitable for parsing but had no way of
showing this information.

This introduces "%(upstream:gone)" to display "gone" in the formatted
output if the ref does not exist or an empty string otherwise, analogous
to git branch -vv.

Hmm. So this sounds like the minimum thing to implement "branch -vv"
output, but it feels sort of weirdly non-orthogonal. I guess you'd say:

  %(upstream:track)%(upstream:gone)

and assume that only one of them will show any data.

I almost wonder if %(upstream:track) should just output some specific
token for the "gone" case, which matches what "branch -vv" does.

(I'm also not sure we can match "branch -vv" exactly here anyway, as it
looks like "[%(upstream): %(upstream:track)"], but our
"%(upstream:track)" uses its own brackets.)

I suppose that is a backwards-incompatible change for
"%(upstream:track)", but I'm not sure how much we have promised about
its format. The error cases seem totally undocumented.

---
 Documentation/git-for-each-ref.txt |  5 +++--
 ref-filter.c                       | 10 +++++++++-
 t/t6300-for-each-ref.sh            | 12 ++++++++++++
 3 files changed, 24 insertions(+), 3 deletions(-)

The code itself looks OK to me (assuming we want upstream:gone as the
interface), with a few minor nits in the test:

+test_expect_success 'Check that :gone produces expected results' '
+	cat >expected <<-\EOF &&
+gone
+	EOF

The "<<-" will strip leading tabs, meaning you can indent "gone" here to
match the rest of the test.

+	test_when_finished "git config branch.master.merge refs/heads/master" &&
+	git config branch.master.merge refs/heads/does-not-exist &&

I thought this could be test_config, but it is not clever enough to
restore an old value, only to remove a value we just added. So this is
probably the best solution.

+	git for-each-ref \
+		--format="%(upstream:gone)" \
+		refs/heads >actual &&
+	test_cmp expected actual
+'

This tests only that we show "gone"; do you want to add a second branch
and make sure that it shows nothing? Maybe you could even use a new
branch name, which makes test_config applicable again:

  cat >expected <<-\EOF &&
  master 
  no-upstream gone
  EOF
  git branch refs/heads/no-upstream &&
  test_config branch.no-upstream.remote . &&
  test_config branch.no-upstream.merge refs/heads/does-not-exist &&
  git for-each-ref --format="%(refname:short) %(upstream:gone)" >actual &&
  test_cmp expected actual

-Peff