revision: add new parameter to exclude hidden refs

Users can optionally hide refs from remote users in git-upload-pack(1),
git-receive-pack(1) and others via the `transfer.hideRefs`, but there is
not an easy way to obtain the list of all visible or hidden refs right
now. We'll require just that though for a performance improvement in our
connectivity check.

Add a new option `--exclude-hidden=` that excludes any hidden refs from
the next pseudo-ref like `--all` or `--branches`.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Taylor Blau <me@ttaylorr.com>
diff --git a/t/t6021-rev-list-exclude-hidden.sh b/t/t6021-rev-list-exclude-hidden.sh
new file mode 100755
index 0000000..32b2b09
--- /dev/null
+++ b/t/t6021-rev-list-exclude-hidden.sh
@@ -0,0 +1,163 @@
+#!/bin/sh
+
+test_description='git rev-list --exclude-hidden test'
+
+. ./test-lib.sh
+
+test_expect_success 'setup' '
+	test_commit_bulk --id=commit --ref=refs/heads/branch 1 &&
+	COMMIT=$(git rev-parse refs/heads/branch) &&
+	test_commit_bulk --id=tag --ref=refs/tags/lightweight 1 &&
+	TAG=$(git rev-parse refs/tags/lightweight) &&
+	test_commit_bulk --id=hidden --ref=refs/hidden/commit 1 &&
+	HIDDEN=$(git rev-parse refs/hidden/commit) &&
+	test_commit_bulk --id=namespace --ref=refs/namespaces/namespace/refs/namespaced/commit 1 &&
+	NAMESPACE=$(git rev-parse refs/namespaces/namespace/refs/namespaced/commit)
+'
+
+test_expect_success 'invalid section' '
+	echo "fatal: unsupported section for hidden refs: unsupported" >expected &&
+	test_must_fail git rev-list --exclude-hidden=unsupported 2>err &&
+	test_cmp expected err
+'
+
+for section in receive uploadpack
+do
+	test_expect_success "$section: passed multiple times" '
+		echo "fatal: --exclude-hidden= passed more than once" >expected &&
+		test_must_fail git rev-list --exclude-hidden=$section --exclude-hidden=$section 2>err &&
+		test_cmp expected err
+	'
+
+	test_expect_success "$section: without hiddenRefs" '
+		git rev-list --exclude-hidden=$section --all >out &&
+		cat >expected <<-EOF &&
+		$NAMESPACE
+		$HIDDEN
+		$TAG
+		$COMMIT
+		EOF
+		test_cmp expected out
+	'
+
+	test_expect_success "$section: hidden via transfer.hideRefs" '
+		git -c transfer.hideRefs=refs/hidden/ rev-list --exclude-hidden=$section --all >out &&
+		cat >expected <<-EOF &&
+		$NAMESPACE
+		$TAG
+		$COMMIT
+		EOF
+		test_cmp expected out
+	'
+
+	test_expect_success "$section: hidden via $section.hideRefs" '
+		git -c $section.hideRefs=refs/hidden/ rev-list --exclude-hidden=$section --all >out &&
+		cat >expected <<-EOF &&
+		$NAMESPACE
+		$TAG
+		$COMMIT
+		EOF
+		test_cmp expected out
+	'
+
+	test_expect_success "$section: respects both transfer.hideRefs and $section.hideRefs" '
+		git -c transfer.hideRefs=refs/tags/ -c $section.hideRefs=refs/hidden/ rev-list --exclude-hidden=$section --all >out &&
+		cat >expected <<-EOF &&
+		$NAMESPACE
+		$COMMIT
+		EOF
+		test_cmp expected out
+	'
+
+	test_expect_success "$section: negation without hidden refs marks everything as uninteresting" '
+		git rev-list --all --exclude-hidden=$section --not --all >out &&
+		test_must_be_empty out
+	'
+
+	test_expect_success "$section: negation with hidden refs marks them as interesting" '
+		git -c transfer.hideRefs=refs/hidden/ rev-list --all --exclude-hidden=$section --not --all >out &&
+		cat >expected <<-EOF &&
+		$HIDDEN
+		EOF
+		test_cmp expected out
+	'
+
+	test_expect_success "$section: hidden refs and excludes work together" '
+		git -c transfer.hideRefs=refs/hidden/ rev-list --exclude=refs/tags/* --exclude-hidden=$section --all >out &&
+		cat >expected <<-EOF &&
+		$NAMESPACE
+		$COMMIT
+		EOF
+		test_cmp expected out
+	'
+
+	test_expect_success "$section: excluded hidden refs get reset" '
+		git -c transfer.hideRefs=refs/ rev-list --exclude-hidden=$section --all --all >out &&
+		cat >expected <<-EOF &&
+		$NAMESPACE
+		$HIDDEN
+		$TAG
+		$COMMIT
+		EOF
+		test_cmp expected out
+	'
+
+	test_expect_success "$section: excluded hidden refs can be used with multiple pseudo-refs" '
+		git -c transfer.hideRefs=refs/ rev-list --exclude-hidden=$section --all --exclude-hidden=$section --all >out &&
+		test_must_be_empty out
+	'
+
+	test_expect_success "$section: works with --glob" '
+		git -c transfer.hideRefs=refs/hidden/ rev-list --exclude-hidden=$section --glob=refs/h* >out &&
+		cat >expected <<-EOF &&
+		$COMMIT
+		EOF
+		test_cmp expected out
+	'
+
+	test_expect_success "$section: operates on stripped refs by default" '
+		GIT_NAMESPACE=namespace git -c transfer.hideRefs=refs/namespaced/ rev-list --exclude-hidden=$section --all >out &&
+		cat >expected <<-EOF &&
+		$HIDDEN
+		$TAG
+		$COMMIT
+		EOF
+		test_cmp expected out
+	'
+
+	test_expect_success "$section: does not hide namespace by default" '
+		GIT_NAMESPACE=namespace git -c transfer.hideRefs=refs/namespaces/namespace/ rev-list --exclude-hidden=$section --all >out &&
+		cat >expected <<-EOF &&
+		$NAMESPACE
+		$HIDDEN
+		$TAG
+		$COMMIT
+		EOF
+		test_cmp expected out
+	'
+
+	test_expect_success "$section: can operate on unstripped refs" '
+		GIT_NAMESPACE=namespace git -c transfer.hideRefs=^refs/namespaces/namespace/ rev-list --exclude-hidden=$section --all >out &&
+		cat >expected <<-EOF &&
+		$HIDDEN
+		$TAG
+		$COMMIT
+		EOF
+		test_cmp expected out
+	'
+
+	for pseudoopt in remotes branches tags
+	do
+		test_expect_success "$section: fails with --$pseudoopt" '
+			test_must_fail git rev-list --exclude-hidden=$section --$pseudoopt 2>err &&
+			test_i18ngrep "error: --exclude-hidden cannot be used together with --$pseudoopt" err
+		'
+
+		test_expect_success "$section: fails with --$pseudoopt=pattern" '
+			test_must_fail git rev-list --exclude-hidden=$section --$pseudoopt=pattern 2>err &&
+			test_i18ngrep "error: --exclude-hidden cannot be used together with --$pseudoopt" err
+		'
+	done
+done
+
+test_done