Merge branch 'tc/clone-single-revision'

"git clone" learned to make a shallow clone for a single commit
that is not necessarily be at the tip of any branch.

* tc/clone-single-revision:
  builtin/clone: teach git-clone(1) the --revision= option
  parse-options: introduce die_for_incompatible_opt2()
  clone: introduce struct clone_opts in builtin/clone.c
  clone: add tags refspec earlier to fetch refspec
  clone: refactor wanted_peer_refs()
  clone: make it possible to specify --tags
  clone: cut down on global variables in clone.c

2 files changed, 123 insertions, 0 deletions

diff --git a/t/meson.build b/t/meson.build
index 4574280590..a03ebc81fd 100644
--- a/t/meson.build
+++ b/t/meson.build
@@ -721,6 +721,7 @@ integration_tests = [
   't5617-clone-submodules-remote.sh',
   't5618-alternate-refs.sh',
   't5619-clone-local-ambiguous-transport.sh',
+  't5621-clone-revision.sh',
   't5700-protocol-v1.sh',
   't5701-git-serve.sh',
   't5702-protocol-v2.sh',
diff --git a/t/t5621-clone-revision.sh b/t/t5621-clone-revision.sh
new file mode 100755
index 0000000000..db3b8cff55
--- /dev/null
+++ b/t/t5621-clone-revision.sh
@@ -0,0 +1,122 @@
+#!/bin/sh
+
+test_description='tests for git clone --revision'
+GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME=main
+export GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME
+
+. ./test-lib.sh
+
+test_expect_success 'setup' '
+	test_commit --no-tag "initial commit" README "Hello" &&
+	test_commit --annotate "second commit" README "Hello world" v1.0 &&
+	test_commit --no-tag "third commit" README "Hello world!" &&
+	git switch -c feature v1.0 &&
+	test_commit --no-tag "feature commit" README "Hello world!" &&
+	git switch main
+'
+
+test_expect_success 'clone with --revision being a branch' '
+	test_when_finished "rm -rf dst" &&
+	git clone --revision=refs/heads/feature . dst &&
+	git rev-parse refs/heads/feature >expect &&
+	git -C dst rev-parse HEAD >actual &&
+	test_must_fail git -C dst symbolic-ref -q HEAD >/dev/null &&
+	test_cmp expect actual &&
+	git -C dst for-each-ref refs >expect &&
+	test_must_be_empty expect &&
+	test_must_fail git -C dst config remote.origin.fetch
+'
+
+test_expect_success 'clone with --depth and --revision being a branch' '
+	test_when_finished "rm -rf dst" &&
+	git clone --no-local --depth=1 --revision=refs/heads/feature . dst &&
+	git rev-parse refs/heads/feature >expect &&
+	git -C dst rev-parse HEAD >actual &&
+	test_must_fail git -C dst symbolic-ref -q HEAD >/dev/null &&
+	test_cmp expect actual &&
+	git -C dst for-each-ref refs >expect &&
+	test_must_be_empty expect &&
+	test_must_fail git -C dst config remote.origin.fetch &&
+	git -C dst rev-list HEAD >actual &&
+	test_line_count = 1 actual
+'
+
+test_expect_success 'clone with --revision being a tag' '
+	test_when_finished "rm -rf dst" &&
+	git clone --revision=refs/tags/v1.0 . dst &&
+	git rev-parse refs/tags/v1.0^{} >expect &&
+	git -C dst rev-parse HEAD >actual &&
+	test_must_fail git -C dst symbolic-ref -q HEAD >/dev/null &&
+	test_cmp expect actual &&
+	git -C dst for-each-ref refs >expect &&
+	test_must_be_empty expect &&
+	test_must_fail git -C dst config remote.origin.fetch
+'
+
+test_expect_success 'clone with --revision being HEAD' '
+	test_when_finished "rm -rf dst" &&
+	git clone --revision=HEAD . dst &&
+	git rev-parse HEAD >expect &&
+	git -C dst rev-parse HEAD >actual &&
+	test_must_fail git -C dst symbolic-ref -q HEAD >/dev/null &&
+	test_cmp expect actual &&
+	git -C dst for-each-ref refs >expect &&
+	test_must_be_empty expect &&
+	test_must_fail git -C dst config remote.origin.fetch
+'
+
+test_expect_success 'clone with --revision being a raw commit hash' '
+	test_when_finished "rm -rf dst" &&
+	oid=$(git rev-parse refs/heads/feature) &&
+	git clone --revision=$oid . dst &&
+	echo $oid >expect &&
+	git -C dst rev-parse HEAD >actual &&
+	test_must_fail git -C dst symbolic-ref -q HEAD >/dev/null &&
+	test_cmp expect actual &&
+	git -C dst for-each-ref refs >expect &&
+	test_must_be_empty expect &&
+	test_must_fail git -C dst config remote.origin.fetch
+'
+
+test_expect_success 'clone with --revision and --bare' '
+	test_when_finished "rm -rf dst" &&
+	git clone --revision=refs/heads/main --bare . dst &&
+	oid=$(git rev-parse refs/heads/main) &&
+	git -C dst cat-file -t $oid >actual &&
+	echo "commit" >expect &&
+	test_cmp expect actual &&
+	git -C dst for-each-ref refs >expect &&
+	test_must_be_empty expect &&
+	test_must_fail git -C dst config remote.origin.fetch
+'
+
+test_expect_success 'clone with --revision being a short raw commit hash' '
+	test_when_finished "rm -rf dst" &&
+	oid=$(git rev-parse --short refs/heads/feature) &&
+	test_must_fail git clone --revision=$oid . dst 2>err &&
+	test_grep "fatal: Remote revision $oid not found in upstream origin" err
+'
+
+test_expect_success 'clone with --revision being a tree hash' '
+	test_when_finished "rm -rf dst" &&
+	oid=$(git rev-parse refs/heads/feature^{tree}) &&
+	test_must_fail git clone --revision=$oid . dst 2>err &&
+	test_grep "error: object $oid is a tree, not a commit" err
+'
+
+test_expect_success 'clone with --revision being the parent of a ref fails' '
+	test_when_finished "rm -rf dst" &&
+	test_must_fail git clone --revision=refs/heads/main^ . dst
+'
+
+test_expect_success 'clone with --revision and --branch fails' '
+	test_when_finished "rm -rf dst" &&
+	test_must_fail git clone --revision=refs/heads/main --branch=main . dst
+'
+
+test_expect_success 'clone with --revision and --mirror fails' '
+	test_when_finished "rm -rf dst" &&
+	test_must_fail git clone --revision=refs/heads/main --mirror . dst
+'
+
+test_done