git/list[1] front-page[2] threads[3] people[4] search[5] about
 

[PATCH v3] transport-helper: enforce atomic in push_refs_with_push

From
Emily Shaffer <emilyshaffer@google.com>
Date
Jul 11, 2019, 21:19 UTC
Message-ID
<20190711211919.32734-1-emilyshaffer@google.com>
In-Reply-To
<20190709211043.48597-1-emilyshaffer@google.com>

Teach transport-helper how to notice if skipping a ref during push would violate atomicity on the client side. We notice that a ref would be rejected, and choose not to send it, but don't notice that if the client has asked for --atomic we are violating atomicity if all the other pushes we are sending would succeed. Asking the server end to uphold atomicity wouldn't work here as the server doesn't have any idea that we tried to update a ref that's broken.

The added test-case is a succinct way to reproduce this issue that fails today. The same steps work fine when we aren't using a transport-helper to get to the upstream, i.e. when we've added a local repository as a remote:

  git remote add ~/upstream upstream
Signed-off-by: Emily Shaffer <emilyshaffer@google.com>
---
Since the previous version, made a couple changes based on Junio's
comments on the testcase.
- Use show-ref instead of rev-parse to avoid a corner case where a tag
  is named the same thing as the branch we hope not to create
- Reduce number of grep processes by using a longer regex instead
- Check the real contents of the upstream repo instead of just relying
  on the client side's reporting
  - The check on the client side remains, however, to ensure the user is
    made aware of why their perfectly good ref failed to push.
Thanks, all.
 t/t5541-http-push-smart.sh | 49 ++++++++++++++++++++++++++++++++++++++
 transport-helper.c         |  6 +++++
 transport.c                | 13 ++++++++++
 3 files changed, 68 insertions(+)
diff --git a/t/t5541-http-push-smart.sh b/t/t5541-http-push-smart.sh
index 8ef8763e06..92bac43257 100755
--- a/t/t5541-http-push-smart.sh
+++ b/t/t5541-http-push-smart.sh
@@ -177,6 +177,55 @@ test_expect_success 'push (chunked)' '
 	 test $HEAD = $(git rev-parse --verify HEAD))
 '
 
+test_expect_success 'push --atomic also prevents branch creation, reports collateral' '
+	# Setup upstream repo - empty for now
+	d=$HTTPD_DOCUMENT_ROOT_PATH/atomic-branches.git &&
+	git init --bare "$d" &&
+	test_config -C "$d" http.receivepack true &&
+	up="$HTTPD_URL"/smart/atomic-branches.git &&
+
+	# Tell "$up" about two branches for now
+	test_commit atomic1 &&
+	test_commit atomic2 &&
+	git branch collateral &&
+	git push "$up" master collateral &&
+
+	# collateral is a valid push, but should be failed by atomic push
+	git checkout collateral &&
+	test_commit collateral1 &&
+
+	# Make master incompatible with upstream to provoke atomic
+	git checkout master &&
+	git reset --hard HEAD^ &&
+
+	# Add a new branch which should be failed by atomic push. This is a
+	# regression case.
+	git branch atomic &&
+
+	# --atomic should cause entire push to be rejected
+	test_must_fail git push --atomic "$up" master atomic collateral 2>output &&
+
+	# the new branch should not have been created upstream
+	test_must_fail git -C "$d" show-ref --verify refs/heads/atomic &&
+
+	# upstream should still reflect atomic2, the last thing we pushed
+	# successfully
+	git rev-parse atomic2 >expected &&
+	# on master...
+	git -C "$d" rev-parse refs/heads/master >actual &&
+	test_cmp expected actual &&
+	# ...and collateral.
+	git -C "$d" rev-parse refs/heads/collateral >actual &&
+	test_cmp expected actual &&
+
+	# the failed refs should be indicated to the user
+	grep "^ ! .*rejected.* master -> master" output &&
+
+	# the collateral failure refs should be indicated to the user
+	grep "^ ! .*rejected.* atomic -> atomic .*atomic push failed" output &&
+	grep "^ ! .*rejected.* collateral -> collateral .*atomic push failed" output
+'
+
 test_expect_success 'push --all can push to empty repo' '
 	d=$HTTPD_DOCUMENT_ROOT_PATH/empty-all.git &&
 	git init --bare "$d" &&
diff --git a/transport-helper.c b/transport-helper.c
index c7e17ec9cb..6b05a88faf 100644
--- a/transport-helper.c
+++ b/transport-helper.c
@@ -853,6 +853,7 @@ static int push_refs_with_push(struct transport *transport,
 {
 	int force_all = flags & TRANSPORT_PUSH_FORCE;
 	int mirror = flags & TRANSPORT_PUSH_MIRROR;
+	int atomic = flags & TRANSPORT_PUSH_ATOMIC;
 	struct helper_data *data = transport->data;
 	struct strbuf buf = STRBUF_INIT;
 	struct ref *ref;
@@ -872,6 +873,11 @@ static int push_refs_with_push(struct transport *transport,
 		case REF_STATUS_REJECT_NONFASTFORWARD:
 		case REF_STATUS_REJECT_STALE:
 		case REF_STATUS_REJECT_ALREADY_EXISTS:
+			if (atomic) {
+				string_list_clear(&cas_options, 0);
+				return 0;
+			} else
+				continue;
 		case REF_STATUS_UPTODATE:
 			continue;
 		default:
diff --git a/transport.c b/transport.c
index f1fcd2c4b0..d768bc275e 100644
--- a/transport.c
+++ b/transport.c
@@ -1226,6 +1226,19 @@ int transport_push(struct repository *r,
 		err = push_had_errors(remote_refs);
 		ret = push_ret | err;
 
+		if ((flags & TRANSPORT_PUSH_ATOMIC) && err) {
+			for (struct ref *it = remote_refs; it; it = it->next)
+				switch (it->status) {
+				case REF_STATUS_NONE:
+				case REF_STATUS_UPTODATE:
+				case REF_STATUS_OK:
+					it->status = REF_STATUS_ATOMIC_PUSH_FAILED;
+					break;
+				default:
+					break;
+				}
+		}
+
 		if (!quiet || err)
 			transport_print_push_status(transport->url, remote_refs,
 					verbose | porcelain, porcelain,
-- 
2.22.0.410.gd8fdbe21b5-goog
Previous: Junio C HamanoNext: Junio C Hamano
Message 24 of 45 in “transport-helper: enforce atomic in push_refs_with_push”
  1. transport-helper: enforce atomic in push_refs_with_pushEmily Shaffer, Jul 2, 2019
  2. Johannes SchindelinJul 2, 2019
  3. Junio C HamanoJul 2, 2019
  4. Emily ShafferJul 3, 2019
  5. Emily ShafferJul 3, 2019
  6. Johannes SchindelinJul 3, 2019
  7. Emily ShafferJul 3, 2019
  8. Johannes SchindelinJul 4, 2019
  9. Emily ShafferJul 9, 2019
  10. Junio C HamanoJul 2, 2019
  11. Junio C HamanoJul 2, 2019
  12. Emily ShafferJul 3, 2019
  13. Junio C HamanoJul 2, 2019
  14. Emily ShafferJul 3, 2019
  15. SZEDER GáborJul 3, 2019
  16. Junio C HamanoJul 3, 2019
  17. Emily ShafferJul 3, 2019
  18. transport-helper: enforce atomic in push_refs_with_pushEmily Shaffer, Jul 9, 2019
  19. Junio C HamanoJul 10, 2019
  20. Junio C HamanoJul 10, 2019
  21. Emily ShafferJul 11, 2019
  22. Emily ShafferJul 11, 2019
  23. Junio C HamanoJul 11, 2019
  24. transport-helper: enforce atomic in push_refs_with_pushEmily Shaffer, Jul 11, 2019
  25. Junio C HamanoJul 12, 2019
  26. Carlo ArenasJul 16, 2019
  27. Junio C HamanoJul 16, 2019
  28. CodingGuidelines: spell out post-C89 rulesJunio C Hamano, Jul 16, 2019
  29. Jonathan NiederJul 17, 2019
  30. Junio C HamanoJul 17, 2019
  31. Jonathan NiederJul 19, 2019
  32. Bryan TurnerJul 17, 2019
  33. Junio C HamanoJul 17, 2019
  34. Carlo ArenasJul 16, 2019
  35. transport-helper: avoid var decl in for () loop controlJunio C Hamano, Jul 16, 2019
  36. Jonathan NiederJul 17, 2019
  37. SZEDER GáborJul 18, 2019
  38. Junio C HamanoJul 18, 2019
  39. SZEDER GáborJul 18, 2019
  40. Eric SunshineJul 18, 2019
  41. Jonathan NiederJul 19, 2019
  42. Carlo ArenasJul 19, 2019
  43. Junio C HamanoJul 19, 2019
  44. SZEDER GáborJul 27, 2019
  45. Junio C HamanoJul 27, 2019

Read the whole thread, see it on lore, or plain text.

$ cat FOOTERMessages come from the public archive at lore.kernel.org/git, fetched every hour. The front page is chosen and written each morning by an AI editor and can be wrong; the threads themselves are the record. About and API. For agents: an MCP server at https://gitlist.dev/mcp, and any thread, story or person page as Markdown by adding .md to its URL (or sending Accept: text/markdown). Details in /llms.txt.