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

[PATCH v10 42/44] refs.c: pass a skip list to name_conflict_fn

From
Ronnie Sahlberg <sahlberg@google.com>
Date
May 16, 2014, 17:37 UTC
Message-ID
<1400261852-31303-43-git-send-email-sahlberg@google.com>
In-Reply-To
<1400261852-31303-1-git-send-email-sahlberg@google.com>

Allow passing a list of refs to skip checking to name_conflict_fn. There are some conditions where we want to allow a temporary conflict and skip checking those refs. For example if we have a transaction that 1, guarantees that m is a packed refs and there is no loose ref for m 2, the transaction will delete m from the packed ref 3, the transaction will create conflicting m/m

For this case we want to be able to lock and create m/m since we know that the conflict is only transient. I.e. the conflict will be automatically resolved by the transaction when it deletes m.

Signed-off-by: Ronnie Sahlberg <sahlberg@google.com>
---
 refs.c | 43 +++++++++++++++++++++++++++++++++----------
 1 file changed, 33 insertions(+), 10 deletions(-)
diff --git a/refs.c b/refs.c
index c5d41bb..3967333 100644
--- a/refs.c
+++ b/refs.c
@@ -798,11 +798,19 @@ struct name_conflict_cb {
 	const char *refname;
 	const char *oldrefname;
 	const char *conflicting_refname;
+	const char **skip;
+	int skipnum;
 };
 
 static int name_conflict_fn(struct ref_entry *entry, void *cb_data)
 {
 	struct name_conflict_cb *data = (struct name_conflict_cb *)cb_data;
+	int i;
+	for(i = 0; i < data->skipnum; i++) {
+		if (!strcmp(entry->name, data->skip[i])) {
+			return 0;
+		}
+	}
 	if (data->oldrefname && !strcmp(data->oldrefname, entry->name))
 		return 0;
 	if (names_conflict(data->refname, entry->name)) {
@@ -817,15 +825,21 @@ static int name_conflict_fn(struct ref_entry *entry, void *cb_data)
  * conflicting with the name of an existing reference in dir.  If
  * oldrefname is non-NULL, ignore potential conflicts with oldrefname
  * (e.g., because oldrefname is scheduled for deletion in the same
- * operation).
+ * operation). skip contains a list of refs we want to skip checking for
+ * conflicts with. Refs may be skipped due to us knowing that it will
+ * be deleted later during a transaction that deletes one reference and then
+ * creates a new conflicting reference. For example a rename from m to m/m.
  */
 static int is_refname_available(const char *refname, const char *oldrefname,
-				struct ref_dir *dir)
+				struct ref_dir *dir,
+				const char **skip, int skipnum)
 {
 	struct name_conflict_cb data;
 	data.refname = refname;
 	data.oldrefname = oldrefname;
 	data.conflicting_refname = NULL;
+	data.skip = skip;
+	data.skipnum = skipnum;
 
 	sort_ref_dir(dir);
 	if (do_for_each_entry_in_dir(dir, 0, name_conflict_fn, &data)) {
@@ -2037,7 +2051,8 @@ int dwim_log(const char *str, int len, unsigned char *sha1, char **log)
 
 static struct ref_lock *lock_ref_sha1_basic(const char *refname,
 					    const unsigned char *old_sha1,
-					    int flags, int *type_p)
+					    int flags, int *type_p,
+					    const char **skip, int skipnum)
 {
 	char *ref_file;
 	const char *orig_refname = refname;
@@ -2084,7 +2099,9 @@ static struct ref_lock *lock_ref_sha1_basic(const char *refname,
 	 * name is a proper prefix of our refname.
 	 */
 	if (missing &&
-	     !is_refname_available(refname, NULL, get_packed_refs(&ref_cache))) {
+	     !is_refname_available(refname, NULL,
+				   get_packed_refs(&ref_cache),
+				   skip, skipnum)) {
 		last_errno = ENOTDIR;
 		goto error_return;
 	}
@@ -2142,7 +2159,7 @@ struct ref_lock *lock_any_ref_for_update(const char *refname,
 					 const unsigned char *old_sha1,
 					 int flags, int *type_p)
 {
-	return lock_ref_sha1_basic(refname, old_sha1, flags, type_p);
+	return lock_ref_sha1_basic(refname, old_sha1, flags, type_p, NULL, 0);
 }
 
 /*
@@ -2620,6 +2637,9 @@ int rename_ref(const char *oldrefname, const char *newrefname, const char *logms
 	int log = !lstat(git_path("logs/%s", oldrefname), &loginfo);
 	const char *symref = NULL;
 
+	if (!strcmp(oldrefname, newrefname))
+		return 0;
+
 	if (log && S_ISLNK(loginfo.st_mode))
 		return error("reflog for %s is a symlink", oldrefname);
 
@@ -2630,10 +2650,12 @@ int rename_ref(const char *oldrefname, const char *newrefname, const char *logms
 	if (!symref)
 		return error("refname %s not found", oldrefname);
 
-	if (!is_refname_available(newrefname, oldrefname, get_packed_refs(&ref_cache)))
+	if (!is_refname_available(newrefname, oldrefname,
+				  get_packed_refs(&ref_cache), NULL, 0))
 		return 1;
 
-	if (!is_refname_available(newrefname, oldrefname, get_loose_refs(&ref_cache)))
+	if (!is_refname_available(newrefname, oldrefname,
+				  get_loose_refs(&ref_cache), NULL, 0))
 		return 1;
 
 	if (log && rename(git_path("logs/%s", oldrefname), git_path(TMP_RENAMED_LOG)))
@@ -2666,7 +2688,7 @@ int rename_ref(const char *oldrefname, const char *newrefname, const char *logms
 
 	logmoved = log;
 
-	lock = lock_ref_sha1_basic(newrefname, NULL, 0, NULL);
+	lock = lock_ref_sha1_basic(newrefname, NULL, 0, NULL, NULL, 0);
 	if (!lock) {
 		error("unable to lock %s for update", newrefname);
 		goto rollback;
@@ -2681,7 +2703,7 @@ int rename_ref(const char *oldrefname, const char *newrefname, const char *logms
 	return 0;
 
  rollback:
-	lock = lock_ref_sha1_basic(oldrefname, NULL, 0, NULL);
+	lock = lock_ref_sha1_basic(oldrefname, NULL, 0, NULL, NULL, 0);
 	if (!lock) {
 		error("unable to lock %s for rollback", oldrefname);
 		goto rollbacklog;
@@ -3536,7 +3558,8 @@ int ref_transaction_commit(struct ref_transaction *transaction,
 						    update->old_sha1 :
 						    NULL),
 						   update->flags,
-						   &update->type);
+						   &update->type,
+						   delnames, delnum);
 		if (!update->lock) {
 			if (err)
 				strbuf_addf(err, "Cannot lock the ref '%s'.",

-- 
2.0.0.rc3.510.g20c254b
Previous: Ronnie SahlbergNext: Ronnie Sahlberg
Message 62 of 65 in “Use ref transactions for all ref updates”
  1. 00/44 Use ref transactions for all ref updatesRonnie Sahlberg, May 16, 2014
  2. 01/44 refs.c: constify the sha arguments for ref_transaction_create|delete|updateRonnie Sahlberg, May 16, 2014
  3. 02/44 refs.c: allow passing NULL to ref_transaction_freeRonnie Sahlberg, May 16, 2014
  4. 03/44 refs.c: add a strbuf argument to ref_transaction_commit for error loggingRonnie Sahlberg, May 16, 2014
  5. 04/44 refs.c: add an err argument to repack_without_refsRonnie Sahlberg, May 16, 2014
  6. Michael HaggertyMay 17, 2014
  7. Ronnie SahlbergMay 27, 2014
  8. 05/44 refs.c: make ref_update_reject_duplicates take a strbuf argument for errorsRonnie Sahlberg, May 16, 2014
  9. 06/44 refs.c: add an err argument to delete_ref_looseRonnie Sahlberg, May 16, 2014
  10. 07/44 refs.c: make update_ref_write update a strbuf on failureRonnie Sahlberg, May 16, 2014
  11. 08/44 update-ref.c: log transaction error from the update_refRonnie Sahlberg, May 16, 2014
  12. 09/44 refs.c: remove the onerr argument to ref_transaction_commitRonnie Sahlberg, May 16, 2014
  13. 10/44 refs.c: change ref_transaction_update() to do error checking and return statusRonnie Sahlberg, May 16, 2014
  14. 11/44 refs.c: change ref_transaction_create to do error checking and return statusRonnie Sahlberg, May 16, 2014
  15. 12/44 refs.c: ref_transaction_delete to check for error and return statusRonnie Sahlberg, May 16, 2014
  16. 13/44 tag.c: use ref transactions when doing updatesRonnie Sahlberg, May 16, 2014
  17. Michael HaggertyMay 17, 2014
  18. Ronnie SahlbergMay 19, 2014
  19. Ronnie SahlbergMay 19, 2014
  20. 14/44 replace.c: use the ref transaction functions for updatesRonnie Sahlberg, May 16, 2014
  21. Michael HaggertyMay 17, 2014
  22. Ronnie SahlbergMay 19, 2014
  23. 15/44 commit.c: use ref transactions for updatesRonnie Sahlberg, May 16, 2014
  24. 16/44 sequencer.c: use ref transactions for all ref updatesRonnie Sahlberg, May 16, 2014
  25. 17/44 fast-import.c: change update_branch to use ref transactionsRonnie Sahlberg, May 16, 2014
  26. 18/44 branch.c: use ref transaction for all ref updatesRonnie Sahlberg, May 16, 2014
  27. Michael HaggertyMay 17, 2014
  28. Ronnie SahlbergMay 19, 2014
  29. 19/44 refs.c: change update_ref to use a transactionRonnie Sahlberg, May 16, 2014
  30. 20/44 refs.c: free the transaction before returning when number of updates is 0Ronnie Sahlberg, May 16, 2014
  31. 21/44 refs.c: ref_transaction_commit should not free the transactionRonnie Sahlberg, May 16, 2014
  32. 22/44 fetch.c: clear errno before calling functions that might set itRonnie Sahlberg, May 16, 2014
  33. Michael HaggertyMay 17, 2014
  34. Ronnie SahlbergMay 27, 2014
  35. 23/44 fetch.c: change s_update_ref to use a ref transactionRonnie Sahlberg, May 16, 2014
  36. 24/44 fetch.c: use a single ref transaction for all ref updatesRonnie Sahlberg, May 16, 2014
  37. Michael HaggertyMay 17, 2014
  38. Michael HaggertyMay 17, 2014
  39. 25/44 receive-pack.c: use a reference transaction for updating the refsRonnie Sahlberg, May 16, 2014
  40. Michael HaggertyMay 17, 2014
  41. Ronnie SahlbergMay 19, 2014
  42. Michael HaggertyMay 23, 2014
  43. Ronnie SahlbergMay 23, 2014
  44. Michael HaggertyMay 23, 2014
  45. Ronnie SahlbergMay 27, 2014
  46. 26/44 fast-import.c: use a ref transaction when dumping tagsRonnie Sahlberg, May 16, 2014
  47. 27/44 walker.c: use ref transaction for ref updatesRonnie Sahlberg, May 16, 2014
  48. 28/44 refs.c: make write_ref_sha1 staticRonnie Sahlberg, May 16, 2014
  49. 29/44 refs.c: make lock_ref_sha1 staticRonnie Sahlberg, May 16, 2014
  50. 30/44 refs.c: add transaction.status and track OPEN/CLOSED/ERRORRonnie Sahlberg, May 16, 2014
  51. 31/44 refs.c: remove the update_ref_lock functionRonnie Sahlberg, May 16, 2014
  52. 32/44 refs.c: remove the update_ref_write functionRonnie Sahlberg, May 16, 2014
  53. 33/44 refs.c: remove lock_ref_sha1Ronnie Sahlberg, May 16, 2014
  54. 34/44 refs.c: make prune_ref use a transaction to delete the refRonnie Sahlberg, May 16, 2014
  55. 35/44 refs.c: make delete_ref use a transactionRonnie Sahlberg, May 16, 2014
  56. 36/44 refs.c: pass the ref log message to _create/delete/update instead of _commitRonnie Sahlberg, May 16, 2014
  57. 37/44 refs.c: pass NULL as *flags to read_ref_fullRonnie Sahlberg, May 16, 2014
  58. 38/44 refs.c: pack all refs before we start to rename a refRonnie Sahlberg, May 16, 2014
  59. 39/44 refs.c: move the check for valid refname to lock_ref_sha1_basicRonnie Sahlberg, May 16, 2014
  60. 40/44 refs.c: call lock_ref_sha1_basic directly from commitRonnie Sahlberg, May 16, 2014
  61. 41/44 refs.c: add a new flag for transaction delete for refs we know are packed onlyRonnie Sahlberg, May 16, 2014
  62. 42/44 refs.c: pass a skip list to name_conflict_fnRonnie Sahlberg, May 16, 2014
  63. 43/44 refs.c: make rename_ref use a transactionRonnie Sahlberg, May 16, 2014
  64. 44/44 refs.c: remove forward declaration of write_ref_sha1Ronnie Sahlberg, May 16, 2014
  65. Jonathan NiederMay 16, 2014

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.