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[PATCH v18 20/48] refs.c: change ref_transaction_update() to do error checking and return status

From
Ronnie Sahlberg <sahlberg@google.com>
Date
Jun 17, 2014, 15:53 UTC
Message-ID
<1403020442-31049-21-git-send-email-sahlberg@google.com>
In-Reply-To
<1403020442-31049-1-git-send-email-sahlberg@google.com>

Update ref_transaction_update() do some basic error checking and return non-zero on error. Update all callers to check ref_transaction_update() for error. There are currently no conditions in _update that will return error but there will be in the future. Add an err argument that will be updated on failure. In future patches we will start doing both locking and checking for name conflicts in _update instead of _commit at which time this function will start returning errors for these conditions.

Also check for BUGs during update and die(BUG:...) if we are calling _update with have_old but the old_sha1 pointer is NULL.

Reviewed-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Ronnie Sahlberg <sahlberg@google.com>
---
 builtin/update-ref.c | 12 +++++++-----
 refs.c               | 18 ++++++++++++------
 refs.h               | 14 +++++++++-----
 3 files changed, 28 insertions(+), 16 deletions(-)
diff --git a/builtin/update-ref.c b/builtin/update-ref.c
index 88ab785..3067b11 100644
--- a/builtin/update-ref.c
+++ b/builtin/update-ref.c
@@ -16,6 +16,7 @@ static struct ref_transaction *transaction;
 
 static char line_termination = '\n';
 static int update_flags;
+static struct strbuf err = STRBUF_INIT;
 
 /*
  * Parse one whitespace- or NUL-terminated, possibly C-quoted argument
@@ -197,8 +198,9 @@ static const char *parse_cmd_update(struct strbuf *input, const char *next)
 	if (*next != line_termination)
 		die("update %s: extra input: %s", refname, next);
 
-	ref_transaction_update(transaction, refname, new_sha1, old_sha1,
-			       update_flags, have_old);
+	if (ref_transaction_update(transaction, refname, new_sha1, old_sha1,
+				   update_flags, have_old, &err))
+		die("%s", err.buf);
 
 	update_flags = 0;
 	free(refname);
@@ -286,8 +288,9 @@ static const char *parse_cmd_verify(struct strbuf *input, const char *next)
 	if (*next != line_termination)
 		die("verify %s: extra input: %s", refname, next);
 
-	ref_transaction_update(transaction, refname, new_sha1, old_sha1,
-			       update_flags, have_old);
+	if (ref_transaction_update(transaction, refname, new_sha1, old_sha1,
+				   update_flags, have_old, &err))
+		die("%s", err.buf);
 
 	update_flags = 0;
 	free(refname);
@@ -342,7 +345,6 @@ int cmd_update_ref(int argc, const char **argv, const char *prefix)
 	const char *refname, *oldval, *msg = NULL;
 	unsigned char sha1[20], oldsha1[20];
 	int delete = 0, no_deref = 0, read_stdin = 0, end_null = 0, flags = 0;
-	struct strbuf err = STRBUF_INIT;
 	struct option options[] = {
 		OPT_STRING( 'm', NULL, &msg, N_("reason"), N_("reason of the update")),
 		OPT_BOOL('d', NULL, &delete, N_("delete the reference")),
diff --git a/refs.c b/refs.c
index ebd4d59..88d2df4 100644
--- a/refs.c
+++ b/refs.c
@@ -3451,19 +3451,25 @@ static struct ref_update *add_update(struct ref_transaction *transaction,
 	return update;
 }
 
-void ref_transaction_update(struct ref_transaction *transaction,
-			    const char *refname,
-			    const unsigned char *new_sha1,
-			    const unsigned char *old_sha1,
-			    int flags, int have_old)
+int ref_transaction_update(struct ref_transaction *transaction,
+			   const char *refname,
+			   const unsigned char *new_sha1,
+			   const unsigned char *old_sha1,
+			   int flags, int have_old,
+			   struct strbuf *err)
 {
-	struct ref_update *update = add_update(transaction, refname);
+	struct ref_update *update;
+
+	if (have_old && !old_sha1)
+		die("BUG: have_old is true but old_sha1 is NULL");
 
+	update = add_update(transaction, refname);
 	hashcpy(update->new_sha1, new_sha1);
 	update->flags = flags;
 	update->have_old = have_old;
 	if (have_old)
 		hashcpy(update->old_sha1, old_sha1);
+	return 0;
 }
 
 void ref_transaction_create(struct ref_transaction *transaction,
diff --git a/refs.h b/refs.h
index c92f59f..6c99ccf 100644
--- a/refs.h
+++ b/refs.h
@@ -246,12 +246,16 @@ struct ref_transaction *ref_transaction_begin(void);
  * be deleted.  If have_old is true, then old_sha1 holds the value
  * that the reference should have had before the update, or zeros if
  * it must not have existed beforehand.
+ * Function returns 0 on success and non-zero on failure. A failure to update
+ * means that the transaction as a whole has failed and will need to be
+ * rolled back. On failure the err buffer will be updated.
  */
-void ref_transaction_update(struct ref_transaction *transaction,
-			    const char *refname,
-			    const unsigned char *new_sha1,
-			    const unsigned char *old_sha1,
-			    int flags, int have_old);
+int ref_transaction_update(struct ref_transaction *transaction,
+			   const char *refname,
+			   const unsigned char *new_sha1,
+			   const unsigned char *old_sha1,
+			   int flags, int have_old,
+			   struct strbuf *err);
 
 /*
  * Add a reference creation to transaction.  new_sha1 is the value

-- 
2.0.0.438.gec92e5c
Previous: Ronnie SahlbergNext: Ronnie Sahlberg
Message 33 of 61 in “Use ref transactions”
  1. 00/48 Use ref transactionsRonnie Sahlberg, Jun 17, 2014
  2. 01/48 refs.c: remove ref_transaction_rollbackRonnie Sahlberg, Jun 17, 2014
  3. 02/48 refs.c: ref_transaction_commit should not free the transactionRonnie Sahlberg, Jun 17, 2014
  4. 03/48 refs.c: constify the sha arguments for ref_transaction_create|delete|updateRonnie Sahlberg, Jun 17, 2014
  5. 04/48 refs.c: allow passing NULL to ref_transaction_freeRonnie Sahlberg, Jun 17, 2014
  6. 05/48 refs.c: add a strbuf argument to ref_transaction_commit for error loggingRonnie Sahlberg, Jun 17, 2014
  7. 06/48 lockfile.c: add a new public function unable_to_lock_messageRonnie Sahlberg, Jun 17, 2014
  8. 07/48 lockfile.c: make lock_file return a meaningful errno on failureiRonnie Sahlberg, Jun 17, 2014
  9. Michael HaggertyJun 18, 2014
  10. Michael HaggertyJun 18, 2014
  11. 08/48 refs.c: add an err argument to repack_without_refsRonnie Sahlberg, Jun 17, 2014
  12. 09/48 refs.c: make sure log_ref_setup returns a meaningful errnoRonnie Sahlberg, Jun 17, 2014
  13. 10/48 refs.c: verify_lock should set errno to something meaningfulRonnie Sahlberg, Jun 17, 2014
  14. Michael HaggertyJun 18, 2014
  15. Ronnie SahlbergJun 18, 2014
  16. 11/48 refs.c: make remove_empty_directories alwasy set errno to something saneRonnie Sahlberg, Jun 17, 2014
  17. Michael HaggertyJun 18, 2014
  18. Ronnie SahlbergJun 18, 2014
  19. 12/48 refs.c: commit_packed_refs to return a meaningful errno on failureRonnie Sahlberg, Jun 17, 2014
  20. 13/48 refs.c: make resolve_ref_unsafe set errno to something meaningful on errorRonnie Sahlberg, Jun 17, 2014
  21. 14/48 refs.c: log_ref_write should try to return meaningful errnoRonnie Sahlberg, Jun 17, 2014
  22. Michael HaggertyJun 18, 2014
  23. Ronnie SahlbergJun 18, 2014
  24. 15/48 refs.c: make ref_update_reject_duplicates take a strbuf argument for errorsRonnie Sahlberg, Jun 17, 2014
  25. 16/48 refs.c: add an err argument to delete_ref_looseRonnie Sahlberg, Jun 17, 2014
  26. Michael HaggertyJun 18, 2014
  27. Ronnie SahlbergJun 18, 2014
  28. Michael HaggertyJun 18, 2014
  29. Ronnie SahlbergJun 19, 2014
  30. 17/48 refs.c: make update_ref_write update a strbuf on failureRonnie Sahlberg, Jun 17, 2014
  31. 18/48 update-ref: use err argument to get error from ref_transaction_commitRonnie Sahlberg, Jun 17, 2014
  32. 19/48 refs.c: remove the onerr argument to ref_transaction_commitRonnie Sahlberg, Jun 17, 2014
  33. 20/48 refs.c: change ref_transaction_update() to do error checking and return statusRonnie Sahlberg, Jun 17, 2014
  34. 21/48 refs.c: change ref_transaction_create to do error checking and return statusRonnie Sahlberg, Jun 17, 2014
  35. 22/48 refs.c: update ref_transaction_delete to check for error and return statusRonnie Sahlberg, Jun 17, 2014
  36. 23/48 refs.c: make ref_transaction_begin take an err argumentRonnie Sahlberg, Jun 17, 2014
  37. 24/48 refs.c: add transaction.status and track OPEN/CLOSED/ERRORRonnie Sahlberg, Jun 17, 2014
  38. 25/48 tag.c: use ref transactions when doing updatesRonnie Sahlberg, Jun 17, 2014
  39. 26/48 replace.c: use the ref transaction functions for updatesRonnie Sahlberg, Jun 17, 2014
  40. 27/48 commit.c: use ref transactions for updatesRonnie Sahlberg, Jun 17, 2014
  41. 28/48 sequencer.c: use ref transactions for all ref updatesRonnie Sahlberg, Jun 17, 2014
  42. 29/48 fast-import.c: change update_branch to use ref transactionsRonnie Sahlberg, Jun 17, 2014
  43. 30/48 branch.c: use ref transaction for all ref updatesRonnie Sahlberg, Jun 17, 2014
  44. 31/48 refs.c: change update_ref to use a transactionRonnie Sahlberg, Jun 17, 2014
  45. 32/48 receive-pack.c: use a reference transaction for updating the refsRonnie Sahlberg, Jun 17, 2014
  46. 33/48 fast-import.c: use a ref transaction when dumping tagsRonnie Sahlberg, Jun 17, 2014
  47. 34/48 walker.c: use ref transaction for ref updatesRonnie Sahlberg, Jun 17, 2014
  48. 35/48 refs.c: make lock_ref_sha1 staticRonnie Sahlberg, Jun 17, 2014
  49. 36/48 refs.c: remove the update_ref_lock functionRonnie Sahlberg, Jun 17, 2014
  50. 37/48 refs.c: remove the update_ref_write functionRonnie Sahlberg, Jun 17, 2014
  51. 38/48 refs.c: remove lock_ref_sha1Ronnie Sahlberg, Jun 17, 2014
  52. 39/48 refs.c: make prune_ref use a transaction to delete the refRonnie Sahlberg, Jun 17, 2014
  53. 40/48 refs.c: make delete_ref use a transactionRonnie Sahlberg, Jun 17, 2014
  54. 41/48 refs.c: pass the ref log message to _create/delete/update instead of _commitRonnie Sahlberg, Jun 17, 2014
  55. 42/48 refs.c: pass NULL as *flags to read_ref_fullRonnie Sahlberg, Jun 17, 2014
  56. 43/48 refs.c: move the check for valid refname to lock_ref_sha1_basicRonnie Sahlberg, Jun 17, 2014
  57. 44/48 refs.c: call lock_ref_sha1_basic directly from commitRonnie Sahlberg, Jun 17, 2014
  58. 45/48 refs.c: pass a skip list to name_conflict_fnRonnie Sahlberg, Jun 17, 2014
  59. 46/48 refs.c: propagate any errno==ENOTDIR from _commit back to the callersRonnie Sahlberg, Jun 17, 2014
  60. 47/48 fetch.c: change s_update_ref to use a ref transactionRonnie Sahlberg, Jun 17, 2014
  61. 48/48 refs.c: make write_ref_sha1 staticRonnie Sahlberg, Jun 17, 2014

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