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[PATCH v14 12/40] refs.c: change ref_transaction_update() to do error checking and return status

From
Ronnie Sahlberg <sahlberg@google.com>
Date
Jun 6, 2014, 22:28 UTC
Message-ID
<1402093758-3162-13-git-send-email-sahlberg@google.com>
In-Reply-To
<1402093758-3162-1-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 fb44978..f5e7a12 100644
--- a/refs.c
+++ b/refs.c
@@ -3418,19 +3418,25 @@ 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 6ee9c9e..32edf3f 100644
--- a/refs.h
+++ b/refs.h
@@ -234,12 +234,16 @@ 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

-- 
2.0.0.582.ge25c160
Previous: Ronnie SahlbergNext: Ronnie Sahlberg
Message 17 of 51 in “Use ref transactions”
  1. 00/40 Use ref transactionsRonnie Sahlberg, Jun 6, 2014
  2. 01/40 refs.c: remove ref_transaction_rollbackRonnie Sahlberg, Jun 6, 2014
  3. 02/40 refs.c: ref_transaction_commit should not free the transactionRonnie Sahlberg, Jun 6, 2014
  4. 03/40 refs.c: constify the sha arguments for ref_transaction_create|delete|updateRonnie Sahlberg, Jun 6, 2014
  5. 04/40 refs.c: allow passing NULL to ref_transaction_freeRonnie Sahlberg, Jun 6, 2014
  6. 05/40 refs.c: add a strbuf argument to ref_transaction_commit for error loggingRonnie Sahlberg, Jun 6, 2014
  7. 06/40 refs.c: add an err argument to repack_without_refsRonnie Sahlberg, Jun 6, 2014
  8. Jonathan NiederJun 10, 2014
  9. Ronnie SahlbergJun 10, 2014
  10. 07/40 refs.c: make ref_update_reject_duplicates take a strbuf argument for errorsRonnie Sahlberg, Jun 6, 2014
  11. 08/40 refs.c: add an err argument to delete_ref_looseRonnie Sahlberg, Jun 6, 2014
  12. Jonathan NiederJun 10, 2014
  13. Ronnie SahlbergJun 11, 2014
  14. 09/40 refs.c: make update_ref_write update a strbuf on failureRonnie Sahlberg, Jun 6, 2014
  15. 10/40 update-ref: use err argument to get error from ref_transaction_commitRonnie Sahlberg, Jun 6, 2014
  16. 11/40 refs.c: remove the onerr argument to ref_transaction_commitRonnie Sahlberg, Jun 6, 2014
  17. 12/40 refs.c: change ref_transaction_update() to do error checking and return statusRonnie Sahlberg, Jun 6, 2014
  18. 13/40 refs.c: change ref_transaction_create to do error checking and return statusRonnie Sahlberg, Jun 6, 2014
  19. 14/40 refs.c: update ref_transaction_delete to check for error and return statusRonnie Sahlberg, Jun 6, 2014
  20. 15/40 refs.c: make ref_transaction_begin take an err argumentRonnie Sahlberg, Jun 6, 2014
  21. 16/40 refs.c: add transaction.status and track OPEN/CLOSED/ERRORRonnie Sahlberg, Jun 6, 2014
  22. Jonathan NiederJun 10, 2014
  23. 17/40 tag.c: use ref transactions when doing updatesRonnie Sahlberg, Jun 6, 2014
  24. 18/40 replace.c: use the ref transaction functions for updatesRonnie Sahlberg, Jun 6, 2014
  25. 19/40 commit.c: use ref transactions for updatesRonnie Sahlberg, Jun 6, 2014
  26. 20/40 sequencer.c: use ref transactions for all ref updatesRonnie Sahlberg, Jun 6, 2014
  27. 21/40 fast-import.c: change update_branch to use ref transactionsRonnie Sahlberg, Jun 6, 2014
  28. 22/40 branch.c: use ref transaction for all ref updatesRonnie Sahlberg, Jun 6, 2014
  29. 23/40 refs.c: change update_ref to use a transactionRonnie Sahlberg, Jun 6, 2014
  30. 24/40 receive-pack.c: use a reference transaction for updating the refsRonnie Sahlberg, Jun 6, 2014
  31. Jonathan NiederJun 10, 2014
  32. Ronnie SahlbergJun 11, 2014
  33. 25/40 fast-import.c: use a ref transaction when dumping tagsRonnie Sahlberg, Jun 6, 2014
  34. Jonathan NiederJun 10, 2014
  35. 26/40 walker.c: use ref transaction for ref updatesRonnie Sahlberg, Jun 6, 2014
  36. Jonathan NiederJun 10, 2014
  37. 27/40 refs.c: make lock_ref_sha1 staticRonnie Sahlberg, Jun 6, 2014
  38. 28/40 refs.c: remove the update_ref_lock functionRonnie Sahlberg, Jun 6, 2014
  39. 29/40 refs.c: remove the update_ref_write functionRonnie Sahlberg, Jun 6, 2014
  40. 30/40 refs.c: remove lock_ref_sha1Ronnie Sahlberg, Jun 6, 2014
  41. 31/40 refs.c: make prune_ref use a transaction to delete the refRonnie Sahlberg, Jun 6, 2014
  42. Jonathan NiederJun 10, 2014
  43. 32/40 refs.c: make delete_ref use a transactionRonnie Sahlberg, Jun 6, 2014
  44. 33/40 refs.c: pass the ref log message to _create/delete/update instead of _commitRonnie Sahlberg, Jun 6, 2014
  45. 34/40 refs.c: pass NULL as *flags to read_ref_fullRonnie Sahlberg, Jun 6, 2014
  46. 35/40 refs.c: move the check for valid refname to lock_ref_sha1_basicRonnie Sahlberg, Jun 6, 2014
  47. 36/40 refs.c: call lock_ref_sha1_basic directly from commitRonnie Sahlberg, Jun 6, 2014
  48. 37/40 refs.c: pass a skip list to name_conflict_fnRonnie Sahlberg, Jun 6, 2014
  49. 38/40 refs.c: propagate any errno==ENOTDIR from _commit back to the callersRonnie Sahlberg, Jun 6, 2014
  50. 39/40 fetch.c: change s_update_ref to use a ref transactionRonnie Sahlberg, Jun 6, 2014
  51. 40/40 refs.c: make write_ref_sha1 staticRonnie Sahlberg, Jun 6, 2014

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