Re: [PATCH v4 15/27] fast-import.c: change update_branch to use ref transactions

On Mon, Apr 28, 2014 at 7:18 PM, Eric Sunshine [off-list ref] wrote:

On Mon, Apr 28, 2014 at 6:54 PM, Ronnie Sahlberg [off-list ref] wrote:

quoted

Change update_branch() to use ref transactions for updates.

Signed-off-by: Ronnie Sahlberg <redacted>
---
 fast-import.c | 20 ++++++++++++--------
 1 file changed, 12 insertions(+), 8 deletions(-)

diff --git a/fast-import.c b/fast-import.c
index fb4738d..300c8dc 100644
--- a/fast-import.c
+++ b/fast-import.c

@@ -1678,36 +1678,40 @@ found_entry:
 static int update_branch(struct branch *b)
 {
        static const char *msg = "fast-import";
-       struct ref_lock *lock;
+       struct ref_transaction *transaction;
        unsigned char old_sha1[20];
+       struct strbuf err = STRBUF_INIT;

        if (is_null_sha1(b->sha1))
                return 0;
        if (read_ref(b->name, old_sha1))
                hashclr(old_sha1);
-       lock = lock_any_ref_for_update(b->name, old_sha1, 0, NULL);
-       if (!lock)
-               return error("Unable to lock %s", b->name);
        if (!force_update && !is_null_sha1(old_sha1)) {
                struct commit *old_cmit, *new_cmit;

                old_cmit = lookup_commit_reference_gently(old_sha1, 0);
                new_cmit = lookup_commit_reference_gently(b->sha1, 0);
                if (!old_cmit || !new_cmit) {
-                       unlock_ref(lock);
                        return error("Branch %s is missing commits.", b->name);
                }

                if (!in_merge_bases(old_cmit, new_cmit)) {
-                       unlock_ref(lock);
                        warning("Not updating %s"
                                " (new tip %s does not contain %s)",
                                b->name, sha1_to_hex(b->sha1), sha1_to_hex(old_sha1));
                        return -1;
                }
        }
-       if (write_ref_sha1(lock, b->sha1, msg) < 0)
-               return error("Unable to update %s", b->name);
+       transaction = ref_transaction_begin();
+       if ((!transaction ||
+           ref_transaction_update(transaction, b->name, b->sha1, old_sha1,
+                                  0, 1)) ||
+           (ref_transaction_commit(transaction, msg, &err) &&
+            !(transaction = NULL))) {
+               ref_transaction_rollback(transaction);
+               return error("Unable to update branch %s: %s", b->name,
+                            strbuf_detach(&err, NULL));

Iffy strbuf handling. The strbuf content is being leaked here whether
detached or not.

Thanks!

I have updated this and all other patches to make sure we do a
strbuf_release() any time we have
added to the string.

I also did a quick audit of the strbuf_detach() use in builtin/*
(which I based my use on)
and there seems to be quite common that strbuf_detach() is used in a
way that will leak memory.


I will make a note and perhaps audit all the other strbuf_detach()
calls for a future patch series.

quoted

+       }
        return 0;
 }

--
1.9.1.528.g98b8868.dirty