Merge branch 'mh/expire-updateref-fixes'
[gitweb.git] / refs.c
diff --git a/refs.c b/refs.c
index b6a2535fd07425a391e278e96051b4ed870c4f51..e23542b3869b38e47f59f102d28648d30d506574 100644 (file)
--- a/refs.c
+++ b/refs.c
@@ -12,7 +12,6 @@ struct ref_lock {
        struct lock_file *lk;
        unsigned char old_sha1[20];
        int lock_fd;
-       int force_write;
 };
 
 /*
@@ -35,10 +34,29 @@ static unsigned char refname_disposition[256] = {
 };
 
 /*
- * Used as a flag to ref_transaction_delete when a loose ref is being
+ * Flag passed to lock_ref_sha1_basic() telling it to tolerate broken
+ * refs (i.e., because the reference is about to be deleted anyway).
+ */
+#define REF_DELETING   0x02
+
+/*
+ * Used as a flag in ref_update::flags when a loose ref is being
  * pruned.
  */
-#define REF_ISPRUNING  0x0100
+#define REF_ISPRUNING  0x04
+
+/*
+ * Used as a flag in ref_update::flags when the reference should be
+ * updated to new_sha1.
+ */
+#define REF_HAVE_NEW   0x08
+
+/*
+ * Used as a flag in ref_update::flags when old_sha1 should be
+ * checked.
+ */
+#define REF_HAVE_OLD   0x10
+
 /*
  * Try to read one refname component from the front of refname.
  * Return the length of the component found, or -1 if the component is
@@ -1627,8 +1645,7 @@ const char *resolve_ref_unsafe(const char *refname, int resolve_flags, unsigned
 
 char *resolve_refdup(const char *ref, int resolve_flags, unsigned char *sha1, int *flags)
 {
-       const char *ret = resolve_ref_unsafe(ref, resolve_flags, sha1, flags);
-       return ret ? xstrdup(ret) : NULL;
+       return xstrdup_or_null(resolve_ref_unsafe(ref, resolve_flags, sha1, flags));
 }
 
 /* The argument to filter_refs */
@@ -2250,7 +2267,7 @@ 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,
                                            const struct string_list *skip,
-                                           int flags, int *type_p)
+                                           unsigned int flags, int *type_p)
 {
        char *ref_file;
        const char *orig_refname = refname;
@@ -2319,8 +2336,6 @@ static struct ref_lock *lock_ref_sha1_basic(const char *refname,
        lock->ref_name = xstrdup(refname);
        lock->orig_ref_name = xstrdup(orig_refname);
        ref_file = git_path("%s", refname);
-       if ((flags & REF_NODEREF) && (type & REF_ISSYMREF))
-               lock->force_write = 1;
 
  retry:
        switch (safe_create_leading_directories(ref_file)) {
@@ -2561,7 +2576,7 @@ static void prune_ref(struct ref_to_prune *r)
        transaction = ref_transaction_begin(&err);
        if (!transaction ||
            ref_transaction_delete(transaction, r->name, r->sha1,
-                                  REF_ISPRUNING, 1, NULL, &err) ||
+                                  REF_ISPRUNING, NULL, &err) ||
            ref_transaction_commit(transaction, &err)) {
                ref_transaction_free(transaction);
                error("%s", err.buf);
@@ -2731,15 +2746,16 @@ static int delete_ref_loose(struct ref_lock *lock, int flag, struct strbuf *err)
        return 0;
 }
 
-int delete_ref(const char *refname, const unsigned char *sha1, int delopt)
+int delete_ref(const char *refname, const unsigned char *sha1, unsigned int flags)
 {
        struct ref_transaction *transaction;
        struct strbuf err = STRBUF_INIT;
 
        transaction = ref_transaction_begin(&err);
        if (!transaction ||
-           ref_transaction_delete(transaction, refname, sha1, delopt,
-                                  sha1 && !is_null_sha1(sha1), NULL, &err) ||
+           ref_transaction_delete(transaction, refname,
+                                  (sha1 && !is_null_sha1(sha1)) ? sha1 : NULL,
+                                  flags, NULL, &err) ||
            ref_transaction_commit(transaction, &err)) {
                error("%s", err.buf);
                ref_transaction_free(transaction);
@@ -3544,16 +3560,27 @@ int for_each_reflog(each_ref_fn fn, void *cb_data)
 }
 
 /**
- * Information needed for a single ref update.  Set new_sha1 to the
- * new value or to zero to delete the ref.  To check the old value
- * while locking the ref, set have_old to 1 and set old_sha1 to the
- * value or to zero to ensure the ref does not exist before update.
+ * Information needed for a single ref update. Set new_sha1 to the new
+ * value or to null_sha1 to delete the ref. To check the old value
+ * while the ref is locked, set (flags & REF_HAVE_OLD) and set
+ * old_sha1 to the old value, or to null_sha1 to ensure the ref does
+ * not exist before update.
  */
 struct ref_update {
+       /*
+        * If (flags & REF_HAVE_NEW), set the reference to this value:
+        */
        unsigned char new_sha1[20];
+       /*
+        * If (flags & REF_HAVE_OLD), check that the reference
+        * previously had this value:
+        */
        unsigned char old_sha1[20];
-       int flags; /* REF_NODEREF? */
-       int have_old; /* 1 if old_sha1 is valid, 0 otherwise */
+       /*
+        * One or more of REF_HAVE_NEW, REF_HAVE_OLD, REF_NODEREF,
+        * REF_DELETING, and REF_ISPRUNING:
+        */
+       unsigned int flags;
        struct ref_lock *lock;
        int type;
        char *msg;
@@ -3625,7 +3652,7 @@ 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, const char *msg,
+                          unsigned int flags, const char *msg,
                           struct strbuf *err)
 {
        struct ref_update *update;
@@ -3635,10 +3662,7 @@ int ref_transaction_update(struct ref_transaction *transaction,
        if (transaction->state != REF_TRANSACTION_OPEN)
                die("BUG: update called for transaction that is not open");
 
-       if (have_old && !old_sha1)
-               die("BUG: have_old is true but old_sha1 is NULL");
-
-       if (!is_null_sha1(new_sha1) &&
+       if (new_sha1 && !is_null_sha1(new_sha1) &&
            check_refname_format(refname, REFNAME_ALLOW_ONELEVEL)) {
                strbuf_addf(err, "refusing to update ref with bad name %s",
                            refname);
@@ -3646,11 +3670,15 @@ int ref_transaction_update(struct ref_transaction *transaction,
        }
 
        update = add_update(transaction, refname);
-       hashcpy(update->new_sha1, new_sha1);
-       update->flags = flags;
-       update->have_old = have_old;
-       if (have_old)
+       if (new_sha1) {
+               hashcpy(update->new_sha1, new_sha1);
+               flags |= REF_HAVE_NEW;
+       }
+       if (old_sha1) {
                hashcpy(update->old_sha1, old_sha1);
+               flags |= REF_HAVE_OLD;
+       }
+       update->flags = flags;
        if (msg)
                update->msg = xstrdup(msg);
        return 0;
@@ -3659,34 +3687,52 @@ int ref_transaction_update(struct ref_transaction *transaction,
 int ref_transaction_create(struct ref_transaction *transaction,
                           const char *refname,
                           const unsigned char *new_sha1,
-                          int flags, const char *msg,
+                          unsigned int flags, const char *msg,
                           struct strbuf *err)
 {
+       if (!new_sha1 || is_null_sha1(new_sha1))
+               die("BUG: create called without valid new_sha1");
        return ref_transaction_update(transaction, refname, new_sha1,
-                                     null_sha1, flags, 1, msg, err);
+                                     null_sha1, flags, msg, err);
 }
 
 int ref_transaction_delete(struct ref_transaction *transaction,
                           const char *refname,
                           const unsigned char *old_sha1,
-                          int flags, int have_old, const char *msg,
+                          unsigned int flags, const char *msg,
+                          struct strbuf *err)
+{
+       if (old_sha1 && is_null_sha1(old_sha1))
+               die("BUG: delete called with old_sha1 set to zeros");
+       return ref_transaction_update(transaction, refname,
+                                     null_sha1, old_sha1,
+                                     flags, msg, err);
+}
+
+int ref_transaction_verify(struct ref_transaction *transaction,
+                          const char *refname,
+                          const unsigned char *old_sha1,
+                          unsigned int flags,
                           struct strbuf *err)
 {
-       return ref_transaction_update(transaction, refname, null_sha1,
-                                     old_sha1, flags, have_old, msg, err);
+       if (!old_sha1)
+               die("BUG: verify called with old_sha1 set to NULL");
+       return ref_transaction_update(transaction, refname,
+                                     NULL, old_sha1,
+                                     flags, NULL, err);
 }
 
-int update_ref(const char *action, const char *refname,
-              const unsigned char *sha1, const unsigned char *oldval,
-              int flags, enum action_on_err onerr)
+int update_ref(const char *msg, const char *refname,
+              const unsigned char *new_sha1, const unsigned char *old_sha1,
+              unsigned int flags, enum action_on_err onerr)
 {
        struct ref_transaction *t;
        struct strbuf err = STRBUF_INIT;
 
        t = ref_transaction_begin(&err);
        if (!t ||
-           ref_transaction_update(t, refname, sha1, oldval, flags,
-                                  !!oldval, action, &err) ||
+           ref_transaction_update(t, refname, new_sha1, old_sha1,
+                                  flags, msg, &err) ||
            ref_transaction_commit(t, &err)) {
                const char *str = "update_ref failed for ref '%s': %s";
 
@@ -3762,17 +3808,17 @@ int ref_transaction_commit(struct ref_transaction *transaction,
        /* Acquire all locks while verifying old values */
        for (i = 0; i < n; i++) {
                struct ref_update *update = updates[i];
-               int flags = update->flags;
+               unsigned int flags = update->flags;
 
-               if (is_null_sha1(update->new_sha1))
+               if ((flags & REF_HAVE_NEW) && is_null_sha1(update->new_sha1))
                        flags |= REF_DELETING;
-               update->lock = lock_ref_sha1_basic(update->refname,
-                                                  (update->have_old ?
-                                                   update->old_sha1 :
-                                                   NULL),
-                                                  NULL,
-                                                  flags,
-                                                  &update->type);
+               update->lock = lock_ref_sha1_basic(
+                               update->refname,
+                               ((update->flags & REF_HAVE_OLD) ?
+                                update->old_sha1 : NULL),
+                               NULL,
+                               flags,
+                               &update->type);
                if (!update->lock) {
                        ret = (errno == ENOTDIR)
                                ? TRANSACTION_NAME_CONFLICT
@@ -3786,10 +3832,18 @@ int ref_transaction_commit(struct ref_transaction *transaction,
        /* Perform updates first so live commits remain referenced */
        for (i = 0; i < n; i++) {
                struct ref_update *update = updates[i];
+               int flags = update->flags;
+
+               if ((flags & REF_HAVE_NEW) && !is_null_sha1(update->new_sha1)) {
+                       int overwriting_symref = ((update->type & REF_ISSYMREF) &&
+                                                 (update->flags & REF_NODEREF));
 
-               if (!is_null_sha1(update->new_sha1)) {
-                       if (!update->lock->force_write &&
-                           !hashcmp(update->lock->old_sha1, update->new_sha1)) {
+                       if (!overwriting_symref
+                           && !hashcmp(update->lock->old_sha1, update->new_sha1)) {
+                               /*
+                                * The reference already has the desired
+                                * value, so we don't need to write it.
+                                */
                                unlock_ref(update->lock);
                                update->lock = NULL;
                        } else if (write_ref_sha1(update->lock, update->new_sha1,
@@ -3809,14 +3863,15 @@ int ref_transaction_commit(struct ref_transaction *transaction,
        /* Perform deletes now that updates are safely completed */
        for (i = 0; i < n; i++) {
                struct ref_update *update = updates[i];
+               int flags = update->flags;
 
-               if (update->lock) {
+               if ((flags & REF_HAVE_NEW) && is_null_sha1(update->new_sha1)) {
                        if (delete_ref_loose(update->lock, update->type, err)) {
                                ret = TRANSACTION_GENERIC_ERROR;
                                goto cleanup;
                        }
 
-                       if (!(update->flags & REF_ISPRUNING))
+                       if (!(flags & REF_ISPRUNING))
                                string_list_append(&refs_to_delete,
                                                   update->lock->ref_name);
                }
@@ -4025,6 +4080,7 @@ int reflog_expire(const char *refname, const unsigned char *sha1,
        struct ref_lock *lock;
        char *log_file;
        int status = 0;
+       int type;
 
        memset(&cb, 0, sizeof(cb));
        cb.flags = flags;
@@ -4036,7 +4092,7 @@ int reflog_expire(const char *refname, const unsigned char *sha1,
         * reference itself, plus we might need to update the
         * reference if --updateref was specified:
         */
-       lock = lock_ref_sha1_basic(refname, sha1, NULL, 0, NULL);
+       lock = lock_ref_sha1_basic(refname, sha1, NULL, 0, &type);
        if (!lock)
                return error("cannot lock ref '%s'", refname);
        if (!reflog_exists(refname)) {
@@ -4073,10 +4129,21 @@ int reflog_expire(const char *refname, const unsigned char *sha1,
        (*cleanup_fn)(cb.policy_cb);
 
        if (!(flags & EXPIRE_REFLOGS_DRY_RUN)) {
+               /*
+                * It doesn't make sense to adjust a reference pointed
+                * to by a symbolic ref based on expiring entries in
+                * the symbolic reference's reflog. Nor can we update
+                * a reference if there are no remaining reflog
+                * entries.
+                */
+               int update = (flags & EXPIRE_REFLOGS_UPDATE_REF) &&
+                       !(type & REF_ISSYMREF) &&
+                       !is_null_sha1(cb.last_kept_sha1);
+
                if (close_lock_file(&reflog_lock)) {
                        status |= error("couldn't write %s: %s", log_file,
                                        strerror(errno));
-               } else if ((flags & EXPIRE_REFLOGS_UPDATE_REF) &&
+               } else if (update &&
                        (write_in_full(lock->lock_fd,
                                sha1_to_hex(cb.last_kept_sha1), 40) != 40 ||
                         write_str_in_full(lock->lock_fd, "\n") != 1 ||
@@ -4087,7 +4154,7 @@ int reflog_expire(const char *refname, const unsigned char *sha1,
                } else if (commit_lock_file(&reflog_lock)) {
                        status |= error("unable to commit reflog '%s' (%s)",
                                        log_file, strerror(errno));
-               } else if ((flags & EXPIRE_REFLOGS_UPDATE_REF) && commit_ref(lock)) {
+               } else if (update && commit_ref(lock)) {
                        status |= error("couldn't set %s", lock->ref_name);
                }
        }