svn commit: r1074591 - in /subversion/trunk/subversion: include/svn_error.h svnsync/main.c

[ph...@apache.org]

Author: philip
Date: Fri Feb 25 15:51:32 2011
New Revision: 1074591

URL: http://svn.apache.org/viewvc?rev=1074591&view=rev
Log:
Calling svn_error_compose_create with two functions as parameters
allows the functions to be called in either order.  This is usually
a bug, and was a bug in svnsync.

* subversion/include/svn_error.h
  (svn_error_compose_create, svn_error_compose): Add comment about
   potential usage error.

* subversion/svnsync/main.c
  (with_locked): Avoid undefined order of evaluation problem.

Modified:
    subversion/trunk/subversion/include/svn_error.h
    subversion/trunk/subversion/svnsync/main.c

Modified: subversion/trunk/subversion/include/svn_error.h
URL: http://svn.apache.org/viewvc/subversion/trunk/subversion/include/svn_error.h?rev=1074591&r1=1074590&r2=1074591&view=diff
==============================================================================
--- subversion/trunk/subversion/include/svn_error.h (original)
+++ subversion/trunk/subversion/include/svn_error.h Fri Feb 25 15:51:32 2011
@@ -148,6 +148,10 @@ svn_error_quick_wrap(svn_error_t *child,
  * @a err2 may be @c SVN_NO_ERROR.  If both are not @c SVN_NO_ERROR,
  * @a err2 will follow @a err1 in the chain of the returned error.
  *
+ * Either @a err1 or @a err2 can be functions that return svn_error_t*
+ * but if both are functions they can be evaluated in either order as
+ * per the C language rules.
+ *
  * @since New in 1.6.
  */
 svn_error_t *
@@ -157,6 +161,10 @@ svn_error_compose_create(svn_error_t *er
 /** Add @a new_err to the end of @a chain's chain of errors.  The @a new_err
  * chain will be copied into @a chain's pool and destroyed, so @a new_err
  * itself becomes invalid after this function.
+ *
+ * Either @a chain or @a new_err can be functions that return svn_error_t*
+ * but if both are functions they can be evaluated in either order as
+ * per the C language rules.
  */
 void
 svn_error_compose(svn_error_t *chain,

Modified: subversion/trunk/subversion/svnsync/main.c
URL: http://svn.apache.org/viewvc/subversion/trunk/subversion/svnsync/main.c?rev=1074591&r1=1074590&r2=1074591&view=diff
==============================================================================
--- subversion/trunk/subversion/svnsync/main.c (original)
+++ subversion/trunk/subversion/svnsync/main.c Fri Feb 25 15:51:32 2011
@@ -393,11 +393,12 @@ with_locked(svn_ra_session_t *session,
             apr_pool_t *pool)
 {
   const svn_string_t *lock_string;
+  svn_error_t *err;
 
   SVN_ERR(get_lock(&lock_string, session, steal_lock, pool));
 
-  return svn_error_compose_create(
-             func(session, baton, pool),
+  err = func(session, baton, pool);
+  return svn_error_compose_create(err,
              svn_ra__release_operational_lock(session, SVNSYNC_PROP_LOCK,
                                               lock_string, pool));
 }