On 12/24/10 6:07 AM, Hyrum K Wright wrote:
On Fri, Dec 24, 2010 at 12:10 AM, Blair Zajac<bl...@orcaware.com> wrote:
The addition of "tracing" to svn_error_t in 1.7 currently uses a special
message string "traced call". Instead of doing this, can we safely add an
svn_boolean_t to svn_error_t the indicates if it is a traced error?
While svn_error_t is public, I'm hoping most people are creating them with
svn_error_create*(), so if that's the case, then code written and compiled
against svn<= 1.6 would work fine when linked against a 1.7 library.
Thoughts?
We don't explicitly say "only use approved methods to create this
object", but we are pretty implicit about it, with an entire
documentation group for "Error creation and destruction". I'm on the
fence on this, but would lean toward "go ahead and extend the struct"
if pressured.
What problem are you trying to solve?
There's this comment in svn_error__is_tracing_link():
svn_boolean_t
svn_error__is_tracing_link(svn_error_t *err)
{
#ifdef SVN_ERR__TRACING
/* ### A strcmp()? Really? I think it's the best we can do unless
### we add a boolean field to svn_error_t that's set only for
### these "placeholder error chain" items. Not such a bad idea,
### really... */
return (err && err->message && !strcmp(err->message, SVN_ERR__TRACED));
#else
return FALSE;
#endif
}
I thought of two other solutions:
1) a sentinel message and we compare by address.
2) negative source file line numbers.
Blair
