Re: Printing error stacks. (was: Re: svn_error_symbolic_name)

[Daniel Shahaf]

Stefan Sperling wrote on Sat, Apr 13, 2013 at 01:55:01 +0200:
> On Fri, Apr 12, 2013 at 02:34:26PM -0400, C. Michael Pilato wrote:
> > svn: E180003: Unable to connect to a repository at URL
> > 'file:///home/cmpilato/tests/arch'
> > svn: E180012: Unable to open an ra_local session to URL
> > svn: E180001: Unable to open repository 'file:///home/cmpilato/tests/arch'
> > (E1800001 = SVN_ERR_RA_LOCAL_REPOS_OPEN_FAILED)
> > (E1800003 = SVN_ERR_SOMETHING_ELSE)
> > (E1800012 = SVN_ERR_YET_ANOTHER_FAILURE)
> > 
> > Thoughts?
> 
> Of the suggestions given in this thread so far, I like this suggestion
> best (and I've read the entire thread).
> 
> Today on IRC I said that I'd rather see symbolic names instead
> of error numbers. I still think that might be nice. The current
> proposals in this thread seem to focus on displaying *both* numbers
> and their symbolic names and I think that's too much verbosity.

Here's a quick shot at that.

% $svn diff -x-p
Index: subversion/libsvn_subr/error.c
===================================================================
--- subversion/libsvn_subr/error.c      (revision 1467481)
+++ subversion/libsvn_subr/error.c      (working copy)
@@ -562,8 +562,7 @@ svn_handle_error2(svn_error_t *err,
   apr_pool_create(&subpool, err->pool);
   empties = apr_array_make(subpool, 0, sizeof(apr_status_t));
 
-  tmp_err = err;
-  while (tmp_err)
+  for (tmp_err = err; tmp_err; tmp_err = tmp_err->child)
     {
       svn_boolean_t printed_already = FALSE;
 
@@ -589,9 +588,21 @@ svn_handle_error2(svn_error_t *err,
               APR_ARRAY_PUSH(empties, apr_status_t) = tmp_err->apr_err;
             }
         }
+    }
 
-      tmp_err = tmp_err->child;
-    }
+  for (tmp_err = err; tmp_err; tmp_err = tmp_err->child)
+    if (! (tmp_err->child && tmp_err->apr_err == tmp_err->child->apr_err))
+      {
+        const char *symbolic_name = svn_error_symbolic_name(tmp_err->apr_err);
+        if (symbolic_name && !strncmp(symbolic_name, "SVN_ERR_", 8))
+          symbolic_name += 8;
+        else if (! symbolic_name)
+          symbolic_name = "N/A";
+        svn_error_clear(svn_cmdline_fprintf(stream, err->pool,
+                                            "(E%06d = %s)\n",
+                                            tmp_err->apr_err,
+                                            symbolic_name));
+      }
 
   svn_pool_destroy(subpool);
 
% $svnadmin create /
svnadmin: E200011: Repository creation failed
svnadmin: E200011: Could not create top-level directory
svnadmin: E200011: '/' exists and is non-empty
(E200011 = DIR_NOT_EMPTY)
% 

Daniel