This involves two things: - log syntax errors to the console - provide some kind of trace of what data is being examined

This is fairly easy, but waiting for bug 321171 before making more template changes.

Two types of messages are output: 1. Syntax errors in template queries 2. If flags="logging" is used on the template root node, each generated item is logged to the console. This makes it easier to see that data is arriving, being generated, and matching or not matching any rules. I'm not sure how clear the messages are but don't want the strings to be too lengthy.

Note that I built this on top of the patch in bug 321169 so it may not apply perfectly without that one.

(In reply to comment #4) > Note that I built this on top of the patch in bug 321169 so it may not apply You're wrong, this is bug 321169, you probably meant a different bug.

I meant bug 321177.

Comment on attachment 416909 [details] [diff] [review] add some logging and template parsing error messages r=me Would be nice to have a localization story here though.

Comment on attachment 416909 [details] [diff] [review] add some logging and template parsing error messages >- return PR_FALSE; >+ return NS_ERROR_FAILURE; PRBool return value (twice) >+void >+nsXULContentUtils::LogMessage(const char* aStr) >+{ >+ nsAutoString message; >+ message.AssignLiteral("Error parsing template: "); Name the method LogTemplateError instead perhaps? >+ printf("%s\n", NS_ConvertUTF16toUTF8(message).get()); ("Error parsing template: %s\n", str) perhaps? >+ nsTemplateMatch *newmatch = nsnull; I assume you want to specify a specific ordering of logging. Perhaps you could log the match to be removed/replaced first, before processing the new result? >+#ifdef PR_LOGGING >+ // always enable logging if the debug setting is used >+ if (PR_LOG_TEST(gXULTemplateLog, PR_LOG_DEBUG)) Except you now always send the output to stdout instead. >- PR_LOG(gXULTemplateLog, PR_LOG_ALWAYS, >- ("xultemplate[%p] unrecognized binding <%s>", >- this, tagstrC.get())); Does this no longer get logged? > eDontTestEmpty = (1 << 0), >- eDontRecurse = (2 << 0) >+ eDontRecurse = (2 << 0), >+ eLoggingEnabled = (4 << 0) 1 << 0, 1 << 1, 1 << 2 etc. > nsCOMPtr<nsIRDFResource> pres; >+ if (predicate.IsEmpty() || predicate[0] == PRUnichar('?')) { >+ nsXULContentUtils::LogMessage(ERROR_TEMPLATE_TRIPLE_BAD_PREDICATE); > return NS_OK; > } >+ else { Don't else after return. >- NS_ENSURE_SUCCESS(rv, rv); >+ if (NS_FAILED(rv)) { >+ nsXULContentUtils::LogMessage(ERROR_TEMPLATE_BAD_XPATH); >+ return NS_OK; Why the change in return value?

Also fixes some includes that were only being includes in debug builds, and an issue with a couple of the tests. > Except you now always send the output to stdout instead. Changed to use PR_LOG instead. >>- PR_LOG(gXULTemplateLog, PR_LOG_ALWAYS, >>- ("xultemplate[%p] unrecognized binding <%s>", >>- this, tagstrC.get())); >Does this no longer get logged? As the <bindings> element is optional, it caused unnecessary warnings, so this message should just be removed.

Do these show up in the web console or only in the older error console?

Documented here: https://developer.mozilla.org/en/XUL/Template_Guide/Debugging_XUL_templates Linked from: https://developer.mozilla.org/en/XUL/Template_Guide#Additional_Topics and from Firefox 4 for developers

It's actually already documented in the template guide at https://developer.mozilla.org/en/XUL/Template_Guide/Template_Logging