Saxon

Working on the Saxon 11 branch, I've started by creating a test in TransformTests that uses setLogger() with a custom logger; this provides a way of testing the content of messages that would normally go to System.err (from a simulated command line call) in a JUnit test.

This shows up the NPE when reporting the license file serial number.

I'm now going to try and ensure that all such messages go via the Logger.

Most messages sent to System.err are now changed to go via configuration.getLogger().

Current exceptions:

• Help messages from CommandLineOptions in response to -? go directly to System.err, because they are output before a Configuration has been created.

• Messages from the (default) MessageEmitter (for xsl:message) go to config.getErrorOutputStream()

• Messages that are never output except when doing internal debugging

• Some messages for fatal error conditions where no Configuration is available

So what to do about get/set StandardErrorOutput in Configuration?

The only place it's now used is for xsl:message output, and I'm handling that by adding a Logger.asWriter() method (with a default implementation) that supplies a Writer which writes to the Logger, and the default MessageEmitter will use this by default.

We have a write-only configuration property Feature.STANDARD_ERROR_OUTPUT_FILE which can be used (in principle) to redirect standard error output. I propose that this property, and the method Configuration.setStandardErrorOutput(), should take no action unless the Logger is a StandardLogger, in which case they should set the output destination for the standard logger.

Similarly, redefine Configuration.getStandardErrorOutput() so it returns the output destination of the Logger if it's a StandardLogger, or System.err otherwise.

Bug fix applied in the Saxon 10.3 maintenance release