Hi all,
Configuration problems in our builders are handled in multiple ways:
1. Sometimes we call `LOGGER.error` and return `null`.
2. Sometimes we throw an explicit exception. The types of exceptions
vary: NPE, IllegalArgumentException, IllegalStateException, etc. There
is a `o.a.l.l.core.config.ConfigurationException`, but it doesn't seem
to be used often.
3. Sometimes exceptions, usually NPEs, are thrown by the constructor of
a plugin. Most of the time I consider these bugs.
Could we agree on a preferred way to signal configuration errors? I
don't plan to modify the behavior of old code, but we should apply a
consistent strategy on new builders.
I do like throwing exceptions, which often simplifies flow control, but
when I started working on Log4j, I was told 1. was the way to go.
On a related matter, Ralph said on Slack that:
> Failure during configuration should be caught and cause the previous
configuration to remain intact.
While I agree with this "all-or-nothing" strategy, this is not the way
it currently works. Regardless of the strategy chosen to communicate the
problem, a misconfigured component will simply be omitted. This can
cause problems down the line, like:
2025-03-03T11:49:26.081922076Z main ERROR RollingFileAppender 'ROLLING':
When no file name is provided a DirectFileRolloverStrategy must be
configured
2025-03-03T11:49:26.082046726Z main ERROR Null object returned for
RollingFile in Appenders.
2025-03-03T11:49:26.083912635Z main ERROR Unable to locate appender
"ROLLING" for logger config "root"
However, these problems are not fatal and the configuration replaces the
previous one.
What do you think?
Piotr
