On Fri, 17 Dec 2021 17:51:17 GMT, Pavel Rappo <pra...@openjdk.org> wrote:
> Using a custom taglet may result in exceptions, not all of which are javadoc
> bugs. Some of these exceptions are taglet bugs.
>
> It was noticed that an exception in a static initializer of a custom taglet
> looks like a javadoc bug, which it is not. The fix was to trivially catch
> java.lang.ExceptionInInitializerError and translate it into an error like it
> is already done for some other exceptions.
>
> While working on this fix, I noticed that there were no tests that cover
> various exceptions that could arise while registering a taglet:
>
> * ClassNotFoundException
> * NoSuchMethodException
> * InstantiationException
> * InvocationTargetException
>
> I added a test to cover all of those as well as ExceptionInInitializerError
> and ClassCastException, which I proactively handled similarly to
> ExceptionInInitializerError.
>
> I note that a typical taglet-registration error message is quite poor and
> should be improved in the future. For example, it is unclear that the method
> that javadoc cannot find is the nullary (i.e. parameterless or no-arg)
> MyTaglet constructor:
>
> Error - Exception java.lang.NoSuchMethodException thrown while trying to
> register Taglet MyTaglet...
LGTM, within the spirit of the existing code.
Please file a followup bug for a more comprehensive cleanup to protect against
errors in user code, like (untrusted) user-provided tablets and doclets.
While this could be loosely modeled on `javac` `ClientCodeWrapper` and
`ClientCodeException`, this time round it might be reasonable to use a
`Proxy`-based wrapper, to catch exceptions in user-code and then throw them in
a wrapped exception for better handling at a higher level. That suggests that
going forward, failure to init a taglet should be a fatal error. _Note:_ one
potential complication for `javadoc` not found in `javac` is the hard
tool-to-doclet abstraction barrier.
test/langtools/jdk/javadoc/doclet/testCustomTagletRegistration/ExceptionInInitializerErrorTaglet.java
line 36:
> 34:
> 35: static {
> 36: if (true) {
Does the `if (true)` have any significance?
javac will optimize it, per JLS.
-------------
Marked as reviewed by jjg (Reviewer).
PR: https://git.openjdk.java.net/jdk18/pull/44
