Psalm: Catch classes should implement Throwable or extend Exception

[muglug]

class A {}

try {
  echo "hello";
} catch (A $a) {}

should fail with InvalidCatch

[TysonAndre]

A note about fixing occurences of InvalidCatch: InvalidCatch may be seen when a class implements an interface (my_interface_exception).

Zend PHP allows you to have catch (my_interface_exception $e) {}, and will catch an interface.
Aside: HHVM doesn't allow you to do that.

This can easily be solved in PHP7 by adding interface my_interface_exception extends Throwable if my_interface_exception isn't already throwable.

[muglug]

yeah, that problem is implicitly referenced in this test: https://github.com/vimeo/psalm/blob/fdff250c4ab2105a84867a98fc6d82d57e074f50/tests/TryCatchTest.php#L28-L37

[weirdan]

Also, docblock suppression needs to be on the try keyword (also shown by the test above).

[ndench]

@muglug why does psalm fail with InvalidCatch when catching a random interface? Shouldn't that be allowed?

[Wirone]

@ndench that interface should extend \Throwable. It's known issue, for example with GuzzleException (interface).

@muglug is it possible to suppress InvalidCatch by configuration? referencedClass does not work.

[muglug]

@ndench @Wirone I've just made both InvalidClass and InvalidCatch both configurable by class.

[TysonAndre]

This can easily be solved in PHP7 by adding interface my_interface_exception extends Throwable if my_interface_exception isn't already throwable.

My earlier comment was incorrect: classes/interfaces can't (EDIT: directly) implement throwable, that causes a PHP error. Classes can only (EDIT: indirectly implement Throwable if they) extend Error/Exception

[weirdan]

Classes can implement Throwable (or interfaces extending that) if they also extend Exception/Error.

[muglug]

Yeah, the exception I allow via the config is for 5.6-compatible exception-like interfaces. But I very much hope it’s a dwindling need

[Wirone]

@muglug great news! when will it be released?

[muglug]

There was a 2.x release the day after - sorry, should have pinged this issue.