Common
```kotlin
interface UncaughtExceptionHandler
```
An optional error handler that can be set to catch exceptions thrown during the layout, draw,
and teardown phases of the associated composition. If an exception is thrown to this
callback, the composition is already in an unrecoverable state and must be abandoned. Tests
may choose to catch exceptions to forward or process them differently. By default, no
exception handler is present and exceptions are thrown on the composer's thread, which may
cause the process to crash.
This interface should generally not be used in production, and is intended for error routing
or introspection rather than true error recovery.
## Functions
onUncaughtException
```kotlin
fun onUncaughtException(t: Throwable)
```
Invoked for testing infrastructure to be able to redirect an exception `t` that occurred
during the layout, measure, or draw phase of the underlying view. When this function is
invoked, the associated composition is in an unrecoverable state. The original exception
may be re-thrown to propagate it.
If this callback swallows an exception to prevent a crash, you should expect other
follow-up exceptions to be directed here as more operations are executed on the
degenerate composition. The first exception passed to this callback is likely to be the
only useful exception.
#### Parameters
| | |
| --- | --- |
| t | The exception thrown by the composition hierarchy during the layout, measure, or draw phase of the associated view. |