RFR: 8276966: Improve diagnostic output for the mismatching parts of a hybrid snippet

[Pavel Rappo]

On Fri, 3 Oct 2025 11:07:02 GMT, Hannes Wallnöfer <hannesw at openjdk.org> wrote:

> Please review a trivial change to improve the error output for hybrid snippets with mismatching inline and external snippet text.
> 
> Since the logging code drops trailing blank lines, differences in trailing whitespace were not displayed properly. See [JDK-8304408](https://bugs.openjdk.org/browse/JDK-8304408) for an example where this occurs. By adding a terminal separator we make sure trailing blank lines are not discarded. This makes it also easier to see where the snippet diff ends. 
> 
> Old output:
> 
> 
>   ----------------- inline -------------------
>   inline snippet
>   ----------------- external -----------------
>   external snippet
> 
> 
> New output:
> 
> 
>   ----------------- inline -------------------
>   inline snippet
>   ----------------- external -----------------
>   external snippet
>   --------------------------------------------

Does it make sense to add a test for this assertion?

> By adding a terminal separator we make sure trailing blank lines are not discarded.

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PR Comment: https://git.openjdk.org/jdk/pull/27621#issuecomment-3365674029