RFR: 8367149: Add ergonomic construction for creating ad-hoc VMErrorCallback [v2]

[Axel Boldt-Christmas]

On Wed, 10 Sep 2025 09:03:40 GMT, Albert Mingkun Yang <ayang at openjdk.org> wrote:

>> Axel Boldt-Christmas has updated the pull request incrementally with three additional commits since the last revision:
>> 
>>  - Add a comment explaining the deduction rules
>>  - Skip multiple inheritance and allow more than lambda like callables.
>>  - Update doc example
>
> src/hotspot/share/utilities/vmError.hpp line 254:
> 
>> 252: };
>> 253: 
>> 254: // Ergonomic construction for creating ad-hoc VMErrorCallback which automatically
> 
> Does `Ergonomic construction` have specific meanings in cpp/this context? If not, I wonder if `lightweight` is clearer, as it is less technical.

Not that I know of. 

I ment it to mean that this is type with makes it ergonomic (as in, efficient and comfortable) to create an ad-hoc VMErrorCallback. So rather than having to do something like:
```C++
   struct AdHocVMErrorCallback : public VMErrorCallback {
      ThisType& _instance;
      ValueType _value;

      AdHocVMErrorCallback(ThisType& instance) 
        : _instance(instance), 
          _value(_instance.get_important_value) {}

      void call(outputStream* st) final {
        // Dump the important bits.
        st->print("Prior value: ");
        _value.print_on(st);
        st->print("During crash: ")
        _instance.get_the_value().print_on(st);
        // Dump whole the whole state.
        _instance.print_on(st);
      }
  } on_error(*this);

you can use this construction with a lambda.

Not sure if lightweight capture I intended to convey, but it also seems like `Ergonomic construction` missed the mark. Maybe just call it `A construction for creating ad-hoc VMErrorCallback`

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PR Review Comment: https://git.openjdk.org/jdk/pull/27159#discussion_r2338631227