Fix uninitialized memory in ModelicaInternal_readLine, ModelicaStrings_scanIdentifier and ModelicaStrings_scanString

[beutlich]

As reported by modelica/ModelicaSpecification#2403

[henrikt-ma]

Why don't we wait and see whether ModelicaAllocateString is supposed to terminate these strings?

[sjoelund]

Safe thing to do regardless of what the specification says or will say (the library is also backwards compatible with older versions of MSL)

[beutlich]

Why don't we wait and see whether ModelicaAllocateString is supposed to terminate these strings?

Because I consider it a bug. See #3004 for a similar issue fixed recently.

[henrikt-ma]

I agree with @sjoelund point that the library should also be compatible with external code written for older MLS versions when the terminating null wasn't granted.

[HansOlsson]

Note: I was going to comment on this - seems I was too late.

The most obvious solution would be to just return ""; as the specification only states that non-literal return strings must be allocated with ModelicaAllocateString.

[henrikt-ma]

The most obvious solution would be to just return ""; as the specification only states that non-literal return strings must be allocated with ModelicaAllocateString.

Right, but in that case I would suggest to also make sure that we have test models that take these code paths, so that implementations really become aware that they must do the tedious analysis of what kind of pointer that is being returned.