Created attachment 340231 [details] [review]
Fix converting enumerations and flags to arrays

The generic array conversions fail to special-case enumerations and flags type, which most of the time results in incorrect arrays.  It is the same underlying issue as https://bugzilla.gnome.org/show_bug.cgi?id=597737

This issue breaks real apps in hard-to-understand ways, see for example https://bugzilla.gnome.org/show_bug.cgi?id=774653

Attached patch adds special handling for those so they are (generally) correctly handled.  Below is the patch's description:

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Fix converting enumerations and flags to arrays

Enumerations and flags are classed types for Vala, not integers, so they don't fall in the `typeof(G) == typeof(int)` kind of tests. This leads to using the generic code in which Vala assumes pointer-sized elements, which is often not true for enumerations and flags.

Add special case for those to use the `int` converters for enumerations and flags.

This is most generally correct, but not always: the compiler will likely chose a larger type for a specific enumeration if one of its value is larger than `int`.  It would be tempting to use the enumeration's class minimum and maximum values to determine the appropriate type, but unfortunately the API for this uses int itself, so doesn't help.