RFR: 8287609: macOS: SIGSEGV at [CoreFoundation] CFArrayGetCount / sun.font.CFont.getTableBytesNative

[Phil Race]

On Tue, 31 May 2022 23:39:09 GMT, Nikita Gubarkov <duke at openjdk.java.net> wrote:

> `CTFontCopyAvailableTables` can return null, which causes subsequent call to `CFArrayGetCount` to crash with SEGFAULT, just added a null-check.

All supported font formats on macOS have such tables, so it must be something else.
I don't see how it can fail unless there is something wrong with the CTFont that
would have been previously signalled or we have a bad font handle, or there is a bad table entry.
There's no way to tell from the stack trace. 
So this fixes the symptom (temporarily, since it leaves the caller to deal with not being
able to get the tables it expects are there) but doesn't explain why it happens.

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PR: https://git.openjdk.java.net/jdk/pull/8962