kqueue: ignore events with Ident=0 #590
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To be honest I'm not entirely sure if this is actually the right thing to do ... Probably more testing is needed to determine exactly what's going on. |
On macOS it seems that sometimes an event with Ident=0 is delivered, and
no other flags/information beyond that, even though we never saw such a
file descriptor. For example in TestWatchSymlink/277 (usually at the
end, but sometimes sooner):
# Okay, expected
CREATE "/foo"
REMOVE "/foo"
CREATE "/apple"
CREATE "/pear"
RENAME "/apple"
REMOVE "/pear"
# One or more write events without any ident or information?!
WRITE ""
Printing some debug in the loop right after we receive events shows:
unix.Kevent_t{Ident:0x2a, Filter:-4, Flags:0x25, Fflags:0x2, Data:0, Udata:(*uint8)(nil)}
unix.Kevent_t{Ident:0x0, Filter:-4, Flags:0x25, Fflags:0x2, Data:0, Udata:(*uint8)(nil)}
The first is a normal event, the second with Ident 0. No error flag, no
data, no ... nothing.
I read a bit through bsd/kern_event.c from the xnu source, but I don't
really see an obvious location where this is triggered – this doesn't
seem intentional, but idk...
Technically fd 0 is a valid descriptor, so only skip it if there's no
path, and if we're on macOS.
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On macOS it seems that sometimes an event with Ident=0 is delivered, and
no other flags/information beyond that, even though we never saw such a
file descriptor. For example in TestWatchSymlink/277 (usually at the
end, but sometimes sooner):
Printing some debug in the loop right after we receive events shows:
The first is a normal event, the second with Ident 0. No error flag, no
data, no ... nothing.
I read a bit through bsd/kern_event.c from the xnu source, but I don't
really see an obvious location where this is triggered – this doesn't
seem intentional, but idk...
Technically fd 0 is a valid descriptor, so only skip it if there's no
path, and if we're on macOS.