fileset: detect unintentional existing() invocation at runtime...
fileset: detect unintentional existing() invocation at runtime
A fileset predicate can invoke 'matchctx.existing()' successfully,
even if it isn't marked as "existing caller". It is aborted only in
some corner cases: e.g. there were one deleted file in the working
directory (see
8a0513bf030a for detail).
This patch makes 'matchctx.existing()' invocation abort if not
'_existingenabled', which is true only while "existing caller"
running.
After this changes, non-"existing caller" predicate function is
aborted immediately, whenever it invokes 'matchctx.existing()'. This
prevent developer from forgetting to mark a predicate as "existing
caller".
BTW, unintentional 'matchctx.status()' invocation can be detected
easily without any additional trick like this patch, because it
returns 'None' if a predicate isn't marked as "status caller", and
referring field (e.g. '.modified') of it is always aborted.
