Previously in 4882396163, strings that
resembled a filepath (ie res/foo/file), would be assigned to a
ResFileValue, which when attempted to be casted to ResScalarValue would
error out.
Attempting to check the filesystem for such files, slowed apktool's
execution majorly. In order to prevent this, the ClassCastException
and other checks related to checking ResFileValue when type is string
was added.
This allows bogus strings such as (res/foo/file) to be added, but the
exception is caught and allows decoding to continues. Fixes#921.
