Following #7890, this patch introduces the ability to read the contents
of a file to the fs module.
This patch introduces the ability to read files at configure time, but
has some restrictions:
- binary files are not supported (I don't think this will prove a
problem, and if people are wanting to do something with binary
files, they should probably be shelling out to their own script).
- Only files outside the build directory allowed. This limitation
should prevent build loops.
Given that reading an arbitrary file at configure time can affect the
configuration in almost arbitrary ways, meson should force a reconfigure
when the given file changes. This is non-configurable, but this can
easily be changed with a future keyword argument.
is_samepath better reflects the nature of this function--that files
and directories can be compared.
Also, instead of raising exceptions, simply return False when one
or both .is_samepath(path1, path1) don't exist. This is more
intuitive behavior and avoids having an extra if fs.exist() to go
with every fs.is_samepath()
