[Python-ideas] Adding '**' recursive search to glob.glob

[Nick Coghlan]

On Tue, Jan 15, 2013 at 11:31 AM, Steven D'Aprano <steve at pearwood.info> wrote:
> All this assumes that we need to care about backward compatibility
> of ** in existing globs. It does seem to be an unlikely thing for
> people to write. If we don't, then no need for a flag at all.
> Instead, we could raise a warning for globs with ** in 3.4, and
> then drop the warning in 3.5.
>
> Another option, is a new function. Bool parameters that do nothing
> but change the behaviour of a function are somewhat of a mild
> anti-pattern. Perhaps it is better to just keep glob.glob as is,
> and add glob.recglob or rglob to support **.

Making boolean parameters less awful from a readability perspective is
part of the rationale for keyword-only arguments: they force you to
include the parameter name, thus making the call self-documenting.

In this case, the conservative backwards compatible migration path would be:

In 3.4:
- add the recursive globbing capability
- add "allow_recursive=None" as a keyword-only argument
- emit a DeprecationWarning if the double-star pattern is seen when
allow_recursive is None (but not when it is explicitly False)

In 3.5:
- switch the allow_recursive default value to True
- drop the deprecation warning

Cheers,
Nick.

-- 
Nick Coghlan   |   ncoghlan at gmail.com   |   Brisbane, Australia