Re: [PATCH 08/17] revert: Separate cmdline parsing from functional code

From: Ramkumar Ramachandra <artagnon@gmail.com>
Date: Jul 18, 2011, 20:53 UTC
Message-ID: <CALkWK0mQ0M7ZjJk=dwZjuK=fp4p1+Cz4OfeWpdi+CTO1pZVH0Q@mail.gmail.com>
In-Reply-To: <20110712182046.GD14120@elie>

Hi,

Jonathan Nieder writes:

Show 7 quoted lines

> Ramkumar Ramachandra wrote:
>> Currently, revert_or_cherry_pick does too many things including
>> argument parsing and setting up to pick the commits; this doesn't make
>> a good API.
>
> On the contrary, generally speaking single-call APIs are often very
> pleasant to work with.

[...]

> So this is probably not about the function doing too many things but
> something else.

Took me some time to figure this out. I suppose I could also phrase this as "prepare to make revert_or_cherry_pick the starting point for continuing in future", but it might result in a huge explanation about what continuing means, and why continuing won't need to do argument parsing. I think I'll put in a more superficial intent (Justified because I like this change even if we never support continuing in the future).

New commit message.

revert: Separate cmdline parsing from functional code

Currently, revert_or_cherry_pick sets up a default git config, parses command-line arguments, before preparing to pick commits. This makes for a bad API as the central worry of callers is to assert whether or not a conflict occured while cherry picking. The current API is like:

if (revert_or_cherry_pick(argc, argv, opts) < 0)
   print "Something failed, I'm not sure what"

Simplify and rename revert_or_cherry_pick to pick_commits so that it only has the responsibility of setting up the revision walker and picking commits in a loop. Transfer the remaining work to its callers. Now, the API is simplified as:

if (parse_args(argc, argv, opts) < 0)
   print "Can't parse arguments"
if (pick_commits(opts) < 0)
   print "Something in the picking mechanism failed"

Later in the series, pick_commits will serve as the starting point for continuing a cherry-pick or revert.

-- Ram