Re: [PATCH 1/5] treewide: rename 'struct exclude' to 'struct path_pattern'

[Jeff King <peff@peff.net>]

On Tue, Sep 03, 2019 at 11:04:55AM -0700, Derrick Stolee via GitGitGadget wrote:

> From: Derrick Stolee <dstolee@microsoft.com>
> 
> The first consumer of pattern-matching filenames was the
> .gitignore feature. In that context, storing a list of patterns
> as a list of 'struct exclude' items makes sense. However, the
> sparse-checkout feature then adopted these structures and methods,
> but with the opposite meaning: these patterns match the files
> that should be included!
> 
> It would be clearer to rename this entire library as a "pattern
> matching" library, and the callers apply exclusion/inclusion
> logic accordingly based on their needs.
> 
> This commit renames 'struct exclude' to 'struct path_pattern'
> and renames several variable names to match. 'struct pattern'
> was already taken by attr.c, and this more completely describes
> that the patterns are specific to file paths.

I agree that the current name is overly restrictive, and this is a step
in the right direction. However, when I see path_pattern that makes me
think of our command-line pathspecs.

I wonder if there's a name that could more clearly distinguish the two.
Or if it's sufficient to just become Git jargon that "pathspec" is the
command-line one and "path_pattern" is the file-based one (we're at
least pretty consistent about the former already).

I think one could also make an argument that the name collision is a
sign that these two things should actually share both syntax and
implementation, since we're exposing too similar-but-not-quite versions
of the same idea to users. But given the compatibility issues, it's
probably not worth changing the user facing parts at this point (and I
also haven't thought too hard about it; there may be reasons why the two
_should_ differ).

-Peff