DRAFT: refactor: COLOR_MODE to OnceCell

[bconn98]

Refactor COLOR_MODE to be easier for testing and for using features in the standard library come v1.71.0.

Addresses: #368

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Codecov Report

Attention: Patch coverage is 93.33333% with 1 line in your changes missing coverage. Please review.

Project coverage is 64.20%. Comparing base (f688e38) to head (863c336). Report is 1 commits behind head on main.

Files	Patch %	Lines
src/encode/writer/console.rs	93.33%	1 Missing :warning:

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Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #365 +/- ## ========================================== + Coverage 63.42% 64.20% +0.78% ========================================== Files 25 25 Lines 1572 1573 +1 ========================================== + Hits 997 1010 +13 + Misses 575 563 -12 ```

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[estk]

Looks like CI is failing on this one still...

[bconn98]

I see what you're saying but I don't think we get any test benefit with that change (which may be okay because of the integration tests). That said, I don't think I agree that using Lazy is any more lightweight. Both will be initialized once and return a reference on access if I'm reading the docs correctly.

[estk]

@bconn98 by lightweight i mean not having the following copy pasted at every callsite. There are other options if you prefer, you could wrap the Lazy in a struct and in cfg(test) mode internally it could simply be a Mutex that you can mutate as necessary.

            let color_mode_init = {
                let no_color = env::var("NO_COLOR");
                let clicolor_force = env::var("CLICOLOR_FORCE");
                let clicolor = env::var("CLICOLOR");
                get_color_mode(no_color, clicolor_force, clicolor)
            };

[bconn98]

I tried a couple different versions of using mutex.

1. Locking the whole tests
2. Like you suggested a struct with a mutex locked getter (using deref and force)

But no avail, the Lazy will not execute a second time thereby causing tests to fail. I wouldn't want to put the actual ENV values inside of mutex's as that would invalidate the majority of the test.

[bconn98]

I found a solution that I think is satisfactory. By Option wrapping all the args, we can dependency inject during testing or otherwise just pass Nones and pull from the env. I would like this MR to merge in the initial migration, than a follow on MR will come to bump our MSRV and use the solution that is now part of the std lib.