feat(ext/console): convert colors to supported space

[marvinhagemeister]

The default Terminal on macOS doesn't support 24bit True Colors, which lead to colors being rendered unexpectedly at times. This can be seen in the fresh initialization wizard where the expected colors should look like this (rendered in a True Color terminal):

With the changes in this PR we now check for the supported color space by the terminal and lower the color space if needed.

Before:

After:

Support table:

Terminal	OS	Ansi	Ansi 256	24bit True Color	$TERM	$COLORTERM
Apple Terminal	macOS	✅	✅		xterm-256color
iTerm2	macOS	✅	✅	✅	xterm-256color	truecolor
cmd.exe	Windows	✅	✅	✅
PowerShell	Windows	✅	✅	✅
BuildKite
GitHub Actions	Linux (Ubuntu)	✅	✅	✅	dumb
GitLab CI

[bartlomieju]

Looks great @marvinhagemeister! I will wait for @kt3k's review before landing this, but overall LGTM

[kt3k]

👍

[kt3k]

Looks very nice feature to have! I'm in favor of the idea.

@marvinhagemeister Can you write a few more integration type test cases which simulate various terminals/environments by setting COLORTERM, TERM, or CI env vars?

[bartlomieju]

@marvinhagemeister when you find the time, could you please rebase and add a test case mentioned above?

[marvinhagemeister]

@kt3k @bartlomieju Tried adding some tests but I have trouble setting the environment variables before a test in rust. It seems like env::set_var does nothing. Not sure why at the moment.

[bartlomieju]

@kt3k @bartlomieju Tried adding some tests but I have trouble setting the environment variables before a test in rust. It seems like env::set_var does nothing. Not sure why at the moment.

@marvinhagemeister by default tests in Rust are run on multiple threads - I'm pretty sure the tests are overriding env vars set by other tests. I suggest to do an integration test using itest! macro somewhere in run_tests.rs. You can find examples there that use custom environmental variables.

[kt3k]

@marvinhagemeister You can create a small script like the below:

console.log("%chello", "color: #123456");

in cli/tests/testdata/run with expected output files next to it. And then execute it from cli/tests/integration/run_test.rs with itest macro, which would look like, for example:

itest!(test_color_support_term_256 {
  envs: vec![("TERM".to_string(), "256".to_string())],
  args: "run run/test_color_support.js",
  output: "run/test_color_support.js.out",
});

(Note: The file names are arbitrary. You probably need several output file patterns.)

[idranme]

🥰

[idranme]

Is it possible to provide an interface for applications to query color levels directly?

Such as: Deno.colorSupportLevel

[iuioiua]

Hi guys, I just wanted to check-in. Is this something you guys still want to pursue? This is a blocker for denoland/std#2602. It'd be good to have that one closed off 🙂