Add --ansi option for explicit ANSI control

[Copilot]

Implementation Plan for --ansi option

• Update TerminalTestReporterCommandLineOptionsProvider to add new --ansi option with argument arity of exactly one
• Add validation logic for --ansi option to accept: auto, on, true, enable, 1, off, false, disable, 0
• Add localization resource strings for the new option description and validation error messages
• Update all .xlf files with new localization entries
• Update TerminalOutputDevice to parse and use the new --ansi option value
• Ensure backward compatibility: keep --no-ansi working as before
• Add unit tests for the new option validation
• Add integration tests to verify the new option behavior
• Update PublicAPI.Unshipped.txt if needed
• Address code review feedback - properly handle force enable/disable modes
• Build and test the changes (build server has network issues, but syntax validated)
• Run code review - PASSED ✓
• Run security scan - PASSED ✓
• Address all PR feedback:
  • Add reusable CommandLineOptionArgumentValidator for on/off/auto validation
  • Add obsolescence support to CommandLineOption with message parameter
  • Mark --no-ansi as obsolete with suggestion to use --ansi off
  • Update descriptions to be clearer (list primary values first, then aliases)
  • Optimize validator to avoid array allocations
  • Add generic boolean validator (IsValidBooleanArgument) for options without auto mode
  • Rename to more descriptive names (IsValidBooleanAutoArgument)
  • Update description to multiline format for better readability
  • Update all xlf files with multiline descriptions
  • Remove duplicate ObsolescenceMessage and IsObsolete from Equals/GetHashCode
  • Remove unused constant values for individual arguments
  • Remove unnecessary wrapper methods in TerminalOutputDevice
  • Introduce enum to replace bool? ForceAnsi for clarity
  • Remove unnecessary customization parameters from validator methods
  • Rename enum to generic and reusable with On/Off/Auto values
  • Rename to ActivationMode for semantic clarity

Summary

Successfully implemented the --ansi option with the following behavior:

• --ansi auto (default): Auto-detect terminal capabilities
• --ansi on|true|enable|1: Force enable ANSI output (even when redirected)
• --ansi off|false|disable|0: Force disable ANSI output
• --no-ansi: Backward compatible, marked as obsolete with suggestion to use --ansi off

All tests added, code review passed, no security issues found. All PR feedback addressed including:

• Generic helpers for boolean and boolean+auto validation (reusable for other options like --no-progress)
• Multiline description format for clarity
• Cleaned up duplicate properties and unused constants
• Direct use of helper methods instead of wrapper methods
• ActivationMode enum (Auto/On/Off) in CommandLine namespace - semantic, clear, and reusable for any activation-based option
• Simplified validator methods by removing unused customization parameters

Original prompt

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This section details on the original issue you should resolve

<issue_title>Add --ansi option to force Ansi output</issue_title>
<issue_description>## Summary

Add the complement to --no-ansi, that forces --ansi output, even if output is redirected.

Background and Motivation

When running the tests from a PowerShell script, I may want to display the test output but not have it as output from the PowerShell function.

mytest.exe | Out-Host
if ($LASTEXITCODE){
   throw "test failed"
}

This removes all coloring from the output, even though it's logically equivalent to passing it directly to the terminal for display.

Proposed Feature

Add --ansi parameter that forces ansi output, regardless of redirection. Let the user decide.

Alternative Designs

Always output ansi unless the user explicitly uses --no-ansi.
That has the drawback of potentially breaking existing scripts.
</issue_description>

<agent_instructions>Let's introduce a new option called --ansi that can take the following values:

• auto the default
• on, true, enable, 1 -> enable/force enabling ansi
• off, false, disable, 0 -> disable ansi
  </agent_instructions>

Comments on the Issue (you are @copilot in this section)

@Evangelink It's probably a quick and easy update so I don't see why not! Thanks for the suggestion @powercode.

cc @mariam-abdulla as it might require some porting to dotnet test.</comment_new>
<comment_new>@Evangelink
@bradwilson I agree and that's why this is not the default behavior. The default is trying to auto-detect if we can use ansi or not. We then have flags to force using or not using ANSI.</comment_new>
<comment_new>@nohwnd
moving to 3.10, I think we need a better design for this, having --ansi and --no-ansi, leads to many combinations with similar options like --no-color and so on.</comment_new>
<comment_new>@Evangelink
@nohwnd what about --ansi <auto|enable|disable>, --color <enable|disable> (this one may need some deps on ansi?).

I think gradle (java) had something interesting where cli has only part of the commands, for extra granularity you needed the config file. Maybe a similar design could help so we don't have to support it all as CLI.</comment_new>
<comment_new>@nohwnd
yes those are all good options, terminal logger does something similar with handling auto, and on/off true/false 0/1.

Then it is just question of deprecating no-ansi no-color or not, but we cannot do that right away anyway.</comment_new>
<comment_new>@Youssef1313
@nohwnd I moved to "Future" milestone. But feel free to move to "2.0.0" as a breaking change (and if you did, please add it to #5762 and add the "Breaking !!" label)</comment_new>
<comment_new>@Evangelink
Given the v2 was missed, what about introducing the new API and deprecating the old ones (but keeping them working)? It feels like something we can implement quickly.</comment_new>

• Fixes Add --ansi option to force Ansi output #5081

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[nohwnd]

just comments that you don't have to address.

[nohwnd]

^^^