Command plugin API has no ability to specify traits to use for a build

[cmcgee1024]

Is it reproducible with SwiftPM command-line tools: swift build, swift test, swift package etc?

• Confirmed reproduction steps with SwiftPM CLI. The description text must include reproduction steps with either of command-line SwiftPM commands, swift build, swift test, swift package etc.

Description

When writing a command plugin that performs a build of the current SwiftPM package, there's no ability to specify the traits that should be explicitly enabled for that build. There's no equivalent to doing something like this at the command-line within the command plugin:

swift build --traits foo,bar

Expected behavior

No response

Actual behavior

No response

Steps to reproduce

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Swift Package Manager version/commit hash

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Swift & OS version (output of swift --version ; uname -a)

No response