[vidigoat]

What type of PR is this?

• bug

What this PR does / why we need it:

FlagNamePrefixer and FlagEnvHinter are exported variables documented as "used by the default FlagStringer", but stringifyFlag calls prefixedNames and withEnvHint directly, so setting them changes nothing:

cli.FlagEnvHinter = func(envVars []string, str string) string {
	return str + " (env: " + strings.Join(envVars, ", ") + ")"
}
// help still shows:  --token string   [$TOKEN]

stringifyFlag now calls the two variables. Their defaults are prefixedNames and withEnvHint, so help output only changes for programs that set them. This includes the per-flag Stringer override path, since that falls back to FlagStringer.

FlagFileHinter has the same comment, but help doesn't show file sources at all today (FlagFileHinter and withFileHint haven't been called since v2), so using it would add text to the help of every flag with a File source. Instead, its comment and FlagFileHintFunc's now say the default FlagStringer doesn't use it (the old comment also said "environment variable details").

Which issue(s) this PR fixes:

None, found while reading the help code.

Testing

• TestFlagEnvHinter had been commented out since the v2 merge (its table was later renamed to var _ to silence the linter). It's restored for v3 (Sources, the string placeholder), with a new TestFlagNamePrefixer next to it. Both fail on main.
• make (generate, vet, tests, binary size, gfmrun), make lint and make v3diff pass. go test -race passes, as do the tests with urfave_cli_no_template, urfave_cli_no_docs and urfave_cli_no_suggest.

The change and the tests were written with Claude Code (AI).

Release Notes

Setting FlagNamePrefixer or FlagEnvHinter now changes the default flag help text, as documented.

🤖 Generated with Claude Code

[Juneezee]

Thanks! Confirmed on main: setting FlagEnvHinter or FlagNamePrefixer doesn't change the help output, and with this PR it does. Both new tests fail on main and pass here.

I pushed a few changes:

• Rebased onto main.
• Removed the table from the old TestFlagNamePrefixer, which was still a dead var _. Your new TestFlagNamePrefixer replaces it.
• Reworded the FlagFileHinter and FlagFileHintFunc comments to say the default FlagStringer doesn't use them. Showing file sources would change the help of every flag with a File source, so I kept this to the comments. I also updated the description to match.