Improve error for nightly-only '--message-format' args#6780
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ytmimi merged 1 commit intorust-lang:mainfrom Apr 29, 2026
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Improve error for nightly-only '--message-format' args#6780ytmimi merged 1 commit intorust-lang:mainfrom
ytmimi merged 1 commit intorust-lang:mainfrom
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Previously on a stable build (`json` is only supported in `nightly`
builds):
$ cargo fmt --message-format json
Invalid value for `--emit` - using an unstable value without `--unstable-features`
With this change:
$ CFG_RELEASE_CHANNEL=stable cargo make bin-build
$ PATH="./target/debug:$PATH" cargo fmt --message-format json
--message-format json is only supported in nightly builds
This utility formats all bin and lib files of the current crate using rustfmt.
<-- SNIP: the rest of the usage follows -->
This behaviour is similar to how args to `--emit` are handled in
`rustfmt`.
This change also drops displaying `json` as an option to
`--message-format` on stable builds:
$ PATH="./target/debug:$PATH" cargo fmt --help | grep --max-count 1 --after-context 1 message-format
--message-format <message-format>
Specify message-format: short|human
This required rewriting the check for nightly builds (copying from the
one in `src/release_channel.rs`) to be `const` so I could rewrite the
`--message-format` flag's help string.
Issue: rust-lang#6752
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This PR was rebased onto a different main commit. Here's a range-diff highlighting what actually changed. Rebasing is a normal part of keeping PRs up to date, so no action is needed—this note is just to help reviewers. |
jieyouxu
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@jieyouxu thanks for taking a look and thank you @matthewhughes934 for working on this.
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Previously on a stable build (
jsonis only supported innightlybuilds):With this change:
This behaviour is similar to how args to
--emitare handled inrustfmt.This change also drops displaying
jsonas an option to--message-formaton stable builds:This required rewriting the check for nightly builds (copying from the one in
src/release_channel.rs) to beconstso I could rewrite the--message-formatflag's help string.Fixes #6752