Prepare for merging into cargo #61

Blockers

• Re-license as Apache/MIT? #84
• Settle on long term name #47
• What should the CLI look like? #86
• Add --explain flag for lints #49
• Add --base-version argument #50
• Add --base-git <repo> argument #51
• Add --base-manifest-path <path> argument  #52
• Allow selecting the packages to check with common --workspace, --package, --exclude flags #53
• Mark the rustdoc flags as perma-unstable, behind a -Z flag #54
• Make default baseline the previous stable version in the registry #55
• Lint level control #58
• Manifest checks #48 so we can verify the CLI is general enough
• Feature parity with cargo-semverver; major blockers here:
  • Represent type information in the Trustfall schema #149
  • Tracking issue: Checking cross-crate items #638
• private/hidden features rust-lang/cargo#10882 (see Generating rustdoc with --all-features exposes APIs in an unstable feature #321 for context)
• stable/unstable/nightly-only features rust-lang/cargo#10881 (see Add the ability to exclude experimental features from consideration #315 for context)
• Tracking issue for RFC 1977: public & private dependencies rust-lang/rust#44663
• stabilized existence of rustdoc JSON (unstable format is okay) — RFC in progress

Nice-to-haves

• Changelog output mode #60
• Report "minimum new version" in output #56
• Added deprecated attribute API lint, minor incompatibility level #57
• New API entry lint, minor incompatibility level #59

Open questions

• Integrated into cargo or separate rustup component like clippy?
• How does the process for making new rustdoc JSON formats work w.r.t. cargo-semver-checks merged into cargo?
  • PRs to rust-lang/rust run submodule test suites, like cargo's. Presumably they would test the merged cargo-semver-checks as well.
  • If a PR to rust-lang/rust emits a new rustdoc JSON format version, cargo-semver-checks would need to be updated to support it.
  • That appears to be a chicken-and-egg problem: the PR won't pass, so no new versions of rustdoc-types will exist, so no new cargo-semver-checks -> cycle.

Things to remove

• Leading _ is hidden (blocked on private/hidden features rust-lang/cargo#10882)
• bench, nostd, no_std, private, unstable, unstable[-_].*, nightly (blocked on private/hidden features rust-lang/cargo#10882, stable/unstable/nightly-only features rust-lang/cargo#10881)
• --default-features, --only-explicit-features

Merge Proposal (example):

Motivation

Drawbacks

Behavior

Alternatives

Prior Art

Future Possibilities