This is a tracking issue for the RFC: Deduplicate Cargo workspace information (rust-lang/rfcs#2906).

Documentation:

• [workspace.package]
• [workspace.dependencies]
• inheriting-a-dependency-from-a-workspace

Steps:

• Implement the RFC (cc @rust-lang/cargo -- can anyone write up mentoring
  instructions?)
  • Support for inheriting in root package (Part 1 of RFC2906 - Packages can inherit fields from their root workspace #10497)
  • Support inheriting in any workspace member (Part 2 of RFC2906 -- allow inheriting from a different Cargo.toml #10517)
  • Correctly inherit fields that are relative paths (Part 3 of RFC2906 - Add support for inheriting license-path, and depednency.path #10538, Part 4 of RFC2906 - Add support for inheriting readme #10548)
  • Add rust-version (not in RFC), see epage's comment (Part 5 of RFC2906 - Add support for inheriting rust-version #10563)
  • Switch the inheritance source from workspace to workspace.package, see epage's comment (Part 6 of RFC2906 - Switch the inheritance source from workspace to… #10564)
  • Add include and exclude now that workspace.package is done, see epage's comment (Part 7 of RFC2906 - Add support for inheriting exclude and include #10565)
  • cargo-add support (Cargo add support for workspace inheritance #10606)
    • Non-blocking: add a flag to cargo add to put dependency in workspace and inherit it #10608
  • Optimizations, as needed (Part 8 of RFC2906 - Keep InheritableFields in a LazyCell inside `… #10568)
• Adjust documentation (Update documentation for workspace inheritance #10611)
  • Decide on documented style (key = {worskspace = true} vs key.workspace = true)
• Stabilization PR (see instructions on cargo-dev-guide)

Changes from RFC

• Not locking workspace dependencies, see alexchrichton's comment
• Not inserting a version into path dependencies when publishing, see epage's comment
• Changed the table package fields inherit from, from workspace to workspace.package, see epage's comment
• Fields
  • Explicitly not supporting resolver, see epage's comment
  • Supporting edition which the RFC showed inconsistent status for
  • Supporting rust-version which is newer than the RFC
  • Supporting include and exclude which the RFC couldn't, see epage's comment

Unresolved questions:

• Do we stablize inheriting from workspace.package and workspace.dependencies or do we switch which tables we use? see epage's comment
• Preferred documentation style: RFC uses field = { workspace = true } but TOML allows field.workspace = true
• Is the performance good enough?