Manage the rustdoc cache

cheadergen invokes cargo +<nightly> doc --output-format=json under the hood, which is the slowest step of the whole pipeline. To keep iteration fast, cheadergen keeps the resulting JSON in a per-crate on-disk cache and reuses it on subsequent runs.

You normally don’t have to touch the cache, it builds up incrementally as you run cheadergen generate. This page documents the cheadergen cache subcommands for the cases where you do.

Inspect the cache location

cheadergen cache show dir

Prints the absolute path to the cache directory and exits. The location is platform-specific.

Use this in CI configs to feed the cache directory into your runner’s cache action.

Pre-warm the cache

cheadergen cache warm                                # Cargo-style default
cheadergen cache warm --input-dir crates/alpha       # one workspace directory
cheadergen cache warm --input-dir a --input-dir b    # several workspace directories
cheadergen cache warm -p alpha -p beta               # specific workspace members by name

cache warm issues a single batched cargo doc -p crate1 -p crate2 ... invocation, maximising parallelism within cargo.

Clear the cache

cheadergen cache clear

Removes the cache directory and exits.

In practice you rarely need this. Reasons you might:

• The cache directory has grown large enough to matter on a developer machine and you want a fresh start.
• You’re chasing a reproducibility bug and want to confirm the issue isn’t a stale cache entry.

See also

• The processing pipeline for where the cache fits into a generate invocation.
• Integrate with Cargo for the broader workflow cheadergen slots into.