Crate lihaaf 

Fast compile-fail and compile-pass testing for Rust proc macros.

lihaaf is a trybuild-style test harness optimized for quick iteration. It is designed for proc-macro crates that need many compile-pass and compile-fail fixtures without paying unnecessary rebuild overhead.

lihaaf (“quilt”; Urdu and Punjabi, also written ਲਿਹਾਫ਼ in Gurmukhi) compiles the consumer crate once as a dynamic library, then runs each fixture as a standalone rustc invocation that links the prebuilt dylib via --extern. In many real projects this is the difference between waiting forever and getting quick feedback.

Public surface

The exposed surface is intentionally CLI-shaped:

• The cargo-lihaaf binary (Cargo subcommand convention; invoked as cargo lihaaf [OPTIONS]).
• [package.metadata.lihaaf] schema in the consumer’s Cargo.toml (see config::Config).
• Verdict catalog (see verdict::Verdict) and exit codes (see exit::ExitCode).
• A small set of crate-root re-exports for adopters who do want to drive lihaaf from Rust: Cli, Config, Verdict, ExitCode, Error, Outcome, run, Report.
• Compat mode (cargo lihaaf --compat): a migration workflow for trybuild fixture corpora that generates a deterministic JSON comparison envelope. The compat mode Rust API surface is intentionally #[doc(hidden)]; the supported entry is always the CLI.

All other modules are pub(crate) and may evolve freely across v0.1.x point releases. Adopters who want to drive lihaaf from Rust today should prefer the crate-root re-exports above (or subprocess-spawn cargo lihaaf); the internal module paths are not part of any v0.1 stability contract.

What lives where

Module	Responsibility
cli	clap argument parsing, flag-to-action mapping.
config	Parse + validate [package.metadata.lihaaf].
toolchain	Capture rustc --version --verbose for drift checks. (pub(crate))
dylib	cargo rustc --crate-type=dylib invocation, copy mechanic. (pub(crate))
suite_workspace	Opted-in staged Cargo workspace that builds fixture dev_deps beside the dylib. (pub(crate))
manifest	target/lihaaf/manifest.json schema + atomic write. (pub(crate))
freshness	Per-dispatch the policy invariant re-check (mtime / SHA-256 / rustc). (pub(crate))
lock	Session-wide advisory file lock on target/lihaaf/.session.lock. (pub(crate))
discovery	Walk fixture_dirs, classify pass/fail, sort. (pub(crate))
worker	Per-fixture rustc spawn, RSS sampling, OOM, timeout. (pub(crate))
normalize	Stderr normalization (fixed-string, byte-level). (pub(crate))
diff	Hand-rolled Myers diff with line granularity. (pub(crate))
snapshot	.stderr file I/O + --bless semantics. (pub(crate))
verdict	Per-fixture verdict + session reporter.
exit	Exit-code mapping per the policy.
session	Lifecycle orchestration (stages 1–9 of the policy). (pub(crate))
error	Crate-wide error type. (pub(crate))
util	Atomic file write + sha256 helpers. (pub(crate))

Re-exports

pub use cli::Cli;

pub use config::Config;

pub use exit::ExitCode;

pub use verdict::Verdict;

Modules

cli

CLI argument parsing.

config

[package.metadata.lihaaf] parsing + validation.

exit

Exit codes for the v0.1 stable contract.

verdict

Per-fixture verdict catalog.

Structs

Report

Aggregate result of a session run.

Enums

Error

Crate-wide error type.

Outcome

Session outcomes reported before fixture verdicts can run.

Constants

VERSION

The semver-stable lihaaf release the binary identifies as.

Functions

run

Run the full session.