Module external_storage 

Storage layouts for contracts that are not part of the local project.

When a forked test touches a contract that isn’t in the local artifacts, its storage slots can still be decoded by compiling the verified source a block explorer has for it.

Finding that source is the caller’s job — foundry-evm-traces already knows how to ask a block explorer for it. This module owns what happens next: compiling it for a storage layout, which costs a full solc invocation, and making sure that cost is paid once. forge test runs test contracts in parallel, so lookups are:

• deduplicated process-wide by LOOKUPS, so concurrent tests touching the same contract compile it once instead of racing each other;
• persisted to disk once resolved, so later runs skip straight to the layout.

Unverified responses are memoized only for this run so later runs can discover newly verified contracts.

Structs

CachedStorageLayout 🔒

Disk representation of a resolved lookup. Cleared by forge cache clean.

Constants

BASE_PATH_SOLC 🔒

First solc release with --base-path support.

CACHE_VERSION 🔒

Current CachedStorageLayout format.

MIN_STORAGE_LAYOUT_SOLC 🔒

First solc release that emits storageLayout. Matches the floor cast storage enforces.

NO_IMPORT_CALLBACK_SOLC 🔒

First solc release with --no-import-callback support.

Statics

CACHE_TEMP_ID 🔒

Makes cache publication paths unique within one process; the PID separates processes.

COMPILER 🔒

Bounds expensive compiler installation and execution across parallel tests.

LOOKUPS 🔒

Per-(chain, address) lookup slots, shared across the whole process.

Functions

cache_path 🔒

Path of the cache entry for address.

compile_storage_layout 🔒

Compiles a verified source with storageLayout output enabled and extracts the layout.

fetch_external_storage_layouts

Resolves the storage layouts of addresses on chain, compiling verified sources as needed.

lock_until

Acquires a lock without exceeding the caller’s deadline.

read_cached_layout 🔒

Reads the layout a previous run resolved for address, if there is one.

resolve 🔒

fetch_external_storage_layouts with the cache location supplied, so tests can point it somewhere other than the user’s home directory.

run_solc 🔒

Runs solc in an empty directory and terminates it if the remaining lookup budget expires.

write_cached_layout 🔒

Persists a resolved layout so later runs can skip the fetch and the compile.

Type Aliases

ExternalStorageLayout 🔒

A resolved storage layout, or None if the contract has no layout we can use.

LookupSlot 🔒

A single address’ lookup slot: None until the lookup completes, then its memoized result.