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[Bug]: Foundry sourceList indices don't match bytecode source map file references #652

@Mike4751

Description

@Mike4751

Summary

When using crytic-compile with Foundry projects that have subdirectories with their own foundry.toml using relative paths, the sourceList in exported combined_solc.json becomes misaligned with the source IDs in bytecode source maps. This causes Echidna coverage reports and Slither analysis to attribute results to incorrect source files.

Minimal Reproduction

https://github.com/Mike4751/crytic-compile-sourcelist-bug

git clone https://github.com/Mike4751/crytic-compile-sourcelist-bug
cd crytic-compile-sourcelist-bug/test/fuzzing
forge build --build-info
crytic-compile . --export-format solc --export-dir crytic-export --foundry-ignore-compile
python3 ../../scripts/verify_sourcelist.py

Result with unpatched crytic-compile:

sourceList[0]: expected 'Main.sol' but got 'Base.sol' - MISMATCH!
sourceList[1]: expected 'Base.sol' but got 'IPrice.sol' - MISMATCH!
...
BUG DETECTED: 8 mismatches out of 8 sources

Environment

  • crytic-compile: 0.3.11
  • Foundry/Forge: 0.3.0
  • Python: 3.14
  • OS: macOS

When It Occurs

The bug manifests when:

  1. A subdirectory has its own foundry.toml with relative paths (e.g., libs = ["../../lib", "../../node_modules"])
  2. The same files are referenced with different path representations (absolute vs relative)
  3. JSON key order in build-info differs from source ID order

Root Cause

In crytic_compile/platform/hardhat.py, the hardhat_like_parsing() function iterates over targets_json["sources"] in JSON key order rather than sorted by the id field:

# Current code
for path, info in targets_json["sources"].items():  # Not sorted by ID!
    source_unit = compilation_unit.create_source_unit(path)

When JSON key order differs from ID order, the resulting sourceList indices don't match source IDs.

Backwards Compatibility

The fix has been tested on both complex and simple project structures:

Environment Structure Unpatched Patched
Simple (A→B→C) Standard 0 mismatches 0 mismatches ✓
Relative paths Complex 8 mismatches 0 mismatches ✓
Large project (~470 files) Complex 470 mismatches 0 mismatches ✓

The fix resolves the bug without breaking existing projects.

Proposed Fix

I have a working fix ready: https://github.com/Mike4751/crytic-compile/tree/fix-foundry-sourcelist-order

Will submit PR shortly.

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