Function check_dependencies_changed

ci/wasm_compile_pch.py:205–248

Check if any PCH dependencies are newer than the PCH output. Args: depfile: Path to .d dependency file pch_output: Path to PCH output file Returns: (changed, reason) tuple

(depfile: Path, pch_output: Path)

def check_dependencies_changed(depfile: Path, pch_output: Path) -> tuple[bool, str]:
    """
    Check if any PCH dependencies are newer than the PCH output.

    Args:
        depfile: Path to .d dependency file
        pch_output: Path to PCH output file

    Returns:
        (changed, reason) tuple
    """
    if not depfile.exists():
        return False, ""  # No depfile, can't check dependencies

    if not pch_output.exists():
        return True, "PCH output does not exist"

    # Get PCH output modification time
    pch_mtime = pch_output.stat().st_mtime
    depfile_mtime = depfile.stat().st_mtime

    # If depfile is older than PCH, it's stale - ignore it
    # (This can happen after PCH is rebuilt but before depfile is regenerated)
    if depfile_mtime < pch_mtime:
        return False, ""  # Stale depfile, rely on other checks

    # Parse dependencies
    deps = parse_dependency_file(depfile)
    if not deps:
        return False, ""  # Empty or unparseable depfile

    # Check each dependency
    for dep in deps:
        if not dep.exists():
            # Dependency was deleted - rebuild needed
            # Note: This is expected during initial builds or after clean
            return True, f"dependency missing: {dep.name}"

        dep_mtime = dep.stat().st_mtime
        if dep_mtime > pch_mtime:
            # Dependency is newer than PCH - rebuild needed
            return True, f"dependency changed: {dep.name}"

    return False, ""


def needs_rebuild(