Function needs_rebuild

ci/wasm_compile_pch.py:251–293

Determine if PCH needs to be rebuilt. Returns: (needs_rebuild, reason) tuple

(
    emcc: str,
    flags: dict[str, list[str]],
    force: bool = False,
)

def needs_rebuild(
    emcc: str,
    flags: dict[str, list[str]],
    force: bool = False,
) -> tuple[bool, str]:
    """
    Determine if PCH needs to be rebuilt.

    Returns:
        (needs_rebuild, reason) tuple
    """
    if force:
        return True, "forced rebuild (--force flag)"

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

    # Load metadata from previous build
    metadata = load_metadata()
    if not metadata:
        return True, "no previous build metadata found"

    # Check header content hash
    current_header_hash = compute_content_hash(PCH_HEADER)
    if metadata.get("header_hash") != current_header_hash:
        return True, "PCH header content changed"

    # Check flags hash
    current_flags_hash = compute_flags_hash(flags)
    if metadata.get("flags_hash") != current_flags_hash:
        return True, "compilation flags changed"

    # Check compiler version
    current_compiler_version = get_compiler_version(emcc)
    if metadata.get("compiler_version") != current_compiler_version:
        return True, "compiler version changed"

    # Check if any dependencies have changed (NEW: dependency tracking)
    deps_changed, reason = check_dependencies_changed(PCH_DEPFILE, PCH_OUTPUT)
    if deps_changed:
        return True, reason

    return False, "PCH is up to date"


def compile_pch(