Function is_yarn_v2

src/packagedcode/npm.py:829–854

Return True if this is a yarn.lock format version 2 and False if this is version 1. Raise an UnknownYarnLockFormat exception if neither v1 or v2. v1 is a custom, almost-like-YAMl format. v2 is a proper subset of YAML. The start of v1 file has this: # THIS IS AN AUTOGENERAT

(location)

def is_yarn_v2(location):
    """
    Return True if this is a yarn.lock format version 2 and False if this is
    version 1. Raise an UnknownYarnLockFormat exception if neither v1 or v2.

    v1 is a custom, almost-like-YAMl format. v2 is a proper subset of YAML.

    The start of v1 file has this:
        # THIS IS AN AUTOGENERATED FILE. DO NOT EDIT THIS FILE DIRECTLY.
        # yarn lockfile v1

    The start of v2 file has this:
        # This file is generated by running "yarn install" inside your project.
        # Manual changes might be lost - proceed with caution!

        __metadata:
    """
    with open(location) as ylf:
        # check only in the first 10 lines
        for line in islice(ylf, 0, 10):
            if '__metadata:' in line:
                return True
            if 'yarn lockfile v1' in line:
                return False

    raise UnknownYarnLockFormat(location)


class YarnLockV2Handler(BaseNpmHandler):