check_protocol_compatibility.py

#!/usr/bin/env python
# Copyright (c) 2011 Google Inc. All rights reserved.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions are
# met:
#
#     * Redistributions of source code must retain the above copyright
# notice, this list of conditions and the following disclaimer.
#     * Redistributions in binary form must reproduce the above
# copyright notice, this list of conditions and the following disclaimer
# in the documentation and/or other materials provided with the
# distribution.
#     * Neither the name of Google Inc. nor the names of its
# contributors may be used to endorse or promote products derived from
# this software without specific prior written permission.
#
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#
# Inspector protocol validator.
#
# Tests that subsequent protocol changes are not breaking backwards compatibility.
# Following violations are reported:
#
#   - Domain has been removed
#   - Command has been removed
#   - Required command parameter was added or changed from optional
#   - Required response parameter was removed or changed to optional
#   - Event has been removed
#   - Required event parameter was removed or changed to optional
#   - Parameter type has changed.
#
# For the parameters with composite types the above checks are also applied
# recursively to every property of the type.
#
# Adding --show_changes to the command line prints out a list of valid public API changes.

from __future__ import print_function
import copy
import os.path
import optparse
import sys

import pdl

try:
    import json
except ImportError:
    import simplejson as json


def list_to_map(items, key):
    result = {}
    for item in items:
        if "experimental" not in item and "hidden" not in item:
            result[item[key]] = item
    return result


def named_list_to_map(container, name, key):
    if name in container:
        return list_to_map(container[name], key)
    return {}


def removed(reverse):
    if reverse:
        return "added"
    return "removed"


def required(reverse):
    if reverse:
        return "optional"
    return "required"


def compare_schemas(d_1, d_2, reverse):
    errors = []
    domains_1 = copy.deepcopy(d_1)
    domains_2 = copy.deepcopy(d_2)
    types_1 = normalize_types_in_schema(domains_1)
    types_2 = normalize_types_in_schema(domains_2)

    domains_by_name_1 = list_to_map(domains_1, "domain")
    domains_by_name_2 = list_to_map(domains_2, "domain")

    for name in domains_by_name_1:
        domain_1 = domains_by_name_1[name]
        if name not in domains_by_name_2:
            errors.append("%s: domain has been %s" % (name, removed(reverse)))
            continue
        compare_domains(domain_1, domains_by_name_2[name], types_1, types_2, errors, reverse)
    return errors


def compare_domains(domain_1, domain_2, types_map_1, types_map_2, errors, reverse):
    domain_name = domain_1["domain"]
    commands_1 = named_list_to_map(domain_1, "commands", "name")
    commands_2 = named_list_to_map(domain_2, "commands", "name")
    for name in commands_1:
        command_1 = commands_1[name]
        if name not in commands_2:
            errors.append("%s.%s: command has been %s" % (domain_1["domain"], name, removed(reverse)))
            continue
        compare_commands(domain_name, command_1, commands_2[name], types_map_1, types_map_2, errors, reverse)

    events_1 = named_list_to_map(domain_1, "events", "name")
    events_2 = named_list_to_map(domain_2, "events", "name")
    for name in events_1:
        event_1 = events_1[name]
        if name not in events_2:
            errors.append("%s.%s: event has been %s" % (domain_1["domain"], name, removed(reverse)))
            continue
        compare_events(domain_name, event_1, events_2[name], types_map_1, types_map_2, errors, reverse)


def compare_commands(domain_name, command_1, command_2, types_map_1, types_map_2, errors, reverse):
    context = domain_name + "." + command_1["name"]

    params_1 = named_list_to_map(command_1, "parameters", "name")
    params_2 = named_list_to_map(command_2, "parameters", "name")
    # Note the reversed order: we allow removing but forbid adding parameters.
    compare_params_list(context, "parameter", params_2, params_1, types_map_2, types_map_1, 0, errors, not reverse)

    returns_1 = named_list_to_map(command_1, "returns", "name")
    returns_2 = named_list_to_map(command_2, "returns", "name")
    compare_params_list(context, "response parameter", returns_1, returns_2, types_map_1, types_map_2, 0, errors, reverse)


def compare_events(domain_name, event_1, event_2, types_map_1, types_map_2, errors, reverse):
    context = domain_name + "." + event_1["name"]
    params_1 = named_list_to_map(event_1, "parameters", "name")
    params_2 = named_list_to_map(event_2, "parameters", "name")
    compare_params_list(context, "parameter", params_1, params_2, types_map_1, types_map_2, 0, errors, reverse)


def compare_params_list(context, kind, params_1, params_2, types_map_1, types_map_2, depth, errors, reverse):
    for name in params_1:
        param_1 = params_1[name]
        if name not in params_2:
            if "optional" not in param_1:
                errors.append("%s.%s: required %s has been %s" % (context, name, kind, removed(reverse)))
            continue

        param_2 = params_2[name]
        if param_2 and "optional" in param_2 and "optional" not in param_1:
            errors.append("%s.%s: %s %s is now %s" % (context, name, required(reverse), kind, required(not reverse)))
            continue
        type_1 = extract_type(param_1, types_map_1, errors)
        type_2 = extract_type(param_2, types_map_2, errors)
        compare_types(context + "." + name, kind, type_1, type_2, types_map_1, types_map_2, depth, errors, reverse)


def compare_types(context, kind, type_1, type_2, types_map_1, types_map_2, depth, errors, reverse):
    if depth > 5:
        return

    base_type_1 = type_1["type"]
    base_type_2 = type_2["type"]

    # Binary and string have the same wire representation in JSON.
    if ((base_type_1 == "string" and base_type_2 == "binary") or
        (base_type_2 == "string" and base_type_1 == "binary")):
      return

    if base_type_1 != base_type_2:
        errors.append("%s: %s base type mismatch, '%s' vs '%s'" % (context, kind, base_type_1, base_type_2))
    elif base_type_1 == "object":
        params_1 = named_list_to_map(type_1, "properties", "name")
        params_2 = named_list_to_map(type_2, "properties", "name")
        # If both parameters have the same named type use it in the context.
        if "id" in type_1 and "id" in type_2 and type_1["id"] == type_2["id"]:
            type_name = type_1["id"]
        else:
            type_name = "<object>"
        context += " %s->%s" % (kind, type_name)
        compare_params_list(context, "property", params_1, params_2, types_map_1, types_map_2, depth + 1, errors, reverse)
    elif base_type_1 == "array":
        item_type_1 = extract_type(type_1["items"], types_map_1, errors)
        item_type_2 = extract_type(type_2["items"], types_map_2, errors)
        compare_types(context, kind, item_type_1, item_type_2, types_map_1, types_map_2, depth + 1, errors, reverse)


def extract_type(typed_object, types_map, errors):
    if "type" in typed_object:
        result = {"id": "<transient>", "type": typed_object["type"]}
        if typed_object["type"] == "object":
            result["properties"] = []
        elif typed_object["type"] == "array":
            result["items"] = typed_object["items"]
        return result
    elif "$ref" in typed_object:
        ref = typed_object["$ref"]
        if ref not in types_map:
            errors.append("Can not resolve type: %s" % ref)
            types_map[ref] = {"id": "<transient>", "type": "object"}
        return types_map[ref]


def normalize_types_in_schema(domains):
    types = {}
    for domain in domains:
        domain_name = domain["domain"]
        normalize_types(domain, domain_name, types)
    return types


def normalize_types(obj, domain_name, types):
    if isinstance(obj, list):
        for item in obj:
            normalize_types(item, domain_name, types)
    elif isinstance(obj, dict):
        for key, value in obj.items():
            if key == "$ref" and value.find(".") == -1:
                obj[key] = "%s.%s" % (domain_name, value)
            elif key == "id":
                obj[key] = "%s.%s" % (domain_name, value)
                types[obj[key]] = obj
            else:
                normalize_types(value, domain_name, types)


def load_schema(file_name, domains):
    # pylint: disable=W0613
    if not os.path.isfile(file_name):
        return
    input_file = open(file_name, "r")
    parsed_json = pdl.loads(input_file.read(), file_name)
    input_file.close()
    domains += parsed_json["domains"]
    return parsed_json["version"]


def self_test():
    def create_test_schema_1():
        return [
            {
                "domain": "Network",
                "types": [
                    {
                        "id": "LoaderId",
                        "type": "string"
                    },
                    {
                        "id": "Headers",
                        "type": "object"
                    },
                    {
                        "id": "Request",
                        "type": "object",
                        "properties": [
                            {"name": "url", "type": "string"},
                            {"name": "method", "type": "string"},
                            {"name": "headers", "$ref": "Headers"},
                            {"name": "becameOptionalField", "type": "string"},
                            {"name": "removedField", "type": "string"},
                        ]
                    }
                ],
                "commands": [
                    {
                        "name": "removedCommand",
                    },
                    {
                        "name": "setExtraHTTPHeaders",
                        "parameters": [
                            {"name": "headers", "$ref": "Headers"},
                            {"name": "mismatched", "type": "string"},
                            {"name": "becameOptional", "$ref": "Headers"},
                            {"name": "removedRequired", "$ref": "Headers"},
                            {"name": "becameRequired", "$ref": "Headers", "optional": True},
                            {"name": "removedOptional", "$ref": "Headers", "optional": True},
                        ],
                        "returns": [
                            {"name": "mimeType", "type": "string"},
                            {"name": "becameOptional", "type": "string"},
                            {"name": "removedRequired", "type": "string"},
                            {"name": "becameRequired", "type": "string", "optional": True},
                            {"name": "removedOptional", "type": "string", "optional": True},
                        ]
                    }
                ],
                "events": [
                    {
                        "name": "requestWillBeSent",
                        "parameters": [
                            {"name": "frameId", "type": "string", "experimental": True},
                            {"name": "request", "$ref": "Request"},
                            {"name": "becameOptional", "type": "string"},
                            {"name": "removedRequired", "type": "string"},
                            {"name": "becameRequired", "type": "string", "optional": True},
                            {"name": "removedOptional", "type": "string", "optional": True},
                        ]
                    },
                    {
                        "name": "removedEvent",
                        "parameters": [
                            {"name": "errorText", "type": "string"},
                            {"name": "canceled", "type": "boolean", "optional": True}
                        ]
                    }
                ]
            },
            {
                "domain":  "removedDomain"
            }
        ]

    def create_test_schema_2():
        return [
            {
                "domain": "Network",
                "types": [
                    {
                        "id": "LoaderId",
                        "type": "string"
                    },
                    {
                        "id": "Request",
                        "type": "object",
                        "properties": [
                            {"name": "url", "type": "string"},
                            {"name": "method", "type": "string"},
                            {"name": "headers", "type": "object"},
                            {"name": "becameOptionalField", "type": "string", "optional": True},
                        ]
                    }
                ],
                "commands": [
                    {
                        "name": "addedCommand",
                    },
                    {
                        "name": "setExtraHTTPHeaders",
                        "parameters": [
                            {"name": "headers", "type": "object"},
                            {"name": "mismatched", "type": "object"},
                            {"name": "becameOptional", "type": "object", "optional": True},
                            {"name": "addedRequired", "type": "object"},
                            {"name": "becameRequired", "type": "object"},
                            {"name": "addedOptional", "type": "object", "optional": True},
                        ],
                        "returns": [
                            {"name": "mimeType", "type": "string"},
                            {"name": "becameOptional", "type": "string", "optional": True},
                            {"name": "addedRequired", "type": "string"},
                            {"name": "becameRequired", "type": "string"},
                            {"name": "addedOptional", "type": "string", "optional": True},
                        ]
                    }
                ],
                "events": [
                    {
                        "name": "requestWillBeSent",
                        "parameters": [
                            {"name": "request", "$ref": "Request"},
                            {"name": "becameOptional", "type": "string", "optional": True},
                            {"name": "addedRequired", "type": "string"},
                            {"name": "becameRequired", "type": "string"},
                            {"name": "addedOptional", "type": "string", "optional": True},
                        ]
                    },
                    {
                        "name": "addedEvent"
                    }
                ]
            },
            {
                "domain": "addedDomain"
            }
        ]

    expected_errors = [
        "removedDomain: domain has been removed",
        "Network.removedCommand: command has been removed",
        "Network.removedEvent: event has been removed",
        "Network.setExtraHTTPHeaders.mismatched: parameter base type mismatch, 'object' vs 'string'",
        "Network.setExtraHTTPHeaders.addedRequired: required parameter has been added",
        "Network.setExtraHTTPHeaders.becameRequired: optional parameter is now required",
        "Network.setExtraHTTPHeaders.removedRequired: required response parameter has been removed",
        "Network.setExtraHTTPHeaders.becameOptional: required response parameter is now optional",
        "Network.requestWillBeSent.removedRequired: required parameter has been removed",
        "Network.requestWillBeSent.becameOptional: required parameter is now optional",
        "Network.requestWillBeSent.request parameter->Network.Request.removedField: required property has been removed",
        "Network.requestWillBeSent.request parameter->Network.Request.becameOptionalField: required property is now optional",
    ]

    expected_errors_reverse = [
        "addedDomain: domain has been added",
        "Network.addedEvent: event has been added",
        "Network.addedCommand: command has been added",
        "Network.setExtraHTTPHeaders.mismatched: parameter base type mismatch, 'string' vs 'object'",
        "Network.setExtraHTTPHeaders.removedRequired: required parameter has been removed",
        "Network.setExtraHTTPHeaders.becameOptional: required parameter is now optional",
        "Network.setExtraHTTPHeaders.addedRequired: required response parameter has been added",
        "Network.setExtraHTTPHeaders.becameRequired: optional response parameter is now required",
        "Network.requestWillBeSent.becameRequired: optional parameter is now required",
        "Network.requestWillBeSent.addedRequired: required parameter has been added",
    ]

    def is_subset(subset, superset, message):
        for i in range(len(subset)):
            if subset[i] not in superset:
                sys.stderr.write("%s error: %s\n" % (message, subset[i]))
                return False
        return True

    def errors_match(expected, actual):
        return (is_subset(actual, expected, "Unexpected") and
                is_subset(expected, actual, "Missing"))

    return (errors_match(expected_errors,
                         compare_schemas(create_test_schema_1(), create_test_schema_2(), False)) and
            errors_match(expected_errors_reverse,
                         compare_schemas(create_test_schema_2(), create_test_schema_1(), True)))


def load_domains_and_baselines(file_name, domains, baseline_domains):
    version = load_schema(os.path.normpath(file_name), domains)
    suffix = "-%s.%s.json" % (version["major"], version["minor"])
    baseline_file = file_name.replace(".json", suffix)
    baseline_file = file_name.replace(".pdl", suffix)
    load_schema(os.path.normpath(baseline_file), baseline_domains)
    return version


def main():
    if not self_test():
        sys.stderr.write("Self-test failed")
        return 1

    cmdline_parser = optparse.OptionParser()
    cmdline_parser.add_option("--show_changes")
    cmdline_parser.add_option("--expected_errors")
    cmdline_parser.add_option("--stamp")
    arg_options, arg_values = cmdline_parser.parse_args()

    if len(arg_values) < 1:
        sys.stderr.write("Usage: %s [--show_changes] <protocol-1> [, <protocol-2>...]\n" % sys.argv[0])
        return 1

    domains = []
    baseline_domains = []
    version = load_domains_and_baselines(arg_values[0], domains, baseline_domains)
    for dependency in arg_values[1:]:
        load_domains_and_baselines(dependency, domains, baseline_domains)

    expected_errors = []
    if arg_options.expected_errors:
        expected_errors_file = open(arg_options.expected_errors, "r")
        expected_errors = json.loads(expected_errors_file.read())["errors"]
        expected_errors_file.close()

    errors = compare_schemas(baseline_domains, domains, False)
    unexpected_errors = []
    for i in range(len(errors)):
        if errors[i] not in expected_errors:
            unexpected_errors.append(errors[i])
    if len(unexpected_errors) > 0:
        sys.stderr.write("  Compatibility checks FAILED\n")
        for error in unexpected_errors:
            sys.stderr.write("    %s\n" % error)
        return 1

    if arg_options.show_changes:
        changes = compare_schemas(domains, baseline_domains, True)
        if len(changes) > 0:
            print("  Public changes since %s:" % version)
            for change in changes:
                print("    %s" % change)

    if arg_options.stamp:
        with open(arg_options.stamp, 'a') as _:
            pass

if __name__ == '__main__':
    sys.exit(main())