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Leaner generated validation code (~1.5x on object-heavy schemas), no behavior change #233

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Leaner generated validation code (~1.5x on object-heavy schemas), no behavior change #233

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1 change: 1 addition & 0 deletions CHANGELOG.txt
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Original file line number Diff line number Diff line change
Expand Up @@ -7,6 +7,7 @@
* Added `message` to `JsonSchemaValuesException` joining messages of all collected errors
* Fixed the `date-time` format accepting months, days and hours out of range (such as `2020-19-39T29:00:00Z`) and rejecting a leap second (`23:59:60Z`)
* Fixed the `time` format accepting hours, minutes, seconds and offsets out of range (such as `29:99:99`)
* Improved validation performance (about 1.5x on object-heavy schemas) by generating leaner code: no set operations for `required`, no `_keys` bookkeeping when nothing consumes it, tuple membership for all-string `enum`s. No behavior change.

=== 2.22.2 (2026-08-15)

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56 changes: 41 additions & 15 deletions fastjsonschema/draft04.py
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Original file line number Diff line number Diff line change
Expand Up @@ -111,8 +111,12 @@ def generate_enum(self):
raise JsonSchemaDefinitionException('enum must be an array')
matches = ' or '.join(self._enum_value_matches(self._variable, value) for value in enum)
if matches:
with self.l('if not ({}):', matches):
self.exc('{name} must be one of {}', self.e(enum), rule='enum')
if all(isinstance(value, str) for value in enum):
with self.l('if {variable} not in {enum_values}:', enum_values=tuple(enum)):
self.exc('{name} must be one of {}', self.e(enum), rule='enum')
else:
with self.l('if not ({}):', matches):
self.exc('{name} must be one of {}', self.e(enum), rule='enum')
else:
with self.l('if True:'):
self.exc('{name} must be one of {}', self.e(enum), rule='enum')
Expand Down Expand Up @@ -508,6 +512,21 @@ def generate_max_properties(self):
with self.l('if {variable}_len > {maxProperties}:'):
self.exc('{name} must contain less than or equal to {maxProperties} properties', rule='maxProperties')

def _needs_keys_set(self):
"""
Whether generated code for this object level needs the
``{variable}_keys`` set at all. It is only consumed by
``additionalProperties`` (schema or False form) and by
``propertyNames: false``; otherwise building + pruning it per
object is dead weight on the valid path.
"""
addl = self._definition.get('additionalProperties', True)
if addl is not True and addl != {}:
return True
if self._definition.get('propertyNames') is False:
return True
return False

def generate_required(self):
self.create_variable_is_dict()
with self.l('if {variable}_is_dict:'):
Expand All @@ -525,7 +544,7 @@ def generate_required(self):
]
if not_possible:
raise JsonSchemaDefinitionException('{}: items {} are required but not allowed'.format(self._variable, not_possible))
self.l('{variable}__missing_keys = set({required}) - {variable}.keys()')
self.l('{variable}__missing_keys = [key for key in {required} if key not in {variable}]')
with self.l('if {variable}__missing_keys:'):
dynamic = 'str(sorted({variable}__missing_keys)) + " properties"'
self.exc('{name} must contain ', self.e(self._definition['required']), rule='required', append_to_msg=dynamic)
Expand All @@ -544,15 +563,20 @@ def generate_properties(self):

Valid object is containing key called 'key' and value any number.
"""
if not self._definition['properties']:
return
self.create_variable_is_dict()
with self.l('if {variable}_is_dict:'):
self.create_variable_keys()
keys_suffix = '_keys' if self._needs_keys_set() else ''
if keys_suffix:
self.create_variable_keys()
for key, prop_definition in self._definition['properties'].items():
key_name = re.sub(r'($[^a-zA-Z]|[^a-zA-Z0-9])', '', key)
if not isinstance(prop_definition, (dict, bool)):
raise JsonSchemaDefinitionException('{}[{}] must be object'.format(self._variable, key_name))
with self.l('if "{}" in {variable}_keys:', self.e(key)):
self.l('{variable}_keys.remove("{}")', self.e(key))
with self.l('if "{}" in {variable}' + keys_suffix + ':', self.e(key)):
if keys_suffix:
self.l('{variable}_keys.remove("{}")', self.e(key))
self.l('{variable}__{0} = {variable}["{1}"]', key_name, self.e(key))
self.generate_func_code_block(
prop_definition,
Expand All @@ -577,19 +601,21 @@ def generate_pattern_properties(self):

Valid object is containing key starting with a 'x' and value any number.
"""
pattern_prop_definition = self._definition['patternProperties']
if pattern_prop_definition == {}:
return
self.create_variable_is_dict()
with self.l('if {variable}_is_dict:'):
self.create_variable_keys()
pattern_prop_definition = self._definition['patternProperties']
if pattern_prop_definition == {}:
return
if self._needs_keys_set():
self.create_variable_keys()
for pattern, definition in pattern_prop_definition.items():
self._compile_regexps[pattern] = re.compile(pattern)
with self.l('for {variable}_key, {variable}_val in {variable}.items():'):
for pattern, definition in self._definition['patternProperties'].items():
with self.l('if REGEX_PATTERNS[{}].search({variable}_key):', repr(pattern)):
with self.l('if {variable}_key in {variable}_keys:'):
self.l('{variable}_keys.remove({variable}_key)')
if self._needs_keys_set():
with self.l('if {variable}_key in {variable}_keys:'):
self.l('{variable}_keys.remove({variable}_key)')
self.generate_func_code_block(
definition,
'{}_val'.format(self._variable),
Expand All @@ -613,12 +639,12 @@ def generate_additional_properties(self):
Valid object is containing key called 'key' and it's value any number and
any other key with any string.
"""
add_prop_definition = self._definition["additionalProperties"]
if add_prop_definition is True or add_prop_definition == {}:
return
self.create_variable_is_dict()
with self.l('if {variable}_is_dict:'):
self.create_variable_keys()
add_prop_definition = self._definition["additionalProperties"]
if add_prop_definition is True or add_prop_definition == {}:
return
if add_prop_definition:
properties_keys = list(self._definition.get("properties", {}).keys())
with self.l('for {variable}_key in {variable}_keys:'):
Expand Down