Add fail-fast for dicts (#1543)

Co-authored-by: David Hewitt <[email protected]>

Author: uriyyo

python/pydantic_core/core_schema.py

@@ -1939,6 +1939,7 @@ class DictSchema(TypedDict, total=False):
     values_schema: CoreSchema  # default: AnySchema
     min_length: int
     max_length: int
+    fail_fast: bool
     strict: bool
     ref: str
     metadata: dict[str, Any]
@@ -1951,6 +1952,7 @@ def dict_schema(
     *,
     min_length: int | None = None,
     max_length: int | None = None,
+    fail_fast: bool | None = None,
     strict: bool | None = None,
     ref: str | None = None,
     metadata: dict[str, Any] | None = None,
@@ -1974,6 +1976,7 @@ def dict_schema(
         values_schema: The value must be a dict with values that match this schema
         min_length: The value must be a dict with at least this many items
         max_length: The value must be a dict with at most this many items
+        fail_fast: Stop validation on the first error
         strict: Whether the keys and values should be validated with strict mode
         ref: optional unique identifier of the schema, used to reference the schema in other places
         metadata: Any other information you want to include with the schema, not used by pydantic-core
@@ -1985,6 +1988,7 @@ def dict_schema(
         values_schema=values_schema,
         min_length=min_length,
         max_length=max_length,
+        fail_fast=fail_fast,
         strict=strict,
         ref=ref,
         metadata=metadata,

src/validators/dict.rs

@@ -21,6 +21,7 @@ pub struct DictValidator {
     value_validator: Box<CombinedValidator>,
     min_length: Option<usize>,
     max_length: Option<usize>,
+    fail_fast: bool,
     name: String,
 }
 
@@ -53,6 +54,7 @@ impl BuildValidator for DictValidator {
             value_validator,
             min_length: schema.get_as(intern!(py, "min_length"))?,
             max_length: schema.get_as(intern!(py, "max_length"))?,
+            fail_fast: schema.get_as(intern!(py, "fail_fast"))?.unwrap_or(false),
             name,
         }
         .into())
@@ -78,6 +80,7 @@ impl Validator for DictValidator {
             input,
             min_length: self.min_length,
             max_length: self.max_length,
+            fail_fast: self.fail_fast,
             key_validator: &self.key_validator,
             value_validator: &self.value_validator,
             state,
@@ -94,6 +97,7 @@ struct ValidateToDict<'a, 's, 'py, I: Input<'py> + ?Sized> {
     input: &'a I,
     min_length: Option<usize>,
     max_length: Option<usize>,
+    fail_fast: bool,
     key_validator: &'a CombinedValidator,
     value_validator: &'a CombinedValidator,
     state: &'a mut ValidationState<'s, 'py>,
@@ -111,6 +115,12 @@ where
         let mut errors: Vec<ValLineError> = Vec::new();
         let allow_partial = self.state.allow_partial;
 
+        macro_rules! should_fail_fast {
+            () => {
+                self.fail_fast && !errors.is_empty()
+            };
+        }
+
         for (_, is_last_partial, item_result) in self.state.enumerate_last_partial(iterator) {
             self.state.allow_partial = false.into();
             let (key, value) = item_result?;
@@ -130,6 +140,11 @@ where
                 true => allow_partial,
                 false => false.into(),
             };
+
+            if should_fail_fast!() {
+                break;
+            }
+
             let output_value = match self.value_validator.validate(self.py, value.borrow_input(), self.state) {
                 Ok(value) => value,
                 Err(ValError::LineErrors(line_errors)) => {
@@ -141,6 +156,11 @@ where
                 Err(ValError::Omit) => continue,
                 Err(err) => return Err(err),
             };
+
+            if should_fail_fast!() {
+                break;
+            }
+
             if let Some(key) = output_key {
                 output.set_item(key, output_value)?;
             }

tests/validators/test_dict.py

@@ -255,3 +255,61 @@ def test_json_dict_complex_key():
     assert v.validate_json('{"1+2j": 2, "infj": 4}') == {complex(1, 2): 2, complex(0, float('inf')): 4}
     with pytest.raises(ValidationError, match='Input should be a valid complex string'):
         v.validate_json('{"1+2j": 2, "": 4}') == {complex(1, 2): 2, complex(0, float('inf')): 4}
+
+
+@pytest.mark.parametrize(
+    ('fail_fast', 'expected'),
+    [
+        pytest.param(
+            True,
+            [
+                {
+                    'type': 'int_parsing',
+                    'loc': ('a', '[key]'),
+                    'msg': 'Input should be a valid integer, unable to parse string as an integer',
+                    'input': 'a',
+                },
+            ],
+            id='fail_fast',
+        ),
+        pytest.param(
+            False,
+            [
+                {
+                    'type': 'int_parsing',
+                    'loc': ('a', '[key]'),
+                    'msg': 'Input should be a valid integer, unable to parse string as an integer',
+                    'input': 'a',
+                },
+                {
+                    'type': 'int_parsing',
+                    'loc': ('a',),
+                    'msg': 'Input should be a valid integer, unable to parse string as an integer',
+                    'input': 'b',
+                },
+                {
+                    'type': 'int_parsing',
+                    'loc': ('c', '[key]'),
+                    'msg': 'Input should be a valid integer, unable to parse string as an integer',
+                    'input': 'c',
+                },
+                {
+                    'type': 'int_parsing',
+                    'loc': ('c',),
+                    'msg': 'Input should be a valid integer, unable to parse string as an integer',
+                    'input': 'd',
+                },
+            ],
+            id='not_fail_fast',
+        ),
+    ],
+)
+def test_dict_fail_fast(fail_fast, expected):
+    v = SchemaValidator(
+        {'type': 'dict', 'keys_schema': {'type': 'int'}, 'values_schema': {'type': 'int'}, 'fail_fast': fail_fast}
+    )
+
+    with pytest.raises(ValidationError) as exc_info:
+        v.validate_python({'a': 'b', 'c': 'd'})
+
+    assert exc_info.value.errors(include_url=False) == expected