Support strict setting in all decoders

benchmarks/bench_encodings.py

@@ -31,7 +31,7 @@ class Directory(msgspec.Struct, tag="directory"):
 def bench(dumps, loads, ndata, schema=None):
     data = make_filesystem_data(ndata)
     if schema:
-        data = msgspec.from_builtins(data, schema)
+        data = msgspec.convert(data, schema)
     timer = timeit.Timer("func(data)", globals={"func": dumps, "data": data})
     n, t = timer.autorange()
     dumps_time = t / n

benchmarks/bench_validation.py

@@ -40,7 +40,7 @@ def bench_msgspec(n):
     dec = msgspec.json.Decoder(Directory)
 
     def convert(data):
-        return msgspec.from_builtins(data, Directory)
+        return msgspec.convert(data, Directory)
 
     return bench(enc.encode, dec.decode, n, convert)
 

docs/source/supported-types.rst

@@ -87,6 +87,15 @@ lacks a ``null`` value, attempted to encode a message containing ``None`` to
     >>> msgspec.json.decode(b'null')
     None
 
+If ``strict=False`` is specified, a string value of ``"null"`` (case
+insensitive) may also be coerced to ``None``. See :ref:`strict-vs-lax` for more
+information.
+
+.. code-block:: python
+
+   >>> msgspec.json.decode(b'"null"', type=None, strict=False)
+   None
+
 ``bool``
 --------
 
@@ -101,6 +110,18 @@ supported protocols.
     >>> msgspec.json.decode(b'true')
     True
 
+If ``strict=False`` is specified, string values of ``"true"``/``"1"`` or
+``"false"``/``"0"`` (case insensitive) may also be coerced to
+``True``/``False`` respectively. See :ref:`strict-vs-lax` for more information.
+
+.. code-block:: python
+
+   >>> msgspec.json.decode(b'"false"', type=bool, strict=False)
+   False
+
+   >>> msgspec.json.decode(b'"TRUE"', type=bool, strict=False)
+   True
+
 ``int``
 -------
 
@@ -122,6 +143,15 @@ Support for large integers varies by protocol:
     >>> msgspec.json.decode(b"123", type=int)
     123
 
+If ``strict=False`` is specified, string values may also be coerced to
+integers, following the same restrictions as above. See :ref:`strict-vs-lax`
+for more information.
+
+.. code-block:: python
+
+   >>> msgspec.json.decode(b'"123"', type=int, strict=False)
+   123
+
 
 ``float``
 ---------
@@ -151,6 +181,19 @@ provided, the `int` will be automatically converted.
     ... msgspec.json.decode(b"123", type=float)
     123.0
 
+If ``strict=False`` is specified, string values may also be coerced to floats.
+Note that in this case the strings ``"nan"``, ``"inf"``/``"infinity"``,
+``"-inf"``/``"-infinity"`` (case insensitive) will coerce to
+``nan``/``inf``/``-inf``. See :ref:`strict-vs-lax` for more information.
+
+.. code-block:: python
+
+   >>> msgspec.json.decode(b'"123.45"', type=float, strict=False)
+   123.45
+
+   >>> msgspec.json.decode(b'"-inf"', type=float, strict=False)
+   -inf
+
 ``str``
 -------
 

docs/source/usage.rst

@@ -131,10 +131,15 @@ If a message doesn't match the expected type, an error is raised.
       File "<stdin>", line 1, in <module>
     msgspec.ValidationError: Expected `str`, got `int` - at `$.groups[1]`
 
+.. _strict-vs-lax:
+
+"Strict" vs "Lax" Mode
+~~~~~~~~~~~~~~~~~~~~~~
+
 Unlike some other libraries (e.g. pydantic_), ``msgspec`` won't perform any
-unsafe implicit conversion. For example, if an integer is specified and a
-string is decoded instead, an error is raised rather than attempting to cast
-the string to an int.
+unsafe implicit conversion by default ("strict" mode). For example, if an
+integer is specified and a string is provided instead, an error is raised
+rather than attempting to cast the string to an int.
 
 .. code-block:: python
 
@@ -143,6 +148,17 @@ the string to an int.
       File "<stdin>", line 1, in <module>
     msgspec.ValidationError: Expected `int`, got `str` - at `$[2]`
 
+For cases where you'd like a more lax set of conversion rules, you can pass
+``strict=False`` to any ``decode`` function or ``Decoder`` class ("lax" mode).
+See :doc:`supported-types` for information on how this affects individual
+types.
+
+.. code-block:: python
+
+    >>> msgspec.json.decode(b'[1, 2, "3"]', type=list[int], strict=False)
+    [1, 2, 3]
+
+
 .. _JSON: https://json.org
 .. _MessagePack: https://msgpack.org
 .. _YAML: https://yaml.org