✨ Add docs and tests for Python 3.9 and Python 3.10

.github/workflows/test.yml

@@ -10,7 +10,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        python-version: [3.6, 3.7, 3.8, 3.9]
+        python-version: [3.6, 3.7, 3.8, 3.9, "3.10.0-rc.1"]
       fail-fast: false
 
     steps:

docs/en/docs/python-types.md

@@ -148,37 +148,62 @@ You can use, for example:
 
 There are some data structures that can contain other values, like `dict`, `list`, `set` and `tuple`. And the internal values can have their own type too.
 
-To declare those types and the internal types, you can use the standard Python module `typing`.
+These types that have internal types are called "**generic**" types. And it's possible to declare them, even with their internal types.
 
-It exists specifically to support these type hints.
+To declare those types and the internal types, you can use the standard Python module `typing`. It exists specifically to support these type hints.
 
-#### `List`
+#### Newer versions of Python
+
+The syntax using `typing` is **compatible** with all versions, from Python 3.6 to the latest ones, including Python 3.9, Python 3.10, etc.
+
+As Python advances, **newer versions** come with improved support for these type annotations and in many cases you won't even need to import and use the `typing` module to declare the type annotations.
+
+If you can chose a more recent version of Python for your project, you will be able to take advantage of that extra simplicity. See some examples below.
+
+#### List
 
 For example, let's define a variable to be a `list` of `str`.
 
-From `typing`, import `List` (with a capital `L`):
+=== "Python 3.6 and above"
 
-```Python hl_lines="1"
-{!../../../docs_src/python_types/tutorial006.py!}
-```
+    From `typing`, import `List` (with a capital `L`):
 
-Declare the variable, with the same colon (`:`) syntax.
+    ``` Python hl_lines="1"
+    {!> ../../../docs_src/python_types/tutorial006.py!}
+    ```
 
-As the type, put the `List`.
+    Declare the variable, with the same colon (`:`) syntax.
 
-As the list is a type that contains some internal types, you put them in square brackets:
+    As the type, put the `List` that you imported from `typing`.
 
-```Python hl_lines="4"
-{!../../../docs_src/python_types/tutorial006.py!}
-```
+    As the list is a type that contains some internal types, you put them in square brackets:
 
-!!! tip
+    ```Python hl_lines="4"
+    {!> ../../../docs_src/python_types/tutorial006.py!}
+    ```
+
+=== "Python 3.9 and above"
+
+    Declare the variable, with the same colon (`:`) syntax.
+
+    As the type, put `list`.
+
+    As the list is a type that contains some internal types, you put them in square brackets:
+
+    ```Python hl_lines="1"
+    {!> ../../../docs_src/python_types/tutorial006_py39.py!}
+    ```
+
+!!! info
     Those internal types in the square brackets are called "type parameters".
 
-    In this case, `str` is the type parameter passed to `List`.
+    In this case, `str` is the type parameter passed to `List` (or `list` in Python 3.9 and above).
 
 That means: "the variable `items` is a `list`, and each of the items in this list is a `str`".
 
+!!! tip
+    If you use Python 3.9 or above, you don't have to import `List` from `typing`, you can use the same regular `list` type instead.
+
 By doing that, your editor can provide support even while processing items from the list:
 
 <img src="/img/python-types/image05.png">
@@ -189,59 +214,154 @@ Notice that the variable `item` is one of the elements in the list `items`.
 
 And still, the editor knows it is a `str`, and provides support for that.
 
-#### `Tuple` and `Set`
+#### Tuple and Set
 
 You would do the same to declare `tuple`s and `set`s:
 
-```Python hl_lines="1  4"
-{!../../../docs_src/python_types/tutorial007.py!}
-```
+=== "Python 3.6 and above"
+
+    ```Python hl_lines="1  4"
+    {!> ../../../docs_src/python_types/tutorial007.py!}
+    ```
+
+=== "Python 3.9 and above"
+
+    ```Python hl_lines="1"
+    {!> ../../../docs_src/python_types/tutorial007_py39.py!}
+    ```
 
 This means:
 
 * The variable `items_t` is a `tuple` with 3 items, an `int`, another `int`, and a `str`.
 * The variable `items_s` is a `set`, and each of its items is of type `bytes`.
 
-#### `Dict`
+#### Dict
 
 To define a `dict`, you pass 2 type parameters, separated by commas.
 
 The first type parameter is for the keys of the `dict`.
 
 The second type parameter is for the values of the `dict`:
 
-```Python hl_lines="1  4"
-{!../../../docs_src/python_types/tutorial008.py!}
-```
+=== "Python 3.6 and above"
+
+    ```Python hl_lines="1  4"
+    {!> ../../../docs_src/python_types/tutorial008.py!}
+    ```
+
+=== "Python 3.9 and above"
+
+    ```Python hl_lines="1"
+    {!> ../../../docs_src/python_types/tutorial008.py!}
+    ```
 
 This means:
 
 * The variable `prices` is a `dict`:
     * The keys of this `dict` are of type `str` (let's say, the name of each item).
     * The values of this `dict` are of type `float` (let's say, the price of each item).
 
-#### `Optional`
+#### Union
+
+You can declare that a variable can be any of **several types**, for example, an `int` or a `str`.
+
+In Python 3.6 and above (including Python 3.10) you can use the `Union` type from `typing` and put inside the square brackets the possible types to accept.
+
+In Python 3.10 there's also an **alternative syntax** were you can put the possible types separated by a <abbr title='also called "bitwise or operator", but that meaning is not relevant here'>vertical bar (`|`)</abbr>.
 
-You can also use `Optional` to declare that a variable has a type, like `str`, but that it is "optional", which means that it could also be `None`:
+=== "Python 3.6 and above"
+
+    ```Python hl_lines="1  4"
+    {!> ../../../docs_src/python_types/tutorial008b.py!}
+    ```
+
+=== "Python 3.10 and above"
+
+    ```Python hl_lines="1"
+    {!> ../../../docs_src/python_types/tutorial008b_py310.py!}
+    ```
+
+In both cases this means that `item` could be an `int` or a `str`.
+
+#### Possibly `None`
+
+You can declare that a value could have a type, like `str`, but that it could also be `None`.
+
+In Python 3.6 and above (including Python 3.10) you can declare it by importing and using `Optional` from the `typing` module.
 
 ```Python hl_lines="1  4"
 {!../../../docs_src/python_types/tutorial009.py!}
 ```
 
 Using `Optional[str]` instead of just `str` will let the editor help you detecting errors where you could be assuming that a value is always a `str`, when it could actually be `None` too.
 
+`Optional[Something]` is actually a shortcut for `Union[Something, None]`, they are equivalent.
+
+This also means that in Python 3.10, you can use `Something | None`:
+
+=== "Python 3.6 and above"
+
+    ```Python hl_lines="1  4"
+    {!> ../../../docs_src/python_types/tutorial009.py!}
+    ```
+
+=== "Python 3.6 and above - alternative"
+
+    ```Python hl_lines="1  4"
+    {!> ../../../docs_src/python_types/tutorial009b.py!}
+    ```
+
+=== "Python 3.10 and above"
+
+    ```Python hl_lines="1"
+    {!> ../../../docs_src/python_types/tutorial009_py310.py!}
+    ```
+
 #### Generic types
 
-These types that take type parameters in square brackets, like:
+These types that take type parameters in square brackets are called **Generic types** or **Generics**, for example:
 
-* `List`
-* `Tuple`
-* `Set`
-* `Dict`
-* `Optional`
-* ...and others.
+=== "Python 3.6 and above"
 
-are called **Generic types** or **Generics**.
+    * `List`
+    * `Tuple`
+    * `Set`
+    * `Dict`
+    * `Union`
+    * `Optional`
+    * ...and others.
+
+=== "Python 3.9 and above"
+
+    You can use the same builtin types as generics (with square brakets and types inside):
+
+    * `list`
+    * `tuple`
+    * `set`
+    * `dict`
+
+    And the same as with Python 3.6, from the `typing` module:
+
+    * `Union`
+    * `Optional`
+    * ...and others.
+
+=== "Python 3.10 and above"
+
+    You can use the same builtin types as generics (with square brakets and types inside):
+
+    * `list`
+    * `tuple`
+    * `set`
+    * `dict`
+
+    And the same as with Python 3.6, from the `typing` module:
+
+    * `Union`
+    * `Optional` (the same as with Python 3.6)
+    * ...and others.
+
+    In Python 3.10, as an alternative to using the generics `Union` and `Optional`, you can use the <abbr title='also called "bitwise or operator", but that meaning is not relevant here'>vertical bar (`|`)</abbr> to declare unions of types.
 
 ### Classes as types
 
@@ -275,11 +395,25 @@ Then you create an instance of that class with some values and it will validate
 
 And you get all the editor support with that resulting object.
 
-Taken from the official Pydantic docs:
+An example from the official Pydantic docs:
 
-```Python
-{!../../../docs_src/python_types/tutorial011.py!}
-```
+=== "Python 3.6 and above"
+
+    ```Python
+    {!> ../../../docs_src/python_types/tutorial011.py!}
+    ```
+
+=== "Python 3.9 and above"
+
+    ```Python
+    {!> ../../../docs_src/python_types/tutorial011_py39.py!}
+    ```
+
+=== "Python 3.10 and above"
+
+    ```Python
+    {!> ../../../docs_src/python_types/tutorial011_py310.py!}
+    ```
 
 !!! info
     To learn more about <a href="https://pydantic-docs.helpmanual.io/" class="external-link" target="_blank">Pydantic, check its docs</a>.

docs/en/docs/tutorial/background-tasks.md

@@ -57,9 +57,17 @@ Using `BackgroundTasks` also works with the dependency injection system, you can
 
 **FastAPI** knows what to do in each case and how to re-use the same object, so that all the background tasks are merged together and are run in the background afterwards:
 
-```Python hl_lines="13  15  22  25"
-{!../../../docs_src/background_tasks/tutorial002.py!}
-```
+=== "Python 3.6 and above"
+
+    ```Python hl_lines="13  15  22  25"
+    {!> ../../../docs_src/background_tasks/tutorial002.py!}
+    ```
+
+=== "Python 3.10 and above"
+
+    ```Python hl_lines="11  13  20  23"
+    {!> ../../../docs_src/background_tasks/tutorial002_py310.py!}
+    ```
 
 In this example, the messages will be written to the `log.txt` file *after* the response is sent.
 

docs/en/docs/tutorial/body-fields.md

@@ -6,9 +6,17 @@ The same way you can declare additional validation and metadata in *path operati
 
 First, you have to import it:
 
-```Python hl_lines="4"
-{!../../../docs_src/body_fields/tutorial001.py!}
-```
+=== "Python 3.6 and above"
+
+    ```Python hl_lines="4"
+    {!> ../../../docs_src/body_fields/tutorial001.py!}
+    ```
+
+=== "Python 3.10 and above"
+
+    ```Python hl_lines="2"
+    {!> ../../../docs_src/body_fields/tutorial001_py310.py!}
+    ```
 
 !!! warning
     Notice that `Field` is imported directly from `pydantic`, not from `fastapi` as are all the rest (`Query`, `Path`, `Body`, etc).
@@ -17,9 +25,17 @@ First, you have to import it:
 
 You can then use `Field` with model attributes:
 
-```Python hl_lines="11-14"
-{!../../../docs_src/body_fields/tutorial001.py!}
-```
+=== "Python 3.6 and above"
+
+    ```Python hl_lines="11-14"
+    {!> ../../../docs_src/body_fields/tutorial001.py!}
+    ```
+
+=== "Python 3.10 and above"
+
+    ```Python hl_lines="9-12"
+    {!> ../../../docs_src/body_fields/tutorial001_py310.py!}
+    ```
 
 `Field` works the same way as `Query`, `Path` and `Body`, it has all the same parameters, etc.