From b554208b35edef64b2aa65a4e1013f3c00437c85 Mon Sep 17 00:00:00 2001
From: Viicos <65306057+Viicos@users.noreply.github.com>
Date: Sun, 14 Jan 2024 12:23:58 +0100
Subject: [PATCH 1/7] WIP: Improve typing in template registry

---
 django-stubs/template/defaultfilters.pyi  |  9 +++++---
 django-stubs/template/library.pyi         | 23 +++++++++++++++----
 tests/typecheck/template/test_library.yml | 28 +++++++++++++++++++++++
 3 files changed, 53 insertions(+), 7 deletions(-)

diff --git a/django-stubs/template/defaultfilters.pyi b/django-stubs/template/defaultfilters.pyi
index 7eacd3fa7..b560ea252 100644
--- a/django-stubs/template/defaultfilters.pyi
+++ b/django-stubs/template/defaultfilters.pyi
@@ -2,13 +2,16 @@ from collections.abc import Callable
 from datetime import date as _date
 from datetime import datetime
 from datetime import time as _time
-from typing import Any
+from typing import Any, TypeVar
 
+from django.template.library import Library
 from django.utils.safestring import SafeString
 
-register: Any
+_C = TypeVar("_C", bound=Callable[..., Any])
 
-def stringfilter(func: Callable) -> Callable: ...
+register: Library
+
+def stringfilter(func: _C) -> _C: ...
 def addslashes(value: str) -> str: ...
 def capfirst(value: str) -> str: ...
 def escapejs_filter(value: str) -> SafeString: ...
diff --git a/django-stubs/template/library.pyi b/django-stubs/template/library.pyi
index 927918e2c..d98ec8376 100644
--- a/django-stubs/template/library.pyi
+++ b/django-stubs/template/library.pyi
@@ -10,9 +10,10 @@ from .base import Node, Template
 class InvalidTemplateLibrary(Exception): ...
 
 _C = TypeVar("_C", bound=Callable[..., Any])
+_FilterC = TypeVar("_FilterC", bound=Callable[[Any], Any] | Callable[[Any, Any], Any])
 
 class Library:
-    filters: dict[str, Callable]
+    filters: dict[str, Callable[[Any], Any] | Callable[[Any, Any], Any]]
     tags: dict[str, Callable]
     def __init__(self) -> None: ...
     @overload
@@ -23,11 +24,25 @@ class Library:
     def tag(self, name: str | None = ..., compile_function: None = ...) -> Callable[[_C], _C]: ...
     def tag_function(self, func: _C) -> _C: ...
     @overload
-    def filter(self, name: _C, filter_func: None = ..., **flags: Any) -> _C: ...
+    def filter(self, name: _FilterC, /) -> _FilterC: ...
     @overload
-    def filter(self, name: str | None, filter_func: _C, **flags: Any) -> _C: ...
+    def filter(
+        self,
+        name: str | None = ...,
+        filter_func: None = ...,
+        is_safe: bool = ...,
+        needs_autoescape: bool = ...,
+        expects_localtime: bool = ...,
+    ) -> Callable[[_FilterC], _FilterC]: ...
     @overload
-    def filter(self, name: str | None = ..., filter_func: None = ..., **flags: Any) -> Callable[[_C], _C]: ...
+    def filter(
+        self,
+        name: str,
+        filter_func: _FilterC,
+        is_safe: bool = ...,
+        needs_autoescape: bool = ...,
+        expects_localtime: bool = ...,
+    ) -> _FilterC: ...
     @overload
     def simple_tag(self, func: _C) -> _C: ...
     @overload
diff --git a/tests/typecheck/template/test_library.yml b/tests/typecheck/template/test_library.yml
index b3fd4dde0..a8529a5d7 100644
--- a/tests/typecheck/template/test_library.yml
+++ b/tests/typecheck/template/test_library.yml
@@ -20,6 +20,34 @@
 
         reveal_type(lower) # N: Revealed type is "def (value: builtins.str) -> builtins.str"
 
+-   case: register_filter_no_decorator
+    main: |
+        from django import template
+        register = template.Library()
+
+        def lower(value: str) -> str:
+            return value.lower()
+
+        registered = register.filter("tolower", lower)
+
+        reveal_type(registered) # N: Revealed type is "def (value: builtins.str) -> builtins.str"
+
+-   case: register_bad_filters
+    main: |
+        from django import template
+        register = template.Library()
+
+        @register.filter
+        def lower() -> str:
+            return ""
+
+        @register.filter(name="toomanyargs")
+        def toomanyargs(arg1: str, arg2: str, arg3: str) -> str:
+            return ""
+    out: |
+        main:4: error: Value of type variable "_FilterC" of "filter" of "Library" cannot be "Callable[[], str]"  [type-var]
+        main:8: error: Value of type variable "_FilterC" of function cannot be "Callable[[str, str, str], str]"  [type-var]
+
 -   case: register_simple_tag_no_args
     main: |
         import datetime

From 15cbe0ccf43b7bc111f36dd1abc772fd9948b0ea Mon Sep 17 00:00:00 2001
From: Viicos <65306057+Viicos@users.noreply.github.com>
Date: Sun, 14 Jan 2024 21:53:24 +0100
Subject: [PATCH 2/7] WIP: more work and fixes

---
 django-stubs/template/defaultfilters.pyi  |  7 +++++--
 django-stubs/template/library.pyi         | 23 +++++++++++++++++------
 tests/typecheck/template/test_library.yml | 10 ++++++++++
 3 files changed, 32 insertions(+), 8 deletions(-)

diff --git a/django-stubs/template/defaultfilters.pyi b/django-stubs/template/defaultfilters.pyi
index b560ea252..870b86cd9 100644
--- a/django-stubs/template/defaultfilters.pyi
+++ b/django-stubs/template/defaultfilters.pyi
@@ -4,14 +4,17 @@ from datetime import datetime
 from datetime import time as _time
 from typing import Any, TypeVar
 
+from typing_extensions import Concatenate, ParamSpec
+
 from django.template.library import Library
 from django.utils.safestring import SafeString
 
-_C = TypeVar("_C", bound=Callable[..., Any])
+_P = ParamSpec("_P")
+_R = TypeVar("_R")
 
 register: Library
 
-def stringfilter(func: _C) -> _C: ...
+def stringfilter(func: Callable[Concatenate[str, _P], _R]) -> Callable[Concatenate[object, _P], _R]: ...
 def addslashes(value: str) -> str: ...
 def capfirst(value: str) -> str: ...
 def escapejs_filter(value: str) -> SafeString: ...
diff --git a/django-stubs/template/library.pyi b/django-stubs/template/library.pyi
index d98ec8376..3438550e1 100644
--- a/django-stubs/template/library.pyi
+++ b/django-stubs/template/library.pyi
@@ -1,5 +1,7 @@
 from collections.abc import Callable, Collection, Iterable, Mapping, Sequence, Sized
-from typing import Any, TypeVar, overload
+from typing import Any, Literal, TypeVar, overload
+
+from typing_extensions import Concatenate
 
 from django.template.base import FilterExpression, Origin, Parser, Token
 from django.template.context import Context
@@ -11,23 +13,25 @@ class InvalidTemplateLibrary(Exception): ...
 
 _C = TypeVar("_C", bound=Callable[..., Any])
 _FilterC = TypeVar("_FilterC", bound=Callable[[Any], Any] | Callable[[Any, Any], Any])
+_TakesContextC = TypeVar("_TakesContextC", bound=Callable[Concatenate[Context, ...], Any])
 
 class Library:
     filters: dict[str, Callable[[Any], Any] | Callable[[Any, Any], Any]]
     tags: dict[str, Callable]
     def __init__(self) -> None: ...
     @overload
-    def tag(self, name: _C) -> _C: ...
+    def tag(self, name: _C, /) -> _C: ...
     @overload
-    def tag(self, name: str, compile_function: _C) -> _C: ...
+    def tag(self, *, name: str, compile_function: _C) -> _C: ...
     @overload
-    def tag(self, name: str | None = ..., compile_function: None = ...) -> Callable[[_C], _C]: ...
+    def tag(self, *, name: str | None = ..., compile_function: None = ...) -> Callable[[_C], _C]: ...
     def tag_function(self, func: _C) -> _C: ...
     @overload
     def filter(self, name: _FilterC, /) -> _FilterC: ...
     @overload
     def filter(
         self,
+        *,
         name: str | None = ...,
         filter_func: None = ...,
         is_safe: bool = ...,
@@ -37,6 +41,7 @@ class Library:
     @overload
     def filter(
         self,
+        *,
         name: str,
         filter_func: _FilterC,
         is_safe: bool = ...,
@@ -44,9 +49,15 @@ class Library:
         expects_localtime: bool = ...,
     ) -> _FilterC: ...
     @overload
-    def simple_tag(self, func: _C) -> _C: ...
+    def simple_tag(self, func: _C, /) -> _C: ...
+    @overload
+    def simple_tag(
+        self, *, takes_context: Literal[True], name: str | None = ...
+    ) -> Callable[[_TakesContextC], _TakesContextC]: ...
     @overload
-    def simple_tag(self, takes_context: bool | None = ..., name: str | None = ...) -> Callable[[_C], _C]: ...
+    def simple_tag(
+        self, *, takes_context: Literal[False] | None = ..., name: str | None = ...
+    ) -> Callable[[_C], _C]: ...
     def inclusion_tag(
         self,
         filename: Template | str,
diff --git a/tests/typecheck/template/test_library.yml b/tests/typecheck/template/test_library.yml
index a8529a5d7..23f42da2c 100644
--- a/tests/typecheck/template/test_library.yml
+++ b/tests/typecheck/template/test_library.yml
@@ -122,3 +122,13 @@
             return ', '.join(results)
 
         reveal_type(format_results) # N: Revealed type is "def (results: builtins.list[builtins.str]) -> builtins.str"
+
+-   case: stringfilter
+    main: |
+        from django.template.defaultfilters import stringfilter
+
+        @stringfilter
+        def lower(value: str) -> str:
+            return value.lower()
+
+        reveal_type(lower) # N: Revealed type is "def (value: object) -> builtins.str"

From 28925709becd18d8485d1dc8815b35acc76608f2 Mon Sep 17 00:00:00 2001
From: "pre-commit-ci[bot]"
 <66853113+pre-commit-ci[bot]@users.noreply.github.com>
Date: Sun, 14 Jan 2024 20:53:40 +0000
Subject: [PATCH 3/7] [pre-commit.ci] auto fixes from pre-commit.com hooks

---
 django-stubs/template/defaultfilters.pyi | 3 +--
 django-stubs/template/library.pyi        | 3 +--
 2 files changed, 2 insertions(+), 4 deletions(-)

diff --git a/django-stubs/template/defaultfilters.pyi b/django-stubs/template/defaultfilters.pyi
index 870b86cd9..f6a40d4ff 100644
--- a/django-stubs/template/defaultfilters.pyi
+++ b/django-stubs/template/defaultfilters.pyi
@@ -4,10 +4,9 @@ from datetime import datetime
 from datetime import time as _time
 from typing import Any, TypeVar
 
-from typing_extensions import Concatenate, ParamSpec
-
 from django.template.library import Library
 from django.utils.safestring import SafeString
+from typing_extensions import Concatenate, ParamSpec
 
 _P = ParamSpec("_P")
 _R = TypeVar("_R")
diff --git a/django-stubs/template/library.pyi b/django-stubs/template/library.pyi
index 3438550e1..e1dce92cd 100644
--- a/django-stubs/template/library.pyi
+++ b/django-stubs/template/library.pyi
@@ -1,11 +1,10 @@
 from collections.abc import Callable, Collection, Iterable, Mapping, Sequence, Sized
 from typing import Any, Literal, TypeVar, overload
 
-from typing_extensions import Concatenate
-
 from django.template.base import FilterExpression, Origin, Parser, Token
 from django.template.context import Context
 from django.utils.safestring import SafeString
+from typing_extensions import Concatenate
 
 from .base import Node, Template
 

From b21f0f5a11e99631ef53e410e8cd78ea6ad22583 Mon Sep 17 00:00:00 2001
From: Viicos <65306057+Viicos@users.noreply.github.com>
Date: Mon, 15 Jan 2024 09:07:32 +0100
Subject: [PATCH 4/7] Fix stararg position

---
 django-stubs/template/library.pyi | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/django-stubs/template/library.pyi b/django-stubs/template/library.pyi
index e1dce92cd..8838ac844 100644
--- a/django-stubs/template/library.pyi
+++ b/django-stubs/template/library.pyi
@@ -21,9 +21,9 @@ class Library:
     @overload
     def tag(self, name: _C, /) -> _C: ...
     @overload
-    def tag(self, *, name: str, compile_function: _C) -> _C: ...
+    def tag(self, name: str, compile_function: _C) -> _C: ...
     @overload
-    def tag(self, *, name: str | None = ..., compile_function: None = ...) -> Callable[[_C], _C]: ...
+    def tag(self, name: str | None = ..., compile_function: None = ...) -> Callable[[_C], _C]: ...
     def tag_function(self, func: _C) -> _C: ...
     @overload
     def filter(self, name: _FilterC, /) -> _FilterC: ...
@@ -40,9 +40,9 @@ class Library:
     @overload
     def filter(
         self,
-        *,
         name: str,
         filter_func: _FilterC,
+        *,
         is_safe: bool = ...,
         needs_autoescape: bool = ...,
         expects_localtime: bool = ...,

From 329090ea83c4fcbdc2cb5f28c13016423785ab85 Mon Sep 17 00:00:00 2001
From: Viicos <65306057+Viicos@users.noreply.github.com>
Date: Mon, 15 Jan 2024 14:04:15 +0100
Subject: [PATCH 5/7] More improvements

---
 django-stubs/template/library.pyi         | 25 ++++++++++++++++-------
 tests/typecheck/template/test_library.yml | 21 ++++++++++++++++---
 2 files changed, 36 insertions(+), 10 deletions(-)

diff --git a/django-stubs/template/library.pyi b/django-stubs/template/library.pyi
index 8838ac844..93be4f83c 100644
--- a/django-stubs/template/library.pyi
+++ b/django-stubs/template/library.pyi
@@ -11,20 +11,21 @@ from .base import Node, Template
 class InvalidTemplateLibrary(Exception): ...
 
 _C = TypeVar("_C", bound=Callable[..., Any])
+_CompileC = TypeVar("_CompileC", bound=Callable[[Parser, Token], Node])
 _FilterC = TypeVar("_FilterC", bound=Callable[[Any], Any] | Callable[[Any, Any], Any])
 _TakesContextC = TypeVar("_TakesContextC", bound=Callable[Concatenate[Context, ...], Any])
 
 class Library:
     filters: dict[str, Callable[[Any], Any] | Callable[[Any, Any], Any]]
-    tags: dict[str, Callable]
+    tags: dict[str, Callable[[Parser, Token], Node]]
     def __init__(self) -> None: ...
     @overload
-    def tag(self, name: _C, /) -> _C: ...
+    def tag(self, name: _CompileC, /) -> _CompileC: ...
     @overload
-    def tag(self, name: str, compile_function: _C) -> _C: ...
+    def tag(self, name: str, compile_function: _CompileC) -> _CompileC: ...
     @overload
-    def tag(self, name: str | None = ..., compile_function: None = ...) -> Callable[[_C], _C]: ...
-    def tag_function(self, func: _C) -> _C: ...
+    def tag(self, name: str | None = ..., compile_function: None = ...) -> Callable[[_CompileC], _CompileC]: ...
+    def tag_function(self, func: _CompileC) -> _CompileC: ...
     @overload
     def filter(self, name: _FilterC, /) -> _FilterC: ...
     @overload
@@ -57,11 +58,21 @@ class Library:
     def simple_tag(
         self, *, takes_context: Literal[False] | None = ..., name: str | None = ...
     ) -> Callable[[_C], _C]: ...
+    @overload
+    def inclusion_tag(
+        self,
+        filename: Template | str,
+        func: Callable[..., Any] | None = ...,
+        *,
+        takes_context: Literal[True],
+        name: str | None = ...,
+    ) -> Callable[[_TakesContextC], _TakesContextC]: ...
+    @overload
     def inclusion_tag(
         self,
         filename: Template | str,
-        func: Callable | None = ...,
-        takes_context: bool | None = ...,
+        func: Callable[..., Any] | None = ...,
+        takes_context: Literal[False] | None = ...,
         name: str | None = ...,
     ) -> Callable[[_C], _C]: ...
 
diff --git a/tests/typecheck/template/test_library.yml b/tests/typecheck/template/test_library.yml
index 23f42da2c..3ed0b8336 100644
--- a/tests/typecheck/template/test_library.yml
+++ b/tests/typecheck/template/test_library.yml
@@ -63,15 +63,16 @@
 -   case: register_simple_tag_context
     main: |
         from django import template
+        from django.template.context import Context
         from typing import Dict, Any
         register = template.Library()
 
         @register.simple_tag(takes_context=True)
-        def current_time(context: Dict[str, Any], format_string: str) -> str:
+        def current_time(context: Context, format_string: str) -> str:
             timezone = context['timezone']
             return "test"
 
-        reveal_type(current_time) # N: Revealed type is "def (context: builtins.dict[builtins.str, Any], format_string: builtins.str) -> builtins.str"
+        reveal_type(current_time) # N: Revealed type is "def (context: Context, format_string: builtins.str) -> builtins.str"
 
 -   case: register_simple_tag_named
     main: |
@@ -123,6 +124,20 @@
 
         reveal_type(format_results) # N: Revealed type is "def (results: builtins.list[builtins.str]) -> builtins.str"
 
+-   case: register_inclusion_tag_takes_context
+    main: |
+        from django import template
+        from django.template.context import Context
+
+        from typing import List
+        register = template.Library()
+
+        @register.inclusion_tag('results.html', takes_context=True)
+        def format_results(context: Context, results: List[str]) -> str:
+            return ', '.join(results)
+
+        reveal_type(format_results) # N: Revealed type is "def (context: Context, results: builtins.list[builtins.str]) -> builtins.str"
+
 -   case: stringfilter
     main: |
         from django.template.defaultfilters import stringfilter
@@ -131,4 +146,4 @@
         def lower(value: str) -> str:
             return value.lower()
 
-        reveal_type(lower) # N: Revealed type is "def (value: object) -> builtins.str"
+        reveal_type(lower) # N: Revealed type is "def (builtins.object) -> builtins.str"

From e65f0b5a5a94d9e29bfd8ac40d4a14ab688b5076 Mon Sep 17 00:00:00 2001
From: Viicos <65306057+Viicos@users.noreply.github.com>
Date: Mon, 15 Jan 2024 17:50:01 +0100
Subject: [PATCH 6/7] Fix tests

---
 tests/typecheck/template/test_library.yml | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/tests/typecheck/template/test_library.yml b/tests/typecheck/template/test_library.yml
index 3ed0b8336..0759099c1 100644
--- a/tests/typecheck/template/test_library.yml
+++ b/tests/typecheck/template/test_library.yml
@@ -72,7 +72,7 @@
             timezone = context['timezone']
             return "test"
 
-        reveal_type(current_time) # N: Revealed type is "def (context: Context, format_string: builtins.str) -> builtins.str"
+        reveal_type(current_time) # N: Revealed type is "def (context: django.template.context.Context, format_string: builtins.str) -> builtins.str"
 
 -   case: register_simple_tag_named
     main: |
@@ -136,7 +136,7 @@
         def format_results(context: Context, results: List[str]) -> str:
             return ', '.join(results)
 
-        reveal_type(format_results) # N: Revealed type is "def (context: Context, results: builtins.list[builtins.str]) -> builtins.str"
+        reveal_type(format_results) # N: Revealed type is "def (context: django.template.context.Context, results: builtins.list[builtins.str]) -> builtins.str"
 
 -   case: stringfilter
     main: |

From 8b80b84d8bed361fb125f1cb824bdf8bae8f1d2e Mon Sep 17 00:00:00 2001
From: Viicos <65306057+Viicos@users.noreply.github.com>
Date: Tue, 2 Apr 2024 19:52:51 +0200
Subject: [PATCH 7/7] Add comments

Comments taken from the Django source code
---
 django-stubs/template/library.pyi | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/django-stubs/template/library.pyi b/django-stubs/template/library.pyi
index 93be4f83c..6327ef084 100644
--- a/django-stubs/template/library.pyi
+++ b/django-stubs/template/library.pyi
@@ -19,15 +19,22 @@ class Library:
     filters: dict[str, Callable[[Any], Any] | Callable[[Any, Any], Any]]
     tags: dict[str, Callable[[Parser, Token], Node]]
     def __init__(self) -> None: ...
+    # @register.tag
     @overload
     def tag(self, name: _CompileC, /) -> _CompileC: ...
+    # register.tag("somename", somefunc)
     @overload
     def tag(self, name: str, compile_function: _CompileC) -> _CompileC: ...
+    # @register.tag()
+    # @register.tag("somename") or @register.tag(name="somename")
     @overload
     def tag(self, name: str | None = ..., compile_function: None = ...) -> Callable[[_CompileC], _CompileC]: ...
     def tag_function(self, func: _CompileC) -> _CompileC: ...
+    # @register.filter
     @overload
     def filter(self, name: _FilterC, /) -> _FilterC: ...
+    # @register.filter()
+    # @register.filter("somename") or @register.filter(name='somename')
     @overload
     def filter(
         self,
@@ -38,6 +45,7 @@ class Library:
         needs_autoescape: bool = ...,
         expects_localtime: bool = ...,
     ) -> Callable[[_FilterC], _FilterC]: ...
+    # register.filter("somename", somefunc)
     @overload
     def filter(
         self,
@@ -48,12 +56,16 @@ class Library:
         needs_autoescape: bool = ...,
         expects_localtime: bool = ...,
     ) -> _FilterC: ...
+    # @register.simple_tag
     @overload
     def simple_tag(self, func: _C, /) -> _C: ...
+    # @register.simple_tag(takes_context=True)
     @overload
     def simple_tag(
         self, *, takes_context: Literal[True], name: str | None = ...
     ) -> Callable[[_TakesContextC], _TakesContextC]: ...
+    # @register.simple_tag(takes_context=False)
+    # @register.simple_tag(...)
     @overload
     def simple_tag(
         self, *, takes_context: Literal[False] | None = ..., name: str | None = ...