feat: add flash plugin

[euri10]

Description

• added a flash plugin ala flask, uses the request state

Closes

Closes #1455, #2560

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 98.25%. Comparing base (bfeb5e9) to head (ba71a7e).
Report is 103 commits behind head on develop.

Additional details and impacted files

@@             Coverage Diff             @@
##           develop    #3145      +/-   ##
===========================================
+ Coverage    98.23%   98.25%   +0.02%     
===========================================
  Files          312      321       +9     
  Lines        14121    14518     +397     
  Branches      2430     2331      -99     
===========================================
+ Hits         13872    14265     +393     
- Misses         107      111       +4     
  Partials       142      142              

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[euri10]

diff --git a/docs/examples/templating/template_functions_minijinja.py b/docs/examples/templating/template_functions_minijinja.py
index 0fccdccb3..5655f92e5 100644
--- a/docs/examples/templating/template_functions_minijinja.py
+++ b/docs/examples/templating/template_functions_minijinja.py
@@ -26,4 +26,4 @@ def index() -> Template:
     return Template(template_name="index.html.minijinja")
 
 
-app = Litestar(route_handlers=[index], template_config=template_config)
+app = Litestar(route_handlers=[index], template_config=template_config, debug=True)
diff --git a/litestar/contrib/minijinja.py b/litestar/contrib/minijinja.py
index 6829ff45c..f7775a0c0 100644
--- a/litestar/contrib/minijinja.py
+++ b/litestar/contrib/minijinja.py
@@ -7,7 +7,6 @@ from typing import TYPE_CHECKING, Any, Mapping, Protocol, TypeVar, cast
 from typing_extensions import ParamSpec
 
 from litestar.exceptions import ImproperlyConfiguredException, MissingDependencyException, TemplateNotFoundException
-from litestar.plugins.flash import get_flashes as _get_flashes
 from litestar.template.base import (
     TemplateCallableType,
     TemplateEngineProtocol,
@@ -162,17 +161,24 @@ class MiniJinjaTemplateEngine(TemplateEngineProtocol["MiniJinjaTemplate", StateP
         return MiniJinjaTemplate(self.engine, template_name)
 
     def register_template_callable(
-        self, key: str, template_callable: TemplateCallableType[StateProtocol, P, T]
+        self, key: str, template_callable: TemplateCallableType[StateProtocol, P, T], transform: bool = False
     ) -> None:
         """Register a callable on the template engine.
 
         Args:
             key: The callable key, i.e. the value to use inside the template to call the callable.
             template_callable: A callable to register.
+            transform: If True, the callable will be transformed to receive a ``StateProtocol`` instance as first argument.
 
         Returns:
             None
         """
+
+        def is_decorated(func):
+            return hasattr(func, "__wrapped__") or func.__name__ not in globals()
+
+        if not is_decorated(template_callable) or transform:  # or comes from a plugin...
+            template_callable = _transform_state(template_callable)
         self.engine.add_global(key, pass_state(template_callable))
 
     def render_string(self, template_string: str, context: Mapping[str, Any]) -> str:
@@ -206,9 +212,6 @@ def _minijinja_from_state(func: Callable, state: StateProtocol, *args: Any, **kw
     return cast(str, func(template_context, *args, **kwargs))
 
 
-get_flashes = _transform_state(_get_flashes)
-
-
 def __getattr__(name: str) -> Any:
     if name == "minijinja_from_state":
         warn_deprecation(
diff --git a/litestar/plugins/flash.py b/litestar/plugins/flash.py
index 0ffde4a55..4b34d7897 100644
--- a/litestar/plugins/flash.py
+++ b/litestar/plugins/flash.py
@@ -1,10 +1,10 @@
-import contextlib
 from dataclasses import dataclass
 from enum import Enum
 from typing import Any, Mapping
 
 from litestar.config.app import AppConfig
 from litestar.connection import ASGIConnection
+from litestar.contrib.minijinja import MiniJinjaTemplateEngine
 from litestar.plugins import InitPluginProtocol
 from litestar.template import TemplateConfig
 from litestar.template.base import _get_request_from_context
@@ -35,18 +35,10 @@ class FlashPlugin(InitPluginProtocol):
 
     def on_app_init(self, app_config: AppConfig) -> AppConfig:
         """Register the message callable on the template engine instance."""
-        with contextlib.suppress(ImportError):
-            # minijinja needs a different callable here
-            from litestar.contrib.minijinja import MiniJinjaTemplateEngine
-            from litestar.contrib.minijinja import get_flashes as minijinja_get_flashes
-
-            if isinstance(self.config.template_config.engine_instance, MiniJinjaTemplateEngine):
-                self.config.template_config.engine_instance.register_template_callable(
-                    "get_flashes", minijinja_get_flashes
-                )
-                return app_config
-
-        self.config.template_config.engine_instance.register_template_callable("get_flashes", get_flashes)
+        if isinstance(self.config.template_config.engine_instance, MiniJinjaTemplateEngine):
+            self.config.template_config.engine_instance.register_template_callable("get_flashes", get_flashes, True)
+        else:
+            self.config.template_config.engine_instance.register_template_callable("get_flashes", get_flashes)
         return app_config

@provinzkraut this is a small diff between your semi-ugly fix and my semi-ugly one.
Honestly I dont have a real preference, my gut feeling just tells me somehow we should do more in the minijinja implementation to detect if the callable we wanna register is or is not wrapped correctly, or defer that responsability to the caller (but would that be breaking ?)
that's an interesting case because imho the plugin should not have to do that switch dance in the app_init and that should be handled oob in the implementation but I dont see an easy way in minijinja's case to tell hey I've been called by a plugin, pass me the state

[euri10]

it would be somewhat better to pass an enum of the possible message categories to the FlashConfig so that the category passed to flash(message, category) belongs to that enum only, but I dont know if this is feasible.
the mypy errors seems unrelated to me

[JacobCoffee]

this is awesome.

I have put up euri10#1 for documentation - i can work on the placeholder data if you dont feel like if it gets merged

[euri10]

this is awesome.

I have put up euri10#1 for documentation - i can work on the placeholder data if you dont feel like if it gets merged

sorry I'm slow and didn't understood at first it was on my fork :) need to wake up !

[euri10]

working on docs, back to draft mode

[JacobCoffee]

Sorry i caught this late, feel free to disregard - i just thought about the API docs and added those but ended up doing more.

not 100% on the validity.

euri10#2

anyways its working good for me in testing ty for your PR :)

[JacobCoffee]

commit tree looks weird

[provinzkraut]

commit tree looks weird

Needs a rebase

[euri10]

honestly I dont get the rebase and stuff, now we have a PR with 127 changes :(
should I just close this and redo from scratch ?

[euri10]

are we better now ?

[provinzkraut]

are we better now ?

Looks good! You did it! :)

[euri10]

are we better now ?

Looks good! You did it! :)

@Alc-Alc did ;)

[JacobCoffee]

Failing types arent even related to PR :(
https://github.com/litestar-org/litestar/actions/runs/8223737329/job/22486749530?pr=3145

[euri10]

Failing types arent even related to PR :( litestar-org/litestar/actions/runs/8223737329/job/22486749530?pr=3145

I had a pdm.lock change, hopefully this will solve it

[github-actions]

Documentation preview will be available shortly at https://litestar-org.github.io/litestar-docs-preview/3145