fix: message where missing dependency name doesn't match install extra (

#2921)

* Fix faulty exception wording

* Fix another spotted mismatch

* PR review

---------

Co-authored-by: Peter Schutt <peter.github@proton.me>

litestar/contrib/jinja.py

@@ -17,7 +17,7 @@
     from jinja2 import Environment, FileSystemLoader, pass_context
     from jinja2 import TemplateNotFound as JinjaTemplateNotFound
 except ImportError as e:
-    raise MissingDependencyException("jinja2") from e
+    raise MissingDependencyException("jinja2", extra="jinja") from e
 
 if TYPE_CHECKING:
     from pathlib import Path

litestar/contrib/prometheus/config.py

@@ -15,7 +15,7 @@
 try:
     import prometheus_client  # noqa: F401
 except ImportError as e:
-    raise MissingDependencyException("prometheus_client") from e
+    raise MissingDependencyException("prometheus_client", "prometheus-client", "prometheus") from e
 
 
 if TYPE_CHECKING:

litestar/contrib/prometheus/controller.py

@@ -9,7 +9,7 @@
 try:
     import prometheus_client  # noqa: F401
 except ImportError as e:
-    raise MissingDependencyException("prometheus_client") from e
+    raise MissingDependencyException("prometheus_client", "prometheus-client", "prometheus") from e
 
 from prometheus_client import (
     CONTENT_TYPE_LATEST,

litestar/contrib/prometheus/middleware.py

@@ -16,7 +16,7 @@
 try:
     import prometheus_client  # noqa: F401
 except ImportError as e:
-    raise MissingDependencyException("prometheus_client") from e
+    raise MissingDependencyException("prometheus_client", "prometheus-client", "prometheus") from e
 
 from prometheus_client import Counter, Gauge, Histogram
 

litestar/exceptions/base_exceptions.py

@@ -41,10 +41,10 @@ class MissingDependencyException(LitestarException, ImportError):
     This exception is raised only when a module depends on a dependency that has not been installed.
     """
 
-    def __init__(self, package: str, install_package: str | None = None) -> None:
+    def __init__(self, package: str, install_package: str | None = None, extra: str | None = None) -> None:
         super().__init__(
             f"Package {package!r} is not installed but required. You can install it by running "
-            f"'pip install litestar[{install_package or package}]' to install litestar with the required extra "
+            f"'pip install litestar[{extra or install_package or package}]' to install litestar with the required extra "
             f"or 'pip install {install_package or package}' to install the package separately"
         )
 

tests/unit/test_exceptions.py

@@ -146,10 +146,10 @@ def test_missing_dependency_exception() -> None:
 
 
 def test_missing_dependency_exception_differing_package_name() -> None:
-    exc = MissingDependencyException("some_package", "install_via_this")
+    exc = MissingDependencyException("some_package", "install_via_this", "other-extra")
     expected = (
         "Package 'some_package' is not installed but required. You can install it by running 'pip install "
-        "litestar[install_via_this]' to install litestar with the required extra or 'pip install install_via_this' to "
+        "litestar[other-extra]' to install litestar with the required extra or 'pip install install_via_this' to "
         "install the package separately"
     )