Fix: Remove only targetted package (#220)

Fix an issue where all default dependencies were removed instead of just the selected one (fixes #4632)

poetry/core/packages/dependency_group.py

@@ -26,13 +26,13 @@ def is_optional(self) -> bool:
     def add_dependency(self, dependency: "DependencyTypes") -> None:
         self._dependencies.append(dependency)
 
-    def remove_dependency(self, name: "str") -> None:
+    def remove_dependency(self, name: str) -> None:
         from poetry.core.utils.helpers import canonicalize_name
 
         name = canonicalize_name(name)
 
         dependencies = []
-        for dependency in dependencies:
+        for dependency in self.dependencies:
             if dependency.name == name:
                 continue
 

tests/packages/test_dependency_group.py

@@ -0,0 +1,24 @@
+from poetry.core.packages.dependency import Dependency
+from poetry.core.packages.dependency_group import DependencyGroup
+
+
+def test_dependency_group_remove_dependency():
+    group = DependencyGroup(name="linter")
+    group.add_dependency(Dependency(name="black", constraint="*"))
+    group.add_dependency(Dependency(name="isort", constraint="*"))
+    group.add_dependency(Dependency(name="flake8", constraint="*"))
+
+    assert {dependency.name for dependency in group.dependencies} == {
+        "black",
+        "isort",
+        "flake8",
+    }
+
+    group.remove_dependency("isort")
+    assert {dependency.name for dependency in group.dependencies} == {"black", "flake8"}
+
+    group.remove_dependency("black")
+    assert {dependency.name for dependency in group.dependencies} == {"flake8"}
+
+    group.remove_dependency("flake8")
+    assert {dependency.name for dependency in group.dependencies} == set()