package category is not useful (#7637)

package.category doesn't make a lot of sense in the richer world of dependency groups.

The only use that is made of the category in poetry and poetry-core is that it is written to and read back from the lockfile. But no use is made of that information.

src/poetry/packages/locker.py

@@ -126,7 +126,6 @@ def locked_repository(self) -> LockfileRepository:
                 source_subdirectory=source.get("subdirectory"),
             )
             package.description = info.get("description", "")
-            package.category = info.get("category", "main")
             package.optional = info["optional"]
             metadata = cast("dict[str, Any]", lock_data["metadata"])
 
@@ -425,7 +424,6 @@ def _dump_package(self, package: Package) -> dict[str, Any]:
             "name": package.pretty_name,
             "version": package.pretty_version,
             "description": package.description or "",
-            "category": package.category,
             "optional": package.optional,
             "python-versions": package.python_versions,
             "files": sorted(

src/poetry/puzzle/solver.py

@@ -9,8 +9,6 @@
 from typing import Tuple
 from typing import TypeVar
 
-from poetry.core.packages.dependency_group import MAIN_GROUP
-
 from poetry.mixology import resolve_version
 from poetry.mixology.failure import SolveFailure
 from poetry.puzzle.exceptions import OverrideNeeded
@@ -273,11 +271,9 @@ def __init__(
         self.depth = -1
 
         if not previous:
-            self.category = "dev"
             self.groups: frozenset[str] = frozenset()
             self.optional = True
         elif dep:
-            self.category = "main" if MAIN_GROUP in dep.groups else "dev"
             self.groups = dep.groups
             self.optional = dep.is_optional()
         else:
@@ -327,14 +323,11 @@ def aggregate_package_nodes(nodes: list[PackageNode]) -> tuple[Package, int]:
     for node in nodes:
         groups.extend(node.groups)
 
-    category = "main" if any(MAIN_GROUP in node.groups for node in nodes) else "dev"
     optional = all(node.optional for node in nodes)
     for node in nodes:
         node.depth = depth
-        node.category = category
         node.optional = optional
 
-    package.category = category
     package.optional = optional
 
     return package, depth

tests/console/commands/self/test_remove_plugins.py

@@ -45,7 +45,6 @@ def install_plugin(installed: Repository) -> None:
             {
                 "name": "poetry-plugin",
                 "version": "1.2.3",
-                "category": "main",
                 "optional": False,
                 "platform": "*",
                 "python-versions": "*",