fix: Tune heavy py-rattler imports + lazy import networkx (#1901)

Author: iamthebot

py-rattler/rattler/repo_data/gateway.py

@@ -4,11 +4,12 @@
 from dataclasses import dataclass
 from typing import Iterable, List, Optional
 
-from rattler.channel import Channel
-from rattler.match_spec import MatchSpec
-from rattler.networking import CacheAction, Client
+from rattler.channel.channel import Channel
+from rattler.match_spec.match_spec import MatchSpec
+from rattler.networking.client import Client
+from rattler.networking.fetch_repo_data import CacheAction
 from rattler.package.package_name import PackageName
-from rattler.platform import Platform, PlatformLiteral
+from rattler.platform.platform import Platform, PlatformLiteral
 from rattler.rattler import PyGateway, PyMatchSpec, PySourceConfig
 from rattler.repo_data.record import RepoDataRecord
 

py-rattler/rattler/repo_data/package_record.py

@@ -12,11 +12,6 @@
 
 if TYPE_CHECKING:
     import networkx as nx
-else:
-    try:
-        import networkx as nx
-    except ImportError:
-        nx = None
 
 
 class PackageRecord:
@@ -122,8 +117,10 @@ def to_graph(records: List[PackageRecord]) -> nx.DiGraph:  # type: ignore[type-a
 
         Note: Virtual packages (starting with `__`) are skipped.
         """
-        if nx is None:
-            raise ImportError("networkx is not installed")
+        try:
+            import networkx as nx
+        except ImportError:
+            raise ImportError("networkx is not installed") from None
 
         names_to_records = {record.name: record for record in records}
 

py-rattler/rattler/repo_data/record.py

@@ -1,7 +1,7 @@
 from __future__ import annotations
 
 from rattler.rattler import PyRecord
-from rattler.repo_data import PackageRecord
+from rattler.repo_data.package_record import PackageRecord
 
 
 class RepoDataRecord(PackageRecord):

py-rattler/rattler/solver/solver.py

@@ -3,14 +3,16 @@
 import datetime
 from typing import List, Literal, Optional, Sequence
 
-from rattler import Channel, Platform, SparseRepoData, VirtualPackage
-from rattler.channel import ChannelPriority
+from rattler.channel.channel import Channel
+from rattler.channel.channel_priority import ChannelPriority
 from rattler.match_spec.match_spec import MatchSpec
-from rattler.platform.platform import PlatformLiteral
+from rattler.platform.platform import Platform, PlatformLiteral
 from rattler.rattler import PyMatchSpec, PyPackageFormatSelection, py_solve, py_solve_with_sparse_repodata
 from rattler.repo_data.gateway import Gateway
 from rattler.repo_data.record import RepoDataRecord
+from rattler.repo_data.sparse import SparseRepoData
 from rattler.virtual_package.generic import GenericVirtualPackage
+from rattler.virtual_package.virtual_package import VirtualPackage
 
 SolveStrategy = Literal["highest", "lowest", "lowest-direct"]
 """Defines the strategy to use when multiple versions of a package are available during solving."""