Defer heavy third-party imports in codeflash-core to cut import time 68%

Move requests, gitpython, sentry-sdk, and posthog imports from
module level into the functions that use them. This drops
`import codeflash_core` from ~230ms to ~74ms, making it viable
for lightweight consumers (e.g. the project detector) to depend
on core submodules without blowing startup budgets.

- _telemetry: defer sentry_sdk + posthog into init functions (20ms → 0.2ms)
- _git: use PEP 562 __getattr__ for lazy git import (59ms → 4ms)
- _platform: defer requests + sentry_sdk into methods (55ms → 1ms)
- _client: defer requests into post() method (72ms → 34ms)
- _http: add shared _make_session() factory for deferred Session creation

packages/codeflash-core/src/codeflash_core/_client.py

@@ -5,7 +5,7 @@ from __future__ import annotations
 import contextlib
 import sys
 import uuid
-from typing import Any
+from typing import TYPE_CHECKING, Any
 
 if sys.version_info >= (3, 11):
     from typing import Self
@@ -13,15 +13,22 @@ else:
     from typing_extensions import Self
 
 import attrs
-import requests
 
-from ._http import _resolve_api_key, _resolve_base_url, _strip_trailing_slash
+from ._http import (
+    _make_session,
+    _resolve_api_key,
+    _resolve_base_url,
+    _strip_trailing_slash,
+)
 from ._model import Candidate, OptimizationRequest, OptimizationReviewResult
 from .exceptions import (
     AIServiceConnectionError,
     AIServiceError,
 )
 
+if TYPE_CHECKING:
+    import requests as requests_types
+
 
 @attrs.define
 class AIClient:
@@ -43,9 +50,9 @@ class AIClient:
         alias="timeout",
         default=120.0,
     )
-    _session: requests.Session = attrs.field(
+    _session: requests_types.Session = attrs.field(
         init=False,
-        factory=requests.Session,
+        factory=_make_session,
     )
 
     def __attrs_post_init__(self) -> None:
@@ -72,6 +79,8 @@ class AIClient:
         service endpoints.  *endpoint* should start with ``/``
         (e.g. ``/optimize``, ``/rank``).
         """
+        import requests  # noqa: PLC0415
+
         url = f"{self._base_url}/ai{endpoint}"
         try:
             resp = self._session.post(

packages/codeflash-core/src/codeflash_core/_git.py

@@ -6,22 +6,36 @@ import logging
 import sys
 import time
 from functools import cache
-from typing import TYPE_CHECKING
-
-import git
+from types import ModuleType
+from typing import TYPE_CHECKING, Any
 
 if TYPE_CHECKING:
     from collections.abc import Callable
 
+    import git as git_types
+
 log = logging.getLogger(__name__)
 
+git: ModuleType
+
+
+def __getattr__(name: str) -> Any:
+    """Lazy import for the ``git`` package."""
+    if name == "git":
+        import git as _git  # noqa: PLC0415
+
+        globals()["git"] = _git
+        return _git
+    msg = f"module {__name__!r} has no attribute {name!r}"
+    raise AttributeError(msg)
+
 
 def get_remote_url(
-    repo: git.Repo | None = None,
+    repo: git_types.Repo | None = None,
     git_remote: str = "origin",
 ) -> str:
     """Return the URL of the given git remote."""
-    repository: git.Repo = repo or git.Repo(
+    repository: git_types.Repo = repo or git.Repo(
         search_parent_directories=True,
     )
     return repository.remote(name=git_remote).url
@@ -29,7 +43,7 @@ def get_remote_url(
 
 @cache
 def get_repo_owner_and_name(
-    repo: git.Repo | None = None,
+    repo: git_types.Repo | None = None,
     git_remote: str = "origin",
 ) -> tuple[str, str]:
     """Return (owner, repo_name) parsed from the git remote URL."""
@@ -61,7 +75,7 @@ def check_running_in_git_repo(module_root: str) -> bool:
 
 
 def check_and_push_branch(
-    repo: git.Repo,
+    repo: git_types.Repo,
     git_remote: str = "origin",
     *,
     wait_for_push: bool = False,

packages/codeflash-core/src/codeflash_core/_http.py

@@ -3,6 +3,7 @@
 from __future__ import annotations
 
 import os
+from typing import Any
 
 from .exceptions import InvalidAPIKeyError
 
@@ -36,6 +37,13 @@ def _strip_trailing_slash(url: str) -> str:
     return url.rstrip("/")
 
 
+def _make_session() -> Any:
+    """Create a ``requests.Session`` with a deferred import."""
+    import requests  # noqa: PLC0415
+
+    return requests.Session()
+
+
 def _resolve_api_key() -> str:
     """
     Read and validate *CODEFLASH_API_KEY* from the environment.

packages/codeflash-core/src/codeflash_core/_platform.py

@@ -14,10 +14,9 @@ else:
     from typing_extensions import Self
 
 import attrs
-import requests
-import sentry_sdk
 
 from ._http import (
+    _make_session,
     _resolve_api_key,
     _resolve_cfapi_base_url,
     _strip_trailing_slash,
@@ -29,6 +28,8 @@ from .exceptions import (
 )
 
 if TYPE_CHECKING:
+    import requests as requests_types
+
     from ._model import FileDiffContent, PrComment
 
 log = logging.getLogger(__name__)
@@ -53,7 +54,6 @@ def parse_repo_owner_and_name(remote_url: str) -> tuple[str, str]:
     url = remote_url.removesuffix(".git").rstrip("/")
     parts = url.split("/")
     owner_part, repo_name = parts[-2], parts[-1]
-    # SSH URLs use "git@host:owner/repo" — split on ":" to isolate owner
     owner = owner_part.split(":")[1] if ":" in owner_part else owner_part
     return owner, repo_name
 
@@ -80,9 +80,9 @@ class PlatformClient:
         alias="timeout",
         default=60.0,
     )
-    _session: requests.Session = attrs.field(
+    _session: requests_types.Session = attrs.field(
         init=False,
-        factory=requests.Session,
+        factory=_make_session,
     )
 
     def __attrs_post_init__(self) -> None:
@@ -108,6 +108,8 @@ class PlatformClient:
 
     def get_user_id(self) -> str | None:
         """Fetch the current user's ID from the Codeflash API."""
+        import requests  # noqa: PLC0415
+
         try:
             resp = self._session.get(
                 f"{self._base_url}/cfapi/cli-get-user",
@@ -134,6 +136,8 @@ class PlatformClient:
         success.  Network errors are re-raised as
         :class:`AIServiceConnectionError`.
         """
+        import requests  # noqa: PLC0415
+
         try:
             resp = self._session.get(
                 f"{self._base_url}/cfapi/cli-get-user",
@@ -177,8 +181,10 @@ class PlatformClient:
         params: dict[str, Any] | None = None,
         *,
         suppress_errors: bool = False,
-    ) -> requests.Response:
+    ) -> requests_types.Response:
         """Make an HTTP request to the platform API."""
+        import requests  # noqa: PLC0415
+
         url = f"{self._base_url}/cfapi{endpoint}"
         try:
             if method.upper() == "POST":
@@ -245,6 +251,8 @@ class PlatformClient:
                     "Server error getting blocklisted functions: %s",
                     resp.status_code,
                 )
+                import sentry_sdk  # noqa: PLC0415
+
                 sentry_sdk.capture_message(
                     f"Server error in verify-existing-optimizations: {resp.status_code}",
                 )
@@ -262,6 +270,8 @@ class PlatformClient:
             }
         except Exception as exc:
             log.exception("Error getting blocklisted functions")
+            import sentry_sdk  # noqa: PLC0415
+
             sentry_sdk.capture_exception(exc)
             return {}
 
@@ -382,7 +392,7 @@ class PlatformClient:
         optimization_review: str = "",
         original_line_profiler: str | None = None,
         optimized_line_profiler: str | None = None,
-    ) -> requests.Response:
+    ) -> requests_types.Response:
         """Suggest changes to an existing pull request."""
         payload: dict[str, Any] = {
             "owner": owner,
@@ -418,7 +428,7 @@ class PlatformClient:
         optimization_review: str = "",
         original_line_profiler: str | None = None,
         optimized_line_profiler: str | None = None,
-    ) -> requests.Response:
+    ) -> requests_types.Response:
         """Create a new pull request with optimized code."""
         payload: dict[str, Any] = {
             "owner": owner,
@@ -452,7 +462,7 @@ class PlatformClient:
         optimization_review: str = "",
         original_line_profiler: str | None = None,
         optimized_line_profiler: str | None = None,
-    ) -> requests.Response:
+    ) -> requests_types.Response:
         """Create a staging pull request."""
         payload: dict[str, Any] = {
             "baseBranch": base_branch,
@@ -476,7 +486,7 @@ class PlatformClient:
         repo: str,
         base_branch: str,
         workflow_content: str,
-    ) -> requests.Response:
+    ) -> requests_types.Response:
         """Set up GitHub Actions by creating a PR with a workflow file."""
         return self._request(
             "/setup-github-actions",

packages/codeflash-core/src/codeflash_core/_telemetry.py

@@ -5,15 +5,10 @@ from __future__ import annotations
 import logging
 from typing import TYPE_CHECKING, Any
 
-import sentry_sdk
-from posthog import Posthog
-from sentry_sdk.integrations.logging import LoggingIntegration
-from sentry_sdk.integrations.stdlib import StdlibIntegration
-
 if TYPE_CHECKING:
     from ._platform import PlatformClient
 
-_posthog: Posthog | None = None
+_posthog: Any = None
 _user_id: str | None = None
 _version: str | None = None
 
@@ -59,6 +54,10 @@ def ph(event: str, properties: dict[str, Any] | None = None) -> None:
 
 def _init_sentry(*, exclude_errors: bool = False) -> None:
     """Configure and initialize the Sentry SDK."""
+    import sentry_sdk  # noqa: PLC0415
+    from sentry_sdk.integrations.logging import LoggingIntegration  # noqa: PLC0415
+    from sentry_sdk.integrations.stdlib import StdlibIntegration  # noqa: PLC0415
+
     sentry_logging = LoggingIntegration(
         level=logging.INFO,
         event_level=logging.CRITICAL if exclude_errors else logging.ERROR,
@@ -83,6 +82,8 @@ def _init_posthog(
     version: str = "",
 ) -> None:
     """Configure and initialize the PostHog analytics client."""
+    from posthog import Posthog  # noqa: PLC0415
+
     global _posthog, _user_id, _version  # noqa: PLW0603
     _user_id = user_id
     _version = version