fix(github): resolve circular import issues in context_gatherer and services (#1026)

- Updated import statements in context_gatherer.py to import safe_print from core.io_utils to avoid circular dependencies with the services package.
- Introduced lazy imports in services/__init__.py to prevent circular import issues, detailing the import chain in comments for clarity.
- Added a lazy import handler to load classes on first access, improving module loading efficiency.

apps/backend/runners/github/context_gatherer.py

@@ -27,8 +27,10 @@ try:
     from .gh_client import GHClient, PRTooLargeError
     from .services.io_utils import safe_print
 except (ImportError, ValueError, SystemError):
+    # Import from core.io_utils directly to avoid circular import with services package
+    # (services/__init__.py imports pr_review_engine which imports context_gatherer)
+    from core.io_utils import safe_print
     from gh_client import GHClient, PRTooLargeError
-    from services.io_utils import safe_print
 
 # Validation patterns for git refs and paths (defense-in-depth)
 # These patterns allow common valid characters while rejecting potentially dangerous ones

apps/backend/runners/github/services/__init__.py

@@ -3,14 +3,23 @@ GitHub Orchestrator Services
 ============================
 
 Service layer for GitHub automation workflows.
+
+NOTE: Uses lazy imports to avoid circular dependency with context_gatherer.py.
+The circular import chain was: orchestrator → context_gatherer → services.io_utils
+→ services/__init__ → pr_review_engine → context_gatherer (circular!)
 """
 
-from .autofix_processor import AutoFixProcessor
-from .batch_processor import BatchProcessor
-from .pr_review_engine import PRReviewEngine
-from .prompt_manager import PromptManager
-from .response_parsers import ResponseParser
-from .triage_engine import TriageEngine
+from __future__ import annotations
+
+# Lazy import mapping - classes are loaded on first access
+_LAZY_IMPORTS: dict[str, tuple[str, str]] = {
+    "AutoFixProcessor": (".autofix_processor", "AutoFixProcessor"),
+    "BatchProcessor": (".batch_processor", "BatchProcessor"),
+    "PRReviewEngine": (".pr_review_engine", "PRReviewEngine"),
+    "PromptManager": (".prompt_manager", "PromptManager"),
+    "ResponseParser": (".response_parsers", "ResponseParser"),
+    "TriageEngine": (".triage_engine", "TriageEngine"),
+}
 
 __all__ = [
     "PromptManager",
@@ -20,3 +29,19 @@ __all__ = [
     "AutoFixProcessor",
     "BatchProcessor",
 ]
+
+# Cache for lazily loaded modules
+_loaded: dict[str, object] = {}
+
+
+def __getattr__(name: str) -> object:
+    """Lazy import handler - loads classes on first access."""
+    if name in _LAZY_IMPORTS:
+        if name not in _loaded:
+            module_name, attr_name = _LAZY_IMPORTS[name]
+            import importlib
+
+            module = importlib.import_module(module_name, __name__)
+            _loaded[name] = getattr(module, attr_name)
+        return _loaded[name]
+    raise AttributeError(f"module {__name__!r} has no attribute {name!r}")