fix(auth): prevent repository .env files from injecting workspace bindings (Closes #704)

gitea_auth.py

@@ -22,8 +22,62 @@ import gitea_config
 
 PROJECT_ROOT = os.path.dirname(os.path.abspath(__file__))
 
-# Load standard .env if present
-load_dotenv(os.path.join(PROJECT_ROOT, ".env"))
+# Reserved runtime-control / workspace-binding environment variables (#704).
+# Repository .env files MUST NOT populate or override any of these keys.
+RESERVED_WORKTREE_ENV_KEYS: frozenset[str] = frozenset({
+    "GITEA_ACTIVE_WORKTREE",
+    "GITEA_AUTHOR_WORKTREE",
+    "GITEA_REVIEWER_WORKTREE",
+    "GITEA_MERGER_WORKTREE",
+    "GITEA_RECONCILER_WORKTREE",
+})
+
+
+def is_reserved_worktree_env_key(key: str | None) -> bool:
+    """Return True if *key* is a reserved runtime workspace binding variable (#704)."""
+    if not key:
+        return False
+    k = str(key).upper().strip()
+    return k in RESERVED_WORKTREE_ENV_KEYS or (k.startswith("GITEA_") and k.endswith("_WORKTREE"))
+
+
+def load_env_file_sanitized(
+    env_path: str,
+    *,
+    target_env: dict | os._Environ | None = None,
+) -> list[str]:
+    """Load a .env file without populating or overriding reserved workspace keys (#704).
+
+    Pre-existing process environment values retain their precedence. Reserved
+    runtime-control keys found in repository files are ignored (without logging
+    their values). Returns a list of sanitized rejection reasons.
+    """
+    if target_env is None:
+        target_env = os.environ
+    if not os.path.exists(env_path) or os.path.isdir(env_path):
+        return []
+
+    rejection_reasons: list[str] = []
+    try:
+        file_vals = dotenv_values(env_path)
+        for key, val in file_vals.items():
+            if not key or val is None:
+                continue
+            if is_reserved_worktree_env_key(key):
+                filename = os.path.basename(env_path)
+                rejection_reasons.append(
+                    f"Ignored reserved runtime workspace key '{key}' from repository {filename}"
+                )
+                continue
+            if key not in target_env:
+                target_env[key] = val
+    except Exception:
+        pass
+    return rejection_reasons
+
+
+# Load standard .env if present (sanitized to prevent repo workspace binding contamination #704)
+load_env_file_sanitized(os.path.join(PROJECT_ROOT, ".env"))
 
 # Dictionary to store configurations parsed dynamically from .env.* files
 DYNAMIC_CONFIGS = {}
@@ -37,9 +91,13 @@ for env_path in glob.glob(os.path.join(PROJECT_ROOT, ".env*")):
         continue
     try:
         config_vals = dotenv_values(env_path)
-        site = config_vals.get("GITEA_SITE") or config_vals.get("GITEA_HOST")
+        # Filter out reserved workspace keys from dynamic configs (#704)
+        sanitized_config = {
+            k: v for k, v in config_vals.items() if not is_reserved_worktree_env_key(k)
+        }
+        site = sanitized_config.get("GITEA_SITE") or sanitized_config.get("GITEA_HOST")
         if site:
-            DYNAMIC_CONFIGS[site.lower().strip()] = config_vals
+            DYNAMIC_CONFIGS[site.lower().strip()] = sanitized_config
     except Exception:
         pass