fix(bot): correct combat estimates and enforce client and runner failures

sts2.py

@@ -18,6 +18,7 @@ Never precompute an action list.
 
 from __future__ import annotations
 
+import http.client
 import json
 import urllib.error
 import urllib.request
@@ -78,7 +79,7 @@ class ActionResult:
         return self.status == "ok"
 
 
-def _request(path: str, payload: dict | None = None, timeout: float = TIMEOUT) -> dict:
+def _read(path: str, payload: dict | None = None, timeout: float = TIMEOUT) -> bytes:
     url = BASE + path
     if payload is None:
         request = urllib.request.Request(url, method="GET")
@@ -93,17 +94,30 @@ def _request(path: str, payload: dict | None = None, timeout: float = TIMEOUT) -
         with urllib.request.urlopen(request, timeout=timeout) as response:
             body = response.read()
     except urllib.error.HTTPError as exc:
-        detail = exc.read().decode("utf-8", "replace")
+        try:
+            detail = exc.read().decode("utf-8", "replace")
+        except (OSError, http.client.HTTPException):
+            detail = "could not read the error body"
         raise Sts2Error(f"HTTP {exc.code} on {path}: {detail[:300]}") from exc
     except urllib.error.URLError as exc:
         raise Sts2Error(
             f"cannot reach the game on {BASE}. Is STS2 running with the mod loaded? ({exc})"
         ) from exc
+    except (OSError, http.client.HTTPException) as exc:
+        # A failed POST may already have reached the game. Never retry it here.
+        raise Sts2Error(f"transport failure on {path}: {type(exc).__name__}: {exc}") from exc
+    return body
 
+
+def _request(path: str, payload: dict | None = None, timeout: float = TIMEOUT) -> dict:
+    body = _read(path, payload, timeout)
     try:
-        return json.loads(body)
-    except json.JSONDecodeError as exc:
+        data = json.loads(body)
+    except (json.JSONDecodeError, UnicodeDecodeError) as exc:
         raise Sts2Error(f"non-JSON response from {path}: {body[:200]!r}") from exc
+    if not isinstance(data, dict):
+        raise Sts2Error(f"expected a JSON object from {path}, got {type(data).__name__}")
+    return data
 
 
 # --------------------------------------------------------------------------
@@ -121,9 +135,11 @@ def is_up() -> bool:
 def state(fmt: str = "json") -> dict:
     """Current game state. fmt: 'json' or 'markdown' (markdown returns text)."""
     if fmt == "markdown":
-        req = urllib.request.Request(f"{BASE}/api/v1/singleplayer?format=markdown")
-        with urllib.request.urlopen(req, timeout=TIMEOUT) as response:
-            return {"markdown": response.read().decode("utf-8")}
+        body = _read("/api/v1/singleplayer?format=markdown")
+        try:
+            return {"markdown": body.decode("utf-8")}
+        except UnicodeDecodeError as exc:
+            raise Sts2Error("invalid UTF-8 markdown response") from exc
     return _request("/api/v1/singleplayer?format=json")