test(mcp): tighten systemic failure test assertions and sweep phase comments

- Return IDXPAR_NULL_RESP if supervised run produces NULL response
- Pin exact {"status":"error","outcome":"exit_nonzero"} JSON contract in systemic test
- Update phase comments in mcp.c to document "error" alongside "crash" and "hang"

Signed-off-by: Shashwat Mishra <shashwat78.nits@gmail.com>

Author: shashwatMishra96

src/mcp/mcp.c

@@ -7756,7 +7756,7 @@ static bool supervisor_suspect_contains(char **s, int n, const char *rel) {
     return false;
 }
 
-/* Append one quarantine entry "rel\tphase\n" (phase = "crash"|"hang") to the
+/* Append one quarantine entry "rel\tphase\n" (phase = "crash"|"hang"|"error") to the
  * quarantine list. The worker's loader parses this back and reports the skip's
  * phase in skipped[]; a bare "rel" line is still tolerated there (defaults crash). */
 static bool supervisor_append_quarantine(const char *path, const char *rel, const char *phase) {
@@ -7790,7 +7790,7 @@ cbm_mcp_supervised_result_disposition_t cbm_mcp_supervised_result_disposition(
  *   - the worker's own response on a clean first run (the common path);
  *   - after a crash/hang, the response from a clean single-threaded RECOVERY run
  *     that quarantines the culprit file(s) — status="indexed" with them listed in
- *     skipped[] as phase="crash"/"hang", and the good files indexed;
+ *     skipped[] as phase="crash"/"hang"/"error", and the good files indexed;
  *   - a best-effort PARTIAL index (one final quarantine-only run) if the recovery
  *     loop cannot converge but at least one file was quarantined;
  *   - a contained-failure response only if even that cannot produce a clean run.
@@ -7839,7 +7839,7 @@ static char *index_run_supervised(cbm_mcp_server_t *srv, const char *args) {
      * (for a hang the oldest still-open file IS the stuck one; for a crash
      * it is the longest-running suspect — the best single deterministic
      * pick). A clean run then indexes the good files and reports the
-     * quarantined ones as phase="crash"/"hang" skips via the ordinary
+     * quarantined ones as phase="crash"/"hang"/"error" skips via the ordinary
      * Stage-2 skip plumbing. The old design re-ran SINGLE-THREADED to keep
      * one exact marker; at scale that fell into the sequential crawl, went
      * quiet, was killed as a hang mid-pass, and the stale marker got FOUR

tests/test_mcp.c

@@ -10048,6 +10048,8 @@ enum {
     IDXPAR_NO_QUARANTINE = 64, /* crasher missing from skipped[] */
     IDXPAR_INNOCENT_HIT = 65,  /* a good file was quarantined/skipped */
     IDXPAR_GOOD_MISSING = 66,  /* good file's Function absent from the store */
+    IDXPAR_NOT_ERROR = 67,     /* systemic failure did not report status error */
+    IDXPAR_OUTCOME_WRONG = 68, /* systemic failure outcome is not exit_nonzero */
 };
 
 #ifndef _WIN32
@@ -10176,13 +10178,24 @@ static int idxpar_systemic_exit_nonzero_give_up_check(const char *repo_dir) {
     cbm_unsetenv("CBM_TEST_EXIT_ON");
 
     if (!resp) {
-        return IDXPAR_OK;
+        return IDXPAR_NULL_RESP;
     }
-    bool gave_up = response_contains_json_fragment(resp, "\"status\":\"gave_up\"") ||
-                   response_contains_json_fragment(resp, "\"status\":\"error\"") ||
-                   response_contains_json_fragment(resp, "\"action\":\"give_up\"");
+    bool is_error = response_contains_json_fragment(resp, "\"status\":\"error\"");
+    bool is_exit_nonzero = response_contains_json_fragment(resp, "\"outcome\":\"exit_nonzero\"");
+    bool innocent_hit =
+        strstr(resp, "idxpar_good_a.py") != NULL || strstr(resp, "idxpar_good_b.py") != NULL;
     free(resp);
-    return gave_up ? IDXPAR_OK : 99;
+
+    if (!is_error) {
+        return IDXPAR_NOT_ERROR;
+    }
+    if (!is_exit_nonzero) {
+        return IDXPAR_OUTCOME_WRONG;
+    }
+    if (innocent_hit) {
+        return IDXPAR_INNOCENT_HIT;
+    }
+    return IDXPAR_OK;
 }
 #endif /* !_WIN32 */