testcase_read: error out if repos are added or the system is changed too late

We must not add new solvables after the considered map was created, the solver
was created, or jobs were added. We may not changed the system after jobs have
been added.

(Jobs may point inside the whatproviedes array, so we must not invalidate this
area.)

Author: mlschroe

ext/testcase.c

@@ -1991,6 +1991,7 @@ testcase_read(Pool *pool, FILE *fp, const char *testcase, Queue *job, char **res
   Id *genid = 0;
   int ngenid = 0;
   Queue autoinstq;
+  int oldjobsize = job ? job->count : 0;
 
   if (resultp)
     *resultp = 0;
@@ -2065,6 +2066,21 @@ testcase_read(Pool *pool, FILE *fp, const char *testcase, Queue *job, char **res
 	  int prio, subprio;
 	  const char *rdata;
 
+	  if (pool->considered)
+	    {
+	      pool_error(pool, 0, "testcase_read: cannot add repos after packages were disabled");
+	      continue;
+	    }
+	  if (solv)
+	    {
+	      pool_error(pool, 0, "testcase_read: cannot add repos after the solver was created");
+	      continue;
+	    }
+	  if (job && job->count != oldjobsize)
+	    {
+	      pool_error(pool, 0, "testcase_read: cannot add repos after jobs have been created");
+	      continue;
+	    }
 	  prepared = 0;
           if (!poolflagsreset)
 	    {
@@ -2125,6 +2141,11 @@ testcase_read(Pool *pool, FILE *fp, const char *testcase, Queue *job, char **res
 	  int i;
 
 	  /* must set the disttype before the arch */
+	  if (job && job->count != oldjobsize)
+	    {
+	      pool_error(pool, 0, "testcase_read: cannot change the system after jobs have been created");
+	      continue;
+	    }
 	  prepared = 0;
 	  if (strcmp(pieces[2], "*") != 0)
 	    {