Add tests exercising dictionary iteration during modification.

These are some of the reproducers from #2017 and #2032 by Arne Welzel.

testing/btest/core/dict-iteration-expire1.zeek

@@ -0,0 +1,52 @@
+# @TEST-EXEC: zeek %INPUT
+# @TEST-DOC:  Regression test #2017; no output check, just shouldn't crash
+
+redef table_expire_interval = 0.1sec;
+redef table_incremental_step = 100;
+redef table_expire_delay = 0.5sec;
+
+redef exit_only_after_terminate = T;
+
+global tbl: table[string] of vector of count &default = vector() &create_expire=1sec;
+
+const populates_per_second = 100;
+const populates_num = 100;
+global done = F;
+
+event do_terminate() {
+  terminate();
+}
+
+event cleanup(idx: string) {
+  delete tbl[idx];
+
+  # terminate a bit after all elements will finally have been expired
+  if ( done && |tbl| == 0 )
+    schedule 1sec { do_terminate() };
+}
+
+event populate(round: count) {
+
+  local i = 0;
+  while (++i < populates_num) {
+    local val = rand(1000000);
+    local val_str = cat(val);
+    # print(fmt("round %s %s val=%s", round, i, val));
+    tbl[val_str] = vector(val);
+
+    # Schedule an explicit delete at most a second away.
+    local random_cleanup_delay = double_to_interval(rand(100) / 100.0);
+    schedule random_cleanup_delay { cleanup(val_str) };
+  }
+
+  if ( round <= 200 ) {
+    print(fmt("round %s size=%s", round, |tbl|));
+    schedule 1sec/populates_per_second { populate(++round) };
+  }
+  else
+    done = T;
+}
+
+event zeek_init() {
+  event populate(1);
+}

testing/btest/core/dict-iteration-expire4.zeek

@@ -0,0 +1,108 @@
+# @TEST-EXEC: zcat <$TRACES/echo-connections.pcap.gz | zeek --load-seeds 1.seeds -Cr - %INPUT
+# @TEST-EXEC: zcat <$TRACES/echo-connections.pcap.gz | zeek --load-seeds 2.seeds -Cr - %INPUT
+# @TEST-DOC:  Regression test #2032; no output check, just shouldn't crash
+
+redef table_expire_delay = 0.1sec;
+redef table_incremental_step = 10;
+redef table_expire_interval = 0.01sec;
+
+# redef exit_only_after_terminate = T;
+
+type Key: record {
+  c: count;
+  s1: string;
+  s2: string;
+  a1: addr;
+  a2: addr;
+};
+
+global insert_many: event(n: count);
+global insert_many_f: function(n: count);
+
+function expire(t: table[Key] of Key, k: Key): interval {
+  print(fmt("Expiring %s sz=%s", k, |t|));
+  schedule 0.2sec { insert_many(2 * |t| + 8) };
+  #insert_many_f(2 * |t| + 8);
+  return 0sec;
+}
+
+global tbl: table[Key] of Key &create_expire=0.1sec &expire_func=expire;
+
+function make_key(i: count): Key {
+  return Key(
+    $c=i,
+    $s1=cat(i),
+    $s2=cat(2 * i),
+    $a1=count_to_v4_addr(1000000 + i),
+    $a2=count_to_v4_addr(2000000 + i)
+  );
+}
+
+event insert_many(n: count) {
+  local i = n;
+  while (++i < n + 37) {
+    local k = make_key(i);
+    tbl[k] = k;
+  }
+}
+
+function insert_many_f(n: count) {
+  local i = n;
+  while (++i < n + 37) {
+    local k = make_key(i);
+    tbl[k] = k;
+  }
+}
+
+event zeek_init() {
+ local k = make_key(1);
+ tbl[k] = k;
+}
+
+@TEST-START-FILE 1.seeds
+3569182667
+3864322632
+2737717875
+4292737228
+959594593
+3440781012
+1483058089
+950202215
+611472157
+2218394723
+3885890563
+1396441520
+1851988456
+3540954895
+2626085489
+3793122452
+3535210719
+936980445
+3834222442
+2355333979
+113403102
+@TEST-END-FILE
+
+@TEST-START-FILE 2.seeds
+4013930712
+1835775324
+3393047106
+3151534432
+2727962940
+3990820447
+792628001
+3844857817
+2661636943
+2621115293
+2909873159
+3909343487
+1003041063
+1365337823
+2042927118
+3623503659
+394335333
+302877509
+348858887
+14638654
+4267481449
+@TEST-END-FILE

testing/btest/core/dict-iteration-expire5.zeek

@@ -0,0 +1,68 @@
+# @TEST-EXEC: zcat <$TRACES/echo-connections.pcap.gz | zeek --load-seeds 1.seeds -Cr - %INPUT
+# @TEST-EXEC: zcat <$TRACES/echo-connections.pcap.gz | zeek --load-seeds 2.seeds -Cr - %INPUT
+# @TEST-DOC:  Regression test #2032; no output check, just shouldn't crash
+
+redef table_expire_delay = 0.0001sec;
+redef table_incremental_step = 1;
+redef table_expire_interval = 0.001sec;
+
+
+function expire(t: table[conn_id] of string, k: conn_id): interval {
+  # print(fmt("Expiring %s sz=%s", k, |t|));
+  return 0sec;
+}
+
+global recent_conns: table[conn_id] of string &create_expire=0.05sec &expire_func=expire;
+
+event new_connection(c: connection) {
+  # print(fmt("%s %s", c$id, network_time()));
+  recent_conns[c$id] = c$uid;
+}
+
+@TEST-START-FILE 1.seeds
+3569182667
+3864322632
+2737717875
+4292737228
+959594593
+3440781012
+1483058089
+950202215
+611472157
+2218394723
+3885890563
+1396441520
+1851988456
+3540954895
+2626085489
+3793122452
+3535210719
+936980445
+3834222442
+2355333979
+113403102
+@TEST-END-FILE
+
+@TEST-START-FILE 2.seeds
+4013930712
+1835775324
+3393047106
+3151534432
+2727962940
+3990820447
+792628001
+3844857817
+2661636943
+2621115293
+2909873159
+3909343487
+1003041063
+1365337823
+2042927118
+3623503659
+394335333
+302877509
+348858887
+14638654
+4267481449
+@TEST-END-FILE