rpc: Fix formatting on some fmt lib versions

There's a bug in fmt-8 that prefers implicit type cast to bool over overloaded operator<< when formatting it with the latter. As a result the formatted string is always "true"/"false" instead of some sane value. Marking the operator bool() explicit solves the issue. Also add a test to catch any violations earlier. fixes: #1151 Signed-off-by: Pavel Emelyanov <[email protected]> Message-Id: <[email protected]>
scylladb · Jul 25, 2022 · f1d0b25 · f1d0b25
1 parent c3169e0
commit f1d0b25
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diff --git a/include/seastar/rpc/rpc_types.hh b/include/seastar/rpc/rpc_types.hh
@@ -247,7 +247,7 @@ struct connection_id {
     bool operator==(const connection_id& o) const {
         return id == o.id;
     }
-    operator bool() const {
+    explicit operator bool() const {
         return shard() != 0xffff;
     }
     size_t shard() const {

diff --git a/tests/unit/rpc_test.cc b/tests/unit/rpc_test.cc
@@ -1401,4 +1401,11 @@ SEASTAR_TEST_CASE(test_loggers) {
     });
 }
 
+SEASTAR_TEST_CASE(test_connection_id_format) {
+    rpc::connection_id cid = rpc::connection_id::make_id(0x123, 1);
+    std::string res = format("{}", cid);
+    BOOST_REQUIRE_EQUAL(res, "1230001");
+    return make_ready_future<>();
+}
+
 static_assert(std::is_same_v<decltype(rpc::tuple(1U, 1L)), rpc::tuple<unsigned, long>>, "rpc::tuple deduction guid not working");