Finish off #13046

(cherry picked from commit 3dd3433)

Author: michaelklishin

deps/rabbit/src/rabbit.erl

@@ -1755,17 +1755,19 @@ persist_static_configuration() ->
       ]),
 
     %% Disallow the following two cases:
-    %% 1. Negative value
-    %% 2. MoreCreditAfter larger than InitialCredit.
+    %% 1. Negative values
+    %% 2. MoreCreditAfter greater than InitialCredit
     CreditFlowDefaultCredit = case application:get_env(?MODULE, credit_flow_default_credit) of
                      {ok, {InitialCredit, MoreCreditAfter}}
                        when is_integer(InitialCredit) andalso
-                       is_integer(MoreCreditAfter) andalso
-                       MoreCreditAfter < InitialCredit ->
+                            is_integer(MoreCreditAfter) andalso
+                            InitialCredit > 0 andalso
+                            MoreCreditAfter > 0 andalso
+                            MoreCreditAfter < InitialCredit ->
                          {InitialCredit, MoreCreditAfter};
-                     _ ->
-                       rabbit_log:error("Failed to start due to invalid value of credit_flow_default_credit."),
-                       throw({error, invalid_credit_flow_default_credit_value})
+                     Other ->
+                       rabbit_log:error("Refusing to boot due to an invalid value of 'rabbit.credit_flow_default_credit'"),
+                       throw({error, {invalid_credit_flow_default_credit_value, Other}})
                end,
     ok = persistent_term:put(credit_flow_default_credit, CreditFlowDefaultCredit),