chore: improve dfx cycles messages.

CHANGELOG.md

@@ -18,6 +18,16 @@ Allow setting permissions lists in init arguments just like in upgrade arguments
 - Module hash: f45db224b40fac516c877e3108dc809d4b22fa42d05ee8dfa5002536a3a3daed
 - Bump agent-js to fix error code
 
+### chore!: improve the messages for the subcommands of `dfx cycles`.
+
+If users run subcommands of `dfx cycles` without the `--ic` flag, show below messages to indicate what to do next.
+```
+Error explanation:
+Cycles ledger with canister ID 'um5iw-rqaaa-aaaaq-qaaba-cai' is not installed.
+How to resolve the error:
+Run the command with '--ic' flag if you want to manage the cycles on the mainnet.
+```
+
 # 0.24.2
 
 ### feat: Support canister log allowed viewer list

e2e/tests-dfx/cycles-ledger.bash

@@ -117,6 +117,13 @@ current_time_nanoseconds() {
   assert_eq "2.900 TC (trillion cycles)."
 }
 
+@test "balance without cycles ledger fails as expected" {
+  dfx_start
+
+  assert_command_fail dfx cycles balance
+  assert_contains "Cycles ledger with canister ID 'um5iw-rqaaa-aaaaq-qaaba-cai' is not installed."
+}
+
 @test "transfer" {
   start_and_install_nns
 

src/dfx/src/lib/diagnosis.rs

@@ -54,6 +54,9 @@ pub fn diagnose(err: &AnyhowError) -> Diagnosis {
         } else if *agent_err == AgentError::CertificateNotAuthorized() {
             return subnet_not_authorized();
         }
+        if cycles_ledger_not_found(err) {
+            return diagnose_cycles_ledger_not_found();
+        }
     }
 
     if local_replica_not_running(err) {
@@ -229,3 +232,17 @@ If you're using a local replica and configuring a wallet was a mistake, you can
 recreate the replica with `dfx stop && dfx start --clean` to start over.";
     (Some(explanation.to_string()), Some(suggestion.to_string()))
 }
+
+fn cycles_ledger_not_found(err: &AnyhowError) -> bool {
+    err.to_string()
+        .contains("Canister um5iw-rqaaa-aaaaq-qaaba-cai not found")
+}
+
+fn diagnose_cycles_ledger_not_found() -> Diagnosis {
+    let explanation =
+        "Cycles ledger with canister ID 'um5iw-rqaaa-aaaaq-qaaba-cai' is not installed.";
+    let suggestion =
+        "Run the command with '--ic' flag if you want to manage the cycles on the mainnet.";
+
+    (Some(explanation.to_string()), Some(suggestion.to_string()))
+}