chore: improve error message when asset wasm is not allowlisted in playground

CHANGELOG.md

@@ -10,7 +10,7 @@
 
 This used to be a warning. A hard error can abort the command so that no insecure state will be on the mainnet.
 
-Users can surpress this error by setting `export DFX_WARNING=-mainnet_plaintext_identity`.
+Users can suppress this error by setting `export DFX_WARNING=-mainnet_plaintext_identity`.
 
 The warning won't display when executing commands like `dfx deploy --playground`.
 
@@ -48,6 +48,9 @@ Please top up your cycles balance by converting ICP to cycles like below:
 'dfx cycles convert --amount=0.123'.
 ```
 
+If users run `dfx deploy --playground` but the backend is not updated with the latest frontend canister wasm
+the error message will explain this properly and recommends asking for help on the forum since this can't be resolved by users.
+
 ### chore: improve `dfx cycles convert` messages.
 
 If users run `dfx cycles convert` without enough ICP tokens, show additional messages to indicate what to do next.

src/dfx/src/lib/operations/canister/motoko_playground.rs

@@ -1,5 +1,6 @@
+use crate::lib::diagnosis::DiagnosedError;
 use crate::lib::{environment::Environment, error::DfxResult};
-use anyhow::{bail, Context};
+use anyhow::{anyhow, bail, Context};
 use candid::{encode_args, CandidType, Decode, Deserialize, Encode, Principal};
 use dfx_core::config::model::canister_id_store::AcquisitionDateTime;
 use dfx_core::config::model::network_descriptor::{
@@ -210,7 +211,16 @@ pub async fn playground_install_code(
         .update(&playground_canister, "installCode")
         .with_arg(encoded_arg.as_slice())
         .await
-        .context("install failed")?;
+        .map_err(|err| {
+            if is_asset_canister && err.to_string().contains("Wasm is not whitelisted") {
+                anyhow!(DiagnosedError {
+                    error_explanation: Some("The frontend canister wasm needs to be allowlisted in the playground but it isn't. This is a mistake in the release process.".to_string()),
+                    action_suggestion: Some("Please report this on forum.dfinity.org and mention your dfx version. You can get the version with 'dfx --version'.".to_string()),
+                })
+            } else {
+                anyhow!(err)
+            }
+        })?;
     let out = Decode!(&result, CanisterInfo)?;
     out.get_timestamp()
 }