Show a better error if all vars were blacklisted

Author: matt-aitken

apps/webapp/app/v3/environmentVariables/environmentVariablesRepository.server.ts

@@ -90,11 +90,17 @@ export class EnvironmentVariablesRepository implements Repository {
 
     // Remove `TRIGGER_SECRET_KEY` or `TRIGGER_API_URL`
     let values = removeBlacklistedVariables(options.variables);
+    const removedDuplicates = values.length !== options.variables.length;
 
     //get rid of empty variables
     values = values.filter((v) => v.key.trim() !== "" && v.value.trim() !== "");
     if (values.length === 0) {
-      return { success: false as const, error: `You must set at least one value` };
+      return {
+        success: false as const,
+        error: `You must set at least one valid variable.${
+          removedDuplicates ? " These were ignored because they're blacklisted." : ""
+        }`,
+      };
     }
 
     //check if any of them exist in an environment we're setting