Error map
Missing encryption key to decrypt file with Rails: ArgumentError: Missing encryption key to decrypt file with. Ask your team for your master key and write it to config/master.key or put it in the ENV['RAILS_MASTER_KEY']
Ruby / Rails · layer 4, Application & API
Centre: this error. First ring: errors it is linked with (7). Outer ring: what those are linked with. Colours show the layer of a request each error belongs to. Click any dot to re-centre the map on it; hover to follow its connections. The centre dot opens the error page.
Directly related (7)
Rails: ActiveRecord::IrreversibleMigration — This migration uses remove_column without a type; db:rollback can't reverse it
`rails db:rollback` can't undo the migration because it contains an operation Rails can't invert.
Rails: ActiveRecord::ConnectionNotEstablished: No connection pool for 'ActiveRecord::Base' found
ActiveRecord has no database connection configured or established for this process.
Rails: ActiveRecord::Deadlocked: PG::TRDeadlockDetected: ERROR: deadlock detected
Two transactions locked rows in opposite orders, so PostgreSQL aborted one.
Rails: ActiveSupport::MessageEncryptor::InvalidMessage (credentials.yml.enc can't be decrypted — wrong master.key)
Rails couldn't decrypt `credentials.yml.enc` (or a signed/encrypted cookie) because the key is wrong or the data changed.
Rails: Asset `application.js` was not declared to be precompiled in production / The asset "application.css" is not present in the asset pipeline
A layout references an asset that Sprockets doesn't know to compile or can't find.
Rails: ArgumentError: Missing `secret_key_base` for 'production' environment, set this string with `bin/rails credentials:edit`
Production boot needs a `secret_key_base` to sign/encrypt cookies, and none is configured.
Rails: ActiveRecord::AssociationTypeMismatch: User(#1234) expected, got "42" which is an instance of String(#5678)
You assigned the wrong kind of object (or an id string) to an association.
Two steps away (17)
MySQL ERROR 1146 (42S02): Table 'db.table' doesn't exist
The query references a table that MySQL can’t find in that database.
PostgreSQL: ERROR: relation "x" does not exist
The table/view isn’t found — missing migration, wrong schema, or a case-sensitive quoted name.
MySQL ERROR 1022 (23000): Can't write; duplicate key in table
An ALTER/CREATE produced a duplicate key or constraint name — often a foreign key name that already exists in the database.
Rails: ActionController::InvalidAuthenticityToken (Can't verify CSRF token authenticity)
A non-GET request arrived without a valid CSRF token for the session.
Redis: Error: connect ECONNREFUSED 127.0.0.1:6379 / Could not connect to Redis at 127.0.0.1:6379: Connection refused
Nothing is listening on the Redis host/port your client uses.
Redis: Error: write EPROTO ... SSL routines:ssl3_get_record:wrong version number / Connection reset by peer (TLS vs plaintext)
The client and server disagree about TLS — plaintext client to a TLS port, or TLS client to a plaintext port.
Ruby: NameError: uninitialized constant UsersController::User (Did you mean? Users)
Ruby (or Rails autoloading) couldn't find a class or module with that name in the current scope.
Ruby: NameError: undefined local variable or method 'x' for main:Object
Ruby saw a bare identifier that is neither a local variable nor a method on the current object.
Rails: ActiveRecord::RecordNotFound: Couldn't find User with 'id'=42
`find`/`find_by!` didn't find a row, so Rails raises (and renders a 404 in production).
Laravel: Illuminate\Contracts\Encryption\DecryptException: The payload is invalid. / The MAC is invalid.
Laravel couldn't decrypt a cookie, session or encrypted value — the `APP_KEY` changed or the data was corrupted.
Laravel: Vite manifest not found at: public/build/manifest.json
Laravel’s @vite directive can’t find the compiled asset manifest because assets weren’t built.
Rails: Yarn executable was not detected in the system. Download Yarn at https://yarnpkg.com/en/docs/install
Rails asset tasks (`assets:precompile`, webpacker/jsbundling) need Node and Yarn but they're not installed/on PATH.
Rails: Zeitwerk::NameError: expected file app/models/user_profile.rb to define constant UserProfile, but didn't
Rails autoloading found a file whose name implies a constant the file doesn't define.
Rails: A server is already running (pid: 12345, file: /app/tmp/pids/server.pid). Exiting
Rails thinks another server is running because a stale `server.pid` exists (often after a crash or in Docker).
Rails: ActiveRecord::PendingMigrationError — Migrations are pending. To resolve this issue, run: bin/rails db:migrate
The database schema is behind the migration files in the app.
Rails: ActiveRecord::RecordInvalid: Validation failed: Email can't be blank, Name is too short
`save!`/`create!`/`update!` raised because validations failed.
Rails: ActiveRecord::StatementInvalid: PG::UndefinedTable: ERROR: relation "users" does not exist
Rails queried a table that isn't in the connected PostgreSQL database.
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Popular: 500403400ORA-009331064Critical errorFileNotFoundException assemblyTypeError