elixir-no-shortcuts

Elixir No Shortcuts: Fix the Real Problem

THE IRON LAW

NEVER suppress errors. ALWAYS fix the root cause.

ABSOLUTE PROHIBITIONS

You are NEVER allowed to:

1. Add to dialyzer.ignore

   • Not for "unknown function" errors
   • Not for "pattern can never match" warnings
   • Not for "no local return" issues
   • Not even "temporarily"

2. Modify .credo.exs to disable checks

   • Not adding to disabled: list
   • Not adding to excluded_paths:
   • Not using inline # credo:disable-for-this-file
   • Not raising complexity limits

3. Suppress compiler warnings

   • Not with @compile {:no_warn_undefined, Module}
   • Not with # noqa style comments
   • Not by removing --warnings-as-errors

4. Modify .gitignore to hide problems

   • Not to hide accidentally created files
   • Not to ignore build artifacts in wrong places
   • Fix the process that created them

5. Comment out failing tests

   • Not "just for now"
   • Not "until we figure it out"
   • Fix the test or fix the code

6. Skip quality checks

   • Not removing from pre-commit hook
   • Not skipping with --no-verify
   • Not disabling in CI/CD

INSTEAD: FIX THE ACTUAL PROBLEM

Dialyzer Errors

When Dialyzer complains:

# BAD: Adding to dialyzer.ignore
# dialyzer.ignore
lib/my_app/accounts.ex:42:pattern_can_never_match

# GOOD: Fix with proper @spec
defmodule MyApp.Accounts do
  @spec get_user(integer()) :: {:ok, User.t()} | {:error, :not_found}
  def get_user(id) do
    case Repo.get(User, id) do
      nil -> {:error, :not_found}
      user -> {:ok, user}
    end
  end
end

Common Dialyzer fixes:

1. Unknown function - Add @spec or import the module
2. Pattern can never match - Fix the actual pattern mismatch
3. No local return - Add error handling paths
4. Invalid type specification - Correct the @spec to match reality

Process:

1. Read the full Dialyzer error (don't just scan it)
2. Understand what Dialyzer is telling you
3. Add @spec that matches what the function actually does
4. If function behavior is wrong, fix the function
5. Run mix dialyzer again to verify