KogenCredo.Check.Warning.DiscardedResult (KogenCredo v0.1.0)

Basics

This check has a base priority of low and works with any version of Elixir.

Explanation

A fallible call whose result is dropped hides failures.

Bad:

_ = Repo.update(changeset)
Enum.each(attrs, fn a -> create_post(a) end)

Good:

{:ok, _post} = Repo.update(changeset)
Enum.each(attrs, fn a -> {:ok, _} = create_post(a) end)

Or collect results and handle the errors. Fallibility is guessed from function names; tune fallible_name_patterns and ignored_names.

Check-Specific Parameters

Use the following parameters to configure this check:

:repo_functions

Repo functions that are fallible (non-bang writes).

This parameter defaults to [:insert, :update, :delete, :insert_or_update].

:fallible_name_patterns

Globs of function names treated as fallible.

This parameter defaults to ["create_*", "insert_*", "update_*", "delete_*"].

:ignored_names

Function names never treated as fallible.

This parameter defaults to ["update_in", "update_change", "delete_change", "update_counter", "delete_csrf_token", "delete_session", "delete_req_header", "delete_resp_header", "delete_resp_cookie", "update_resp_header"].

:ignored_modules

Last module segments whose functions are never fallible.

This parameter defaults to ["Map", "Keyword", "Enum", "List", "Access", "Changeset", "Multi", "Kernel"].

:flag_bare_statement

Report fallible calls used as statements (default true).

This parameter defaults to true.

:flag_underscore_assignment

Report _ = fallible() statements (default true).

This parameter defaults to true.

:repo_names

Last module segments accepted as a repo (default ["Repo"]).

This parameter defaults to ["Repo"].

:repo_modules

Full repo module names accepted as a repo (strings).

This parameter defaults to [].

:included_paths

Globs of files to check; empty means every file.

This parameter defaults to [].

:excluded_paths

Globs of files to skip (default ["test/**"]).

This parameter defaults to ["test/**"].

General Parameters

Like with all checks, general params can be applied.

Parameters can be configured via the .credo.exs config file.