Credo.Check.Warning.Dbg does not detect dbg

[Munksgaard]

Environment

• Credo version (mix credo -v): 1.7.0-ref.direct-convert.56413cf+uncommittedchanges
• Erlang/Elixir version (elixir -v): 1.15.6
• Operating system: NixOS

What were you trying to do?

Run mix credo in a project that contains |> dbg

Expected outcome

A warning, because dbg is being called.

Actual outcome

No warning.

[madclaws]

Hi, try {Credo.Check.Warning.Dbg, []} added inside checks: %{enabled: {Credo.Check.Warning.Dbg, []}} in credo.exs, and also running mix credo --strict @Munksgaard .

[Munksgaard]

Thank you @madclaws. I actually already have that setting in my .credo.exs and am running strict, but I realize that that wasn't clear from my original issue description. I should also note that the warnings work great if I use |> dbg() or dbg(something). It is specifically a problem when dbg is called without parenthesis. Which might also explain why the problem happens: dbg and dbg() are parsed differently as evidenced by the following:

 > quote do: :x |> dbg
{:|>, [context: Elixir, imports: [{2, Kernel}]],
 [
   :x,
   {:dbg,
    [
      if_undefined: :apply,
      context: Elixir,
      imports: [{0, Kernel}, {1, Kernel}, {2, Kernel}]
    ], Elixir}
 ]}
 > quote do: :x |> dbg()
{:|>, [context: Elixir, imports: [{2, Kernel}]],
 [
   :x,
   {:dbg, [context: Elixir, imports: [{0, Kernel}, {1, Kernel}, {2, Kernel}]],
    []}
 ]}

Here is my config file for reference:

# This file contains the configuration for Credo and you are probably reading
# this after creating it with `mix credo.gen.config`.
#
# If you find anything wrong or unclear in this file, please report an
# issue on GitHub: https://github.com/rrrene/credo/issues
#
%{
  #
  # You can have as many configs as you like in the `configs:` field.
  configs: [
    %{
      #
      # Run any config using `mix credo -C <name>`. If no config name is given
      # "default" is used.
      #
      name: "default",
      #
      # These are the files included in the analysis:
      files: %{
        #
        # You can give explicit globs or simply directories.
        # In the latter case `**/*.{ex,exs}` will be used.
        #
        included: [
          "lib/",
          "src/",
          "test/",
          "web/",
          "apps/*/lib/",
          "apps/*/src/",
          "apps/*/test/",
          "apps/*/web/"
        ],
        excluded: [~r"/_build/", ~r"/deps/", ~r"/node_modules/"]
      },
      #
      # Load and configure plugins here:
      #
      plugins: [],
      #
      # If you create your own checks, you must specify the source files for
      # them here, so they can be loaded by Credo before running the analysis.
      #
      requires: [],
      #
      # If you want to enforce a style guide and need a more traditional linting
      # experience, you can change `strict` to `true` below:
      #
      strict: true,
      #
      # To modify the timeout for parsing files, change this value:
      #
      parse_timeout: 5000,
      #
      # If you want to use uncolored output by default, you can change `color`
      # to `false` below:
      #
      color: true,
      #
      # You can customize the parameters of any check by adding a second element
      # to the tuple.
      #
      # To disable a check put `false` as second element:
      #
      #     {Credo.Check.Design.DuplicatedCode, false}
      #
      checks: %{
        enabled: [
          #
          ## Consistency Checks
          #
          {Credo.Check.Consistency.ExceptionNames, []},
          {Credo.Check.Consistency.LineEndings, []},
          {Credo.Check.Consistency.ParameterPatternMatching, []},
          {Credo.Check.Consistency.SpaceAroundOperators, []},
          {Credo.Check.Consistency.SpaceInParentheses, []},
          {Credo.Check.Consistency.TabsOrSpaces, []},

          #
          ## Design Checks
          #
          # You can customize the priority of any check
          # Priority values are: `low, normal, high, higher`
          #
          {Credo.Check.Design.AliasUsage,
           [priority: :low, if_nested_deeper_than: 2, if_called_more_often_than: 0]},
          # You can also customize the exit_status of each check.
          # If you don't want TODO comments to cause `mix credo` to fail, just
          # set this value to 0 (zero).
          #
          {Credo.Check.Design.TagTODO, [exit_status: 2]},
          {Credo.Check.Design.TagFIXME, []},

          #
          ## Readability Checks
          #
          {Credo.Check.Readability.AliasOrder, []},
          {Credo.Check.Readability.FunctionNames, []},
          {Credo.Check.Readability.LargeNumbers, []},
          {Credo.Check.Readability.MaxLineLength, [priority: :low, max_length: 120]},
          {Credo.Check.Readability.ModuleAttributeNames, []},
          {Credo.Check.Readability.ModuleDoc, []},
          {Credo.Check.Readability.ModuleNames, []},
          {Credo.Check.Readability.ParenthesesInCondition, []},
          {Credo.Check.Readability.ParenthesesOnZeroArityDefs, []},
          {Credo.Check.Readability.PipeIntoAnonymousFunctions, []},
          {Credo.Check.Readability.PredicateFunctionNames, []},
          {Credo.Check.Readability.PreferImplicitTry, []},
          {Credo.Check.Readability.RedundantBlankLines, []},
          {Credo.Check.Readability.Semicolons, []},
          {Credo.Check.Readability.SpaceAfterCommas, []},
          {Credo.Check.Readability.Specs, []},
          {Credo.Check.Readability.StringSigils, []},
          {Credo.Check.Readability.TrailingBlankLine, []},
          {Credo.Check.Readability.TrailingWhiteSpace, []},
          {Credo.Check.Readability.UnnecessaryAliasExpansion, []},
          {Credo.Check.Readability.VariableNames, []},
          {Credo.Check.Readability.WithSingleClause, []},

          #
          ## Refactoring Opportunities
          #
          {Credo.Check.Refactor.Apply, []},
          {Credo.Check.Refactor.CondStatements, []},
          {Credo.Check.Refactor.CyclomaticComplexity, []},
          {Credo.Check.Refactor.FunctionArity, []},
          {Credo.Check.Refactor.LongQuoteBlocks, []},
          {Credo.Check.Refactor.MatchInCondition, []},
          {Credo.Check.Refactor.MapJoin, []},
          {Credo.Check.Refactor.NegatedConditionsInUnless, []},
          {Credo.Check.Refactor.NegatedConditionsWithElse, []},
          {Credo.Check.Refactor.Nesting, []},
          {Credo.Check.Refactor.UnlessWithElse, []},
          {Credo.Check.Refactor.WithClauses, []},
          {Credo.Check.Refactor.FilterCount, []},
          {Credo.Check.Refactor.FilterFilter, []},
          {Credo.Check.Refactor.RejectReject, []},
          {Credo.Check.Refactor.RedundantWithClauseResult, []},

          #
          ## Warnings
          #
          {Credo.Check.Warning.ApplicationConfigInModuleAttribute, []},
          {Credo.Check.Warning.BoolOperationOnSameValues, []},
          {Credo.Check.Warning.Dbg, []},
          {Credo.Check.Warning.ExpensiveEmptyEnumCheck, []},
          {Credo.Check.Warning.IExPry, []},
          {Credo.Check.Warning.IoInspect, []},
          {Credo.Check.Warning.MissedMetadataKeyInLoggerConfig, []},
          {Credo.Check.Warning.OperationOnSameValues, []},
          {Credo.Check.Warning.OperationWithConstantResult, []},
          {Credo.Check.Warning.RaiseInsideRescue, []},
          {Credo.Check.Warning.SpecWithStruct, []},
          {Credo.Check.Warning.WrongTestFileExtension, []},
          {Credo.Check.Warning.UnusedEnumOperation, []},
          {Credo.Check.Warning.UnusedFileOperation, []},
          {Credo.Check.Warning.UnusedKeywordOperation, []},
          {Credo.Check.Warning.UnusedListOperation, []},
          {Credo.Check.Warning.UnusedPathOperation, []},
          {Credo.Check.Warning.UnusedRegexOperation, []},
          {Credo.Check.Warning.UnusedStringOperation, []},
          {Credo.Check.Warning.UnusedTupleOperation, []},
          {Credo.Check.Warning.UnsafeExec, []}
        ],
        disabled: [
          #
          # Checks scheduled for next check update (opt-in for now, just replace `false` with `[]`)

          #
          # Controversial and experimental checks (opt-in, just move the check to `:enabled`
          #   and be sure to use `mix credo --strict` to see low priority checks)
          #
          {Credo.Check.Consistency.MultiAliasImportRequireUse, []},
          {Credo.Check.Consistency.UnusedVariableNames, []},
          {Credo.Check.Design.DuplicatedCode, []},
          {Credo.Check.Design.SkipTestWithoutComment, []},
          {Credo.Check.Readability.AliasAs, []},
          {Credo.Check.Readability.BlockPipe, []},
          {Credo.Check.Readability.ImplTrue, []},
          {Credo.Check.Readability.MultiAlias, []},
          {Credo.Check.Readability.NestedFunctionCalls, []},
          {Credo.Check.Readability.OneArityFunctionInPipe, []},
          {Credo.Check.Readability.SeparateAliasRequire, []},
          {Credo.Check.Readability.SingleFunctionToBlockPipe, []},
          {Credo.Check.Readability.SinglePipe, []},
          {Credo.Check.Readability.StrictModuleLayout, []},
          {Credo.Check.Readability.WithCustomTaggedTuple, []},
          {Credo.Check.Readability.OnePipePerLine, []},
          {Credo.Check.Refactor.ABCSize, []},
          {Credo.Check.Refactor.AppendSingleItem, []},
          {Credo.Check.Refactor.DoubleBooleanNegation, []},
          {Credo.Check.Refactor.FilterReject, []},
          {Credo.Check.Refactor.IoPuts, []},
          {Credo.Check.Refactor.MapMap, []},
          {Credo.Check.Refactor.ModuleDependencies, []},
          {Credo.Check.Refactor.NegatedIsNil, []},
          {Credo.Check.Refactor.PassAsyncInTestCases, []},
          {Credo.Check.Refactor.PipeChainStart, []},
          {Credo.Check.Refactor.RejectFilter, []},
          {Credo.Check.Refactor.VariableRebinding, []},
          {Credo.Check.Warning.LazyLogging, []},
          {Credo.Check.Warning.LeakyEnvironment, []},
          {Credo.Check.Warning.MapGetUnsafePass, []},
          {Credo.Check.Warning.MixEnv, []},
          {Credo.Check.Warning.UnsafeToAtom, []}

          # {Credo.Check.Refactor.MapInto, []},

          #
          # Custom checks can be created using `mix credo.gen.check`.
          #
        ]
      }
    }
  ]
}

[rrrene]

Which might also explain why the problem happens: dbg and dbg() are parsed differently as evidenced by the following:

It doesn't because Credo does not use quote, as Credo is not running your code.

Can you provide a piece of code where this happens?

[Munksgaard]

If you want a complete sample elixir-project with credo configuration, I will have to get back to you later tonight. But I think it should just be a matter of inserting something like :x |> dbg anywhere in an existing project.

Here's a simple example from my utility module:

  def headers_to_strings(headers) do
    :x |> dbg()
    Enum.map(headers, fn {key, value} -> "#{key}: #{value}" end)
  end

Running credo I get the following (as expected):

$ mix credo
Checking 199 source files (this might take a while) ...

  Warnings - please take a look
┃
┃ [W] ↗ There should be no calls to dbg.
┃       lib/leaf/util.ex:17:11 #(Leaf.Util.headers_to_strings)

Please report incorrect results: https://github.com/rrrene/credo/issues

Analysis took 2.3 seconds (0.1s to load, 2.1s running 68 checks on 199 files)
1149 mods/funs, found 1 warning.

If I remove the parenthesis, I get this instead:

  def headers_to_strings(headers) do
    :x |> dbg
    Enum.map(headers, fn {key, value} -> "#{key}: #{value}" end)
  end

$ mix credo
Checking 199 source files (this might take a while) ...

Please report incorrect results: https://github.com/rrrene/credo/issues

Analysis took 2.5 seconds (0.2s to load, 2.3s running 68 checks on 199 files)
1149 mods/funs, found no issues.

[rrrene]

@Munksgaard found it. Fix incoming 👍 Thx for reporting!

[Munksgaard]

Great stuff @rrrene! Thanks for your work on Credo 🥇

[rrrene]

This is part of 1.7.2-rc.3 👍

[Munksgaard]

Amazing, thank you!