lspitzner / lspitzner/brittany

MultiWayIf receives context-sensitive alignment despite configuration

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bug hs:guards
Dominant language
Haskell
Stars
686
Forks
69
PR merge metrics
No merged PRs in 30d

Description

We make use of configuration to ensure things don't get aligned in context-aware ways, to avoid diff noise:

Configuration
---
conf_debug:
  dconf_roundtrip_exactprint_only: false
  dconf_dump_bridoc_simpl_par: false
  dconf_dump_ast_unknown: false
  dconf_dump_bridoc_simpl_floating: false
  dconf_dump_config: false
  dconf_dump_bridoc_raw: false
  dconf_dump_bridoc_final: false
  dconf_dump_bridoc_simpl_alt: false
  dconf_dump_bridoc_simpl_indent: false
  dconf_dump_annotations: false
  dconf_dump_bridoc_simpl_columns: false
  dconf_dump_ast_full: false
conf_forward:
  options_ghc:
    - -XBangPatterns
    - -XDataKinds
    - -XDeriveAnyClass
    - -XDeriveFoldable
    - -XDeriveFunctor
    - -XDeriveGeneric
    - -XDeriveLift
    - -XDeriveTraversable
    - -XDerivingStrategies
    - -XFlexibleContexts
    - -XFlexibleInstances
    - -XGADTs
    - -XGeneralizedNewtypeDeriving
    - -XLambdaCase
    - -XMultiParamTypeClasses
    - -XNoImplicitPrelude
    - -XNoMonomorphismRestriction
    - -XOverloadedStrings
    - -XRankNTypes
    - -XRecordWildCards
    - -XScopedTypeVariables
    - -XStandaloneDeriving
    - -XTypeApplications
    - -XTypeFamilies
conf_errorHandling:
  econf_ExactPrintFallback: ExactPrintFallbackModeInline
  econf_Werror: false
  econf_omit_output_valid_check: false
  econf_produceOutputOnErrors: false
conf_preprocessor:
  ppconf_CPPMode: CPPModeAbort
  ppconf_hackAroundIncludes: false
conf_obfuscate: false
conf_roundtrip_exactprint_only: false
conf_version: 1
conf_layout:
  lconfig_reformatModulePreamble: true
  lconfig_altChooser:
    tag: AltChooserBoundedSearch
    contents: 3
  lconfig_allowSingleLineExportList: false
  lconfig_importColumn: 60
  lconfig_hangingTypeSignature: false
  lconfig_importAsColumn: 50
  lconfig_alignmentLimit: 1
  lconfig_indentListSpecial: true
  lconfig_indentAmount: 2
  lconfig_alignmentBreakOnMultiline: true
  lconfig_cols: 80
  lconfig_indentPolicy: IndentPolicyLeft
  lconfig_indentWhereSpecial: true
  lconfig_columnAlignMode:
    tag: ColumnAlignModeDisabled
    contents: 0.7

But that doesn't seem to be respected with MultiWayIf:

Given:

example :: A -> B
example = if
  | this > that -> True
  | othrewise -> False

Expected: no changes

Actual:

example :: A -> B
example = if
  | this > that -> True
  | othrewise   -> False
% stack exec brittany -- --version
brittany version 0.13.1.0
Copyright (C) 2016-2019 Lennart Spitzner
Copyright (C) 2019 PRODA LTD
There is NO WARRANTY, to the extent permitted by law.

Contributor guide

No contributing guide indexed for this repository

First steps

  1. Read the whole issue, then the project's contributing guide.
  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

Start by reproducing the reported MultiWayIf formatting with the supplied configuration and brittany 0.13.1.0 command. Trace how the disabled column-alignment setting is handled for MultiWayIf, then verify that the example remains unchanged when alignment is disabled and add regression coverage if the project provides a suitable test location.

Written by the indexing model from the issue text.

Assessment

Tech stack
haskell
Domain
tooling
Issue type
Bug
Difficulty
3/5
Estimated time
1-2 days
Activity status
Stale
Clarity
Mostly clear
Newbie friendliness
38/100

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