如何配置scalafmt使其遵循多行方法调用的自定义格式

问题描述 #

期望的方法调用格式：

newTimeRangeList(
  MonthRanges.Y2021.Jan, MonthRanges.Y2021.Feb, MonthRanges.Y2021.Mar, MonthRanges.Y2021.Apr,
  MonthRanges.Y2021.May, MonthRanges.Y2021.Jun, MonthRanges.Y2021.Jul, MonthRanges.Y2021.Aug,
  MonthRanges.Y2021.Sep, MonthRanges.Y2021.Oct, MonthRanges.Y2021.Nov, MonthRanges.Y2021.Dec
)

当前scalafmt格式化后的结果：

newTimeRangeList(
  MonthRanges.Y2021.Jan,
  MonthRanges.Y2021.Feb,
  MonthRanges.Y2021.Mar,
  MonthRanges.Y2021.Apr,
  MonthRanges.Y2021.May,
  MonthRanges.Y2021.Jun,
  MonthRanges.Y2021.Jul,
  MonthRanges.Y2021.Aug,
  MonthRanges.Y2021.Sep,
  MonthRanges.Y2021.Oct,
  MonthRanges.Y2021.Nov,
  MonthRanges.Y2021.Dec
)

用户当前的scalafmt配置：

version = 3.7.3
docstrings.style = Asterisk
runner.dialect = scala213source3
maxColumn = 120
continuationIndent.defnSite = 2
assumeStandardLibraryStripMargin = true
rewrite.rules = [SortImports, RedundantBraces, RedundantParens, SortModifiers]
rewrite.redundantBraces.ifElseExpressions = false
rewrite.redundantBraces.generalExpressions = false
align = none
align.openParenDefnSite = false
align.openParenCallSite = false
align.tokens = []
optIn = {
  configStyleArguments = false
}
danglingParentheses.preset = false
danglingParentheses.callSite = true
rewrite.trailingCommas.style = keep
rewrite.trailingCommas.allowFolding = false
newlines.implicitParamListModifierForce = [after]
newlines.source=keep

配置调整建议 #

在现有配置基础上，添加或修改以下参数：

• 修改 rewrite.trailingCommas.allowFolding = true：允许在不超出列宽时折叠参数行
• 添加 callSite.multilineArgumentStyle = fold：核心控制参数，让scalafmt优先将参数放在同一行，仅超出列宽时换行
• 添加 callSite.newlineAfterOpenParen = always：保持左括号后换行的格式结构
• 添加 callSite.indentOperator = 2：统一调用点的缩进规则

调整后的完整配置：

version = 3.7.3
docstrings.style = Asterisk
runner.dialect = scala213source3
maxColumn = 120
continuationIndent.defnSite = 2
assumeStandardLibraryStripMargin = true
rewrite.rules = [SortImports, RedundantBraces, RedundantParens, SortModifiers]
rewrite.redundantBraces.ifElseExpressions = false
rewrite.redundantBraces.generalExpressions = false
align = none
align.openParenDefnSite = false
align.openParenCallSite = false
align.tokens = []
optIn = {
  configStyleArguments = false
}
danglingParentheses.preset = false
danglingParentheses.callSite = true
rewrite.trailingCommas.style = keep
rewrite.trailingCommas.allowFolding = true
newlines.implicitParamListModifierForce = [after]
newlines.source=keep
callSite.multilineArgumentStyle = fold
callSite.newlineAfterOpenParen = always
callSite.indentOperator = 2

关键参数说明 #

• callSite.multilineArgumentStyle = fold：这是实现需求的核心，fold 模式会尽可能将参数合并到同一行，只有当总长度超过 maxColumn 限制时才会自动换行
• rewrite.trailingCommas.allowFolding = true：配合折叠模式，允许保留尾随逗号并正常折叠参数行
• callSite.newlineAfterOpenParen = always：确保方法调用的左括号后始终换行，和你手动设置的格式结构一致

内容的提问来源于stack exchange，提问作者Wojciech