如何配置Clang-Format使if-else if-else代码块单行显示？

期望保留的代码格式 #

if (type.empty()) { os << "!EMPTY"; }
    else if (type->as_qubit()) { os << types::qubit_type_name; }
    else { os << *type; }

Clang-Format当前格式化结果 #

if (type.empty()) {
        os << "!EMPTY";
    } else if (type->as_qubit()) {
        os << types::qubit_type_name;
    } else {        
        os << *type;
    }

当前.clang-format配置 #

---
BasedOnStyle: Google
Language: Cpp
AlignAfterOpenBracket: DontAlign
AlignTrailingComments: true
AllowAllArgumentsOnNextLine: true
AllowAllParametersOfDeclarationOnNextLine: true
AllowShortEnumsOnASingleLine: true
AllowShortBlocksOnASingleLine: Always
AllowShortCaseLabelsOnASingleLine: true
AllowShortIfStatementsOnASingleLine: AllIfsAndElse
AllowShortFunctionsOnASingleLine: All
AllowShortLambdasOnASingleLine: All
AllowShortLoopsOnASingleLine: true
BreakBeforeBraces: Attach
BreakConstructorInitializers: BeforeComma
ColumnLimit: 120
ConstructorInitializerIndentWidth: 0
Cpp11BracedListStyle: false
DerivePointerAlignment: false
IndentWidth: 4
PointerAlignment: Right
ReflowComments: false
---

解决方案 #

可以通过调整配置实现目标效果，核心是确保关键选项设置，并补充括号包裹规则：

1. 保留现有配置中已正确设置的两个选项：

   • AllowShortIfStatementsOnASingleLine: AllIfsAndElse：允许if、else if、else语句与代码块在同一行
   • AllowShortBlocksOnASingleLine: Always：允许所有短代码块与括号在同一行

2. 调整BreakBeforeBraces为Custom，并添加BraceWrapping配置，确保if/else的括号不强制换行，同时保留Google风格对其他结构的处理：

修改后的完整配置如下：

---
BasedOnStyle: Google
Language: Cpp
AlignAfterOpenBracket: DontAlign
AlignTrailingComments: true
AllowAllArgumentsOnNextLine: true
AllowAllParametersOfDeclarationOnNextLine: true
AllowShortEnumsOnASingleLine: true
AllowShortBlocksOnASingleLine: Always
AllowShortCaseLabelsOnASingleLine: true
AllowShortIfStatementsOnASingleLine: AllIfsAndElse
AllowShortFunctionsOnASingleLine: All
AllowShortLambdasOnASingleLine: All
AllowShortLoopsOnASingleLine: true
BreakBeforeBraces: Custom
BraceWrapping:
  AfterIf: false
  AfterElse: false
  AfterFunction: Attach
  AfterClass: Attach
  AfterNamespace: Attach
  AfterEnum: Attach
  AfterStruct: Attach
  AfterUnion: Attach
  AfterExternBlock: Attach
  BeforeCatch: true
  BeforeElse: true
  IndentBraces: false
BreakConstructorInitializers: BeforeComma
ColumnLimit: 120
ConstructorInitializerIndentWidth: 0
Cpp11BracedListStyle: false
DerivePointerAlignment: false
IndentWidth: 4
PointerAlignment: Right
ReflowComments: false
---

这样配置后，只要代码块内容长度不超过ColumnLimit（你设置的120），Clang-Format 14就会将if、else if、else与其对应的代码块保持在同一行，同时其他结构（如函数、类）仍遵循Google风格的括号附着规则。

内容的提问来源于stack exchange，提问作者rturrado