How to specify the format call of clangd in VSC?

[juxeii]

I would like to use the formatter of the clangd extension in VSC.
On default it formats the file, but not the way I want.
Is there a way to specify the entire command, like:
clang-format-9 -style=file -i ${file}

How can I do that?

[i-ky]

No, there is no way to specify clang-format command, because clangd does not use clang-format binary, it uses a formatting library instead. However, clangd should respect style options if you put them in .clang-format file in one of the ancestor directories of the file you want to format.

[juxeii]

Thx for the info. But it seems the .clang-format file is ignored. I created one in the project root, but whatever I change it does not make any difference. Is there a way for a more verbose output to see which configuration setting are active?

[HighCommander4]

Please see https://clangd.llvm.org/troubleshooting#gathering-logs fow hoe to collect verbose logs.

It would also help to provide a piece of example code, and indicate the actual vs. expected formatting.

[juxeii]

I have to correct me. The .clang-format file is indeed applied if clangd formats files.
But if I call clang-format-9 directly, it gives a different formatting.

One result snippet of clang-format-9 -style=file somefile.cpp is

return types::CellDynamicParams{std::optional<types::nr_rrc::MeasurementTimingConfiguration>{mtc},
                                    std::nullopt,
                                    std::nullopt,
                                    std::nullopt,
                                    servedPlmnList,
                                    std::nullopt};

Whereas clangd does

return types::CellDynamicParams{
        std::optional<types::nr_rrc::MeasurementTimingConfiguration>{mtc},
        std::nullopt,
        std::nullopt,
        std::nullopt,
        servedPlmnList,
        std::nullopt};

The .clang-format file is

---
BreakBeforeBraces: Allman
ColumnLimit: 120
IndentWidth: 4
TabWidth: 4
UseTab: Never
---
Language: Cpp
AccessModifierOffset: -4
AlignAfterOpenBracket: AlwaysBreak
AlignConsecutiveAssignments: false
AlignConsecutiveDeclarations: false
AlignOperands: false
AlignTrailingComments: false
AlignEscapedNewlinesLeft: true
AllowAllParametersOfDeclarationOnNextLine: false
AllowShortBlocksOnASingleLine: false
AllowShortCaseLabelsOnASingleLine: false
AllowShortIfStatementsOnASingleLine: true
AllowShortLoopsOnASingleLine: false
AllowShortFunctionsOnASingleLine: Inline
AlwaysBreakAfterDefinitionReturnType: None
AlwaysBreakBeforeMultilineStrings: false
AlwaysBreakTemplateDeclarations: true
BinPackArguments: false
BinPackParameters: false
BreakBeforeBinaryOperators: None
BreakBeforeTernaryOperators: true
BreakConstructorInitializersBeforeComma: true
BreakStringLiterals: true
ConstructorInitializerAllOnOneLineOrOnePerLine: true
ConstructorInitializerIndentWidth: 4
ContinuationIndentWidth: 4
Cpp11BracedListStyle: true
DisableFormat: false
FixNamespaceComments: true
IncludeCategories:
  - Regex:           '^<sys/'
    Priority:        1
  - Regex:           '^<'
    Priority:        2
  - Regex:           '^"'
    Priority:        3
IndentCaseLabels: true
KeepEmptyLinesAtTheStartOfBlocks: false
MaxEmptyLinesToKeep: 1
BraceWrapping:
   AfterNamespace: false
   AfterUnion: true
NamespaceIndentation: None
PenaltyReturnTypeOnItsOwnLine: 5000
PointerAlignment: Left
SortIncludes: true
SpaceBeforeAssignmentOperators: true
SpaceBeforeParens: ControlStatements
SpaceInEmptyParentheses: false
Standard: Cpp11
---
Language: Proto
AlwaysBreakAfterReturnType: All
AllowShortFunctionsOnASingleLine: false

What could be the reasons, that clang-format-9 behaves differently?
The enitre project has only this .clang-format file.

I then also copied the above style file into several ancestor paths and even into the src folder, but clang-format-9 keeps on doing its own thing applies something different.

[HighCommander4]

What could be the reasons, that clang-format-9 behaves differently?

Version difference? Presumably your clangd version is newer than 9.

Try clang-format-N where N matches the clangd version, and see if you get the same results as with clangd.

[juxeii]

Now it gets even more chaotic. When I do clang-format-9 --dump-config, we have

---
Language:        Cpp
AccessModifierOffset: -4
AlignAfterOpenBracket: AlwaysBreak
AlignConsecutiveMacros: false
AlignConsecutiveAssignments: false
AlignConsecutiveDeclarations: false
AlignEscapedNewlines: Left
AlignOperands:   false
AlignTrailingComments: false
AllowAllArgumentsOnNextLine: true
AllowAllConstructorInitializersOnNextLine: true
AllowAllParametersOfDeclarationOnNextLine: false
AllowShortBlocksOnASingleLine: false
AllowShortCaseLabelsOnASingleLine: false
AllowShortFunctionsOnASingleLine: Inline
AllowShortLambdasOnASingleLine: All
AllowShortIfStatementsOnASingleLine: WithoutElse
AllowShortLoopsOnASingleLine: false
AlwaysBreakAfterDefinitionReturnType: None
AlwaysBreakAfterReturnType: None
AlwaysBreakBeforeMultilineStrings: false
AlwaysBreakTemplateDeclarations: Yes
BinPackArguments: false
BinPackParameters: false
BraceWrapping:
  AfterCaseLabel:  true
  AfterClass:      true
  AfterControlStatement: true
  AfterEnum:       true
  AfterFunction:   true
  AfterNamespace:  true
  AfterObjCDeclaration: true
  AfterStruct:     true
  AfterUnion:      false
  AfterExternBlock: true
  BeforeCatch:     true
  BeforeElse:      true
  IndentBraces:    false
  SplitEmptyFunction: true
  SplitEmptyRecord: true
  SplitEmptyNamespace: true
BreakBeforeBinaryOperators: None
BreakBeforeBraces: Allman
BreakBeforeInheritanceComma: false
BreakInheritanceList: BeforeColon
BreakBeforeTernaryOperators: true
BreakConstructorInitializersBeforeComma: false
BreakConstructorInitializers: BeforeComma
BreakAfterJavaFieldAnnotations: false
BreakStringLiterals: true
ColumnLimit:     120
CommentPragmas:  '^ IWYU pragma:'
CompactNamespaces: false
ConstructorInitializerAllOnOneLineOrOnePerLine: true
ConstructorInitializerIndentWidth: 4
ContinuationIndentWidth: 4
Cpp11BracedListStyle: true
DerivePointerAlignment: false
DisableFormat:   false
ExperimentalAutoDetectBinPacking: false
FixNamespaceComments: true
ForEachMacros:
  - foreach
  - Q_FOREACH
  - BOOST_FOREACH
IncludeBlocks:   Preserve
IncludeCategories:
  - Regex:           '^<sys/'
    Priority:        1
  - Regex:           '^<'
    Priority:        2
  - Regex:           '^"'
    Priority:        3
IncludeIsMainRegex: '(Test)?$'
IndentCaseLabels: true
IndentPPDirectives: None
IndentWidth:     4
IndentWrappedFunctionNames: false
JavaScriptQuotes: Leave
JavaScriptWrapImports: true
KeepEmptyLinesAtTheStartOfBlocks: false
MacroBlockBegin: ''
MacroBlockEnd:   ''
MaxEmptyLinesToKeep: 1
NamespaceIndentation: None
ObjCBinPackProtocolList: Auto
ObjCBlockIndentWidth: 2
ObjCSpaceAfterProperty: false
ObjCSpaceBeforeProtocolList: true
PenaltyBreakAssignment: 2
PenaltyBreakBeforeFirstCallParameter: 19
PenaltyBreakComment: 300
PenaltyBreakFirstLessLess: 120
PenaltyBreakString: 1000
PenaltyBreakTemplateDeclaration: 10
PenaltyExcessCharacter: 1000000
PenaltyReturnTypeOnItsOwnLine: 5000
PointerAlignment: Left
ReflowComments:  true
SortIncludes:    true
SortUsingDeclarations: true
SpaceAfterCStyleCast: false
SpaceAfterLogicalNot: false
SpaceAfterTemplateKeyword: true
SpaceBeforeAssignmentOperators: true
SpaceBeforeCpp11BracedList: false
SpaceBeforeCtorInitializerColon: true
SpaceBeforeInheritanceColon: true
SpaceBeforeParens: ControlStatements
SpaceBeforeRangeBasedForLoopColon: true
SpaceInEmptyParentheses: false
SpacesBeforeTrailingComments: 1
SpacesInAngles:  false
SpacesInContainerLiterals: true
SpacesInCStyleCastParentheses: false
SpacesInParentheses: false
SpacesInSquareBrackets: false
Standard:        Cpp11
StatementMacros:
  - Q_UNUSED
  - QT_REQUIRE_VERSION
TabWidth:        4
UseTab:          Never
...

I copied this dump to the project .clang-format, but the different indentation is still applied. Where does this indentation problem come from when even the dump-config does it as clangd?
And sorry, we can only use this clang-format-9 binary, since it comes from our SDK.

[HighCommander4]

There could be differences between clang-format-X and clang-format-Y not just in the values of the default settings, but in their behaviour (e.g. a bug could have been fixed in version Y that makes the indentation behaviour different even with the same setting value).

And sorry, we can only use this clang-format-9 binary, since it comes from our SDK.

Then you might want to consider using a dedicated VSCode clang-format plugin which calls this binary, such as https://marketplace.visualstudio.com/items?itemName=xaver.clang-format. You can use the "editor.defaultFormatter" setting to get VSCode to use this plugin for formatting rather than clangd.

[juxeii]

Thank you so much!
This finally solves the issue in many dimensions.
The original reason for all this trouble was that I tried many other extensions where one could specify the entire call to format.
But none of them intergrated nicely with VSC. The main issue is that either the "format" event has not been sent to VSC, or the file has been formatted after is has been saved(and then again saved).
This caused confusion on other extensions.

But finally, your suggestions integrates as it should be :)