clang-tidy with --export-fixes doesn't apply formatting (but it works with --fix)

[sean-mcmanus]

I'm using clang-tidy 14.0.3 (on Windows 11, I could try Linux/Mac if you want, but I assume it doesn't matter).

Use test.cpp

int main()
{
    if (true)
        return 0;
}

with some .clang-format file in the folder like

BasedOnStyle: LLVM
UseTab: Never
IndentWidth: 4
TabWidth: 4
BreakBeforeBraces: Allman
AllowShortIfStatementsOnASingleLine: false
IndentCaseLabels: false
ColumnLimit: 0
AccessModifierOffset: -4
NamespaceIndentation: All
FixNamespaceComments: false
SeparateDefinitionBlocks: Always

and run clang-tidy.exe --config="{Checks: 'readability-braces-around-statements', FormatStyle: file}" --export-fixes=<path>/out.yaml <path>/test.cpp --

Bug: The out.yaml is

---
MainSourceFile:  '<path>/test.cpp'
Diagnostics:
  - DiagnosticName:  readability-braces-around-statements
    DiagnosticMessage:
      Message:         statement should be inside braces
      FilePath:        '<path>/test.cpp'
      FileOffset:      30
      Replacements:
        - FilePath:        '<path>/test.cpp'
          Offset:          30
          Length:          0
          ReplacementText: ' {'
        - FilePath:        '<path>/test.cpp'
          Offset:          49
          Length:          0
          ReplacementText: "\n}"
    Level:           Warning
    BuildDirectory:  '<path>'
...

which doesn't have the formatting applied -- in particular, the } has no indentation.

The bug doesn't repro when --export-fixes isn't used: clang-tidy.exe --config="{Checks: 'readability-braces-around-statements', FormatStyle: file}" --fix <path>/test.cpp -- gives the expected result:

int main()
{
    if (true)
    {
        return 0;
    }
}

It also repros with clang-tidy.exe --config="{Checks: 'modernize-concat-nested-namespaces', FormatStyle: file}" --export-fixes=<path>/out.yaml <path>/test.cpp -- -std=c++17.

with test.cpp

namespace foo1
{
    namespace foo2
    {
        int i;
    }
}

so it seems like it may repro with all checks.

I'm guessing we could work around the issue via running clang-format on the edited lines afterwards.

[llvmbot]

@llvm/issue-subscribers-clang-tidy

[njames93]

The --export-fixes option isn't meant to format any changes.
The idea is the formatting is done after all the fixes have been applied, using clang-apply-replacements.

[sean-mcmanus]

Ok.