`make format` output fails scalastyle IfBraceChecker (scalafmt wraps long brace-less if/else without adding braces)

[comphead]

Describe the bug

make format does not produce code that passes the repo's own scalastyle check, and can itself introduce the violation.

make format runs scalafix:scalafix and spotless:apply (scalafmt). scalafmt (scalafmt.conf: maxColumn = 98, rewrite.rules = [Imports]) wraps a long brace-less if/else so that a branch spans multiple lines, but it never inserts braces — scalafmt has no brace-adding rewrite (RedundantBraces only removes them), and none of the configured scalafix rules (ExplicitResultTypes, NoAutoTupling, RemoveUnused, DisableSyntax, LeakingImplicitClassVal, NoValInForComprehension, ProcedureSyntax, RedundantSyntax) add them.

scalastyle's IfBraceChecker (dev/scalastyle-config.xml, singleLineAllowed=true, doubleLineAllowed=true) then fails the build with If block needs braces, because a brace-less branch that spans multiple lines is neither single- nor double-line. Since make format does not run scalastyle, it reports success while leaving code that the build/CI rejects, and re-running make format cannot fix it — it re-produces the same wrapped, brace-less form.

Steps to reproduce

1. Write a brace-less if/else whose branch is a single expression longer than maxColumn (98) in a .scala file, e.g.:

   def sourceId(field: Any, mirror: SomeReflection): Option[Int] =
     if (dropped) None
     else Some(mirror.getMethod(field.getClass, "sourceId").invoke(field).asInstanceOf[Int])

2. Run make format. scalafmt wraps the else across lines without adding braces:

     if (dropped) None
     else
       Some(
         mirror.getMethod(field.getClass, "sourceId")
           .invoke(field)
           .asInstanceOf[Int])

3. Build (e.g. ./mvnw test-compile -DskipTests). scalastyle fails:

   error file=.../MyFile.scala message=If block needs braces line=... column=...
   

4. Re-run make format — no change; the violation persists.

Expected behavior

make format should produce code that passes the repository's own scalastyle checks. Formatting (make format) and linting (scalastyle in the build) should not disagree in a way that has no automated resolution.

Additional context

There is currently no automated fixer for this in the toolchain: scalafmt (pinned 3.6.1) cannot insert braces into control structures, and the enabled scalafix rules do not add them. Possible resolutions:

• Drop IfBraceChecker from dev/scalastyle-config.xml. scalafmt is the canonical formatter and owns brace/wrapping decisions, so this check overlaps with it and cannot be auto-satisfied for a long brace-less branch.
• Or, if enforcing braces is intended, document that a long if/else must be hand-braced (or its long branch hoisted into a val so the branch stays single-line), since make format will not do it.

Encountered when a long else Some(...) branch in spark/src/main/scala/org/apache/comet/iceberg/IcebergReflection.scala was wrapped by scalafmt and then rejected by scalastyle's IfBraceChecker.

[AshishGhodvinde]

Hey!
I’d like to work on this issue. I’ll first check the current formatting and scalastyle configuration, identify the conflict, and make the necessary configuration/workflow change so make format and the repo’s checks stay consistent. I’ll also test the provided case to verify the fix.

Could you please assign it to me?

[andygrove]

Hey! I’d like to work on this issue. I’ll first check the current formatting and scalastyle configuration, identify the conflict, and make the necessary configuration/workflow change so make format and the repo’s checks stay consistent. I’ll also test the provided case to verify the fix.

Could you please assign it to me?

Thanks @AshishGhodvinde. You can just post a "take" comment on the issue to assign it to yourself

[AshishGhodvinde]

take

[comphead]

This is a CI failing example https://github.com/apache/datafusion-comet/actions/runs/33976116150/job/101333390679