Jetpack Compose false positive for function name capitalization

SonarQube Cloud
1

We’re seeing false positives for Jetpack Compose function names that are annotated with Composable, in which the convention is to capitalize the first letter of the Kotlin function:

@Composable
fun SampleScreen() { ... }

The false positive is:
Rename function "SampleScreen" to match the regular expression ^[a-z][a-zA-Z0-9]*$

This contradicts the style guide for Compose here:

which states:
“Jetpack Compose framework development and Library development MUST name any function that returns Unit and bears the @Composable annotation using PascalCase, and the name MUST be that of a noun, not a verb or verb phrase, nor a nouned preposition, adjective or adverb. Nouns MAY be prefixed by descriptive adjectives. This guideline applies whether the function emits UI elements or not. App development SHOULD follow this same convention.”

4

Hello @kurteous, welcome to the Sonar Community, and thanks for bringing to light this special case to cover in rule S100.

The issue [SONARKT-374] - Jira has been created.

Cheers,
Angelo

8

Hello @kurteous,

I looked at this ticket, and I think the convention you mention applies to any factory function, not just the @Composable functions. See code convention.

I remember we’ve already discussed this point in the team long time ago, and we changed the default to allow PaskalCase. See here: sonar-kotlin/sonar-kotlin-checks/src/main/java/org/sonarsource/kotlin/checks/BadFunctionNameCheck.kt at ec549544a971fbfdee90b0deb366a678265851ac · SonarSource/sonar-kotlin · GitHub

I could think of 2 reasons why you still reference an old regex:

  • You use a pretty old version of SQ (<9.9) which has a very old Kotlin analyzer and doesn’t contain this change
  • You copied a SonarWay quality profile a long time ago before the default parameter was changed, and you never updated it.

As for the resolution, I think I can close the ticket, as the default already works the way code convention requires and according to Compose spec; from your side, since the rule is configurable, just change the parameter to the regex you want. Probably "^[a-zA-Z][a-zA-Z0-9]*$" should work.

Best,
Margarita