Kotlin Linting RuleSetProvider 'trailing-comma' - kotlin

Question

I been trying to create a Ruleset using Pinterest ktlint Library but I can't remove the part of a children parameter list.
https://github.com/pinterest/ktlint/issues/709
Due to the update on Kotlin to support 'trailing-commas', is breaking all my static code analysis (SonarQube Gradle plugin 2.8). So I decided to create a RuleSetProvider to find a remove from the code this annoying comma ',' at the end of all the parameter list found in the project.
class NoTrailingCommaRule : Rule("no-trailing-comma") {
override fun visit(
node: ASTNode,
autoCorrect: Boolean,
emit: (offset: Int, errorMessage: String, canBeAutoCorrected: Boolean) -> Unit
) {
if (node.elementType == ElementType.COMMA) {
node.parents().forEach {
if (it.elementType == ElementType.VALUE_PARAMETER_LIST) {
if (it.text.contains("pepe")) {
println("############# IS PEPE ###############")
println("ParamList-> " + it.text)
println("-------------------------------------")
if (it is PsiParameterList) {
it.parameters.forEach { param ->
println(" -> ${param.text}")
// if (next.elementType == ElementType.COMMA)
// println(" -> comma,")
println("---==---")
}
println("#####################################")
}
}
}
}
}
}
}
/// Sample class to lint
data class PEPE(
val pepe: String,
var pepe1: List<String> = emptyList(), //<- This is the kind of comma I want to remove
)
Thats my current attempt of trying to get the comma and replace, but when I'm able to print the parameter line the comma is not there. 😿

Answer 1

See rule below for which I have sent a PR:
package com.pinterest.ktlint.ruleset.experimental
import com.pinterest.ktlint.core.Rule
import com.pinterest.ktlint.core.ast.ElementType
import com.pinterest.ktlint.core.ast.children
import org.jetbrains.kotlin.com.intellij.lang.ASTNode
import org.jetbrains.kotlin.psi.psiUtil.endOffset
class NoTrailingCommaRule : Rule("no-trailing-comma") {
override fun visit(
node: ASTNode,
autoCorrect: Boolean,
emit: (offset: Int, errorMessage: String, canBeAutoCorrected: Boolean) -> Unit
) {
if (node.elementType == ElementType.VALUE_ARGUMENT_LIST || node.elementType == ElementType.VALUE_PARAMETER_LIST) {
val lastNode = node
.children()
.filter { it.elementType != ElementType.WHITE_SPACE }
.filter { it.elementType != ElementType.EOL_COMMENT }
.filter { it.elementType != ElementType.RPAR }
.last()
if (lastNode.elementType == ElementType.COMMA) {
emit(lastNode.psi.endOffset - 1, "Trailing command in argument list is redundant", true)
if (autoCorrect) {
node.removeChild(lastNode)
}
}
}
}
}
and the tests:
package com.pinterest.ktlint.ruleset.experimental
import com.pinterest.ktlint.core.LintError
import com.pinterest.ktlint.test.format
import com.pinterest.ktlint.test.lint
import org.assertj.core.api.Assertions.assertThat
import org.junit.Test
class NoTrailingCommaRuleTest {
#Test
fun testFormatIsCorrectWithArgumentList() {
val code =
"""
val list1 = listOf("a", "b",)
val list2 = listOf(
"a",
"b", // The comma before the comment should be removed without removing the comment itself
)
""".trimIndent()
val autoCorrectedCode =
"""
val list1 = listOf("a", "b")
val list2 = listOf(
"a",
"b" // The comma before the comment should be removed without removing the comment itself
)
""".trimIndent()
assertThat(NoTrailingCommaRule().lint(code)).isEqualTo(
listOf(
LintError(line = 1, col = 28, ruleId = "no-trailing-comma", detail = "Trailing command in argument list is redundant"),
LintError(line = 4, col = 8, ruleId = "no-trailing-comma", detail = "Trailing command in argument list is redundant"),
)
)
assertThat(NoTrailingCommaRule().format(code))
.isEqualTo(autoCorrectedCode)
}
#Test
fun testFormatIsCorrectWithValueList() {
val code =
"""
data class Foo1(
val bar: Int, // The comma before the comment should be removed without removing the comment itself
)
data class Foo2(val bar: Int,)
""".trimIndent()
val autoCorrectedCode =
"""
data class Foo1(
val bar: Int // The comma before the comment should be removed without removing the comment itself
)
data class Foo2(val bar: Int)
""".trimIndent()
assertThat(NoTrailingCommaRule().lint(code)).isEqualTo(
listOf(
LintError(line = 2, col = 16, ruleId = "no-trailing-comma", detail = "Trailing command in argument list is redundant"),
LintError(line = 4, col = 29, ruleId = "no-trailing-comma", detail = "Trailing command in argument list is redundant"),
)
)
assertThat(NoTrailingCommaRule().format(code))
.isEqualTo(autoCorrectedCode)
}
}