What is the best approach to extract a kotlin multiline string with trimIndent as a string expression

IntelliJ Platform
1

I’m trying to grab the content of multiline string that use trim functions as a simple KtExpression (with properly indented / trimmed string). As far as I got, there’s no easy way even with UAST.

The best I could use is reusing the ToOrdinaryStringLiteralIntention code just to extract the expression. However this has some issues with the latest 2025.1 because K2 is changing things.

E.g. in tests I have

KotlinCacheService should not be used for the K2 mode. See https://kotl.in/analysis-api/ for the migration.
java.lang.IllegalStateException: KotlinCacheService should not be used for the K2 mode. See https://kotl.in/analysis-api/ for the migration.
	at org.jetbrains.kotlin.caches.resolve.KotlinCacheService$Companion.getInstance(KotlinCacheService.kt:24)
	at org.jetbrains.kotlin.idea.caches.resolve.ResolutionUtils.getResolutionFacade(ResolutionUtils.kt:31)
	at org.jetbrains.kotlin.idea.caches.resolve.ExtendedResolutionApiKt.safeAnalyzeNonSourceRootCode(ExtendedResolutionApi.kt:158)
	at org.jetbrains.kotlin.idea.inspections.collections.FunctionUtilsKt.isCalling(FunctionUtils.kt:81)
	at org.jetbrains.kotlin.idea.inspections.collections.FunctionUtilsKt.isCalling$default(FunctionUtils.kt:77)
	at xxx.ToOrdinaryStringLiteral.getTrimIndentCall(KotlinQuirks.kt:112)
	at xxx.ToOrdinaryStringLiteral.applyTo(KotlinQuirks.kt:78)
	at xxx.ToOrdinaryStringLiteral.convertToOrdinaryStringLiteral(KotlinQuirks.kt:73)

Most the code is the same as here : intellij-community/plugins/kotlin/idea/src/org/jetbrains/kotlin/idea/intentions/ToOrdinaryStringLiteralIntention.kt at 468d9bd86c6065a31d78bfbcc9bc08c0af80d07c · JetBrains/intellij-community · GitHub

Thanks in advance for any hints.

2

Right now I have replaced isCalling by this check which seems better

        val qualifiedExpression = element.getQualifiedExpressionForReceiver()?.takeIf {
            // Original IJP code calls: it.callExpression?.isCalling(TRIM_INDENT_FUNCTIONS) == true
            it.callExpression?.toUElementOfType<UCallExpression>()?.let { uce ->
                kotlinTrimMethods.uCallMatches(uce)
            } == true
        } ?: return null

    private val kotlinTrimMethods: CallMatcher =
        CallMatcher.anyOf(
            CallMatcher.staticCall("kotlin.text.StringsKt__IndentKt", "trimIndent", "trimMargin"),
            CallMatcher.staticCall("kotlin.text.StringsKt", "trimIndent", "trimMargin")
        )
3

Our UInjectionHost.getStringRoomExpression() might help a bit.

You can also UExpression.accept and walk children by a visitor.

// to get UInjectionHost from string literal
UastContextKt.toUElement(psi, UInjectionHost.class)
4

getStringRoomExpression() is interesting, but my issue really is how to get the “rendered string” not how it appears in the source code.

With Java multi-line strings are correctly with this simplified code (expression as ULiteralExpression).evaluateString(), e.g.

        method("""
            This is text
            spanning multiple lines
        """);

yields " This is text\n spanning multiple lines\n".

But Kotlin makes it more tricky because the language don’t understand that indents are eliminated, instead it relies on trimMargin / trimIndent methods to indent the string properly. And when traversing the Psi tree with UAST this makes it more difficult to get the string as a simple binary expression with indents removed.

E.g. the indents are not removed

image
image1900×288 50.6 KB

That’s why I was using ToOrdinaryStringLiteralIntention code in the first place, but having this as UAST utility (and kotlin utility too) makes sense in my opinion.