Skip files the Kotlin analysis cannot handle, and always exit

[ofir-blaus]

Small fix on top of #963.

Problem: a .kt file with a top-level destructuring declaration (val (a, b) = Pair(1, 2)) crashes the indexer with No fir element was found for KtDestructuringDeclaration. The whole run is lost. Then the process hangs instead of exiting, because a non-daemon thread keeps the JVM alive. We hit this on a test fixture in a real repo. The code is invalid Kotlin, but it can still show up in a source tree.

Reproduction: two files.

// src/Broken.kt
package repro

fun before(): Int = 1

val (first, second) = Pair(1, 2)

fun after(): Int = before()

// src/Other.kt
package repro

fun other(): Int = after()

The command, run from the folder with src/:

java -cp <scip-kotlin-analysis classpath> org.scip_code.scip_java.kotlin_analysis.MainKt \
  --sourceroot $PWD --targetroot $PWD/out src

Before (kotlin-analysis-api @ a77e133): the indexer crashes, writes no output for either file, and never exits. It was still running after 25 seconds, and the thread dump shows a non-daemon ApplicationImpl pooled thread waiting forever:

Exception in thread "main" org.jetbrains.kotlin.utils.exceptions.KotlinIllegalArgumentExceptionWithAttachments: No fir element was found for KtDestructuringDeclaration
	...
	at org.jetbrains.kotlin.analysis.api.fir.components.KaFirExpressionTypeProvider.getExpressionType(KaFirExpressionTypeProvider.kt:69)
	at org.scip_code.scip_java.kotlin_analysis.KotlinAnalysisIndexer$IndexingVisitor.renderedExpressionType(KotlinAnalysisIndexer.kt:656)
	at org.scip_code.scip_java.kotlin_analysis.KotlinAnalysisIndexer$IndexingVisitor.visitDestructuringDeclaration(KotlinAnalysisIndexer.kt:588)
	...

$ jstack <pid>   # 25s later
"ApplicationImpl pooled thread 1" #34 prio=4 ... waiting on condition
   java.lang.Thread.State: WAITING (parking)
	at java.util.concurrent.SynchronousQueue.take(SynchronousQueue.java:318)

After (this PR): exit 0 in about 1 second, with output for both files:

out/META-INF/scip/src/Broken.kt.scip
out/META-INF/scip/src/Other.kt.scip

Fix:

• Skip a top-level destructuring declaration. The rest of the file is still indexed.
• If indexing a file throws, skip only that file and print one line to stderr.
• If the run fails, exit with status 1 so the process never hangs.

Tests:

• New test: the same two files. Both are indexed, and references between them are kept.
• :scip-kotlin-analysis:test passes, and spotlessCheck passes.
• :scip-snapshots:test: all Kotlin snapshots pass. Locally I see 17 Java snapshot failures, but the same 17 fail on kotlin-analysis-api without this change. My local JDK is 21, not 17.

🤖 Generated with Claude Code