[Bug]: Language Server shuts down when using a Ballerina project with large files

[Nuvindu]

Description

When working with a Ballerina project that includes large files, particularly generated from an OpenAPI specification, the Ballerina Language Server unexpectedly shuts down, resulting in a "Stopping server timed out" error. This issue appears to be triggered when attempting to work with the generated Ballerina files.

Output log:

[Error - 16:53:27] Stopping server failed
Error: Stopping the server timed out
    at /Users/nuvindu/.vscode/extensions/wso2.ballerina-4.5.6/dist/extension.js:2:997853

Steps to Reproduce

1. Download the OpenAPI spec from here.
2. Create a new Ballerina project.
3. Run the bal openapi -i esignature.rest.swagger-v2.1.json --mode client --client-methods resource command to generate client.bal, types.bal, and utils.bal files.
4. Use the generated Ballerina project in the VS Code environment.

[nipunayf]

The error is due to an out-of-memory issue occurring during the project build. The following error message is generated when we execute the bal build command.

[2023-12-13 13:22:19,567] SEVERE {b7a.log.crash} - Java heap space 
java.lang.OutOfMemoryError: Java heap space
        at java.base/java.util.Arrays.copyOf(Arrays.java:3537)
        at java.base/java.lang.AbstractStringBuilder.ensureCapacityInternal(AbstractStringBuilder.java:241)
        at java.base/java.lang.AbstractStringBuilder.append(AbstractStringBuilder.java:685)
        at java.base/java.lang.StringBuffer.append(StringBuffer.java:393)
        at java.base/java.io.StringWriter.write(StringWriter.java:122)
        at com.google.gson.stream.JsonWriter.string(JsonWriter.java:642)
        at com.google.gson.stream.JsonWriter.writeDeferredName(JsonWriter.java:402)
        at com.google.gson.stream.JsonWriter.value(JsonWriter.java:417)
        at com.google.gson.internal.bind.TypeAdapters$28.write(TypeAdapters.java:832)
        at com.google.gson.internal.bind.TypeAdapters$28.write(TypeAdapters.java:846)
        at com.google.gson.internal.bind.TypeAdapters$28.write(TypeAdapters.java:838)
        at com.google.gson.internal.bind.TypeAdapters$28.write(TypeAdapters.java:846)
        at com.google.gson.internal.bind.TypeAdapters$28.write(TypeAdapters.java:838)
        at com.google.gson.internal.bind.TypeAdapters$28.write(TypeAdapters.java:846)
        at com.google.gson.internal.bind.TypeAdapters$28.write(TypeAdapters.java:838)
        at com.google.gson.internal.bind.TypeAdapters$28.write(TypeAdapters.java:846)
        at com.google.gson.internal.bind.TypeAdapters$28.write(TypeAdapters.java:846)
        at com.google.gson.internal.bind.TypeAdapters$28.write(TypeAdapters.java:846)
        at com.google.gson.internal.bind.TypeAdapters$28.write(TypeAdapters.java:838)
        at com.google.gson.internal.bind.TypeAdapters$28.write(TypeAdapters.java:846)
        at com.google.gson.internal.bind.TypeAdapters$28.write(TypeAdapters.java:846)
        at com.google.gson.internal.bind.TypeAdapters$28.write(TypeAdapters.java:838)
        at com.google.gson.internal.bind.TypeAdapters$28.write(TypeAdapters.java:846)
        at com.google.gson.internal.bind.TypeAdapters$28.write(TypeAdapters.java:725)
        at com.google.gson.internal.Streams.write(Streams.java:73)
        at com.google.gson.JsonElement.toString(JsonElement.java:323)
        at org.ballerinalang.observability.anaylze.DefaultObservabilitySymbolCollector.generateSyntaxTreeJsonString(DefaultObservabilitySymbolCollector.java:208)
        at org.ballerinalang.observability.anaylze.DefaultObservabilitySymbolCollector.process(DefaultObservabilitySymbolCollector.java:92)
        at io.ballerina.projects.JBallerinaBackend.<init>(JBallerinaBackend.java:140)
        at io.ballerina.projects.JBallerinaBackend.lambda$from$0(JBallerinaBackend.java:121)
        at io.ballerina.projects.JBallerinaBackend$$Lambda$523/0x0000000301363148.apply(Unknown Source)
        at java.base/java.util.HashMap.computeIfAbsent(HashMap.java:1228)

As a temporary measure, you can increase the max heap size allocated to the Ballerina Java process.

[NipunaMadhushan]

This is related to issue #41725. This has been fixed with 2201.8.3 version along with PR #41569

[nipunayf]

I am using 2201.8.4, and still, the issue exists. However, we can build the project by disabling observabilityIncluded in the Ballerina.toml as a temporary measure.

[KavinduZoysa]

The issue happens at this point.

https://github.com/ballerina-platform/ballerina-lang/blob/master/misc/observability-symbol-collector/src/main/java/org/ballerinalang/observability/anaylze/DefaultObservabilitySymbolCollector.java#L208

According to this example, at this point, the syntax tree JSON element of types.bal is converted to a string using toString(). types.bal file containing 37403 lines.

Also, at this point, we can see a spike in memory usage in visualVM.

Peek.2023-12-15.15-06.mp4

[NipunaMadhushan]

Seems like the above fix (#41569) I mentioned, is still not enough for this use case.

[KavinduZoysa]

One thing we can do here is to split large files into separate files. In this case, we have to do that from the open API side.

Another one is,
Here we use StringBuilder to get the JSON format of the syntax tree to write to a file. We can keep the JsonElement as it is and write element by element into the file(We may need a separate method for that). Still, there is a possibility for OOM because JsonElement is exponentially large.

@NipunaMadhushan, @lnash94, @Nuvindu

[Nuvindu]

@KavinduZoysa I have manually split the types.bal file into separate files. It fixes the lang server shutting down issue but still the same out of memory issue will occur when building the ballerina project.
P.S. Currently building the project by setting the observabilityIncluded to false in the Ballerina.toml file

[KavinduZoysa]

@KavinduZoysa I have manually split the types.bal file into separate files. It fixes the lang server shutting down issue but still the same out of memory issue will occur when building the ballerina project.

Can you please attach your project?

[Nuvindu]

@KavinduZoysa You can download the project from here

[NipunaMadhushan]

There is an issue created to fix this #42001.

This has been fixed with #42002.

[github-actions]

This issue is NOT closed with a proper Reason/ label. Make sure to add proper reason label before closing. Please add or leave a comment with the proper reason label now.

      - Reason/EngineeringMistake - The issue occurred due to a mistake made in the past.
      - Reason/Regression - The issue has introduced a regression.
      - Reason/MultipleComponentInteraction - Issue occured due to interactions in multiple components.
      - Reason/Complex - Issue occurred due to complex scenario.
      - Reason/Invalid - Issue is invalid.
      - Reason/Other - None of the above cases.