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doc: neovim troubleshooting findings #659

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44 changes: 44 additions & 0 deletions TROUBLESHOOTING.md
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Expand Up @@ -7,3 +7,47 @@ The language server is currently a memory hog, mostly due to its use of an in-me
In [the VSCode extension](https://github.com/fwcd/vscode-kotlin), this is in the extension settings in the setting `Kotlin > Java: Opts`.

If you use Emacs, you can try the `setenv` function to set environment variables. Example: `(setenv "JAVA_OPTS" "-Xmx8g")`.

## Neovim / Mason LSP

In case you see the following in your `lsp.log`;

```
[ERROR][2025-09-28 09:46:29] ...lsp/handlers.lua:562 "java.util.concurrent.CompletionException: com.google.gson.JsonSyntaxException: java.lang.IllegalStateException: Expected BEGIN_OBJECT but was BEGIN_ARRAY at path $"
[ERROR][2025-09-28 09:46:29] ...lsp/handlers.lua:562 "\tat java.base/java.util.concurrent.CompletableFuture.encodeThrowable(CompletableFuture.java:315)"
[ERROR][2025-09-28 09:46:29] ...lsp/handlers.lua:562 "\tat java.base/java.util.concurrent.CompletableFuture.completeThrowable(CompletableFuture.java:320)"
[ERROR][2025-09-28 09:46:29] ...lsp/handlers.lua:562 "\tat java.base/java.util.concurrent.CompletableFuture$AsyncSupply.run(CompletableFuture.java:1770)"
[ERROR][2025-09-28 09:46:29] ...lsp/handlers.lua:562 "\tat java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1144)"
[ERROR][2025-09-28 09:46:29] ...lsp/handlers.lua:562 "\tat java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:642)"
[ERROR][2025-09-28 09:46:29] ...lsp/handlers.lua:562 "\tat java.base/java.lang.Thread.run(Thread.java:1583)"
[ERROR][2025-09-28 09:46:29] ...lsp/handlers.lua:562 "Caused by: com.google.gson.JsonSyntaxException: java.lang.IllegalStateException: Expected BEGIN_OBJECT but was BEGIN_ARRAY at path $"
[ERROR][2025-09-28 09:46:29] ...lsp/handlers.lua:562 "\tat com.google.gson.internal.bind.ReflectiveTypeAdapterFactory$Adapter.read(ReflectiveTypeAdapterFactory.java:397)"
[ERROR][2025-09-28 09:46:29] ...lsp/handlers.lua:562 "\tat com.google.gson.Gson.fromJson(Gson.java:1227)"
[ERROR][2025-09-28 09:46:29] ...lsp/handlers.lua:562 "\tat com.google.gson.Gson.fromJson(Gson.java:1329)"
[ERROR][2025-09-28 09:46:29] ...lsp/handlers.lua:562 "\tat com.google.gson.Gson.fromJson(Gson.java:1271)"
[ERROR][2025-09-28 09:46:29] ...lsp/handlers.lua:562 "\tat org.javacs.kt.ConfigurationKt.getStoragePath(Configuration.kt:81)"
[ERROR][2025-09-28 09:46:29] ...lsp/handlers.lua:562 "\tat org.javacs.kt.KotlinLanguageServer.initialize$lambda$6(KotlinLanguageServer.kt:97)"
[ERROR][2025-09-28 09:46:29] ...lsp/handlers.lua:562 "\tat org.javacs.kt.util.AsyncExecutor.compute$lambda$2(AsyncExecutor.kt:19)"
[ERROR][2025-09-28 09:46:29] ...lsp/handlers.lua:562 "\tat java.base/java.util.concurrent.CompletableFuture$AsyncSupply.run(CompletableFuture.java:1768)"
[ERROR][2025-09-28 09:46:29] ...lsp/handlers.lua:562 "\t... 3 more"
[ERROR][2025-09-28 09:46:29] ...lsp/handlers.lua:562 "Caused by: java.lang.IllegalStateException: Expected BEGIN_OBJECT but was BEGIN_ARRAY at path $"
[ERROR][2025-09-28 09:46:29] ...lsp/handlers.lua:562 "\tat com.google.gson.internal.bind.JsonTreeReader.expect(JsonTreeReader.java:165)"
[ERROR][2025-09-28 09:46:29] ...lsp/handlers.lua:562 "\tat com.google.gson.internal.bind.JsonTreeReader.beginObject(JsonTreeReader.java:89)"
[ERROR][2025-09-28 09:46:29] ...lsp/handlers.lua:562 "\tat com.google.gson.internal.bind.ReflectiveTypeAdapterFactory$Adapter.read(ReflectiveTypeAdapterFactory.java:386)"
[ERROR][2025-09-28 09:46:29] ...lsp/handlers.lua:562 "\t... 10 more"
```

The solution is to provide the following LSP config where
`init_options.storagePath` is defined.

```lua
require("mason-lspconfig").setup_handlers {
["kotlin_language_server"] = function ()
require("lspconfig")["kotlin_language_server"].setup {
init_options = {
storagePath = vim.fn.stdpath("data") .. "/kotlin-language-server",
}
-- etc...
}
}
```