Debug Adapter Launch results in "Broken pipe" error from DAP server when sending back reply of "terminate" request

[agarciadom]

Hello everyone,

Within the Eclipse Epsilon project, we've started to experiment with the Debug Adapter Protocol, so we can expose debugging capabilities outside Eclipse. I've got a toy version of a debug adapter and a socket-based server.

I've got it to launch an Epsilon program through an LSP4E "Debug Adapter Launch" launch configuration. It's a pretty minimalistic one. It connects to a running server on 127.0.0.1:4040 and uses these parameters:

{
   "command": "launch",
   "eolScript": "/home/antonio/testLSP.eol"
}

The program completes its execution normally, and I can see the program terminated with an exit value of 0 in the Debug tab, but I always end up seeing this error message in my DAP server when the program finishes running:

Apr 25, 2024 9:13:58 AM org.eclipse.lsp4j.jsonrpc.RemoteEndpoint fallbackResponseError
SEVERE: Internal error: org.eclipse.lsp4j.jsonrpc.JsonRpcException: java.net.SocketException: Broken pipe
java.util.concurrent.CompletionException: org.eclipse.lsp4j.jsonrpc.JsonRpcException: java.net.SocketException: Broken pipe
	at java.base/java.util.concurrent.CompletableFuture.encodeThrowable(CompletableFuture.java:315)
	at java.base/java.util.concurrent.CompletableFuture.completeThrowable(CompletableFuture.java:320)
	at java.base/java.util.concurrent.CompletableFuture$UniAccept.tryFire(CompletableFuture.java:722)
	at java.base/java.util.concurrent.CompletableFuture.postComplete(CompletableFuture.java:510)
	at java.base/java.util.concurrent.CompletableFuture$AsyncRun.run(CompletableFuture.java:1810)
	at java.base/java.util.concurrent.CompletableFuture$AsyncRun.exec(CompletableFuture.java:1796)
	at java.base/java.util.concurrent.ForkJoinTask.doExec(ForkJoinTask.java:373)
	at java.base/java.util.concurrent.ForkJoinPool$WorkQueue.topLevelExec(ForkJoinPool.java:1182)
	at java.base/java.util.concurrent.ForkJoinPool.scan(ForkJoinPool.java:1655)
	at java.base/java.util.concurrent.ForkJoinPool.runWorker(ForkJoinPool.java:1622)
	at java.base/java.util.concurrent.ForkJoinWorkerThread.run(ForkJoinWorkerThread.java:165)
Caused by: org.eclipse.lsp4j.jsonrpc.JsonRpcException: java.net.SocketException: Broken pipe
	at org.eclipse.lsp4j.jsonrpc.json.StreamMessageConsumer.consume(StreamMessageConsumer.java:72)
	at org.eclipse.lsp4j.jsonrpc.RemoteEndpoint.lambda$handleRequest$1(RemoteEndpoint.java:292)
	at java.base/java.util.concurrent.CompletableFuture$UniAccept.tryFire(CompletableFuture.java:718)
	... 8 more
Caused by: java.net.SocketException: Broken pipe
	at java.base/sun.nio.ch.NioSocketImpl.implWrite(NioSocketImpl.java:425)
	at java.base/sun.nio.ch.NioSocketImpl.write(NioSocketImpl.java:445)
	at java.base/sun.nio.ch.NioSocketImpl$2.write(NioSocketImpl.java:831)
	at java.base/java.net.Socket$SocketOutputStream.write(Socket.java:1035)
	at java.base/java.io.OutputStream.write(OutputStream.java:127)
	at org.eclipse.lsp4j.jsonrpc.json.StreamMessageConsumer.consume(StreamMessageConsumer.java:67)
	... 10 more

Apr 25, 2024 9:13:58 AM org.eclipse.lsp4j.jsonrpc.RemoteEndpoint fallbackResponseError
SEVERE: Internal error: org.eclipse.lsp4j.jsonrpc.JsonRpcException: java.net.SocketException: Broken pipe
java.util.concurrent.CompletionException: org.eclipse.lsp4j.jsonrpc.JsonRpcException: java.net.SocketException: Broken pipe
	at java.base/java.util.concurrent.CompletableFuture.encodeThrowable(CompletableFuture.java:315)
	at java.base/java.util.concurrent.CompletableFuture.completeThrowable(CompletableFuture.java:320)
	at java.base/java.util.concurrent.CompletableFuture$UniAccept.tryFire(CompletableFuture.java:722)
	at java.base/java.util.concurrent.CompletableFuture.postComplete(CompletableFuture.java:510)
	at java.base/java.util.concurrent.CompletableFuture$AsyncRun.run(CompletableFuture.java:1810)
	at java.base/java.util.concurrent.CompletableFuture$AsyncRun.exec(CompletableFuture.java:1796)
	at java.base/java.util.concurrent.ForkJoinTask.doExec(ForkJoinTask.java:373)
	at java.base/java.util.concurrent.ForkJoinPool$WorkQueue.topLevelExec(ForkJoinPool.java:1182)
	at java.base/java.util.concurrent.ForkJoinPool.scan(ForkJoinPool.java:1655)
	at java.base/java.util.concurrent.ForkJoinPool.runWorker(ForkJoinPool.java:1622)
	at java.base/java.util.concurrent.ForkJoinWorkerThread.run(ForkJoinWorkerThread.java:165)
Caused by: org.eclipse.lsp4j.jsonrpc.JsonRpcException: java.net.SocketException: Broken pipe
	at org.eclipse.lsp4j.jsonrpc.json.StreamMessageConsumer.consume(StreamMessageConsumer.java:72)
	at org.eclipse.lsp4j.jsonrpc.RemoteEndpoint.lambda$handleRequest$1(RemoteEndpoint.java:292)
	at java.base/java.util.concurrent.CompletableFuture$UniAccept.tryFire(CompletableFuture.java:718)
	... 8 more
Caused by: java.net.SocketException: Broken pipe
	at java.base/sun.nio.ch.NioSocketImpl.implWrite(NioSocketImpl.java:425)
	at java.base/sun.nio.ch.NioSocketImpl.write(NioSocketImpl.java:445)
	at java.base/sun.nio.ch.NioSocketImpl$2.write(NioSocketImpl.java:831)
	at java.base/java.net.Socket$SocketOutputStream.write(Socket.java:1035)
	at java.base/java.io.OutputStream.write(OutputStream.java:127)
	at org.eclipse.lsp4j.jsonrpc.json.StreamMessageConsumer.consume(StreamMessageConsumer.java:67)
	... 10 more

Using an exception breakpoint, I saw that these exceptions appear to be thrown while trying to send back the replies to the terminate and disconnect requests, and also the errors reported from the failure to send those replies. I've listed the messages below.

At this point, I'm not sure if I've misunderstood how to process the terminate/disconnect DAP requests or how to write the DAP server, or if this is a known issue in LSP4E. Any help would be appreciated :-). I've mostly been imitating what I've seen in other debug adapters so far (specifically, the XSLT and Rascal ones).

If it helps, I've also listed the versions of LSP4E and LSP4J I'm using in our target platform.

Best,
Antonio

Target platform definition fragment for LSP4E and LSP4J

https://github.com/eclipse/epsilon/blob/88e849ecc528a4909b2e0fe2ba861917646f4dd0/releng/org.eclipse.epsilon.target/org.eclipse.epsilon.target.tpd#L82-L89

Messages which fail to be sent back

{"type":"response","seq":9,"request_seq":4,"command":"terminate","success":true}

{"type":"response","seq":10,"request_seq":5,"command":"disconnect","success":true}

{"type":"response","seq":11,"request_seq":4,"command":"terminate","success":false,"message":"Internal error.","body":"java.util.concurrent.CompletionException: org.eclipse.lsp4j.jsonrpc.JsonRpcException: java.net.SocketException: Broken pipe\n\tat java.base/java.util.concurrent.CompletableFuture.encodeThrowable(CompletableFuture.java:315)\n\tat java.base/java.util.concurrent.CompletableFuture.completeThrowable(CompletableFuture.java:320)\n\tat java.base/java.util.concurrent.CompletableFuture$UniAccept.tryFire(CompletableFuture.java:722)\n\tat java.base/java.util.concurrent.CompletableFuture.postComplete(CompletableFuture.java:510)\n\tat java.base/java.util.concurrent.CompletableFuture$AsyncRun.run(CompletableFuture.java:1810)\n\tat java.base/java.util.concurrent.CompletableFuture$AsyncRun.exec(CompletableFuture.java:1796)\n\tat java.base/java.util.concurrent.ForkJoinTask.doExec(ForkJoinTask.java:373)\n\tat java.base/java.util.concurrent.ForkJoinPool$WorkQueue.topLevelExec(ForkJoinPool.java:1182)\n\tat java.base/java.util.concurrent.ForkJoinPool.scan(ForkJoinPool.java:1655)\n\tat java.base/java.util.concurrent.ForkJoinPool.runWorker(ForkJoinPool.java:1622)\n\tat java.base/java.util.concurrent.ForkJoinWorkerThread.run(ForkJoinWorkerThread.java:165)\nCaused by: org.eclipse.lsp4j.jsonrpc.JsonRpcException: java.net.SocketException: Broken pipe\n\tat org.eclipse.lsp4j.jsonrpc.json.StreamMessageConsumer.consume(StreamMessageConsumer.java:72)\n\tat org.eclipse.lsp4j.jsonrpc.RemoteEndpoint.lambda$handleRequest$1(RemoteEndpoint.java:292)\n\tat java.base/java.util.concurrent.CompletableFuture$UniAccept.tryFire(CompletableFuture.java:718)\n\t... 8 more\nCaused by: java.net.SocketException: Broken pipe\n\tat java.base/sun.nio.ch.NioSocketImpl.implWrite(NioSocketImpl.java:425)\n\tat java.base/sun.nio.ch.NioSocketImpl.write(NioSocketImpl.java:445)\n\tat java.base/sun.nio.ch.NioSocketImpl$2.write(NioSocketImpl.java:831)\n\tat java.base/java.net.Socket$SocketOutputStream.write(Socket.java:1035)\n\tat java.base/java.io.OutputStream.write(OutputStream.java:127)\n\tat org.eclipse.lsp4j.jsonrpc.json.StreamMessageConsumer.consume(StreamMessageConsumer.java:67)\n\t... 10 more\n"}

{"type":"response","seq":12,"request_seq":5,"command":"disconnect","success":false,"message":"Internal error.","body":"java.util.concurrent.CompletionException: org.eclipse.lsp4j.jsonrpc.JsonRpcException: java.net.SocketException: Broken pipe\n\tat java.base/java.util.concurrent.CompletableFuture.encodeThrowable(CompletableFuture.java:315)\n\tat java.base/java.util.concurrent.CompletableFuture.completeThrowable(CompletableFuture.java:320)\n\tat java.base/java.util.concurrent.CompletableFuture$UniAccept.tryFire(CompletableFuture.java:722)\n\tat java.base/java.util.concurrent.CompletableFuture.postComplete(CompletableFuture.java:510)\n\tat java.base/java.util.concurrent.CompletableFuture$AsyncRun.run(CompletableFuture.java:1810)\n\tat java.base/java.util.concurrent.CompletableFuture$AsyncRun.exec(CompletableFuture.java:1796)\n\tat java.base/java.util.concurrent.ForkJoinTask.doExec(ForkJoinTask.java:373)\n\tat java.base/java.util.concurrent.ForkJoinPool$WorkQueue.topLevelExec(ForkJoinPool.java:1182)\n\tat java.base/java.util.concurrent.ForkJoinPool.scan(ForkJoinPool.java:1655)\n\tat java.base/java.util.concurrent.ForkJoinPool.runWorker(ForkJoinPool.java:1622)\n\tat java.base/java.util.concurrent.ForkJoinWorkerThread.run(ForkJoinWorkerThread.java:165)\nCaused by: org.eclipse.lsp4j.jsonrpc.JsonRpcException: java.net.SocketException: Broken pipe\n\tat org.eclipse.lsp4j.jsonrpc.json.StreamMessageConsumer.consume(StreamMessageConsumer.java:72)\n\tat org.eclipse.lsp4j.jsonrpc.RemoteEndpoint.lambda$handleRequest$1(RemoteEndpoint.java:292)\n\tat java.base/java.util.concurrent.CompletableFuture$UniAccept.tryFire(CompletableFuture.java:718)\n\t... 8 more\nCaused by: java.net.SocketException: Broken pipe\n\tat java.base/sun.nio.ch.NioSocketImpl.implWrite(NioSocketImpl.java:425)\n\tat java.base/sun.nio.ch.NioSocketImpl.write(NioSocketImpl.java:445)\n\tat java.base/sun.nio.ch.NioSocketImpl$2.write(NioSocketImpl.java:831)\n\tat java.base/java.net.Socket$SocketOutputStream.write(Socket.java:1035)\n\tat java.base/java.io.OutputStream.write(OutputStream.java:127)\n\tat org.eclipse.lsp4j.jsonrpc.json.StreamMessageConsumer.consume(StreamMessageConsumer.java:67)\n\t... 10 more\n"}

[agarciadom]

Please ignore the above message: I have put a bit more work on the server (switching it to attach rather than launch) and how it deals with shutdown, and it doesn't exhibit the above errors anymore.