How to make Xlib print error message, but not exit? - error-handling

"The action of the default handlers is to print an explanatory message and exit." (link)
Example of such message:
X Error of failed request: BadWindow (invalid Window parameter)
Major opcode of failed request: 12 (X_ConfigureWindow)
Resource id in failed request: 0xc0007a
Serial number of failed request: 140
Current serial number in output stream: 141
If I set (XSetErrorHandler) my own "ignore everything" error handler, the "explanatory messages" disappear.
How to make Xlib ignore errors, but still print error messages?

If you actually want those error messages you pretty much have two options:
Pull _XPrintDefaultError out of XlibInt.c along with some private headers (with all the caveats of using library-private definitions).
Redefine exit() not to actually exit when _XDefautError calls it.
Neither is especially pretty and both may break and reduce your portability, but they do work.

You have to format your own message. The contents of the message is the contents of the XErrorEvent struct:
http://tronche.com/gui/x/xlib/event-handling/protocol-errors/default-handlers.html

Related

Debugging "Transaction simulation failed" when sending program instruction (Solana Solidity)

When attempting to make a call to a program compiled with #solana/solidity, I'm getting the following error:
Transaction simulation failed: Error processing Instruction 0: Program failed to complete
Program jdN1wZjg5P4xi718DG2HraGuxVx1mM7ebjXpxbJ5R3N invoke [1]
Program log: pxKTQePwHC9MiR52J5AYaRtSLAtkVfcoGS3GaLD24YX
Program log: sender account missing from transaction
Program jdN1wZjg5P4xi718DG2HraGuxVx1mM7ebjXpxbJ5R3N consumed 200000 of 200000 compute units
Program failed to complete: BPF program Panicked in solana.c at 285:0
Program jdN1wZjg5P4xi718DG2HraGuxVx1mM7ebjXpxbJ5R3N failed: Program failed to complete
jdN1wZjg5P4xi718DG2HraGuxVx1mM7ebjXpxbJ5R3N is the program's public key and pxKTQePwHC9MiR52J5AYaRtSLAtkVfcoGS3GaLD24YX is the sender's public key.
I'm using a fork of the #solana/solidity library that exposes the Transaction object so that it can be signed and sent by Phantom Wallet on the front end. The code that results in the error is as follows:
// Generate the transaction
const transaction = contract.transactions.send(...args);
// Add recent blockhash and fee payer
const recentBlockhash = (await connection.getRecentBlockhash()).blockhash;
transaction.recentBlockhash = recentBlockhash;
transaction.feePayer = provider.publicKey;
// Sign and send the transaction (throws an error)
const res = await provider.signAndSendTransaction(transaction);
I would attempt to debug this further myself, but I'm not sure where to start. Looking up the error message hasn't yielded any results and the error message isn't very descriptive. I'm not sure if this error is occurring within the program execution itself or if it's an issue with the composition of the transaction object. If it is an issue within the program execution, is there a way for me to add logs to my solidity code? If it's an issue with the transaction object, what could be missing? How can I better debug issues like this?
Thank you for any help.
Edit: I'm getting a different error now, although I haven't changed any of the provided code. The error message is now the following:
Phantom - RPC Error: Transaction creation failed. {code: -32003, message: 'Transaction creation failed.'}
Unfortunately this error message is even less helpful than the last one. I'm not sure if Phantom Wallet was updated or if a project dependency was updated at some point, but given the vague nature of both of these error messages and the fact that none of my code has changed, I believe they're being caused by the same issue. Again, any help or debugging tips are appreciated.
I was able to solve this issue, and although I've run into another issue it's not related to the contents of this question so I'll post it separately.
Regarding my edit, I found that the difference between the error messages came down to how I was sending the transaction. At first, I tried sending it with Phantom's .signAndSendTransaction() method, which yielded the second error message (listed under my edit). Then I tried signing & sending the transaction manually, like so:
const signed = await provider.request({
method: 'signTransaction',
params: {
message: bs58.encode(transaction.serializeMessage()),
},
});
const signature = bs58.decode(signed.signature);
transaction.addSignature(provider.publicKey, signature);
await connection.sendRawTransaction(transaction.serialize())
Which yielded the more verbose error included in my original post. That error message did turn out to be helpful once I realized what to look for -- the sending account's public key was missing from the keys field on the TransactionInstruction on the Transaction. I added it in my fork of the #solana/solidity library and the error went away.
In short, the way I was able to debug this was by
Using provider.request({ method: 'signTransaction' }) and connection.sendRawTransaction(transaction) rather than Phantom's provider.signAndSendTransaction() method for a more verbose error message
Logging the transaction object and inspecting the instructions closely
I hope this helps someone else in the future.

SDL_CreateWindowFrom vs SDL_DestroyWindow X11 error SDL2

I get a window ID from the command line, and create an SDL window with it:
Window window_id = from_cli(); // e.g. 0x34000c8
w = SDL_CreateWindowFrom((void*) (Window) window_id);
When my program finishes I try to clean up:
SDL_DestroyWindow(w);
And that is when I got an X11 error:
X Error of failed request: BadWindow (invalid Window parameter)
Major opcode of failed request: 3 (X_GetWindowAttributes)
Resource id in failed request: 0x34000c8
Serial number of failed request: 255
Current serial number in output stream: 256
Obviously, the caller of my program - which I cannot change - has already destroyed the X window I was using.
How should I handle this situation?
SDL_DestroyWindow() can be omitted if the SDL window was created with SDL_CreateWindowFrom()
go for SDL_SysWMinfo, pick up x11.display, create my own X11 error handler, and filter errors for window_id?
Looking at the SDL2-2.0.9 source code, it seems that SDL already sets an error handler, which calls the previous error handler, which is the default one that terminates the program on error. (src/video/x11/SDL_x11video.c::X11_SafetyNetErrHandler())
Internally SDL will override this error handler temporarily, when doing its own stuff. (src/video/x11/SDL_x11video.c::X11_CheckWindowManager())
Thus, I guess 2) is the correct way to go.
EDIT:
When omitting SDL_DestroyWindow(), SDL_Quit() will fail with the same X error.
I also realized that SDL may not anticipate a failed X call, so ignoring the error may not be a good idea, after all.
EDIT2:
I just realized that SetErrorHandler() does not require a display.
Adding an X error handler that ignores X errors regarding this particular X window seems to work, not sure if it creates new problems unseen.
Is there preferred way to handle this problem?
Version:
SDL2-2.0.9

SQS Extended - The input receipt handle is invalid

We wrappered an existing queue with the extended functionality. Messages are able to be put on the queue, and we see the message body being stored on S3.
However, when the message is consumed we get the following stack trace:
com.amazonaws.services.sqs.model.ReceiptHandleIsInvalidException: The input receipt handle is invalid. (Service: AmazonSQS; Status Code: 404; Error Code: ReceiptHandleIsInvalid; Request ID: ba9421e9-a9d2-56ba-8e17-70ff7190f05a)
at com.amazonaws.http.AmazonHttpClient.handleErrorResponse(AmazonHttpClient.java:1182)
at com.amazonaws.http.AmazonHttpClient.executeOneRequest(AmazonHttpClient.java:770)
at com.amazonaws.http.AmazonHttpClient.executeHelper(AmazonHttpClient.java:489)
at com.amazonaws.http.AmazonHttpClient.execute(AmazonHttpClient.java:310)
at com.amazonaws.services.sqs.AmazonSQSClient.invoke(AmazonSQSClient.java:2419)
at com.amazonaws.services.sqs.AmazonSQSClient.changeMessageVisibility(AmazonSQSClient.java:485)
at com.amazonaws.services.sqs.AmazonSQSClient.changeMessageVisibility(AmazonSQSClient.java:1692)
at com.amazon.sqs.javamessaging.AmazonSQSExtendedClientBase.changeMessageVisibility(AmazonSQSExtendedClientBase.java:1376)
Which happens when we attempt to change the visibility. Is that not supported?
sqsExtended.changeMessageVisibility(queueUrl, message.getReceiptHandle(), visibilityTimeout);
The answer is that this hasn't been implemented, nor does it try to warn you by throwing an exception when calling the method. There doesn't seem to be a reason to not be implemented, looking at the source code, it would be straightforward.
For our case, we are okay with relaying on the queue default value for this parameter and not setting each individually.

Get a 'clear' error message in Lua

I am using the error function in quite a few of my functions and would like to propagate the error messages to the user. However, I obviously don't want to include information about where the error occured exactly; this information should only go to the log files.
For example, I have a class that manages the connection to a server. If the connection times out, it calls
error("Connection timed out!")
The error message is then caught by the calling code via pcall. However, the message contains not only the message I passed, but also the name of the file that caused the error and the line number:
common/net/enetclient.lua:21: Connection timed out!
The question is: Is there any way to only retrieve the error message itself, or do I have to do this manually like following:
local status, msg = pcall(someFunctionThatThrowsErrors)
if not status then
local file, msg = msg:match("(.-:%d+): (.+)")
print("Error: " .. msg)
end
Cheers,
From the documentation of the error function:
error (message [, level])
Terminates the last protected function called and returns message as the error message. Function error never returns.
Usually, error adds some information about the error position at the beginning of the message, if the message is a string. The level argument specifies how to get the error position. With level 1 (the default), the error position is where the error function was called. Level 2 points the error to where the function that called error was called; and so on. Passing a level 0 avoids the addition of error position information to the message.
From what is stated in the second paragraph, adding a level of 0 to the error call will result in the desired output:
error("Connection timed out!", 0)

What is the correct SMPP error code to indicate corrupt/invalid UDH field values?

I'm trying to handle UDH data for multipart messages and I want to use an appropriate error code when there's a problem with the multipart fields. There are several error codes for bad TLV's, but I don't see anything except generic failure messages that I could use for UDH. Is that the best I can do here, or is there a more direct message I could use?
Your observation is correct - there is not a single error defined for UDH.
If you want, you can use error codes from reserved section and assign specific meaning to one/some of them. I think the "Reserved for SMSC vendor specific errors" (0x400-0x4FF) can be a good candidate.
Actually it looks to me like ESME_RX_R_APPN = 0x66 "ESME receiver reject message error." is the best error code to throw here.
It should correspond to a permanent error for this message only and let further messages be processed.