The "perfect error": untraceable, unnamed, from neverland - debugging

I have an experiment running without problems when I run single modules as selected parts.
The situation is pretty different when I run the entire experiment. In that case it fails, but I cannot know why.
The experiment returns an error and obviously it doesn't let me deploy the web service, while:
1) I cannot know on which module my error is.
2) I don't have an overall description of the error.
3) It could be related to the error here but I cannot know because I don't have any feedback about that. I know that it could be a bug Azure is trying to solve but this is not reported anywhere.
I really need to know if that's a bug and if I can do something about that.

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Need to 'gatsby clean' with essentially every code change

So, our team are working on a Gatsby website, and it's working correctly for most of us.
One developer, however, needs to run gatsby clean on essentially every single code change.
Doesn't matter if it's an error, changing a text value or adding markup.
I realise this is a fairly vague question, but I'm not sure where to start troubleshooting this.
Has anyone encountered this before?

How to debug quickly in phoenix/elixir?

As I am learning Elixir/Phoenix, I happen to run into an issue like this often.
The problem is that this comes from a dependency, so normally I do this:
open deps/something/.../thefile.ex
add some debug code like IO.inspect to see what params are being passed
stop server, recompile with mix deps.recompile something
check the documentation to see what types are expected to that function
compare the types and trace down the problem to my code
This works but I'd like to improve my process, I know I can use Iex to start a repl, but I'd like to get much faster in terms of:
having a repl inside of the error page itself started automatically (like in better_errors gem for Rails)
having a way to see what arguments went into that method without me digging around (could be solved by the former point)
being able to see a method's documentation quickly
Also any other tips are greatly appreciated.
Please open up an issue in Plug: https://github.com/elixir-lang/plug
You have some great suggestions, like accessing the docs and make the arguments explicit. I don't think we can provide a REPL at the place of error though.
EDIT 1: I went ahead and opened an issue here since I got excited about those improvements! :D
EDIT 2: I realize that I should probably have used a comment as this is not quite an answer (yet!)

How to Validate a Cognos report in debug mode ( element-by-element or step-by-step)

We recently migrated from Cognos 10.1.1 to Cognos 10.2.1.1 ( 10.2.1 plus Fix pack1) . Some of our existing reports fail validation now.
From the cogserver.log file , it looks like the BIBUS Process is Crashing on validating the report.
We are working with IBM tech support via a PMR .
Wanted to try if someone here knows if it is possible to Validate a report step by step so that I can get some information or some logs on what element in our report is exactly causing the issue? i.e. Is it possible to do the report validation in a debug mode somehow?
Oh, what a wonderful feature that would be, but to my knowledge nothing like that exists at all. You could try setting the logging on your dispatcher(s) to the maximum to see if you can get any more informative errors.
I would start by trying to view the tabular data for each query individually. If you can identify which query (or queries) are causing your problems, then you can just remove items from the query until it doesn't fail, at which point you should have a pretty good idea of what the source of the problem is.
If that doesn't work, I would just start ripping major chunks of the report out and seeing you can get it to run. For example, if you have a report with 4 charts, delete half of them and try your report. Revert back to the original report, and delete the other half. Get it to work, and then start removing stuff from the half that fails until you can narrow it down to your problem.
It's kind of slow, but these approaches have always worked for me.
On a side note, we're about to make the same upgrade, I'd be interested in hearing what you learn.
EDIT:
Oh, forgot. Make sure you disable DQM and test your reports that way, if you haven't.
Unfortunately, there's no way to debug step by step. Finally got the Core dumps for the crashes, sent them over to IBM Folks ; and they identified it as a known bug in 10.2.1.1. So now we are at 10.2.1.2 (applied Fix pack 2) which solves the issue.

Lightswitch global query breaking app

I'm trying out Lightswitch for the first time, and I'm finding some of the 'built-in' features aren't as easy to implement as the videos show. The most notable being global queries, because everyone I create is causing a specific error that I cannot find a cause for. I've stripped it down to a query that does nothing but return a 'select *' on the table, and removed any code I've added.
Here is the query in my solution explorer:
And here it is in the designer:
Simple enough, so I add a screen for the query:
Everything is pure default, so why do I get this error? It says it doesn't recognize the query at all, and gives a weird dll error.
I've tried recreating it as a couple different kinds of screens, but I followed this tutorial where they use a List and Details Screen in this way. The best I can come up with is that I'm experiencing a bug due to having VS 2012 and .NET 4.5 installed as well (don't ask me why). I'm just curious if this makes sense to anyone else, or if anyone else has been successful in creating these.
P.S. - I've also been unsuccessful in accessing the permissions I created by their name. I eventually figured out I could reference them by their index, but why is that necessary? I saw nothing about needing to add a reference to make this work.
partial void CustomerNew_CanRun(ref bool result)
{
result = User.HasPermission(Permissions.AllPermissions[1]);
}
OK, just to reassure you a bit (maybe), this is not normal, & I haven't seen this or heard of anything similar.
The fact that you can't access any of your permissions by name indicates something's definitely not right. You should be able to use Permissions.NameOfOneOfMyPermissions.
Starting from the basics, have you rebuilt the solution (note rebuilt, not just built)? What you'll often find with LightSwitch is that one error will cause a whole series of other errors to appear in the list, which can look quite daunting. When you fix the original error, the rest disappear. Double-click the error in the Error pane, & you should be taken to where the error is occurring. If you can't make sense of it, past the code here & I'll see if I can figure out what's wrong.
You'll also need to check that there isn't some code left over from any previous attempt at following the tutorial. Try adding a query with a different name, & see if the error has the new name in it, or the old one.

Getting object reference error in my MVP application

I am receiving random object reference error in different modules of my application.The errors m facing is intermittent. I did debug of my code it looks all correct. Moreover, whenever I run into that error and I try again (immediately after I got error) with same steps with same input conditions that error does not come up. This is something which is happening not only in in development regions but also in production regions. I tried to analyze and I got some leads that there might be problem with temporary ASP. But I don't know how that can cause object reference errors. Sometimes I see Source error information like App_Web_ighjds[some kind of ID I guess]. I don't know where exactly the problem is? As far as my code is concerned It looks all fine. I believe if there was problem with my code then it should be reproducible every time. Does anybody have any idea why such error might be happening? If it is issue with temporary asp.net files then what I should do to avoid such error?? Any help is much appreciated. Thanks.
You're looking for ideas: I would suspect your module initializers or any DI container initialization.
Look for code that runs only on application start.
I would recommend to reset your web server completely before starting new debugging session.
I would also recommend setting Visual Studio debugger to "Break when an exception is thrown", by going to "Exceptions" settings (Ctrl-Alt-E) and checking the "CLR Exception" "Thrown" checkbox.

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