Before I get into it I'm sorry for the newbie question but I'm new to Moodle and php development. I'm attempting to figure out how to debug the code in event handlers.
Really what I'm looking for is how to debug code in an event handler since I don't call the page directly and am not able to get output from the functions that it's running (that I'm currently aware of).
I know this is likely off topic for this forum but I'm not really sure where to turn for this.
Make sure xdebug is installed on the development computer where you are testing this, then open up your IDE and put a breakpoint at the start of your event handler. If that isn't hit, put a breakpoint on the code that triggers the event and step through it.
If, for some reason, you really can't install xdebug and step through the code (which is something that is essential for any serious PHP development), try using fopen and fwrite to dump information into a log file, whilst the event is happening.
Related
Coming from Eclipse, I am very used to the option to terminate the possible old and running instance of the code I'm working on. With VS Code, I instead have to select the console, press Ctrl+C, wait for the process to end and only then can I launch a new instance via Ctrl+F5 (same for debug/regular F5).
I was surprised to find no such option in VS Code, am I missing something or is this feature simply not supported ? If this is possible to configure somehow, how would I go about it ? Multiple tags because I'm not sure which part of VS Code would be responsible here. I am specifically developing in Java, if that is relevant.
I have encountered a critical issue that Unity Editor freezes. I've spent many hours debugging step by step of my codes but still can't find where the problem is. So I think maybe I should try thinking from another angle, generally speaking what reasons would cause Unity Editor freezes and not responding?
I can't find a general case discussion about this topic.
From my experience, infinite loop is one reason for sure. Deadlock is critical issue, but not sure if it causes Unity Editor freezes. Unity Editor bug that I encountered only makes the whole editor crashes, instead of freezing. Any other experiences are welcomed. Thank you!
In such case, what kind of tools or methods could I use to debug it? Right now since the editor freezes I can't use "print" to find out what happens after it freezes. So I use Visual studio to debug the Editor thread, in this way I can see all the prints that I wrote. It appears the game is still running, only the editor not responding. And I can use VS click "attach to Unity and play" and put some debugging points, then debug step by step.
The first thing that I would check out is for an infinite loop. At the hang/freeze moment, you can attatch the debugger of your choice and pause the execution. In the case that it is an infinite loop that it is executing, at the exec time pause you might find the execution in a forever running while (true) {...}
Other thing that I would check is the plugins in use. Several Unity plugins like Parse, FMOD, UMP (Universal Media Player), ZFBrowser, or Embedded Browser are using native threads. It’s an issue when a plugin ends up attaching a native thread to the runtime, which then does blocking calls to the OS. This means Unity can't interrupt that thread for the debugger (or domain reload) and hang. Source
To check that you can check the active threads in the visual studio command window af the freeze is reproduced:
View->OtherWindows->CommandWindow and type in this command:
Debug.ListCallStack /AllThreads /ShowExternalCode
In the stack you can check if some thread is there with no need, or if its related with the plugins mentioned above.
Also an interesting point is to check in the windows task manager (in the case that you are using windows) if the CPU usage is to 0%. It can lead you to the type of hang that is taking place.
Good luck.
Edit: I forgot to mention, you need to check also the unity logfiles
I notice this all the time, and its super frustrating.
Unfortunately, this could be any number of issues. I notice this issue most often when working in projects that are made for the Universal Windows Platform.
Try using the Task manager to monitor specific processes / threads running.
Some follow up questions:
What platform is your project currently targeting?
What version of Unity are you running? Have you tried other versions?
What are your computers specs? Is the OS up to date? Graphics Drivers?
Does it happen (or happen more often) when an external code editor is open? Perhaps try going to Preferences>External Editor > Regenerate Project files.
Are you using Unity Collab by chance? I've had issues where collab is stuck trying to communicate with Unity Servers / looking for changes. Try logging out of your Unity account through the editor, and log back in.
Have you tried looking for a Unity editor crash dump, or error log files? I think they can be found here C:\Users\username\AppData\LocalLow\Unity by default. Those files may give you more specific data concerning your problem.
Unity's new versions are getting more slower and slower. From my experience 2019 versions are the best and more stable.
I solved my issue. It's fundamentally an infinite loop.
It's not a simple case such as "while(true)". I'll try to explain.
My game was a PvP game, and I'm making a local AI. Usually my design pattern works fine, however I just turned off the simulation of "AI thinking time", and since the AI codes and server codes all run in local mode, the transmitting of data between server and client are replaced by local method call(meaning instantly executed before everything else).
There is a loophole in my server code. I use "Update" and a flag on server to change a specific game state, however in this particular case, it got into an infinite loop because the local method call is executed before the "Update". And because my AI now doesn't need real time to "think", it "acts" and transmits the event data to server right away. And since the transmitting doesn't need time any more, it calls the server method instantly, hence forming the infinite loop.
When running my code in debug mode, I keep getting 2 error messages:
Could not delete [path_to]\productiondb.log. May be locked by another process
I don't know what process might be locking it. It comes when I make changes to the code while my Pivotal tc Server is running in debug mode, but it dosent seem to create a lot's of trouble. Sometimes however, I get this warning:
Also due to some changes. I usally just restart the server and move on. This isen't the real problem, the real problem is that I get these messages when I havent doen any changes. Somethimes it accures when I run a certen part of the code, other times i occurs when I open certen codes in sts, however, it doen't seem to stop at the same place twice.
I am suspecting that this has something to do with git. I am using git to change between versions and doing tests. So I am thinking that STS has some of the code in memory from before I changed branche with git, and isen't updating it before I run or open the file with that code. But I am rather new to both sts and git, and can't be certan that it would work that way. If it is, does anyone know how to update sts after I have changed branch? If it is not, does anyone know what might causing it?
If you run an app in debug mode, the Eclipse Debugger tells the application when code gets changed and tries to use the debug API to swap in the new code into the running application. This is especially useful if you debug your code, hit a breakpoint, step through the code, fit the issue, change the code, and press save. At that moment, the Eclipse compiler updates the class file and tells the running JVM to swap in the new code. If that succeeds, the debugger will jump back to the last stack frame and the execution of your app will continue with the beginning of the method that you entered. This allows you to directly continue to debug and step through the updated code without restarting the app.
While this is a great feature of the JVM, it is very limited in terms of what scope of changes to the classes the JVM can deal with while doing this hot-swap. It is usually limited to method implementations. So adding new methods, adding or deleting members of the class, etc, are not supported. As a result, the above screenshot will appear. It means that the JVM wasn't able to hot-swap the changed code and will continue to run with the previously loaded code instead of the changed one.
I'm working on a Thunderbird extension, and, unfortunately, can't sort out what's still valid from what's not. There's lots of stuff online, but, most of it is no longer applicable to recent Thunderbird.
At a minimum, I need a way of seeing log messages from the extension, so I can see what's working and what's not. Ideally, I'd like a full debug console. There is a reference on Stackoverflow to Thunderbird Developer Tools, but there doesn't seem to be a way to download them.
I'd also like to be able to execute Javascript that can reference my extension via the console. When I try this via Thunderbird's console, I get error messages. I get this even when using other people's extensions, so I have to assume that extensions are outside the scope of the console
How can I get visibility and interaction to a new Thunderbird extension?
2020 Update:
If you are writing a MailExtension (this is how WebExtension are called for Thunderbird) you should have a look at general debugging in WebExtensions, e.g. https://extensionworkshop.com/documentation/develop/debugging/
You should probably also take a look at the general developer documentation on MailExtension at https://developer.thunderbird.net/add-ons/about-add-ons
The thinks listed below there written for the Legacy Overlay Extension, which do not work in newer Thunderbird versions.
logging messages
As described in https://developer.mozilla.org/en-US/docs/Debugging_JavaScript, there exist 3 different consoles in Gecko. The one best accessible in Thunderbird is the Error Console. You can write messages to it through the nsIConsoleService. If you don't mind that the log messages show up as an error, you can also simply use Components.utils.reportError().
Another way is to log to the (native) console from which Thunderbird is started. This is done through dump().
The newest way to log messages is using the Log.jsm module. It is a very nice wrapper around the different logging methods, and my preferred way to log messages in Thunderbird.
Thunderbird Developer Tools
As you haven't linked to the reference, I'm not 100% sure, but I think you mean the possibility to remotely debug Thunderbird through Firefox. You don't need to download anything to use this, it is already integrated in Thunderbird.
execute Javascript that can reference my extension
Debugging Thunderbird remotely through Firefox gives also access to the console and Scratchpad in the Developer Tools. Both should have also access to the add-on.
You may also want to look at the Tiny JavaScript Debugger. It also allows the execution of arbitrary code while debugging.
I am using Eclipse Kepler Service Release 2 , EPIC 0.5.46 and Strawberry Perl 5 version 18 for perl programming. For debugging I am using Eclipse debugger and PadWalker .
I have an interactive perl program that writes to files based on answers provided by the users to multiple prompts. While debugging , every time i change a single line of code I have to rerun the whole program again and provide inputs to every prompt , which is really time consuming.
Is there a way to make changes to the code in a sub routine , in the middle of debugging session such that the instruction pointer resets itself to the first line of that sub routine. This way i do not have to restart the session to recompile the new code.
Appreciate your inputs and suggestions. Thank You!!!
What you want to do can be done, and I've done it many times in Perl myself. For example, see this.
However although what you describe may work (and is a bit dangerous), the way it is generally done a bit different and safer.
First one has to assume a regular kind of command structure like a command processor, or say a web server.
In a command processor or web server, you read a command (or get a web request), perform an action, then read another command, perform another action and so on. From your description, it sounds like you have such a structure.
In my case, I have each debugger command stored as in Perl file. This is helpful not only for facilitating this task, but also for understanding, testing and changing the code.
Given this kind of program structure, instead of trying to change the program counter, you complete the command and at the level where you are about to read a new command, you make the change and then reload the file which changes the code.
The specific Perl construct to do this is called do. Don't use require or use which will load in a Perl file only if that file or module hasn't been previously loaded. In your situation, you want to reload even if it has been loaded before.
So now how do you get to be able to issue a do command? As you suggest, you could do it through a debugger. Assuming you have this overall program stucture as described above, you put the breakpoint somewhere a common point in the caller which loops over things to process, rather than try to change things in indvidual commands.
And you don't even need a debugger to do this! Many web frameworks like Ruby on Rails, have a "development" mode where they save timestamps on files that implement functionality. If the file has changed they issue the "do" command before running the request.