I have an old VW3/ENVY image with a parcel loaded as unmanaged code (exactly the situation Mastering ENVY/DEVELOPER warns against). Unfortunately, this problem happened a long time ago and it's too late to just "go back" to an image without the parcel loaded.
Apparently, there is a way to solve this problem (we have one development image where this has been solved, and there are normal configuration maps that contain the exact same code as the unmanaged parcel but they can't be loaded), but the exact way has long since been forgotten (and there are some problems with taking that particular dev image as the base for a new runtime image, so I need to find out how how to do it again).
In theory, it should be possible to remove the parcel and reload the code from a configuration map. In practice, all normal ways (using the ParcelBrowser or directly calling UnmanagedCode>>remove) fail. I even tried manually removing the offending selectors from the method dictionary, but past a certain point (involving a call to #primBecome:) the whole image hangs completely (I can't even drop into the debugger). I started hacking the instances of the classes and methods, hoping I'd trick ENVY into thinking that these particular methods are normal versioned code, but without any success yet.
Are there any smalltalk/envy gurus around that still remember enough of VW 3 to provide me with any pointers?
Status update
After a week of trying to solve the problem I finally made it, at least partially, so in case anyone's interested...
First, I had to fix file pointers for the umnanaged code (otherwise, all everything that tried to touch the methods would throw an exception). It looks like ENVY extends Parcel so that, in theory, all integer file pointers are changed to ENVY's void filepointer when loaded, but in my case, I had to do it manually (a Parcel provides enumeration for all selectors it defines). Another way would be to tweak the filePointer code, but that can't easily be done automatically on every image where it's needed.
Then, the parcel can be discarded, which drops the parcel information, but keeps the code. The official "Discard" mechanism needs to have a valid changes file (which envy doesn't use so it has to be set manually, and reset afterwards) and the parcel source (which we fortunately had).
To be able to make any changes to the methods (either manually, or via loading an application or class from ENVY), they need to get rid of their unmanaged status. This can be done by manually tweaking TheClass>>applicationAssocs (I also got rid of all references to the classes in UnmanagedCode sich as timestamps, and removed the reference to the discarded parcel). I actually had some info on how to get to this point from my boss, but I haven't been able to understand the instructions until I almost figured it out by myself.
This finally allowed me to load and reload all the Applications that contained the classes. In theory. In practice, the image still hung completely whenever I tried to load a newer version of the Application (that contained the code formerly in the parcel).
It turned out that the crashes had absolutely nothing to do with the code being unmanaged, but with the fact that the parcel in question modified InputState>>process:, where it caused an exception due to a missing and/or uninitialized class variable (the InputState>>initialize method wasn't called until after the new process: method was in place). I had to modify the Notifier class to dump all exceptions to a file to find out what was going on. Adding the class variable to the source of the class (instead of adding it via reflection), suspending the input processing thread via toBeLoadedCode and starting it again in the loaded method and creating a new version of the application solved even this problem.
Now everything works, in theory. In practice it's still unusable, because reloading the WindowSystem or VisualworksBase applications causes their initialization blocks to run, and a whole lot of settings are reset to their defaults - fonts and font sizes, window colors, UI settings... And there doesn't seem to be any way to just save the settings to a file and load them later on, or just to see what all the settings are (either the official Settings menu doesn't show everything, or we have a heavily tweaked image... so much for reconstructing it from scratch). But that's a completely different question.
Well, normally the recommendation would be that you should be able to rebuild your development image from scratch by loading your code from the repository. But if you had that, then the answer would be simple, just discard that image and reload. I think it's been long enough that I've lost whatever knowledge I've had about how to mess with the internal structures to get it back, and it sounds like you've tried a lot of things. So, although it might be painful, figuring out the recipe to rebuild your development image by loading stuff from the repository sounds like it may be your best bet. It probably isn't all that horrible, there just might be a few dependencies on the image state, or special doits that need to be executed.
You also probably need to validate what's in the repository against what's in the image you're working from. If there was unmanaged code loaded and then someone modified it and saved it, it's not clear to me that it would have been saved to ENVY. So you probably want to audit everything that was unmanaged code and if it's been changed, save that to a repository edition.
Sorry I don't have any better answers.
Related
When I save a method and get back to it later, all of my variable names become temp and all of my parameters becomes arg and the code indentation get changed.
Any thoughts on how I can fix this?
The behaviour that you are experiencing is not code formatting at all. You immage is experiencing an issue where it can't access original source code. Thus it uses a backup solution and decomples method bytecode. During the compilation process the variable names are erased, so they can't be re-created during the decompilation, and generic substitudes are used instead.
Now, why you are missing sources is another question. First of all it's important to check if you get some exceptions. Often these happen when you open or save your image, but also thaty may occur when you save methods.
Depending on the Pharo version you may be missing .changes or .sources files. This often happens when you more an image without moving other supporting files.
On both Xcode 4.4 and 4.4.1 I'm experiencing the same issue in that with the specific project I'm working on, I don't seem to be able to rename any classes or variables from the Refactor menu option.
Each time I try and do a rename, I type in the new name for the class/variable and click Preview at which point the bottom left begins a spinner with Finding files.... However, I then get a message saying:
The selection is not a type that can be renamed.
Make a different selection and try again.
I'm pretty sure that this is not an issue with my specific install of Xcode, because I can refactor other projects fine, it's just that I can't seem to be able to refactor this specific project.
Anyone with any ideas? I don't have any particularly exotic configuration for this project, it just seems to be a random affliction. I've deleted all of my derived data and re-indexed, but that doesn't seem to help.
Since it works OK in other projects, I'm thinking one thing I could try to do is re-generate the actual project file(s) itself. I don't know if there is a way to do this automatically?
If they're in dropbox get them out of there. It mangles project files. I've had it happen numerous times and at times it makes refactoring > renaming not work.
I have managed to solve this issue after trying many different things (tweaking project settings, pch, etc.) and it turns out there was a very simple (and totally counter-intuitive) method of fixing this issue.
All I have done is:-
Copy my entire project folder (so from Project to Project Copy).
Move Project (the original folder) to trash.
Rename Project Copy to Project.
Mysteriously, everything now works fine.
I really cannot figure out why this works. As mentioned previously, I had already deleted all derived data, etc. so I don't know why this should make things spontaneously work, but it does.
Would appreciate anyone who is able to shed some light on this as it does expose just how fiddly Xcode can be, and any understanding of what goes on under the hood is always beneficial.
Sounds like a buggered index.
I usually use the nuke from space option to delete everything in the derived data directory.
Unless you have changed it (I change mine to /tmp/bbum-derived), it'll be at:
~/Library/Developer/Xcode/DerivedData
Thus, I'll quit Xcode and do:
rm -rf ~/Library/Developer/Xcode/DerivedData
Yes, it is a bit brute force, but it works. You can likely force Xcode to rebuild the index from the UI, but I never bother. Of course, I'm also installing quite a few "odd" builds of this and that as a part of my day job...
(that is an rm -rf. It means "nuke everything and don't ask" in unix parlance. It is dangerous. Do not mistype that command.)
It seems you have an active selection somewhere in the gui, perhaps some of your files or classes are selected ? Try unselect in every sub window and retry refactoring.
I'm a bit late to this thread, but I ran into the same problem today and I was able to get it to finally refactor correctly, thought I share it.
So in large part I did what bbum said, I closed xCode, nuked the Derived data for the project the class files were in and re opened the project. Doing just that, it didn't work; the key, I found (at least for me), is that I had to do a clean (command shift k) after xCode restarts. After that I was able to rename the class files again :)
Also as a side note, my project is divided into the main project, and a static library. When I had to rename classes in the static library, I had to quit the main project and do what I described in the static library itself. Somehow I got the same error described in the question when I tried to do the refactor/rename from the main project.
Good luck!
This thread was very helpful for me in determining the problem.
It turned out that I had to Repair Disk with Disk Utility. I had visited a site earlier that had hijacked Safari and was telling me to call a number for emergency repairs, an obvious scam.
I followed the Disk Utility instructions to repair disk (including restarting with CMD-R pressed). Another clue was that I tried to commit to git and Xcode said No Way, Jose.
Afterwards I was able to refactor and commit changes as if nothing ever happened. I hope this helps someone else as a possible cause to investigate.
I'm having a strange issue with my application for Mac OS X. I have a process that runs in a secondary thread. The process repeats a certain action a user-specified number of times in a for loop.
With each iteration of the for loop, there is a string that is initialized with the contents of a strings file. If the content of the strings file equals "YES" then the loop breaks (the file is set to "NO" by default). When the user wants to stop the loop, they hit the "Stop" button which sets the contents of the file to "YES".
This actually works great when I run the application in Xcode and when I export the application as a .app. The problem occurs when I actually turn the application into a pkg and install it. The stop function no longer operates correctly. I'm pretty stumped as to what the issue is. I'm initializing all my references to my file using [NSBundle mainBundle] so I should be referencing the file in my application bundle.
EDIT: I actually decided to switch to checking an atomic BOOL value within the loop that I change when the stop button is pressed. This seems to be a simpler solution for me.
Regular users do not have permission to modify applications installed in the /Application folder for very good security reasons. Also, signed apps (ie, any app sold through the App Store) cannot be modified without invalidating your signed code.
Never, ever, ever rely on the application bundle being modifiable. It's never supposed to be. Always use standard user data folders like "~/Library/Application Support/" or "~/Library/Caches/" for app-related, non-document files.
As to your general approach, repeatedly polling a file - especially in a tight loop - is a lot of disk activity. "Laptop Killah" would be a good name for the app. :-) You should consider changing this approach altogether. If you provide more detail in another question (what you're doing and why) and ask for suggestions, I'm almost positive there'll be a number of better ways that don't chew through your users' battery charge like crack-addled rats in a grocery store.
Also, I'm guessing you never check to see if your file is written successfully. The standard -writeToURL/File:... methods return a BOOL to signal success or failure as well as set an NSError (if you pass a pointer to one) with further details. Get into the habit of not ignoring this. In this case, you might've found your own answer because you'd have known just where your code is breaking. From there, it wouldn't have been a huge leap to figure out why.
What error checking do you do? What error checking is actually necessary? Do we really need to check if a file has saved successfully? Shouldn't it always work if it's tested and works ok from day one?
I find myself error checking for every little thing, and most of the time if feels overkill. Things like checking to see if a file has been written to a file system successfully, checking to see if a database statement failed.......shouldn't these be things that either work or don't?
How much error checking do you do? Are there elements of error checking that you leave out because you trust that it'll just work?
I'm sure I remember reading somewhere something along the lines of "don't test for things that'll never really happen".....can't remember the source though.
So should everything that could possibly fail be checked for failure? Or should we just trust those simpler operations? For example, if we can open a file, should we check to see if reading each line failed or not? Perhaps it depends on the context within the application or the application itself.
It'd be interesting to hear what others do.
UPDATE: As a quick example. I save an object that represents an image in a gallery. I then save the image to disc. If the saving of the file fails I'll have to image to display even though the object thinks there is an image. I could check for failure of the the image saving to disc and then delete the object, or alternatively wrap the image save in a transaction (unit of work) - but that can get expensive when using a db engine that uses table locking.
Thanks,
James.
if you run out of free space and try to write file and don't check errors your appliation will fall silently or with stupid messages. i hate when i see this in other apps.
I'm not addressing the entire question, just this part:
So should everything that could
possibly fail be checked for failure?
Or should we just trust those simpler
operations?
It seems to me that error checking is most important when the NEXT step matters. If failure to open a file will allow error messages to get permanently lost, then that is a problem. If the application will simply die and give the user an error, then I would consider that a different kind of problem. But silently dying, or silently hanging, is a problem that you should really do your best to code against. So whether something is a "simple operation" or not is irrelevant to me; it depends on what happens next, or what would be the result if it failed.
I generally follow these rules.
Excessively validate user input.
Validate public APIs.
Use Asserts that get compiled out of production code for everything else.
Regarding your example...
I save an object that represents an image in a gallery. I then save the image to disc. If the saving of the file fails I'll have [no] image to display even though the object thinks there is an image. I could check for failure of the the image saving to disc and then delete the object, or alternatively wrap the image save in a transaction (unit of work) - but that can get expensive when using a db engine that uses table locking.
In this case, I would recommend saving the image to disk first before saving the object. That way, if the image can't be saved, you don't have to try to roll back the gallery. In general, dependencies should get written to disk (or put in a database) first.
As for error checking... check for errors that make sense. If fopen() gives you a file ID and you don't get an error, then you don't generally need to check for fclose() on that file ID returning "invalid file ID". If, however, file opening and closing are disjoint tasks, it might be a good idea to check for that error.
This may not be the answer you are looking for, but there is only ever a 'right' answer when looked at in the full context of what you're trying to do.
If you're writing a prototype for internal use and if you get the odd error, it doens't matter, then you're wasting time and company money by adding in the extra checking.
On the other hand, if you're writing production software for air traffic control, then the extra time to handle every conceivable error may be well spent.
I see it as a trade off - extra time spent writing the error code versus the benefits of having handled that error if and when it occurs. Religiously handling every error is not necessary optimal IMO.
This is what I'm doing:
extract contents of my JRE's rt.jar
extract src.zip of my JDK (same version)
Now, if I copy Runtime.java from the extracted src folder and compile it using javac.exe without any modifications and then put it in the extracted rt folder to finally put everything back in a jar file using jar.exe, everything works as expected. The JRE runs fine.
However, if I make the slightest change to Runtime.java and compile it and put it in rt.jar, the JRE crashes whenever I attempt to start it. This is an example of a slight change that causes the silent crash:
/** Don't let anyone else instantiate this class */
private Runtime() {
System.out.println("This is a test.");
}
Instead of:
/** Don't let anyone else instantiate this class */
private Runtime() {}
Could anyone tell me why this is causing my JRE to crash?
Thanks in advance.
It's possible that System.out has not been initialised at the time that the Runtime() constructor runs. Usually console output is not considered a "slight" change, but at the wrong time it can invoke way too much stuff that may not be set up at all yet.
You're doing this all wrong. You can't distribute that modified JRE for a start, so it is only useful inside your organization . Install a SecurityManager and don't grant your codebase any of the RuntimePermissions you're trying to protect against.
#Tom - I advise you NOT to try to do this:
You cannot distribute the modified rt.jar file without violating the Sun binary license.
Even if you did, you would not be allowed to call it Java.
As you are finding, there are lots of complications that arise when you make changes, particularly when those changes might interfere with the JVM's behind the scenes initialization. And when things blow up during initialization, the JVM often cannot report the problem in an intelligible way.
If you do succeed in making the modified rt.jar work for one JRE, there is no guarantee that the same hacks will work for a different version.
Nobody in their right mind would knowingly use a modified JVM (especially one modified by a third-party) in a production app.
EDIT : judging from your other questions, I guess you are trying to reverse engineer or modify some third party Java application with a custom launcher. If you provided more information on what you were really trying to do, we might be able to suggest the right way to do it ... rather than using "desperate measures" such as modifying the JRE.
That's pretty strange, as I did the same trick with many classes in rt.jar in past.
Can you provide us with the crashed process output?