cannot debug GWT native code within gwtmockito - gwt

I have a GwtMockitoTestCase and the debugger seems not to enter inside any vanilla GWT class like Widget, ResizeLayoutPanel, etc.
However, when running the same code inside DevMode, the debugger steps correctly through that code.
Does this have to do with GWT running inside a JRE? If not, could it be that my classpath is wrong somehow? Or maybe the gwt-user jar doesn't have debugging information?
I've also tried to extend a GWT class:
ResizeLayoutPanel w = new ResizeLayoutPanel() {
#Override
public void setWidget(Widget pW) {
super.setWidget(pW); (1)
}
};
And breakpoint on line (1) is working but pressing F5, it doesn't go inside ResizeLayoutPanel's setWidget method.
Thank you!

After digging in the GwtMockito code, it seems there are a certain set of classes that are stubbed and some methods' body is removed. Therefore it's not possible to debug those methods.
The question that remains is that somehow GWTMockito breaks the code coverage tool(EclEmma) which shows less code covered than it's supposed to. I've posted a separate question on this topic on SO: false code coverage reported using GwtMockito
Some technical background:
GwtMockitoClassLoader stubs some classes from GWT completely, please check GwtMockitoTestRunner#getClassesToStub() which includes Widget and ResizeLayoutPanel classes.
The stubbing process removes the body completely for the methods returning primitive values or void, see GwtMockitoClassLoader#onLoad. If the return is a java bean, it will return a mocked version for it.

Related

Warning CS7022 - The entry point of the program is global code; ignoring 'Program.Main(string[])' entry point

so I have an issue where I have this warning in my Error List:
Severity Code Description Project File Line Suppression State
Warning CS7022 The entry point of the program is global code; ignoring 'Program.Main(string[])' entry point. Project DirectoryToProject 23 Active
This is essentially where its throwing
namespace MyProgram
{
class Program
{
static async Task Main(string[] args) => await new Program.MainAsync();
}
static async Task MainAsync()
{.. do stuff.. }
}
That is the line of code that is causing the error. I've tried playing around with the Main class, I did have it with the return type void and had my GetAwaiter and GetResult method called on the MainAsync method.
I've tried researching the error but I've had no luck, so hopefully, this thread will help a few others...
I am currently running on C# 9.0
Visual Studio 2019 Build Version: 16.8.30717.126
EDIT: Forgot to show that the MainAsync was in the file... (Sorry) Im trying to limit the amount of methods I show as 95% of them aren't useful the to question... But the issue is that although my application compiles, when executing my program it quits instantly as if it doesn't know where to start...
EDIT 2:
Thanks to Hans Passant -
If anyone experiences something like this try what he mentioned:
"This is a rather awful C# v9 feature. Project > Properties > Build tab, Advanced button > Language version = 7.3 You should now get a decent error message from the code you didn't know you had to post".
Essentially upon changing back to C# 8.0 I saw it was a different file hidden away causing the issue.
Starting with net5.0, I've found that this error can be caused by having stray semicolons above the namespace keyword. Whether this is a bug or intended behavior is beyond me, however make sure you don't have any standalone semicolons as such:
using System.Linq;
using System.Reflection;
using System.Text;
using System.Threading.Tasks;
; // This will cause CS7022
namespace Tomoe.Commands.Public
Be sure to check all your files and not just Program.cs
EDIT: Apparently this is intended behavior, see https://github.com/dotnet/roslyn/issues/53472.
TL;DR, semicolons above namespaces are interpreted as top level statements. Because nothing is being called in said statement, the program exits. This is the same as doing
static void Main() {
;
}
in your Program.cs. While I do feel some change should be made, the design decision behind this is quite logical and entirely understandable.
EDIT 2: According to jcouv on Github, this is now becoming an error instead of a warning. Hopefully, this "bug" shall harass us no more!
This can happen if a file (any file) in the project has global code, that's to say statements outside of a class.
As mentioned by others, this is caused by a new C# 9 feature that is called "Top-level statements". This Feature enables you to write statements in the global context and the compiler will create it's own Main() based on that.
In my case I had a semicolon after my using statements in any of my files. As far as I know Visual Studio or the compiler don't give you any option to find this "entry-point" without changing any settings as descripted by others in this thread.
My solution was to just create another "Top-level statement entry point" in my project. Due to the fact that there is only one allowed the compiler complains about that.
I just added a semicolon directly after the using statements in my Program.cs. Because this file is one of the first that are processed by the compiler any other file that contains a "Top-level statement" will cause an error.
I've also seen this compiler error in the following scenario. You've written your code with top-level statements. Later, you decide to absorb that logic into a Main() method. (Maybe you find you now need to return an async Task, or you need to modify it to meet a company coding standard, for example.) Even though the following code block will compile (in VS2022 at least), it generates the error in question with a green squiggly beneath Main:
static void Main()
{
Console.WriteLine("Inside the Main() method");
//Do some other work here
}
Where's the issue? The method declaration is correct, and it will run, but even when this is the only code in the Program.cs file, and even when no other entry point is specified in the project/solution settings, we do not get the expected output:
Even the Microsoft documentation isn't much help in this case, because it pretty much repeats in more detail what the error is saying.
What's missing is the Program class definition. Without it, the compiler is still looking for a top-level statement - which it finds, namely static void. Then the next thing it finds is the Main() method declaration, but it finds this after the (unintended) top-level statement static void. Hence, the error sorta makes sense now.
The fix is to wrap the above code in a Program class:
class Program
{
static void Main()
{
Console.WriteLine("Inside the Main() method");
}
}
And now we get the expected output:

Getting a scala stacktrace

When my scala-js code throws an error, I'd like to send a sensible stacktrace back to my server to put in the logs. By "sensible stacktrace" I mean something that gives the Scala methods, filenames, and line numbers rather than the transpiled javascript code.
I've made good progress by getting the source map and using the Javascript source-map library (https://github.com/mozilla/source-map) to translate each element of the stacktrace from javascript to the corresponding Scala code.
My issue: I need the column number of the javascript code that threw the error but don't see how to obtain it. Printing a StackTraceElement gives a result similar to
oat.browser.views.query.QueryRunView$.renderParamsTable$1(https://localhost:9443/assets/browser-fastopt.js:34787:188)
I need the "188" at the end of the line but don't see how to get it other than calling toString and parsing the result. Looking at the StackTraceElement code, the column number is a private variable with nothing in the API to access it.
Is there another approach to this that I'm completely overlooking? Anything built into scala-js that converts a javascript stacktrace to a Scala stacktrace?
I subsequently found the StackTraceJS library which does what I needed. I combined a ScalaJS facade for it with a facade for JSNlog to come up with a package that meets my needs pretty well. See jsnlog-facade. It logs to the browser console and/or the server, with Scala stack traces. Demo code included.
There is nothing in the public API to access the column number because this is a Java API, and Scala.js cannot add public members to Java APIs.
To work around this issue in the case of StackTraceElement, we export getColumnNumber(): Int to JavaScript. You can therefore use the following code to retrieve the column number:
def columnNumberOfStackTraceElement(ste: StackTraceElement): Int =
ste.asInstanceOf[js.Dynamic].getColumnNumber().asInstanceOf[Int]
Note that this "feature" is undocumented, and might change without notice in a future major version of Scala.js. If it disappears, it will be replaced by something reliable. In the meantime, the above should get you going.

What causes GWT to output: <SomethingNotNull>.nullMethod()?

I have my own emulation of java.util.Timer (and quite a lot of other stuff missing in GWT). I have even a JUnit test proving it works in the browser.
I've just tried to convert some third-party library to GWT, which needed a Timer, and in some part of it, I call:
SystemUtils.getTimer().scheduleAtFixedRate(timerTask, value, value);
But the GWT compiler turns getTimer().scheduleAtFixedRate() to:
getTimer().nullMethod()
SystemUtils.getTimer() is a static method. I have googled for nullMethod(), but most hits are about:
null.nullMethod();
That doesn't apply to me. What could be going wrong, and what can I do to fix it?
[EDIT] Actually, the java.util.Timer emulation itself works, but it seems that (atm?) SystemUtils.getTimer() returns "undefined". Could that be the reason? Since getTimer() returns an instance created dynamically, how could the GWT compiler possibly make any assumption about the return value of getTimer(), and the presence/usage of the methods of the Timer type?
When I have seen this kind of errors it was caused by unreachable code: GWT had determined that some code was not reachable, turning off compilation for some stuff, but then it still somehow tried to link the unreachable code, showing this kind of errors.
For completeness sake
If this error shows up (which often happens after deploying to App Engine) then compile without obfuscation, turn off super dev mode, restart jetty and refresh the browser. Open the generated javascript and find where the problem occurs by searching for 'nullMethod'. You'll see that the compiler may have removed whole chunks of code that it believes is 'unreachable'.
The code surrounding 'null.nullMethod' is probably very different than what you expected. The simplest way around this is to add a null /undefined check and initializing whatever variable that is generated as 'null'. This forces the compiler to reconsider because now the variable can never be null and the code that follows it must be reachable.
For example, if null.nullMethod is found and 'null' is actually supposed to be var a = ... then add if(a == null) { a = ""; } before it (in Java of course).
For anybody who struggles with this null.nullMethod issue:
It may be possible that your GWT compiler isn't able to find the properties of your JSON bean object if your object variable is declared with its interface type:
MyTypeIF item = ...;
...
item.getStart();
...
In my scenario, GWT compiled that into:
MyTypeIF item = ...;
...
null.nullMethod();
...
Instead, I had to declare and cast it to its real implementation class:
JSMyType item = (JSMyType)...;
...

How to compare files programmatically in eclipse?

I am developing an eclipse plugin that runs code violation checker on the difference of two versions of a file. Right now I am using diff.exe to get the difference between the two files. But as diff.exe is an extrenal app, I realized that its better to use eclipse built-in compare tool to get the file difference.
So I used org.eclipse.compare and reached up to this point:
public static List<Patch> compare(String old, String recent) {
try{
IRangeComparator left = new TokenComparator(old); //what exactly to be passed in this constructor, a file path, a literal value or something else?
IRangeComparator right = new TokenComparator(recent);
RangeDifference[] diffs = RangeDifferencer.findDifferences(left, right); // This line is throwing NPE
//..
// Process RangeDifferences into Collection of Patch collection
//..
}catch(Exception e){}
//Returns a collection of file differences.
return null;
}
Now the problem is I am not sure what exactly to be passed in the constructor TokenComparator(String). The document says this constructor Creates a TokenComparator for the given string. But it is not written what exactly to be passed in this constructor, a file path, a literal value or something else? When I'm passing a file path or a string literal I am getting NullPointerException on the next line of finding differences.
java.lang.NullPointerException
at org.eclipse.compare.internal.core.LCS.isCappingDisabled(LCS.java:98)
at org.eclipse.compare.internal.core.LCS.longestCommonSubsequence(LCS.java:55)
at org.eclipse.compare.rangedifferencer.RangeComparatorLCS.longestCommonSubsequence(RangeComparatorLCS.java:186)
at org.eclipse.compare.rangedifferencer.RangeComparatorLCS.findDifferences(RangeComparatorLCS.java:31)
at org.eclipse.compare.rangedifferencer.RangeDifferencer.findDifferences(RangeDifferencer.java:98)
at org.eclipse.compare.rangedifferencer.RangeDifferencer.findDifferences(RangeDifferencer.java:82)
at org.eclipse.compare.rangedifferencer.RangeDifferencer.findDifferences(RangeDifferencer.java:67)
at com.dassault_systemes.eclipseplugin.codemonview.util.CodeMonDiff.compare(CodeMonDiff.java:48)
at com.dassault_systemes.eclipseplugin.codemonview.util.CodeMonDiff.main(CodeMonDiff.java:56)
Someone please tell what is right way to proceed.
If the question is What value the token comparators constructor takes then the answer is it takes the input string to compare. Specified in javadoc here http://help.eclipse.org/indigo/index.jsp?topic=%2Forg.eclipse.platform.doc.isv%2Freference%2Fapi%2Forg%2Feclipse%2Fcompare%2Fcontentmergeviewer%2FTokenComparator.html
TokenComparator(String text)
Creates a TokenComparator for the given string.
And the null pointer yo are getting is because in function isCappingDisabled it tries to open the compare plugin which seems to be null. You seem to be missing a direct dependency to the plugin "org.eclipse.compare.core"
The org.eclipse.compare plugin was never meant to be used in standalone : many of its functionalities require a running instance of Eclipse. Furthermore, it mixes core and UI code within the same plugin, which will lead to unexpected behavior if you are not very careful about what you use and what dependencies are actually available in your environment.
You mentionned that you were developping an Eclipse plugin. However, the NPE you get indicates that you are not running your code as an Eclipse plugin, but rather as a standard Java program. In an Eclipse environment, ComparePlugin.getDefault() cannot return null : the plugin needs to be started for that call to return anything but null.... and the mere loading of the ComparePlugin class within Eclipse is enough to start it.
The answer will be a choice :
You need your code to run as a standalone Java program out of Eclipse. In such an event, you cannot use org.eclipse.compare and diff.exe is probably your best choice (or you could switch to an implementation of diff that was implemented in Java in order to be independent of the platform).
You do not need your program to work in a standalone environment, only as an Eclipse plugin. In this case, you can keep the code you're using. However, when you run your code, you have to launch it as a new "Eclipse application" instead of "Java Application". You might want to look at a tutorial on how to develop Eclipse plugins for this, This simple tutorial from Lars Vogel shows how to run a new Eclipse Application to test an Hello World plugin. You will need a similar code, with a menu entry to launch your plugin somewhere (right-click on a file then select "check violations" in your case?).

Why am I getting NullPointerException in the CompilationUnit instances returned from ASTParser.createASTs()

I am working on an Eclipse JDT plugin that requires parsing large numbers of source files,
so I am hoping to use the batch method ASTParser.createASTs(). The parsing executes without errors, but within the CompilationUnit instances it produces, many of the org.eclipse.jdt.internal.compiler.lookup.SourceTypeBinding instances have had their scope field set to null. This setting to null is occurring in the CompilationUnitDeclaration.cleanUp() methods, which are invoked on a worker thread that is unrelated to my plugin's code (i.e., my plugin's classes do not appear on the cleanUp() method call stack).
My parsing code looks like this (all rawSources are within the same project):
ASTParser parser = ASTParser.newParser(AST.JLS3);
parser.setResolveBindings(true);
parser.setStatementsRecovery(true);
parser.setBindingsRecovery(true);
parser.setIgnoreMethodBodies(false);
parser.setProject(project);
parser.createASTs(rawSources.values().toArray(new ICompilationUnit[0]), new String[0], this, deltaAnalyzer.progressMonitor);
Alternatively, I can execute the parsing this way, and no such problems occur:
for (ICompilationUnit source : rawSources.values())
{
parser.setResolveBindings(true);
parser.setStatementsRecovery(true);
parser.setBindingsRecovery(true);
parser.setIgnoreMethodBodies(false);
parser.setProject(project);
parser.setSource(source);
CompilationUnit ast = (CompilationUnit)parser.createAST(deltaAnalyzer.progressMonitor);
parsedSources.add(deltaAnalyzer.createParsedSource(source, ast));
}
This issue occurs in both Helios and Indigo (the very latest release build). I filed a bug in Eclipse Bugzilla, but if anyone knows of a way to work around this--or if I am using the API wrong--I would greatly appreciate your help.
Byron
Without knowing exactly what your exception is, I can still offer 2 suggestions:
Have a look at org.eclipse.jdt.ui.SharedASTProvider. If you are not making any changes to ASTs, this class may provide a more robust way of getting the ASTs.
Play around with some of the settings that you are using. Do you really need bindingsRecovery set to true? What about statementRecovery? Setting these to false may help you.