Fix module reload in the presence of file delete or rename

src/org/rascalmpl/exceptions/RascalStackOverflowError.java

@@ -36,7 +36,7 @@ public Throw makeThrow() {
         Environment env = deepestEnvironment;
 
         while (env != null) {
-            trace.add(env.getLocation(), env.getName());
+            trace.add(env.getCreatorLocation(), env.getName());
             env = env.getCallerScope();
         }
 

src/org/rascalmpl/interpreter/Evaluator.java

@@ -578,7 +578,7 @@ public IValue main(IRascalMonitor monitor, String module, String function, Strin
             ModuleEnvironment modEnv = getHeap().getModule(module);
             setCurrentEnvt(modEnv);
 
-            Name name = Names.toName(function, modEnv.getLocation());
+            Name name = Names.toName(function, modEnv.getCreatorLocation());
 
             Result<IValue> func = getCurrentEnvt().getVariable(name);
 
@@ -633,7 +633,7 @@ public IValue main(IRascalMonitor monitor, String module, String function, Map<S
             ModuleEnvironment modEnv = getHeap().getModule(module);
             setCurrentEnvt(modEnv);
 
-            Name name = Names.toName(function, modEnv.getLocation());
+            Name name = Names.toName(function, modEnv.getCreatorLocation());
 
             Result<IValue> func = getCurrentEnvt().getVariable(name);
 
@@ -690,7 +690,7 @@ public IValue call(String name, String module, Map<String, IValue> kwArgs, IValu
     }
 
     private IValue call(String name, Map<String,IValue> kwArgs, IValue... args) {
-        QualifiedName qualifiedName = Names.toQualifiedName(name, getCurrentEnvt().getLocation());
+        QualifiedName qualifiedName = Names.toQualifiedName(name, getCurrentEnvt().getCreatorLocation());
         setCurrentAST(qualifiedName);
         return call(qualifiedName, kwArgs, args);
     }
@@ -807,7 +807,7 @@ public StackTrace getStackTrace() {
         StackTrace trace = new StackTrace();
         Environment env = currentEnvt;
         while (env != null) {
-            trace.add(env.getLocation(), env.getName());
+            trace.add(env.getCreatorLocation(), env.getName());
             env = env.getCallerScope();
         }
         return trace.freeze();
@@ -1174,13 +1174,27 @@ private void reloadModules(IRascalMonitor monitor, Set<String> names, ISourceLoc
 
             for (String mod : names) {
                 if (heap.existsModule(mod)) {
-                    onHeap.add(mod);
+                    var uri = heap.getModuleURI(mod);
+                    assert uri != null : "guaranteed by Import::loadModule";
+
+                    if (resolverRegistry.exists(vf.sourceLocation(uri))) {
+                        // otherwise the file has been renamed or deleted, and we do
+                        // not add it to the todo list.
+                        onHeap.add(mod);
+                    }
+
                     if (recurseToExtending) {
+                        // even if a module was renamed, or deleted, the modules that were
+                        // previously extending it have to be re-evaluated.
                         extendingModules.addAll(heap.getExtendingModules(mod));
                     }
+
+                    // this module starts with a clean slate
                     heap.removeModule(heap.getModule(mod));
                 }
             }
+
+            // all extending modules start with a clean slate too.
             extendingModules.removeAll(names);
 
             job(LOADING_JOB_CONSTANT, onHeap.size(), (jobName, step) ->  {
@@ -1222,7 +1236,7 @@ private void reloadModules(IRascalMonitor monitor, Set<String> names, ISourceLoc
                                 affectedModules.add(mod);
                             }
                             else {
-                                warning("could not reimport " + imp, errorLocation);
+                                warning("File of previously imported module " + imp + " is not available anymore.", errorLocation);
                             }
                         }
                     }
@@ -1240,7 +1254,7 @@ private void reloadModules(IRascalMonitor monitor, Set<String> names, ISourceLoc
                                 env.addExtend(ext);
                             }
                             else {
-                                warning("could not re-extend " + ext, errorLocation);
+                                warning("File of previously extended module " + ext + " is not available anymore.", errorLocation);
                             }
                         }
                     }
@@ -1326,7 +1340,7 @@ public void pushEnv() {
     }
 
     private ISourceLocation getCurrentLocation() {
-        return currentAST != null ? currentAST.getLocation() : getCurrentEnvt().getLocation();
+        return currentAST != null ? currentAST.getLocation() : getCurrentEnvt().getCreatorLocation();
     }
 
     @Override  
@@ -1774,7 +1788,7 @@ public IRascalFrame getTopFrame() {
     @Override
     public ISourceLocation getCurrentPointOfExecution() {
         AbstractAST cpe = getCurrentAST();
-        return cpe != null ? cpe.getLocation() : getCurrentEnvt().getLocation();
+        return cpe != null ? cpe.getLocation() : getCurrentEnvt().getCreatorLocation();
     }
 
     @Override

src/org/rascalmpl/interpreter/env/Environment.java

@@ -205,7 +205,7 @@ public String getName() {
 	/**
 	 * @return the location where this environment was created (i.e. call site) for use in tracing
 	 */
-	public ISourceLocation getLocation() {
+	public ISourceLocation getCreatorLocation() {
 		return loc;
 	}
 

src/org/rascalmpl/interpreter/env/GlobalEnvironment.java

@@ -149,11 +149,9 @@ public ModuleEnvironment getModule(QualifiedName name, AbstractAST ast) {
 		return module;
 	}
 
-
 	public boolean existsModule(String name) {
 		return moduleEnvironment.containsKey(name);
 	}
-
 
 	@Override
 	public String toString(){

src/org/rascalmpl/interpreter/result/AbstractFunction.java

@@ -346,7 +346,7 @@ protected Type bindTypeParameters(Type actualStaticTypes, IValue[] actuals, Type
 		    if (actualStaticTypes.isOpen()) {
 			    // we have to make the environment hygenic now, because the caller scope
 			    // may have the same type variable names as the current scope
-			    actualStaticTypes = renameType(actualStaticTypes, renamings, env.getLocation());
+			    actualStaticTypes = renameType(actualStaticTypes, renamings, env.getCreatorLocation());
 			}
 
 

src/org/rascalmpl/interpreter/result/ConstructorFunction.java

@@ -79,7 +79,7 @@ public Result<IValue> computeDefaultKeywordParameter(String label, IConstructor
 		Set<GenericKeywordParameters> kws = callerEnvironment.lookupGenericKeywordParameters(constructorType.getAbstractDataType());
 		IWithKeywordParameters<? extends IConstructor> wkw = value.asWithKeywordParameters();
 		Environment old = ctx.getCurrentEnvt();
-		Environment resultEnv = new Environment(declarationEnvironment, callerEnvironment, callerEnvironment.getLocation(), URIUtil.rootLocation("initializer"), "keyword parameter initializer");
+		Environment resultEnv = new Environment(declarationEnvironment, callerEnvironment, callerEnvironment.getCreatorLocation(), URIUtil.rootLocation("initializer"), "keyword parameter initializer");
 
 		// first we compute the keyword parameters for the abstract data-type:
 		for (GenericKeywordParameters gkw : kws) {

src/org/rascalmpl/interpreter/result/JavaMethod.java

@@ -202,7 +202,7 @@ private Map<Type, Type> fastBindTypeParameters(Type[] actualStaticTypes, IValue[
 				// we have to make the environment hygenic now, because the caller scope
 				// may have the same type variable names as the current scope
 				renamings = new HashMap<>();
-				actualStaticTypes = fastRenameType(actualStaticTypes, renamings, env.getLocation());
+				actualStaticTypes = fastRenameType(actualStaticTypes, renamings, env.getCreatorLocation());
 			}
 			else {
  				renamings = Collections.emptyMap();

src/org/rascalmpl/interpreter/utils/Profiler.java

@@ -111,10 +111,10 @@ public void run(){
 						env = env.getParent();
 					}
 				if (env != null) {
-					Count currentCount = frame.get(env.getLocation());
+					Count currentCount = frame.get(env.getCreatorLocation());
 					if (currentCount == null) {
-						frame.put(env.getLocation(), new Count());
-						names.put(env.getLocation(), env.getName());
+						frame.put(env.getCreatorLocation(), new Count());
+						names.put(env.getCreatorLocation(), env.getName());
 					}
 					else {
 						currentCount.increment();

src/org/rascalmpl/semantics/dynamic/Import.java

@@ -563,7 +563,7 @@ else if (reg.exists(parserCacheFile)) {
         }
       }
       catch (URISyntaxException | ClassNotFoundException | IOException e) {
-        eval.warning("reusing parsers failed during module import: " + e.getMessage(), env.getLocation());
+        eval.warning("reusing parsers failed during module import: " + e.getMessage(), env.getCreatorLocation());
       }
 
       return result;