Implemented error recovery support in parametric language servers

rascal-lsp/src/main/java/org/rascalmpl/vscode/lsp/parametric/ParametricTextDocumentService.java

@@ -93,8 +93,6 @@
 import org.eclipse.lsp4j.jsonrpc.messages.ResponseErrorCode;
 import org.eclipse.lsp4j.services.LanguageClient;
 import org.eclipse.lsp4j.services.LanguageClientAware;
-import org.rascalmpl.exceptions.Throw;
-import org.rascalmpl.parser.gtd.exception.ParseError;
 import org.rascalmpl.uri.URIResolverRegistry;
 import org.rascalmpl.values.IRascalValueFactory;
 import org.rascalmpl.values.parsetrees.ITree;
@@ -107,7 +105,6 @@
 import org.rascalmpl.vscode.lsp.parametric.model.ParametricSummary.SummaryLookup;
 import org.rascalmpl.vscode.lsp.terminal.ITerminalIDEServer.LanguageParameter;
 import org.rascalmpl.vscode.lsp.util.CodeActions;
-import org.rascalmpl.vscode.lsp.util.Diagnostics;
 import org.rascalmpl.vscode.lsp.util.FoldingRanges;
 import org.rascalmpl.vscode.lsp.util.DocumentSymbols;
 import org.rascalmpl.vscode.lsp.util.SemanticTokenizer;
@@ -227,7 +224,8 @@ public void connect(LanguageClient client) {
     @Override
     public void didOpen(DidOpenTextDocumentParams params) {
         logger.debug("Did Open file: {}", params.getTextDocument());
-        handleParsingErrors(open(params.getTextDocument()));
+        TextDocumentState file = open(params.getTextDocument());
+        handleParsingErrors(file, file.getCurrentDiagnosticsAsync()); // No debounce
         triggerAnalyzer(params.getTextDocument(), Duration.ofMillis(800));
     }
 
@@ -279,37 +277,15 @@ private TextDocumentState updateContents(VersionedTextDocumentIdentifier doc, St
         TextDocumentState file = getFile(doc);
         logger.trace("New contents for {}", doc);
         file.update(doc.getVersion(), newContents);
-        handleParsingErrors(file, file.getCurrentTreeAsync()); // Warning: Might be a later version (when a concurrent update happened)
+        handleParsingErrors(file, file.getCurrentDiagnosticsAsync(Duration.ofMillis(800))); // Warning: Might be a later version (when a concurrent update happened)
         return file;
     }
 
-    private void handleParsingErrors(TextDocumentState file, CompletableFuture<Versioned<ITree>> futureTree) {
-        var version = file.getCurrentContent().version();
-        futureTree.handle((tree, excp) -> {
-            Diagnostic newParseError = null;
-            if (excp instanceof CompletionException) {
-                excp = excp.getCause();
-            }
-
-            if (excp instanceof Throw) {
-                Throw thrown = (Throw) excp;
-                newParseError = Diagnostics.translateRascalParseError(thrown.getException(), columns);
-            }
-            else if (excp instanceof ParseError) {
-                newParseError = Diagnostics.translateDiagnostic((ParseError)excp, columns);
-            }
-            else if (excp != null) {
-                logger.error("Parsing crashed", excp);
-                newParseError = new Diagnostic(
-                    new Range(new Position(0,0), new Position(0,1)),
-                    "Parsing failed: " + excp.getMessage(),
-                    DiagnosticSeverity.Error,
-                    "Rascal Parser");
-            }
-            logger.trace("Finished parsing tree, reporting new parse error: {} for: {}", newParseError, file.getLocation());
-            facts(file.getLocation()).reportParseErrors(file.getLocation(), version,
-                newParseError == null ? Collections.emptyList() : Collections.singletonList(newParseError));
-            return null;
+    private void handleParsingErrors(TextDocumentState file, CompletableFuture<Versioned<List<Diagnostic>>> diagnosticsAsync) {
+        diagnosticsAsync.thenAccept(diagnostics -> {
+            List<Diagnostic> parseErrors = diagnostics.get();
+            logger.trace("Finished parsing tree, reporting new parse errors: {} for: {}", parseErrors, file.getLocation());
+            facts(file.getLocation()).reportParseErrors(file.getLocation(), diagnostics.version(), parseErrors);
         });
     }
 
@@ -382,12 +358,6 @@ private CodeLens locCommandTupleToCodeLense(String languageName, IValue v) {
         return new CodeLens(Locations.toRange(loc, columns), CodeActions.constructorToCommand(dedicatedLanguageName, languageName, command), null);
     }
 
-
-
-    private void handleParsingErrors(TextDocumentState file) {
-        handleParsingErrors(file, file.getCurrentTreeAsync());
-    }
-
     private static <T> T last(List<T> l) {
         return l.get(l.size() - 1);
     }

rascal-lsp/src/main/rascal/demo/lang/pico/LanguageServer.rsc

@@ -46,7 +46,7 @@ Here we group all services such that the LSP server can link them
 with the ((Language)) definition later.
 }
 set[LanguageService] picoLanguageServer() = {
-    parsing(parser(#start[Program])),
+    parsing(parser(#start[Program], allowRecovery=true, allowAmbiguity=false)),
     documentSymbol(picoDocumentSymbolService),
     codeLens(picoCodeLenseService),
     execution(picoExecutionService),
@@ -62,7 +62,7 @@ such that quicky loaded features can be made available while slower to load
 tools come in later.
 }
 set[LanguageService] picoLanguageServerSlowSummary() = {
-    parsing(parser(#start[Program])),
+    parsing(parser(#start[Program], allowRecovery=true, allowAmbiguity=false)),
     analysis(picoAnalysisService, providesImplementations = false),
     build(picoBuildService)
 };
@@ -74,7 +74,7 @@ symbol search in the editor.
 }
 list[DocumentSymbol] picoDocumentSymbolService(start[Program] input)
   = [symbol("<input.src>", DocumentSymbolKind::\file(), input.src, children=[
-      *[symbol("<var.id>", \variable(), var.src) | /IdType var := input]
+      *[symbol("<var.id>", \variable(), var.src) | /IdType var := input, var has id]
   ])];
 
 @synopsis{The analyzer maps pico syntax trees to error messages and references}
@@ -195,7 +195,7 @@ void main() {
             pathConfig(),
             "Pico",
             {"pico", "pico-new"},
-            "demo::lang::pico::NewLanguageServer",
+            "demo::lang::pico::LanguageServer",
             "picoLanguageServer"
         )
     );
@@ -204,7 +204,7 @@ void main() {
             pathConfig(),
             "Pico",
             {"pico", "pico-new"},
-            "demo::lang::pico::NewLanguageServer",
+            "demo::lang::pico::LanguageServer",
             "picoLanguageServerSlowSummary"
         )
     );