Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Add rudimentary form of error recovery to parser #1733

Merged
merged 1 commit into from
Apr 19, 2023
Merged

Add rudimentary form of error recovery to parser #1733

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
203 changes: 126 additions & 77 deletions smithy-model/src/main/java/software/amazon/smithy/model/loader/IdlModelLoader.java
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -232,44 +232,48 @@ private void parseControlSection() {
Set<CharSequence> definedKeys = new HashSet<>();

while (tokenizer.getCurrentToken() == IdlToken.DOLLAR) {
tokenizer.next();
tokenizer.expect(IdlToken.IDENTIFIER, IdlToken.STRING);
String key = tokenizer.internString(tokenizer.getCurrentTokenStringSlice());
try {
tokenizer.next();
tokenizer.expect(IdlToken.IDENTIFIER, IdlToken.STRING);
String key = tokenizer.internString(tokenizer.getCurrentTokenStringSlice());

tokenizer.next();
tokenizer.skipSpaces();
tokenizer.expect(IdlToken.COLON);
tokenizer.next();
tokenizer.skipSpaces();
tokenizer.next();
tokenizer.skipSpaces();
tokenizer.expect(IdlToken.COLON);
tokenizer.next();
tokenizer.skipSpaces();

if (!definedKeys.add(key)) {
throw syntax(format("Duplicate control statement `%s`", key));
}
if (!definedKeys.add(key)) {
throw syntax(format("Duplicate control statement `%s`", key));
}

Node value = IdlNodeParser.expectAndSkipNode(tokenizer, resolver);
Node value = IdlNodeParser.expectAndSkipNode(tokenizer, resolver);

switch (key) {
case "version":
onVersion(value);
break;
case "operationInputSuffix":
operationInputSuffix = value.expectStringNode().getValue();
break;
case "operationOutputSuffix":
operationOutputSuffix = value.expectStringNode().getValue();
break;
default:
emit(ValidationEvent.builder()
.id(Validator.MODEL_ERROR)
.sourceLocation(value)
.severity(Severity.WARNING)
.message(format("Unknown control statement `%s` with value `%s",
key, Node.printJson(value)))
.build());
break;
}
switch (key) {
case "version":
onVersion(value);
break;
case "operationInputSuffix":
operationInputSuffix = value.expectStringNode().getValue();
break;
case "operationOutputSuffix":
operationOutputSuffix = value.expectStringNode().getValue();
break;
default:
emit(ValidationEvent.builder()
.id(Validator.MODEL_ERROR)
.sourceLocation(value)
.severity(Severity.WARNING)
.message(format("Unknown control statement `%s` with value `%s",
key, Node.printJson(value)))
.build());
break;
}

tokenizer.expectAndSkipBr();
tokenizer.expectAndSkipBr();
} catch (ModelSyntaxException e) {
errorRecovery(e);
}
}
}

Expand All @@ -293,19 +297,23 @@ private void onVersion(Node value) {

private void parseMetadataSection() {
while (tokenizer.doesCurrentIdentifierStartWith('m')) {
tokenizer.expectCurrentLexeme("metadata");
tokenizer.next(); // skip "metadata"
tokenizer.expectAndSkipSpaces();
tokenizer.expect(IdlToken.IDENTIFIER, IdlToken.STRING);
String key = tokenizer.internString(tokenizer.getCurrentTokenStringSlice());
tokenizer.next();
tokenizer.skipSpaces();
tokenizer.expect(IdlToken.EQUAL);
tokenizer.next();
tokenizer.skipSpaces();
Node value = IdlNodeParser.expectAndSkipNode(tokenizer, resolver);
operations.accept(new LoadOperation.PutMetadata(modelVersion, key, value));
tokenizer.expectAndSkipBr();
try {
tokenizer.expectCurrentLexeme("metadata");
tokenizer.next(); // skip "metadata"
tokenizer.expectAndSkipSpaces();
tokenizer.expect(IdlToken.IDENTIFIER, IdlToken.STRING);
String key = tokenizer.internString(tokenizer.getCurrentTokenStringSlice());
tokenizer.next();
tokenizer.skipSpaces();
tokenizer.expect(IdlToken.EQUAL);
tokenizer.next();
tokenizer.skipSpaces();
Node value = IdlNodeParser.expectAndSkipNode(tokenizer, resolver);
operations.accept(new LoadOperation.PutMetadata(modelVersion, key, value));
tokenizer.expectAndSkipBr();
} catch (ModelSyntaxException e) {
errorRecovery(e);
}
}
}

Expand Down Expand Up @@ -415,51 +423,92 @@ private void parseApplyStatement() {

private void parseFirstShapeStatement(SourceLocation possibleDocCommentLocation) {
if (tokenizer.getCurrentToken() != IdlToken.EOF) {
if (tokenizer.doesCurrentIdentifierStartWith('a')) {
parseApplyStatement();
} else {
List<IdlTraitParser.Result> traits;
boolean hasDocComment = tokenizer.getCurrentToken() == IdlToken.DOC_COMMENT;

if (possibleDocCommentLocation == null) {
traits = IdlTraitParser.parseDocsAndTraitsBeforeShape(tokenizer, resolver);
try {
if (tokenizer.doesCurrentIdentifierStartWith('a')) {
parseApplyStatement();
} else {
// In this case, this is the first shape encountered for a model file that doesn't have any
// use statements. We need to take the previously skipped documentation comments to parse
// potential use statements and apply them to this first shape.
String docLines = tokenizer.removePendingDocCommentLines();
traits = IdlTraitParser.parseDocsAndTraitsBeforeShape(tokenizer, resolver);
// Note that possibleDocCommentLocation is just a mark of where docs _could be_.
if (docLines != null) {
hasDocComment = true;
traits.add(new IdlTraitParser.Result(DocumentationTrait.ID.toString(),
new StringNode(docLines, possibleDocCommentLocation),
IdlTraitParser.TraitType.DOC_COMMENT));
List<IdlTraitParser.Result> traits;
boolean hasDocComment = tokenizer.getCurrentToken() == IdlToken.DOC_COMMENT;

if (possibleDocCommentLocation == null) {
traits = IdlTraitParser.parseDocsAndTraitsBeforeShape(tokenizer, resolver);
} else {
// In this case, this is the first shape encountered for a model file that doesn't have any
// use statements. We need to take the previously skipped documentation comments to parse
// potential use statements and apply them to this first shape.
String docLines = tokenizer.removePendingDocCommentLines();
traits = IdlTraitParser.parseDocsAndTraitsBeforeShape(tokenizer, resolver);
// Note that possibleDocCommentLocation is just a mark of where docs _could be_.
if (docLines != null) {
hasDocComment = true;
traits.add(new IdlTraitParser.Result(DocumentationTrait.ID.toString(),
new StringNode(docLines, possibleDocCommentLocation),
IdlTraitParser.TraitType.DOC_COMMENT));
}
}
}

if (parseShapeDefinition(traits, hasDocComment)) {
parseShape(traits);
if (parseShapeDefinition(traits, hasDocComment)) {
parseShape(traits);
}
}
} catch (ModelSyntaxException e) {
errorRecovery(e);
}
}
}

private void parseSubsequentShapeStatements() {
while (tokenizer.getCurrentToken() != IdlToken.EOF) {
if (tokenizer.doesCurrentIdentifierStartWith('a')) {
parseApplyStatement();
} else {
List<IdlTraitParser.Result> traits;
boolean hasDocComment = tokenizer.getCurrentToken() == IdlToken.DOC_COMMENT;
traits = IdlTraitParser.parseDocsAndTraitsBeforeShape(tokenizer, resolver);
if (parseShapeDefinition(traits, hasDocComment)) {
parseShape(traits);
while (tokenizer.hasNext()) {
try {
if (tokenizer.doesCurrentIdentifierStartWith('a')) {
parseApplyStatement();
} else {
List<IdlTraitParser.Result> traits;
boolean hasDocComment = tokenizer.getCurrentToken() == IdlToken.DOC_COMMENT;
traits = IdlTraitParser.parseDocsAndTraitsBeforeShape(tokenizer, resolver);
if (parseShapeDefinition(traits, hasDocComment)) {
parseShape(traits);
}
}
} catch (ModelSyntaxException e) {
errorRecovery(e);
}
}
}

private void errorRecovery(ModelSyntaxException e) {
if (!tokenizer.hasNext()) {
throw e;
}

// Here we do rudimentary error recovery to attempt to make sense of the remaining model.
// We do this by scanning tokens until we find the next "$", identifier, docs, or trait at the start of a line.
// The model is still invalid and will fail to validate, but things like IDEs should still be able to do
// things like goto definition.
emit(ValidationEvent.fromSourceException(e));

do {
// Always skip the current token since it was the one that failed.
IdlToken token = tokenizer.next();
if (tokenizer.getCurrentTokenColumn() == 1 && isErrorRecoveryToken(token)) {
break;
}
} while (tokenizer.hasNext());
}

// These tokens are good signals that the next shape is starting.
private boolean isErrorRecoveryToken(IdlToken token) {
switch (token) {
case IDENTIFIER:
case DOC_COMMENT:
case AT:
case DOLLAR:
return true;
default:
return false;
}
}

private boolean parseShapeDefinition(List<IdlTraitParser.Result> traits, boolean hasDocComment) {
if (tokenizer.getCurrentToken() != IdlToken.EOF) {
// Continue to parse if not at the end of the file.
Expand Down
12 changes: 9 additions & 3 deletions smithy-model/src/main/java/software/amazon/smithy/model/loader/IdlTokenizer.java
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -321,7 +321,7 @@ public IdlToken next() {
switch (c) {
case SimpleParser.EOF:
if (currentTokenType == IdlToken.EOF) {
throw new NoSuchElementException("Expected another token but traversed beyond EOF");
throw new NoSuchElementException("Expected another token but reached EOF");
}
currentTokenEnd = parser.position();
return currentTokenType = IdlToken.EOF;
Expand Down Expand Up @@ -750,9 +750,15 @@ private IdlToken parseNumber() {
}

private IdlToken parseIdentifier() {
ParserUtils.consumeIdentifier(parser);
try {
ParserUtils.consumeIdentifier(parser);
currentTokenType = IdlToken.IDENTIFIER;
} catch (RuntimeException e) {
currentTokenType = IdlToken.ERROR;
currentTokenError = e.getMessage();
}
currentTokenEnd = parser.position();
return currentTokenType = IdlToken.IDENTIFIER;
return currentTokenType;
}

private IdlToken parseString() {
Expand Down
Loading