Add ParserOption to ignore single-line comments (#2788)

This commit adds the ability to ignore single-line comments during AST conversion.

Fixes #2767

src/main/java/graphql/language/Comment.java

@@ -4,6 +4,9 @@
 
 import java.io.Serializable;
 
+/**
+ * A single-line comment. These are comments that start with a {@code #} in source documents.
+ */
 @PublicApi
 public class Comment implements Serializable {
     public final String content;

src/main/java/graphql/parser/GraphqlAntlrToLanguage.java

@@ -82,6 +82,7 @@
 @Internal
 public class GraphqlAntlrToLanguage {
 
+    private static final List<Comment> NO_COMMENTS = ImmutableKit.emptyList();
     private static final int CHANNEL_COMMENTS = 2;
     private static final int CHANNEL_IGNORED_CHARS = 3;
     private final CommonTokenStream tokens;
@@ -866,6 +867,10 @@ protected SourceLocation getSourceLocation(Token token) {
     }
 
     protected List<Comment> getComments(ParserRuleContext ctx) {
+        if (!parserOptions.isCaptureLineComments()) {
+            return NO_COMMENTS;
+        }
+
         Token start = ctx.getStart();
         if (start != null) {
             int tokPos = start.getTokenIndex();
@@ -874,7 +879,7 @@ protected List<Comment> getComments(ParserRuleContext ctx) {
                 return getCommentOnChannel(refChannel);
             }
         }
-        return ImmutableKit.emptyList();
+        return NO_COMMENTS;
     }
 
 

src/main/java/graphql/parser/ParserOptions.java

@@ -26,6 +26,7 @@ public class ParserOptions {
     private static ParserOptions defaultJvmParserOptions = newParserOptions()
             .captureIgnoredChars(false)
             .captureSourceLocation(true)
+            .captureLineComments(true)
             .maxTokens(MAX_QUERY_TOKENS) // to prevent a billion laughs style attacks, we set a default for graphql-java
 
             .build();
@@ -66,12 +67,14 @@ public static void setDefaultParserOptions(ParserOptions options) {
 
     private final boolean captureIgnoredChars;
     private final boolean captureSourceLocation;
+    private final boolean captureLineComments;
     private final int maxTokens;
     private final ParsingListener parsingListener;
 
     private ParserOptions(Builder builder) {
         this.captureIgnoredChars = builder.captureIgnoredChars;
         this.captureSourceLocation = builder.captureSourceLocation;
+        this.captureLineComments = builder.captureLineComments;
         this.maxTokens = builder.maxTokens;
         this.parsingListener = builder.parsingListener;
     }
@@ -80,7 +83,7 @@ private ParserOptions(Builder builder) {
      * Significant memory savings can be made if we do NOT capture ignored characters,
      * especially in SDL parsing.  So we have set this to false by default.
      *
-     * @return true if ignored chars are captured in AST nodes
+     * @return true if ignored chars should be captured as AST nodes
      */
     public boolean isCaptureIgnoredChars() {
         return captureIgnoredChars;
@@ -91,14 +94,28 @@ public boolean isCaptureIgnoredChars() {
      * Memory savings can be made if we do NOT set {@link graphql.language.SourceLocation}s
      * on AST nodes,  especially in SDL parsing.
      *
-     * @return true if {@link graphql.language.SourceLocation}s are captured in AST nodes
+     * @return true if {@link graphql.language.SourceLocation}s should be captured as AST nodes
      *
      * @see graphql.language.SourceLocation
      */
     public boolean isCaptureSourceLocation() {
         return captureSourceLocation;
     }
 
+    /**
+     * Single-line {@link graphql.language.Comment}s do not have any semantic meaning in
+     * GraphQL source documents, as such you may wish to ignore them.
+     * <p>
+     * This option does not ignore documentation {@link graphql.language.Description}s.
+     *
+     * @return true if {@link graphql.language.Comment}s should be captured as AST nodes
+     *
+     * @see graphql.language.SourceLocation
+     */
+    public boolean isCaptureLineComments() {
+        return captureLineComments;
+    }
+
     /**
      * A graphql hacking vector is to send nonsensical queries that burn lots of parsing CPU time and burn
      * memory representing a document that won't ever execute.  To prevent this you can set a maximum number of parse
@@ -128,6 +145,7 @@ public static class Builder {
 
         private boolean captureIgnoredChars = false;
         private boolean captureSourceLocation = true;
+        private boolean captureLineComments = true;
         private int maxTokens = MAX_QUERY_TOKENS;
         private ParsingListener parsingListener = ParsingListener.NOOP;
 
@@ -137,6 +155,7 @@ public static class Builder {
         Builder(ParserOptions parserOptions) {
             this.captureIgnoredChars = parserOptions.captureIgnoredChars;
             this.captureSourceLocation = parserOptions.captureSourceLocation;
+            this.captureLineComments = parserOptions.captureLineComments;
             this.maxTokens = parserOptions.maxTokens;
             this.parsingListener = parserOptions.parsingListener;
         }
@@ -151,6 +170,11 @@ public Builder captureSourceLocation(boolean captureSourceLocation) {
             return this;
         }
 
+        public Builder captureLineComments(boolean captureLineComments) {
+            this.captureLineComments = captureLineComments;
+            return this;
+        }
+
         public Builder maxTokens(int maxTokens) {
             this.maxTokens = maxTokens;
             return this;

src/test/groovy/graphql/parser/ParserTest.groovy

@@ -42,6 +42,7 @@ import graphql.language.VariableDefinition
 import graphql.language.VariableReference
 import org.antlr.v4.runtime.CommonTokenStream
 import org.antlr.v4.runtime.ParserRuleContext
+import spock.lang.Issue
 import spock.lang.Specification
 import spock.lang.Unroll
 
@@ -373,6 +374,28 @@ class ParserTest extends Specification {
         helloField.comments.collect { c -> c.content } == [" this is some comment, which should be captured"]
     }
 
+    @Issue("https://github.com/graphql-java/graphql-java/issues/2767")
+    def "parser does not transform comments to AST nodes when ParserOptions.captureLineComments(false)"() {
+        given:
+        def input = """
+            { # this is some comment, which should be captured
+               hello(arg: "hello, world" ) # test 
+               }
+            """
+        def parserOptionsWithoutCaptureLineComments = ParserOptions.newParserOptions()
+                .captureLineComments(false)
+                .build()
+
+        when:
+        def document = new Parser().parseDocument(input, parserOptionsWithoutCaptureLineComments)
+        Field helloField = (document.definitions[0] as OperationDefinition).selectionSet.selections[0] as Field
+
+        then:
+        isEqual(helloField, new Field("hello", [new Argument("arg", new StringValue("hello, world"))]))
+        assert helloField.comments.isEmpty() // No single-line comments on lone fields
+        assert document.comments.isEmpty() // No single-line comments in entire document
+    }
+
     @Unroll
     def "parse floatValue #floatString"() {
         given:
@@ -1118,7 +1141,7 @@ triple3 : """edge cases \\""" "" " \\"" \\" edge cases"""
         then:
         doc != null
         count == 9
-        tokens == ["query" , "{", "f" , "(", "arg", ":", "1", ")", "}"]
+        tokens == ["query", "{", "f", "(", "arg", ":", "1", ")", "}"]
 
         when: "integration test to prove it be supplied via EI"
 
@@ -1138,7 +1161,7 @@ triple3 : """edge cases \\""" "" " \\"" \\" edge cases"""
         then:
         er.errors.size() == 0
         count == 9
-        tokens == ["query" , "{", "f" , "(", "arg", ":", "1", ")", "}"]
+        tokens == ["query", "{", "f", "(", "arg", ":", "1", ")", "}"]
 
     }
 }