Add feature to ignore parse errors when doing nested interpretation

Author: jasmith-hs

src/main/java/com/hubspot/jinjava/interpret/Context.java

@@ -819,6 +819,23 @@ public TemporaryValueClosable<Boolean> withUnwrapRawOverride() {
     return temporaryValueClosable;
   }
 
+  public boolean isIgnoreParseErrors() {
+    return contextConfiguration.isIgnoreParseErrors();
+  }
+
+  private void setIgnoreParseErrors(boolean ignoreParseErrors) {
+    contextConfiguration = contextConfiguration.withIgnoreParseErrors(ignoreParseErrors);
+  }
+
+  public TemporaryValueClosable<Boolean> withIgnoreParseErrors() {
+    TemporaryValueClosable<Boolean> temporaryValueClosable = new TemporaryValueClosable<>(
+      isIgnoreParseErrors(),
+      this::setIgnoreParseErrors
+    );
+    setIgnoreParseErrors(true);
+    return temporaryValueClosable;
+  }
+
   public static class TemporaryValueClosable<T> implements AutoCloseable {
 
     private final T previousValue;
@@ -829,10 +846,26 @@ private TemporaryValueClosable(T previousValue, Consumer<T> resetValueConsumer)
       this.resetValueConsumer = resetValueConsumer;
     }
 
+    public static <T> TemporaryValueClosable<T> noOp() {
+      return new NoOpTemporaryValueClosable<>();
+    }
+
     @Override
     public void close() {
       resetValueConsumer.accept(previousValue);
     }
+
+    private static class NoOpTemporaryValueClosable<T> extends TemporaryValueClosable<T> {
+
+      private NoOpTemporaryValueClosable() {
+        super(null, null);
+      }
+
+      @Override
+      public void close() {
+        // No-op
+      }
+    }
   }
 
   public Node getCurrentNode() {

src/main/java/com/hubspot/jinjava/interpret/ContextConfigurationIF.java

@@ -47,4 +47,12 @@ default boolean isPartialMacroEvaluation() {
   default boolean isUnwrapRawOverride() {
     return false;
   }
+
+  /**
+   * When trying nested interpretation, parsing errors are likely. This flag avoids propogating to differentiate between static and dynamic parsing errors.
+   */
+  @Default
+  default boolean isIgnoreParseErrors() {
+    return false;
+  }
 }

src/main/java/com/hubspot/jinjava/interpret/JinjavaInterpreter.java

@@ -29,6 +29,7 @@
 import com.hubspot.jinjava.el.ExpressionResolver;
 import com.hubspot.jinjava.el.ext.DeferredParsingException;
 import com.hubspot.jinjava.el.ext.ExtendedParser;
+import com.hubspot.jinjava.interpret.Context.TemporaryValueClosable;
 import com.hubspot.jinjava.interpret.TemplateError.ErrorItem;
 import com.hubspot.jinjava.interpret.TemplateError.ErrorReason;
 import com.hubspot.jinjava.interpret.TemplateError.ErrorType;
@@ -83,6 +84,8 @@ public class JinjavaInterpreter implements PyishSerializable {
 
   public static final String OUTPUT_UNDEFINED_VARIABLES_ERROR =
     "OUTPUT_UNDEFINED_VARIABLES_ERROR";
+  public static final String IGNORE_NESTED_INTERPRETATION_PARSE_ERRORS =
+    "IGNORE_NESTED_INTERPRETATION_PARSE_ERRORS";
   private final Multimap<String, BlockInfo> blocks = ArrayListMultimap.create();
   private final LinkedList<Node> extendParentRoots = new LinkedList<>();
   private final Map<String, RevertibleObject> revertibleObjects = new HashMap<>();
@@ -259,7 +262,7 @@ public String renderFlat(String template) {
   public String renderFlat(String template, long renderLimit) {
     int depth = context.getRenderDepth();
 
-    try {
+    try (TemporaryValueClosable<Boolean> c = ignoreParseErrorsIfActivated()) {
       if (depth > config.getMaxRenderDepth()) {
         ENGINE_LOG.warn("Max render depth exceeded: {}", Integer.toString(depth));
         return template;
@@ -272,6 +275,17 @@ public String renderFlat(String template, long renderLimit) {
     }
   }
 
+  private TemporaryValueClosable<Boolean> ignoreParseErrorsIfActivated() {
+    return config
+        .getFeatures()
+        .getActivationStrategy(
+          JinjavaInterpreter.IGNORE_NESTED_INTERPRETATION_PARSE_ERRORS
+        )
+        .isActive(context)
+      ? context.withIgnoreParseErrors()
+      : TemporaryValueClosable.noOp();
+  }
+
   /**
    * Parse the given string into a root Node, and then renders it processing extend parents.
    *

src/main/java/com/hubspot/jinjava/tree/TreeParser.java

@@ -81,7 +81,7 @@ public Node buildTree() {
 
     do {
       if (parent != root) {
-        interpreter.addError(
+        maybeAddError(
           TemplateError.fromException(
             new MissingEndTagException(
               ((TagNode) parent).getEndName(),
@@ -113,7 +113,7 @@ private Node nextNode() {
 
     if (token.getType() == symbols.getFixed()) {
       if (token instanceof UnclosedToken) {
-        interpreter.addError(
+        maybeAddError(
           new TemplateError(
             ErrorType.WARNING,
             ErrorReason.SYNTAX_ERROR,
@@ -134,7 +134,7 @@ private Node nextNode() {
     } else if (token.getType() == symbols.getNote()) {
       String commentClosed = symbols.getClosingComment();
       if (!token.getImage().endsWith(commentClosed)) {
-        interpreter.addError(
+        maybeAddError(
           new TemplateError(
             ErrorType.WARNING,
             ErrorReason.SYNTAX_ERROR,
@@ -148,7 +148,7 @@ private Node nextNode() {
         );
       }
     } else {
-      interpreter.addError(
+      maybeAddError(
         TemplateError.fromException(
           new UnexpectedTokenException(
             token.getImage(),
@@ -237,13 +237,11 @@ private Node tag(TagToken tagToken) {
     try {
       tag = interpreter.getContext().getTag(tagToken.getTagName());
       if (tag == null) {
-        interpreter.addError(
-          TemplateError.fromException(new UnknownTagException(tagToken))
-        );
+        maybeAddError(TemplateError.fromException(new UnknownTagException(tagToken)));
         return null;
       }
     } catch (DisabledException e) {
-      interpreter.addError(
+      maybeAddError(
         new TemplateError(
           ErrorType.FATAL,
           ErrorReason.DISABLED,
@@ -292,7 +290,7 @@ private void endTag(Tag tag, TagToken tagToken) {
         hasMatchingStartTag = true;
         break;
       } else {
-        interpreter.addError(
+        maybeAddError(
           TemplateError.fromException(
             new TemplateSyntaxException(
               tagToken.getImage(),
@@ -305,7 +303,7 @@ private void endTag(Tag tag, TagToken tagToken) {
       }
     }
     if (!hasMatchingStartTag) {
-      interpreter.addError(
+      maybeAddError(
         new TemplateError(
           ErrorType.WARNING,
           ErrorReason.SYNTAX_ERROR,
@@ -326,4 +324,11 @@ private boolean isTrimmingEnabledForToken(Token token, JinjavaConfig jinjavaConf
     }
     return jinjavaConfig.getLegacyOverrides().isUseTrimmingForNotesAndExpressions();
   }
+
+  private void maybeAddError(TemplateError templateError) {
+    if (interpreter.getContext().isIgnoreParseErrors()) {
+      return;
+    }
+    interpreter.addError(templateError);
+  }
 }