Make this a legacy override instead of feature.

hs-lsong · hs-lsong · commit ccb1721d4ebc · 2024-01-03T09:21:28.000-05:00
diff --git a/src/main/java/com/hubspot/jinjava/LegacyOverrides.java b/src/main/java/com/hubspot/jinjava/LegacyOverrides.java
@@ -17,6 +17,7 @@ public class LegacyOverrides {
     .withParseWhitespaceControlStrictly(true)
     .withAllowAdjacentTextNodes(true)
     .withUseTrimmingForNotesAndExpressions(true)
+    .withKeepNullableLoopValues(true)
     .build();
   private final boolean evaluateMapKeys;
   private final boolean iterateOverMapKeys;
@@ -27,6 +28,7 @@ public class LegacyOverrides {
   private final boolean parseWhitespaceControlStrictly;
   private final boolean allowAdjacentTextNodes;
   private final boolean useTrimmingForNotesAndExpressions;
+  private final boolean keepNullableLoopValues;
 
   private LegacyOverrides(Builder builder) {
     evaluateMapKeys = builder.evaluateMapKeys;
@@ -38,6 +40,7 @@ private LegacyOverrides(Builder builder) {
     parseWhitespaceControlStrictly = builder.parseWhitespaceControlStrictly;
     allowAdjacentTextNodes = builder.allowAdjacentTextNodes;
     useTrimmingForNotesAndExpressions = builder.useTrimmingForNotesAndExpressions;
+    keepNullableLoopValues = builder.keepNullableLoopValues;
   }
 
   public static Builder newBuilder() {
@@ -80,6 +83,10 @@ public boolean isUseTrimmingForNotesAndExpressions() {
     return useTrimmingForNotesAndExpressions;
   }
 
+  public boolean isKeepNullableLoopValues() {
+    return keepNullableLoopValues;
+  }
+
   public static class Builder {
     private boolean evaluateMapKeys = false;
     private boolean iterateOverMapKeys = false;
@@ -90,6 +97,7 @@ public static class Builder {
     private boolean parseWhitespaceControlStrictly = false;
     private boolean allowAdjacentTextNodes = false;
     private boolean useTrimmingForNotesAndExpressions = false;
+    private boolean keepNullableLoopValues = false;
 
     private Builder() {}
 
@@ -168,5 +176,10 @@ public Builder withUseTrimmingForNotesAndExpressions(
       this.useTrimmingForNotesAndExpressions = useTrimmingForNotesAndExpressions;
       return this;
     }
+
+    public Builder withKeepNullableLoopValues(boolean keepNullableLoopValues) {
+      this.keepNullableLoopValues = keepNullableLoopValues;
+      return this;
+    }
   }
 }
diff --git a/src/main/java/com/hubspot/jinjava/lib/tag/ForTag.java b/src/main/java/com/hubspot/jinjava/lib/tag/ForTag.java
@@ -201,7 +201,11 @@ public String renderForCollection(
 
         // set item variables
         if (loopVars.size() == 1) {
-          if (val == null && interpreter.getContext().get(loopVars.get(0)) != null) {
+          if (
+            val == null &&
+            interpreter.getContext().get(loopVars.get(0)) != null &&
+            interpreter.getConfig().getLegacyOverrides().isKeepNullableLoopValues()
+          ) {
             interpreter.getContext().put(loopVars.get(0), NullValue.INSTANCE);
           } else {
             interpreter.getContext().put(loopVars.get(0), val);
diff --git a/src/test/java/com/hubspot/jinjava/BaseJinjavaTest.java b/src/test/java/com/hubspot/jinjava/BaseJinjavaTest.java
@@ -12,7 +12,11 @@ public void baseSetup() {
         JinjavaConfig
           .newBuilder()
           .withLegacyOverrides(
-            LegacyOverrides.newBuilder().withUsePyishObjectMapper(true).build()
+            LegacyOverrides
+              .newBuilder()
+              .withUsePyishObjectMapper(true)
+              .withKeepNullableLoopValues(true)
+              .build()
           )
           .build()
       );
diff --git a/src/test/java/com/hubspot/jinjava/lib/tag/eager/EagerForTagTest.java b/src/test/java/com/hubspot/jinjava/lib/tag/eager/EagerForTagTest.java
@@ -32,7 +32,11 @@ public void eagerSetup() {
           .withMaxOutputSize(MAX_OUTPUT_SIZE)
           .withExecutionMode(EagerExecutionMode.instance())
           .withLegacyOverrides(
-            LegacyOverrides.newBuilder().withUsePyishObjectMapper(true).build()
+            LegacyOverrides
+              .newBuilder()
+              .withUsePyishObjectMapper(true)
+              .withKeepNullableLoopValues(true)
+              .build()
           )
           .build()
       );
