Merge pull request #1269 from HubSpot/eager-break-and-continue

Enable break and continue tags to work in eager execution

Author: jasmith-hs

src/main/java/com/hubspot/jinjava/lib/tag/eager/EagerContinueTag.java

@@ -0,0 +1,33 @@
+package com.hubspot.jinjava.lib.tag.eager;
+
+import com.google.common.annotations.Beta;
+import com.hubspot.jinjava.interpret.DeferredValue;
+import com.hubspot.jinjava.interpret.JinjavaInterpreter;
+import com.hubspot.jinjava.lib.tag.ContinueTag;
+import com.hubspot.jinjava.lib.tag.ForTag;
+import com.hubspot.jinjava.tree.parse.TagToken;
+
+/**
+ * Eager decorator for the continue tag that handles reconstruction when the continue
+ * is inside a deferred context (e.g., when in deferred execution mode such as
+ * inside a deferred if condition within a for loop).
+ */
+@Beta
+public class EagerContinueTag extends EagerTagDecorator<ContinueTag> {
+
+  public EagerContinueTag() {
+    super(new ContinueTag());
+  }
+
+  public EagerContinueTag(ContinueTag continueTag) {
+    super(continueTag);
+  }
+
+  @Override
+  public String getEagerTagImage(TagToken tagToken, JinjavaInterpreter interpreter) {
+    if (!(interpreter.getContext().get(ForTag.LOOP) instanceof DeferredValue)) {
+      interpreter.getContext().replace(ForTag.LOOP, DeferredValue.instance());
+    }
+    return super.getEagerTagImage(tagToken, interpreter);
+  }
+}

src/main/java/com/hubspot/jinjava/lib/tag/eager/EagerTagFactory.java

@@ -5,7 +5,6 @@
 import com.google.common.collect.ImmutableMap;
 import com.google.common.collect.ImmutableSet;
 import com.hubspot.jinjava.lib.tag.BlockTag;
-import com.hubspot.jinjava.lib.tag.BreakTag;
 import com.hubspot.jinjava.lib.tag.CallTag;
 import com.hubspot.jinjava.lib.tag.ContinueTag;
 import com.hubspot.jinjava.lib.tag.CycleTag;
@@ -46,6 +45,7 @@ public class EagerTagFactory {
       .put(IfTag.class, EagerIfTag.class)
       .put(UnlessTag.class, EagerUnlessTag.class)
       .put(CallTag.class, EagerCallTag.class)
+      .put(ContinueTag.class, EagerContinueTag.class)
       .build();
   // These classes don't need an eager decorator.
   public static final Set<Class<? extends Tag>> TAG_CLASSES_TO_SKIP = ImmutableSet
@@ -56,8 +56,6 @@ public class EagerTagFactory {
     .add(ElseTag.class)
     .add(RawTag.class)
     .add(ExtendsTag.class) // TODO support reconstructing extends tags
-    .add(BreakTag.class) // TODO support eager break tag
-    .add(ContinueTag.class) // TODO support eager continue tag
     .build();
 
   @SuppressWarnings("unchecked")

src/test/java/com/hubspot/jinjava/EagerTest.java

@@ -24,6 +24,7 @@
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.HashMap;
+import java.util.List;
 import java.util.Map;
 import java.util.Optional;
 import java.util.Set;
@@ -1647,42 +1648,74 @@ public void itWrapsMacroThatWouldChangeCurrentPathInChildScope() {
 
   @Test
   public void itHandlesDeferredBreakInForLoop() {
-    String input = expectedTemplateInterpreter.getFixtureTemplate(
+    expectedTemplateInterpreter.assertExpectedOutput(
       "handles-deferred-break-in-for-loop/test"
     );
-    interpreter.render(input);
-    // We don't support this yet
-    assertThat(interpreter.getContext().getDeferredNodes()).isNotEmpty();
+  }
+
+  @Test
+  public void itHandlesDeferredBreakInForLoopSecondPass() {
+    localContext.put("deferred", 1);
+    expectedTemplateInterpreter.assertExpectedOutput(
+      "handles-deferred-break-in-for-loop/test.expected"
+    );
+    expectedTemplateInterpreter.assertExpectedNonEagerOutput(
+      "handles-deferred-break-in-for-loop/test.expected"
+    );
   }
 
   @Test
   public void itHandlesBreakInDeferredForLoop() {
-    String input = expectedTemplateInterpreter.getFixtureTemplate(
+    expectedTemplateInterpreter.assertExpectedOutput(
       "handles-break-in-deferred-for-loop/test"
     );
-    interpreter.render(input);
-    // We don't support this yet
-    assertThat(interpreter.getContext().getDeferredNodes()).isNotEmpty();
+  }
+
+  @Test
+  public void itHandlesBreakInDeferredForLoopSecondPass() {
+    localContext.put("deferred", List.of(0, 1, 2, 3, 4, 5));
+    expectedTemplateInterpreter.assertExpectedOutput(
+      "handles-break-in-deferred-for-loop/test.expected"
+    );
+    expectedTemplateInterpreter.assertExpectedNonEagerOutput(
+      "handles-break-in-deferred-for-loop/test.expected"
+    );
   }
 
   @Test
   public void itHandlesDeferredContinueInForLoop() {
-    String input = expectedTemplateInterpreter.getFixtureTemplate(
+    expectedTemplateInterpreter.assertExpectedOutput(
       "handles-deferred-continue-in-for-loop/test"
     );
-    interpreter.render(input);
-    // We don't support this yet
-    assertThat(interpreter.getContext().getDeferredNodes()).isNotEmpty();
+  }
+
+  @Test
+  public void itHandlesDeferredContinueInForLoopSecondPass() {
+    localContext.put("deferred", 2);
+    expectedTemplateInterpreter.assertExpectedOutput(
+      "handles-deferred-continue-in-for-loop/test.expected"
+    );
+    expectedTemplateInterpreter.assertExpectedNonEagerOutput(
+      "handles-deferred-continue-in-for-loop/test.expected"
+    );
   }
 
   @Test
   public void itHandlesContinueInDeferredForLoop() {
-    String input = expectedTemplateInterpreter.getFixtureTemplate(
+    expectedTemplateInterpreter.assertExpectedOutput(
       "handles-continue-in-deferred-for-loop/test"
     );
-    interpreter.render(input);
-    // We don't support this yet
-    assertThat(interpreter.getContext().getDeferredNodes()).isNotEmpty();
+  }
+
+  @Test
+  public void itHandlesContinueInDeferredForLoopSecondPass() {
+    localContext.put("deferred", List.of(0, 1, 2, 3, 4, 5));
+    expectedTemplateInterpreter.assertExpectedOutput(
+      "handles-continue-in-deferred-for-loop/test.expected"
+    );
+    expectedTemplateInterpreter.assertExpectedNonEagerOutput(
+      "handles-continue-in-deferred-for-loop/test.expected"
+    );
   }
 
   @Test

src/test/resources/eager/handles-break-in-deferred-for-loop/test.expected.expected.jinja

@@ -0,0 +1,4 @@
+Start loop
+i is: 0
+i is: 1
+End loop

src/test/resources/eager/handles-break-in-deferred-for-loop/test.expected.jinja

@@ -0,0 +1,8 @@
+Start loop
+{% for i in deferred %}\
+  {% if i > 1 %}\
+    {% break '' %}\
+  {% endif %}\
+  i is: {{ i }}
+{% endfor %}\
+End loop

src/test/resources/eager/handles-break-in-deferred-for-loop/test.jinja

@@ -1,8 +1,8 @@
 Start loop
-{% for i in deferred %}
-  {% if i %}
-    {% break %}
-  {% endif %}
+{% for i in deferred -%}
+  {% if i > 1 -%}
+    {% break -%}
+  {% endif -%}
   i is: {{ i }}
-{% endfor %}
+{% endfor -%}
 End loop

src/test/resources/eager/handles-continue-in-deferred-for-loop/test.expected.expected.jinja

@@ -0,0 +1,5 @@
+Start loop
+i is: 1
+i is: 3
+i is: 5
+End loop

src/test/resources/eager/handles-continue-in-deferred-for-loop/test.expected.jinja

@@ -0,0 +1,8 @@
+Start loop
+{% for i in deferred %}\
+  {% if i % 2 == 0 %}\
+    {% continue '' %}\
+  {% endif %}\
+  i is: {{ i }}
+{% endfor %}\
+End loop

src/test/resources/eager/handles-continue-in-deferred-for-loop/test.jinja

@@ -1,8 +1,8 @@
 Start loop
-{% for i in deferred %}
-  {% if i %}
-    {% continue %}
-  {% endif %}
+{% for i in deferred -%}
+  {% if i % 2 == 0 -%}
+    {% continue -%}
+  {% endif -%}
   i is: {{ i }}
-{% endfor %}
+{% endfor -%}
 End loop

src/test/resources/eager/handles-deferred-break-in-for-loop/test.expected.expected.jinja

@@ -0,0 +1,4 @@
+Start loop
+i is: 0
+i is: 1
+End loop