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jmoraledajmoraleda
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Add withKeepTrailingNewline to LegacyOverrides.
1 parent a6c5d0b commit 5d5542a

3 files changed

Lines changed: 150 additions & 2 deletions

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‎src/main/java/com/hubspot/jinjava/LegacyOverrides.java‎

Lines changed: 13 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -21,6 +21,7 @@ public interface LegacyOverrides extends WithLegacyOverrides {
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.withAllowAdjacentTextNodes(true)
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.withUseTrimmingForNotesAndExpressions(true)
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.withKeepNullableLoopValues(true)
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.withKeepTrailingNewline(true)
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.build();
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LegacyOverrides ALL = new Builder()
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.withEvaluateMapKeys(true)
@@ -32,6 +33,7 @@ public interface LegacyOverrides extends WithLegacyOverrides {
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.withAllowAdjacentTextNodes(true)
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.withUseTrimmingForNotesAndExpressions(true)
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.withKeepNullableLoopValues(true)
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.withKeepTrailingNewline(false)
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.build();
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@Value.Default
@@ -79,6 +81,17 @@ default boolean isKeepNullableLoopValues() {
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return false;
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}
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/**
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* When {@code false} (default, legacy behaviour), the trailing newline of
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* the rendered output is preserved — matching Jinjava's historical behaviour.
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* When {@code true}, a single trailing newline is stripped from the rendered
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* output, matching Python Jinja2's default ({@code keep_trailing_newline=False}).
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*/
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@Value.Default
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default boolean isKeepTrailingNewline() {
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return true;
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}
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class Builder extends ImmutableLegacyOverrides.Builder {}
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static Builder newBuilder() {

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

Lines changed: 14 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -510,7 +510,7 @@ private String render(Node root, boolean processExtendRoots, long renderLimit) {
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}
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if (ignoredOutput.length() > 0) {
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return (
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return stripTrailingNewlineIfNeeded(
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EagerReconstructionUtils.labelWithNotes(
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EagerReconstructionUtils.wrapInTag(
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ignoredOutput.toString(),
@@ -524,14 +524,26 @@ private String render(Node root, boolean processExtendRoots, long renderLimit) {
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output.getValue()
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);
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}
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return output.getValue();
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return stripTrailingNewlineIfNeeded(output.getValue());
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} finally {
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if (pushed) {
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JinjavaInterpreter.popCurrent();
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}
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}
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}
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/**
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* Strips a single trailing newline from the rendered output when
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* {@code keepTrailingNewline} is {@code false} in {@link LegacyOverrides},
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* matching Python Jinja2's default {@code keep_trailing_newline=False} behaviour.
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*/
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private String stripTrailingNewlineIfNeeded(String output) {
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if (!config.getLegacyOverrides().isKeepTrailingNewline() && output.endsWith("\n")) {
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return output.substring(0, output.length() - 1);
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}
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return output;
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}
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private void resolveBlockStubs(OutputList output) {
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resolveBlockStubs(output, new Stack<>());
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}

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

Lines changed: 123 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,123 @@
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package com.hubspot.jinjava;
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import static org.assertj.core.api.Assertions.assertThat;
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import com.google.common.collect.ImmutableMap;
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import java.util.HashMap;
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import org.junit.Test;
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public class TrailingNewlineTest {
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private static final String TEMPLATE_WITH_TRAILING_NEWLINE = "hello\n";
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private static final String TEMPLATE_WITHOUT_TRAILING_NEWLINE = "hello";
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private static final String TEMPLATE_MULTIPLE_TRAILING_NEWLINES = "hello\n\n";
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// ── keepTrailingNewline=true (legacy default: preserve \n) ─────────────────
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@Test
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public void itKeepsTrailingNewlineWhenLegacyOverrideIsTrue() {
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Jinjava jinjava = new Jinjava(
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JinjavaConfig
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.newBuilder()
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.withLegacyOverrides(
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LegacyOverrides.newBuilder().withKeepTrailingNewline(true).build()
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)
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.build()
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);
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assertThat(jinjava.render(TEMPLATE_WITH_TRAILING_NEWLINE, new HashMap<>()))
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.isEqualTo("hello\n");
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}
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@Test
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public void itKeepsTrailingNewlineWithNoneLegacyOverrides() {
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// LegacyOverrides.NONE defaults keepTrailingNewline=true (legacy behaviour)
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Jinjava jinjava = new Jinjava(
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JinjavaConfig.newBuilder().withLegacyOverrides(LegacyOverrides.NONE).build()
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);
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assertThat(jinjava.render(TEMPLATE_WITH_TRAILING_NEWLINE, new HashMap<>()))
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.isEqualTo("hello\n");
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}
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// ── keepTrailingNewline=false (Python-compatible: strip trailing \n) ────────
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@Test
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public void itStripsTrailingNewlineWhenLegacyOverrideIsFalse() {
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Jinjava jinjava = new Jinjava(
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JinjavaConfig
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.newBuilder()
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.withLegacyOverrides(
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LegacyOverrides.newBuilder().withKeepTrailingNewline(false).build()
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)
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.build()
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);
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assertThat(jinjava.render(TEMPLATE_WITH_TRAILING_NEWLINE, new HashMap<>()))
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.isEqualTo("hello");
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}
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@Test
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public void itKeepsTrailingNewlineWithThreePointOLegacyOverrides() {
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// LegacyOverrides.THREE_POINT_0 does not opt into Python-compatible stripping
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Jinjava jinjava = new Jinjava(
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JinjavaConfig
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.newBuilder()
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.withLegacyOverrides(LegacyOverrides.THREE_POINT_0)
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.build()
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);
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assertThat(jinjava.render(TEMPLATE_WITH_TRAILING_NEWLINE, new HashMap<>()))
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.isEqualTo("hello\n");
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}
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@Test
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public void itStripsTrailingNewlineWithAllLegacyOverrides() {
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Jinjava jinjava = new Jinjava(
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JinjavaConfig.newBuilder().withLegacyOverrides(LegacyOverrides.ALL).build()
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);
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assertThat(jinjava.render(TEMPLATE_WITH_TRAILING_NEWLINE, new HashMap<>()))
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.isEqualTo("hello");
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}
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// ── Edge cases ──────────────────────────────────────────────────────────────
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@Test
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public void itDoesNotAffectOutputWithNoTrailingNewline() {
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Jinjava jinjava = new Jinjava(
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JinjavaConfig
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.newBuilder()
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.withLegacyOverrides(
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LegacyOverrides.newBuilder().withKeepTrailingNewline(false).build()
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)
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.build()
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);
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assertThat(jinjava.render(TEMPLATE_WITHOUT_TRAILING_NEWLINE, new HashMap<>()))
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.isEqualTo("hello");
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}
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@Test
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public void itStripsOnlyOneTrailingNewlineNotMultiple() {
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// Python only strips a single trailing newline, not all of them.
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Jinjava jinjava = new Jinjava(
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JinjavaConfig
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.newBuilder()
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.withLegacyOverrides(
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LegacyOverrides.newBuilder().withKeepTrailingNewline(false).build()
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)
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.build()
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);
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assertThat(jinjava.render(TEMPLATE_MULTIPLE_TRAILING_NEWLINES, new HashMap<>()))
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.isEqualTo("hello\n");
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}
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@Test
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public void itStripsTrailingNewlineFromRenderedExpressions() {
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Jinjava jinjava = new Jinjava(
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JinjavaConfig
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.newBuilder()
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.withLegacyOverrides(
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LegacyOverrides.newBuilder().withKeepTrailingNewline(false).build()
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)
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.build()
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);
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assertThat(jinjava.render("{{ greeting }}\n", ImmutableMap.of("greeting", "hello")))
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.isEqualTo("hello");
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}
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}

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