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benhalasibenhalasi
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Introduce Whitespace check
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‎error-prone-experimental/src/main/java/tech/picnic/errorprone/experimental/bugpatterns/BlockStartWhitespace.java‎

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package tech.picnic.errorprone.experimental.bugpatterns;
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import static com.google.errorprone.BugPattern.LinkType.CUSTOM;
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import static com.google.errorprone.BugPattern.SeverityLevel.WARNING;
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import static com.google.errorprone.BugPattern.StandardTags.STYLE;
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import static java.util.Objects.requireNonNull;
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import static tech.picnic.errorprone.utils.Documentation.BUG_PATTERNS_BASE_URL;
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import com.google.auto.service.AutoService;
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import com.google.errorprone.BugPattern;
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import com.google.errorprone.VisitorState;
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import com.google.errorprone.annotations.Var;
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import com.google.errorprone.bugpatterns.BugChecker;
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import com.google.errorprone.bugpatterns.BugChecker.BlockTreeMatcher;
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import com.google.errorprone.bugpatterns.BugChecker.ClassTreeMatcher;
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import com.google.errorprone.fixes.SuggestedFix;
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import com.google.errorprone.matchers.Description;
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import com.sun.source.tree.BlockTree;
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import com.sun.source.tree.ClassTree;
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import com.sun.source.tree.Tree;
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/**
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* XXX: Docs: BugChecker that flags blocks that start with a new line. Link corresponding checkstyle
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* rule. XXX: Rename to something more generic, maybe "WhitespaceChecker"?
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*/
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@AutoService(BugChecker.class)
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@BugPattern(
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summary = "XXX",
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link = BUG_PATTERNS_BASE_URL + "BlockStartWhitespace",
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linkType = CUSTOM,
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severity = WARNING,
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tags = STYLE)
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public final class BlockStartWhitespace extends BugChecker
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implements BlockTreeMatcher, ClassTreeMatcher {
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private static final long serialVersionUID = 1L;
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/** Instantiates a new {@link BlockStartWhitespace} instance. */
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public BlockStartWhitespace() {}
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@Override
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public Description matchBlock(BlockTree blockTree, VisitorState state) {
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return match(blockTree, state);
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}
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@Override
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public Description matchClass(ClassTree classTree, VisitorState state) {
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return match(classTree, state);
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}
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@SuppressWarnings({"LoopOverCharArray"})
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private Description match(Tree tree, VisitorState state) {
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String source = requireNonNull(state.getSourceForNode(tree), "Source code");
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@Var boolean isInBlock = false;
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@Var int newLineCount = 0;
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@Var int lastNewLinePos = -1;
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source_loop:
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for (int pos = 0; pos < source.length(); pos++) {
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if (!isInBlock) {
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if (source.charAt(pos) == '{') {
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isInBlock = true;
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}
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continue;
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}
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switch (source.charAt(pos)) {
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// TODO: Windows? 🤢
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case '\n':
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newLineCount++;
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lastNewLinePos = pos;
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continue;
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case ' ', '\t':
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continue;
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default:
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break source_loop;
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}
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}
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if (newLineCount < 2) {
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return Description.NO_MATCH;
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}
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if (lastNewLinePos == -1) {
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throw new RuntimeException("Big oof (lastNewLinePos == -1)");
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}
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// TODO: Do we the source with the correctly formatted one, or do we replace the redundant
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// whitespace with nothing? Colliding replacements and such.
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// SuggestedFix suggestedFix = SuggestedFix.replace(source.indexOf('{') + 1, lastNewLinePos,
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// "");
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String replacement =
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source.substring(0, source.indexOf('{') + 1) + source.substring(lastNewLinePos);
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SuggestedFix suggestedFix = SuggestedFix.replace(tree, replacement);
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return describeMatch(tree, suggestedFix);
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}
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}

‎error-prone-experimental/src/test/java/tech/picnic/errorprone/experimental/bugpatterns/BlockStartWhitespaceTest.java‎

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package tech.picnic.errorprone.experimental.bugpatterns;
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import com.google.errorprone.BugCheckerRefactoringTestHelper;
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import com.google.errorprone.CompilationTestHelper;
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import org.junit.jupiter.api.Test;
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final class BlockStartWhitespaceTest {
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@Test
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void identification() {
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CompilationTestHelper.newInstance(BlockStartWhitespace.class, getClass())
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.addSourceLines(
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"A.java",
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"// BUG: Diagnostic contains:",
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"class A {",
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" ",
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" private static final int foo = 1;",
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" ",
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" ",
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" // BUG: Diagnostic contains:",
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" void method (String foo) {",
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" ",
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" System.out.println(foo);",
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" }",
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"}")
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.addSourceLines(
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"B.java",
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"class B {",
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" private static final int foo = 1;",
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// XXX: Check whitespace in-between members. Enforce different clustering based on the
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// members modifiers, e.g. empty line between static and non static fields.
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" ",
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" ",
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" void method (String foo) {",
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" System.out.println(foo);",
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" }",
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"}")
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.doTest();
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}
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@Test
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void classBodyBlock() {
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BugCheckerRefactoringTestHelper.newInstance(BlockStartWhitespace.class, getClass())
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.addInputLines(
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"Nested.java",
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"class Nested {",
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" static final class A {",
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"",
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" private static final int foo = 1;",
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" }",
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"",
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" static final class B {",
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" ",
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" private static final int foo = 1;",
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" }",
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"",
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" static final class C {",
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"",
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"\t",
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" ",
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" private static final int foo = 1;",
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" }",
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"",
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" static final class D {",
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"",
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" // comment",
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"",
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" private static final int foo = 1;",
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" }",
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"}")
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.addOutputLines(
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"Nested.java",
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"class Nested {",
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" static final class A {",
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" private static final int foo = 1;",
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" }",
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"",
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" static final class B {",
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" private static final int foo = 1;",
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" }",
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"",
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" static final class C {",
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" private static final int foo = 1;",
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" }",
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"",
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" static final class D {",
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" // comment",
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"",
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" private static final int foo = 1;",
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" }",
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"}")
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.doTest(BugCheckerRefactoringTestHelper.TestMode.TEXT_MATCH);
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}
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@Test
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void methodBodyBlock() {
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BugCheckerRefactoringTestHelper.newInstance(BlockStartWhitespace.class, getClass())
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.addInputLines(
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"A.java",
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"class A {",
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" static int methodA() {",
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"",
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" return 1;",
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" }",
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"",
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" static int methodB() {",
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" ",
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" return 1;",
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" }",
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"",
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" static int methodC() {",
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"",
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"\t",
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" ",
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" return 1;",
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" }",
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"",
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" static int methodD() {",
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"",
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" // comment",
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"",
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" return 1;",
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" }",
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"}")
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.addOutputLines(
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"A.java",
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"class A {",
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" static int methodA() {",
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" return 1;",
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" }",
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"",
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" static int methodB() {",
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" return 1;",
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" }",
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"",
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" static int methodC() {",
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" return 1;",
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" }",
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"",
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" static int methodD() {",
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" // comment",
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"",
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" return 1;",
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" }",
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"}")
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.doTest(BugCheckerRefactoringTestHelper.TestMode.TEXT_MATCH);
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}
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}

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