Introduce documentation-support module (#428)

This new module provides the initial version of a framework for the extraction 
of data from bug checkers and Refaster rules, to be used as input for website
generation.
This commit is contained in:
Rick Ossendrijver
2023-02-13 09:27:08 +01:00
committed by GitHub
parent 14b5fa1feb
commit 0f15070883
16 changed files with 791 additions and 0 deletions

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package tech.picnic.errorprone.documentation;
import static com.google.common.base.Verify.verify;
import static com.google.common.collect.ImmutableList.toImmutableList;
import static java.util.Objects.requireNonNull;
import com.google.auto.common.AnnotationMirrors;
import com.google.auto.value.AutoValue;
import com.google.common.collect.ImmutableList;
import com.google.errorprone.BugPattern;
import com.google.errorprone.BugPattern.SeverityLevel;
import com.google.errorprone.annotations.Immutable;
import com.google.errorprone.util.ASTHelpers;
import com.sun.source.tree.AnnotationTree;
import com.sun.source.tree.ClassTree;
import com.sun.tools.javac.code.Attribute;
import com.sun.tools.javac.code.Symbol.ClassSymbol;
import com.sun.tools.javac.util.Context;
import javax.lang.model.element.AnnotationValue;
import tech.picnic.errorprone.documentation.BugPatternExtractor.BugPatternDocumentation;
/**
* An {@link Extractor} that describes how to extract data from a {@code @BugPattern} annotation.
*/
@Immutable
final class BugPatternExtractor implements Extractor<BugPatternDocumentation> {
@Override
public BugPatternDocumentation extract(ClassTree tree, Context context) {
ClassSymbol symbol = ASTHelpers.getSymbol(tree);
BugPattern annotation = symbol.getAnnotation(BugPattern.class);
requireNonNull(annotation, "BugPattern annotation must be present");
return new AutoValue_BugPatternExtractor_BugPatternDocumentation(
symbol.getQualifiedName().toString(),
annotation.name().isEmpty() ? tree.getSimpleName().toString() : annotation.name(),
ImmutableList.copyOf(annotation.altNames()),
annotation.link(),
ImmutableList.copyOf(annotation.tags()),
annotation.summary(),
annotation.explanation(),
annotation.severity(),
annotation.disableable(),
annotation.documentSuppression() ? getSuppressionAnnotations(tree) : ImmutableList.of());
}
@Override
public boolean canExtract(ClassTree tree) {
return ASTHelpers.hasDirectAnnotationWithSimpleName(tree, BugPattern.class.getSimpleName());
}
/**
* Returns the fully-qualified class names of suppression annotations specified by the {@link
* BugPattern} annotation located on the given tree.
*
* @implNote This method cannot simply invoke {@link BugPattern#suppressionAnnotations()}, as that
* will yield an "Attempt to access Class objects for TypeMirrors" exception.
*/
private static ImmutableList<String> getSuppressionAnnotations(ClassTree tree) {
AnnotationTree annotationTree =
ASTHelpers.getAnnotationWithSimpleName(
ASTHelpers.getAnnotations(tree), BugPattern.class.getSimpleName());
requireNonNull(annotationTree, "BugPattern annotation must be present");
Attribute.Array types =
doCast(
AnnotationMirrors.getAnnotationValue(
ASTHelpers.getAnnotationMirror(annotationTree), "suppressionAnnotations"),
Attribute.Array.class);
return types.getValue().stream()
.map(v -> doCast(v, Attribute.Class.class).classType.toString())
.collect(toImmutableList());
}
@SuppressWarnings("unchecked")
private static <T extends AnnotationValue> T doCast(AnnotationValue value, Class<T> target) {
verify(target.isInstance(value), "Value '%s' is not of type '%s'", value, target);
return (T) value;
}
@AutoValue
abstract static class BugPatternDocumentation {
abstract String fullyQualifiedName();
abstract String name();
abstract ImmutableList<String> altNames();
abstract String link();
abstract ImmutableList<String> tags();
abstract String summary();
abstract String explanation();
abstract SeverityLevel severityLevel();
abstract boolean canDisable();
abstract ImmutableList<String> suppressionAnnotations();
}
}

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package tech.picnic.errorprone.documentation;
import static com.google.common.base.Preconditions.checkArgument;
import com.google.auto.service.AutoService;
import com.google.common.annotations.VisibleForTesting;
import com.sun.source.util.JavacTask;
import com.sun.source.util.Plugin;
import com.sun.tools.javac.api.BasicJavacTask;
import java.nio.file.InvalidPathException;
import java.nio.file.Path;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
/**
* A compiler {@link Plugin} that analyzes and extracts relevant information for documentation
* purposes from processed files.
*/
// XXX: Find a better name for this class; it doesn't generate documentation per se.
@AutoService(Plugin.class)
public final class DocumentationGenerator implements Plugin {
@VisibleForTesting static final String OUTPUT_DIRECTORY_FLAG = "-XoutputDirectory";
private static final Pattern OUTPUT_DIRECTORY_FLAG_PATTERN =
Pattern.compile(Pattern.quote(OUTPUT_DIRECTORY_FLAG) + "=(.*)");
/** Instantiates a new {@link DocumentationGenerator} instance. */
public DocumentationGenerator() {}
@Override
public String getName() {
return getClass().getSimpleName();
}
@Override
public void init(JavacTask javacTask, String... args) {
checkArgument(args.length == 1, "Precisely one path must be provided");
javacTask.addTaskListener(
new DocumentationGeneratorTaskListener(
((BasicJavacTask) javacTask).getContext(), getOutputPath(args[0])));
}
@VisibleForTesting
static Path getOutputPath(String pathArg) {
Matcher matcher = OUTPUT_DIRECTORY_FLAG_PATTERN.matcher(pathArg);
checkArgument(
matcher.matches(), "'%s' must be of the form '%s=<value>'", pathArg, OUTPUT_DIRECTORY_FLAG);
String path = matcher.group(1);
try {
return Path.of(path);
} catch (InvalidPathException e) {
throw new IllegalArgumentException(String.format("Invalid path '%s'", path), e);
}
}
}

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package tech.picnic.errorprone.documentation;
import static java.nio.charset.StandardCharsets.UTF_8;
import com.fasterxml.jackson.annotation.JsonAutoDetect.Visibility;
import com.fasterxml.jackson.annotation.PropertyAccessor;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.sun.source.tree.ClassTree;
import com.sun.source.util.TaskEvent;
import com.sun.source.util.TaskEvent.Kind;
import com.sun.source.util.TaskListener;
import com.sun.tools.javac.api.JavacTrees;
import com.sun.tools.javac.util.Context;
import java.io.File;
import java.io.FileWriter;
import java.io.IOException;
import java.io.UncheckedIOException;
import java.net.URI;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import javax.tools.JavaFileObject;
/**
* A {@link TaskListener} that identifies and extracts relevant content for documentation generation
* and writes it to disk.
*/
// XXX: Find a better name for this class; it doesn't generate documentation per se.
final class DocumentationGeneratorTaskListener implements TaskListener {
private static final ObjectMapper OBJECT_MAPPER =
new ObjectMapper().setVisibility(PropertyAccessor.FIELD, Visibility.ANY);
private final Context context;
private final Path docsPath;
DocumentationGeneratorTaskListener(Context context, Path path) {
this.context = context;
this.docsPath = path;
}
@Override
public void started(TaskEvent taskEvent) {
if (taskEvent.getKind() == Kind.ANALYZE) {
createDocsDirectory();
}
}
@Override
public void finished(TaskEvent taskEvent) {
if (taskEvent.getKind() != Kind.ANALYZE) {
return;
}
ClassTree classTree = JavacTrees.instance(context).getTree(taskEvent.getTypeElement());
JavaFileObject sourceFile = taskEvent.getSourceFile();
if (classTree == null || sourceFile == null) {
return;
}
ExtractorType.findMatchingType(classTree)
.ifPresent(
extractorType ->
writeToFile(
extractorType.getIdentifier(),
getSimpleClassName(sourceFile.toUri()),
extractorType.getExtractor().extract(classTree, context)));
}
private void createDocsDirectory() {
try {
Files.createDirectories(docsPath);
} catch (IOException e) {
throw new IllegalStateException(
String.format("Error while creating directory with path '%s'", docsPath), e);
}
}
private <T> void writeToFile(String identifier, String className, T data) {
File file = docsPath.resolve(String.format("%s-%s.json", identifier, className)).toFile();
try (FileWriter fileWriter = new FileWriter(file, UTF_8)) {
OBJECT_MAPPER.writeValue(fileWriter, data);
} catch (IOException e) {
throw new UncheckedIOException(String.format("Cannot write to file '%s'", file.getPath()), e);
}
}
private static String getSimpleClassName(URI path) {
return Paths.get(path).getFileName().toString().replace(".java", "");
}
}

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package tech.picnic.errorprone.documentation;
import com.google.errorprone.annotations.Immutable;
import com.sun.source.tree.ClassTree;
import com.sun.tools.javac.util.Context;
/**
* Interface implemented by classes that define how to extract data of some type {@link T} from a
* given {@link ClassTree}.
*
* @param <T> The type of data that is extracted.
*/
@Immutable
interface Extractor<T> {
/**
* Extracts and returns an instance of {@link T} using the provided arguments.
*
* @param tree The {@link ClassTree} to analyze and from which to extract instances of {@link T}.
* @param context The {@link Context} in which the current compilation takes place.
* @return A non-null instance of {@link T}.
*/
// XXX: Drop `Context` parameter unless used.
T extract(ClassTree tree, Context context);
/**
* Tells whether this {@link Extractor} can extract documentation content from the given {@link
* ClassTree}.
*
* @param tree The {@link ClassTree} of interest.
* @return {@code true} iff data extraction is supported.
*/
boolean canExtract(ClassTree tree);
}

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package tech.picnic.errorprone.documentation;
import com.google.common.collect.ImmutableSet;
import com.google.common.collect.Sets;
import com.sun.source.tree.ClassTree;
import java.util.EnumSet;
import java.util.Optional;
/** An enumeration of {@link Extractor} types. */
enum ExtractorType {
BUG_PATTERN("bugpattern", new BugPatternExtractor());
private static final ImmutableSet<ExtractorType> TYPES =
Sets.immutableEnumSet(EnumSet.allOf(ExtractorType.class));
private final String identifier;
private final Extractor<?> extractor;
ExtractorType(String identifier, Extractor<?> extractor) {
this.identifier = identifier;
this.extractor = extractor;
}
String getIdentifier() {
return identifier;
}
Extractor<?> getExtractor() {
return extractor;
}
static Optional<ExtractorType> findMatchingType(ClassTree tree) {
return TYPES.stream().filter(type -> type.getExtractor().canExtract(tree)).findFirst();
}
}

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/**
* A Java compiler plugin that extracts data from compiled classes, in support of the Error Prone
* Support documentation.
*/
@com.google.errorprone.annotations.CheckReturnValue
@org.jspecify.annotations.NullMarked
package tech.picnic.errorprone.documentation;

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package tech.picnic.errorprone.documentation;
import static com.google.errorprone.BugPattern.SeverityLevel.ERROR;
import static java.nio.charset.StandardCharsets.UTF_8;
import static org.assertj.core.api.Assertions.assertThat;
import static org.assertj.core.api.Assertions.assertThatThrownBy;
import com.google.common.io.Resources;
import com.google.errorprone.BugPattern;
import com.google.errorprone.CompilationTestHelper;
import com.google.errorprone.VisitorState;
import com.google.errorprone.bugpatterns.BugChecker;
import com.google.errorprone.bugpatterns.BugChecker.ClassTreeMatcher;
import com.google.errorprone.matchers.Description;
import com.sun.source.tree.ClassTree;
import java.io.IOException;
import java.nio.file.Files;
import java.nio.file.Path;
import org.junit.jupiter.api.Test;
import org.junit.jupiter.api.io.TempDir;
final class BugPatternExtractorTest {
@Test
void noBugPattern(@TempDir Path outputDirectory) {
Compilation.compileWithDocumentationGenerator(
outputDirectory,
"TestCheckerWithoutAnnotation.java",
"import com.google.errorprone.bugpatterns.BugChecker;",
"",
"public final class TestCheckerWithoutAnnotation extends BugChecker {}");
assertThat(outputDirectory.toAbsolutePath()).isEmptyDirectory();
}
@Test
void minimalBugPattern(@TempDir Path outputDirectory) throws IOException {
Compilation.compileWithDocumentationGenerator(
outputDirectory,
"MinimalBugChecker.java",
"package pkg;",
"",
"import com.google.errorprone.BugPattern;",
"import com.google.errorprone.BugPattern.SeverityLevel;",
"import com.google.errorprone.bugpatterns.BugChecker;",
"",
"@BugPattern(summary = \"MinimalBugChecker summary\", severity = SeverityLevel.ERROR)",
"public final class MinimalBugChecker extends BugChecker {}");
verifyFileMatchesResource(
outputDirectory,
"bugpattern-MinimalBugChecker.json",
"bugpattern-documentation-minimal.json");
}
@Test
void completeBugPattern(@TempDir Path outputDirectory) throws IOException {
Compilation.compileWithDocumentationGenerator(
outputDirectory,
"CompleteBugChecker.java",
"package pkg;",
"",
"import com.google.errorprone.BugPattern;",
"import com.google.errorprone.BugPattern.SeverityLevel;",
"import com.google.errorprone.bugpatterns.BugChecker;",
"import org.junit.jupiter.api.Test;",
"",
"@BugPattern(",
" name = \"OtherName\",",
" summary = \"CompleteBugChecker summary\",",
" linkType = BugPattern.LinkType.CUSTOM,",
" link = \"https://error-prone.picnic.tech\",",
" explanation = \"Example explanation\",",
" severity = SeverityLevel.SUGGESTION,",
" altNames = \"Check\",",
" tags = BugPattern.StandardTags.SIMPLIFICATION,",
" disableable = false,",
" suppressionAnnotations = {BugPattern.class, Test.class})",
"public final class CompleteBugChecker extends BugChecker {}");
verifyFileMatchesResource(
outputDirectory,
"bugpattern-CompleteBugChecker.json",
"bugpattern-documentation-complete.json");
}
@Test
void undocumentedSuppressionBugPattern(@TempDir Path outputDirectory) throws IOException {
Compilation.compileWithDocumentationGenerator(
outputDirectory,
"UndocumentedSuppressionBugPattern.java",
"package pkg;",
"",
"import com.google.errorprone.BugPattern;",
"import com.google.errorprone.BugPattern.SeverityLevel;",
"import com.google.errorprone.bugpatterns.BugChecker;",
"",
"@BugPattern(",
" summary = \"UndocumentedSuppressionBugPattern summary\",",
" severity = SeverityLevel.WARNING,",
" documentSuppression = false)",
"public final class UndocumentedSuppressionBugPattern extends BugChecker {}");
verifyFileMatchesResource(
outputDirectory,
"bugpattern-UndocumentedSuppressionBugPattern.json",
"bugpattern-documentation-undocumented-suppression.json");
}
@Test
void bugPatternAnnotationIsAbsent() {
CompilationTestHelper.newInstance(TestChecker.class, getClass())
.addSourceLines(
"TestChecker.java",
"import com.google.errorprone.bugpatterns.BugChecker;",
"",
"// BUG: Diagnostic contains: Can extract: false",
"public final class TestChecker extends BugChecker {}")
.doTest();
}
private static void verifyFileMatchesResource(
Path outputDirectory, String fileName, String resourceName) throws IOException {
assertThat(Files.readString(outputDirectory.resolve(fileName)))
.isEqualToIgnoringWhitespace(getResource(resourceName));
}
// XXX: Once we support only JDK 15+, drop this method in favour of including the resources as
// text blocks in this class. (This also requires renaming the `verifyFileMatchesResource`
// method.)
private static String getResource(String resourceName) throws IOException {
return Resources.toString(
Resources.getResource(BugPatternExtractorTest.class, resourceName), UTF_8);
}
/** A {@link BugChecker} that validates the {@link BugPatternExtractor}. */
@BugPattern(summary = "Validates `BugPatternExtractor` extraction", severity = ERROR)
public static final class TestChecker extends BugChecker implements ClassTreeMatcher {
private static final long serialVersionUID = 1L;
@Override
public Description matchClass(ClassTree tree, VisitorState state) {
BugPatternExtractor extractor = new BugPatternExtractor();
assertThatThrownBy(() -> extractor.extract(tree, state.context))
.isInstanceOf(NullPointerException.class)
.hasMessage("BugPattern annotation must be present");
return buildDescription(tree)
.setMessage(String.format("Can extract: %s", extractor.canExtract(tree)))
.build();
}
}
}

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package tech.picnic.errorprone.documentation;
import com.google.common.collect.ImmutableList;
import com.google.errorprone.FileManagers;
import com.google.errorprone.FileObjects;
import com.sun.tools.javac.api.JavacTaskImpl;
import com.sun.tools.javac.api.JavacTool;
import com.sun.tools.javac.file.JavacFileManager;
import java.nio.file.Path;
import javax.tools.JavaCompiler;
import javax.tools.JavaFileObject;
// XXX: Generalize and move this class so that it can also be used by `refaster-compiler`.
// XXX: Add support for this class to the `ErrorProneTestHelperSourceFormat` check.
public final class Compilation {
private Compilation() {}
public static void compileWithDocumentationGenerator(
Path outputDirectory, String fileName, String... lines) {
compileWithDocumentationGenerator(outputDirectory.toAbsolutePath().toString(), fileName, lines);
}
public static void compileWithDocumentationGenerator(
String outputDirectory, String fileName, String... lines) {
compile(
ImmutableList.of("-Xplugin:DocumentationGenerator -XoutputDirectory=" + outputDirectory),
FileObjects.forSourceLines(fileName, lines));
}
private static void compile(ImmutableList<String> options, JavaFileObject javaFileObject) {
JavacFileManager javacFileManager = FileManagers.testFileManager();
JavaCompiler compiler = JavacTool.create();
JavacTaskImpl task =
(JavacTaskImpl)
compiler.getTask(
null,
javacFileManager,
null,
options,
ImmutableList.of(),
ImmutableList.of(javaFileObject));
task.call();
}
}

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package tech.picnic.errorprone.documentation;
import static com.google.common.collect.ImmutableList.toImmutableList;
import static java.nio.file.attribute.AclEntryPermission.ADD_SUBDIRECTORY;
import static org.assertj.core.api.Assertions.assertThat;
import static org.assertj.core.api.Assertions.assertThatThrownBy;
import static org.junit.jupiter.api.condition.OS.WINDOWS;
import com.google.common.collect.ImmutableSet;
import com.google.common.collect.Sets;
import java.io.IOException;
import java.nio.file.FileSystemException;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.attribute.AclEntry;
import java.nio.file.attribute.AclFileAttributeView;
import org.junit.jupiter.api.Test;
import org.junit.jupiter.api.condition.DisabledOnOs;
import org.junit.jupiter.api.condition.EnabledOnOs;
import org.junit.jupiter.api.io.TempDir;
final class DocumentationGeneratorTaskListenerTest {
@EnabledOnOs(WINDOWS)
@Test
void readOnlyFileSystemWindows(@TempDir Path outputDirectory) throws IOException {
AclFileAttributeView view =
Files.getFileAttributeView(outputDirectory, AclFileAttributeView.class);
view.setAcl(
view.getAcl().stream()
.map(
entry ->
AclEntry.newBuilder(entry)
.setPermissions(
Sets.difference(entry.permissions(), ImmutableSet.of(ADD_SUBDIRECTORY)))
.build())
.collect(toImmutableList()));
readOnlyFileSystemFailsToWrite(outputDirectory.resolve("nonexistent"));
}
@DisabledOnOs(WINDOWS)
@Test
void readOnlyFileSystemNonWindows(@TempDir Path outputDirectory) {
assertThat(outputDirectory.toFile().setWritable(false))
.describedAs("Failed to make test directory unwritable")
.isTrue();
readOnlyFileSystemFailsToWrite(outputDirectory.resolve("nonexistent"));
}
private static void readOnlyFileSystemFailsToWrite(Path outputDirectory) {
assertThatThrownBy(
() ->
Compilation.compileWithDocumentationGenerator(
outputDirectory, "A.java", "class A {}"))
.hasRootCauseInstanceOf(FileSystemException.class)
.hasCauseInstanceOf(IllegalStateException.class)
.hasMessageEndingWith("Error while creating directory with path '%s'", outputDirectory);
}
@Test
void noClassNoOutput(@TempDir Path outputDirectory) {
Compilation.compileWithDocumentationGenerator(outputDirectory, "A.java", "package pkg;");
assertThat(outputDirectory).isEmptyDirectory();
}
@Test
void excessArguments(@TempDir Path outputDirectory) {
assertThatThrownBy(
() ->
Compilation.compileWithDocumentationGenerator(
outputDirectory.toAbsolutePath() + " extra-arg", "A.java", "package pkg;"))
.isInstanceOf(IllegalArgumentException.class)
.hasMessage("Precisely one path must be provided");
}
}

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package tech.picnic.errorprone.documentation;
import static org.assertj.core.api.Assertions.assertThat;
import static org.assertj.core.api.Assertions.assertThatThrownBy;
import static tech.picnic.errorprone.documentation.DocumentationGenerator.OUTPUT_DIRECTORY_FLAG;
import java.nio.file.InvalidPathException;
import java.nio.file.Path;
import org.junit.jupiter.api.Test;
import org.junit.jupiter.params.ParameterizedTest;
import org.junit.jupiter.params.provider.ValueSource;
final class DocumentationGeneratorTest {
@ParameterizedTest
@ValueSource(strings = {"bar", "foo"})
void getOutputPath(String path) {
assertThat(DocumentationGenerator.getOutputPath(OUTPUT_DIRECTORY_FLAG + '=' + path))
.isEqualTo(Path.of(path));
}
@ParameterizedTest
@ValueSource(strings = {"", "-XoutputDirectory", "invalidOption=Test", "nothing"})
void getOutputPathWithInvalidArgument(String pathArg) {
assertThatThrownBy(() -> DocumentationGenerator.getOutputPath(pathArg))
.isInstanceOf(IllegalArgumentException.class)
.hasMessage("'%s' must be of the form '%s=<value>'", pathArg, OUTPUT_DIRECTORY_FLAG);
}
@Test
void getOutputPathWithInvalidPath() {
String basePath = "path-with-null-char-\0";
assertThatThrownBy(
() -> DocumentationGenerator.getOutputPath(OUTPUT_DIRECTORY_FLAG + '=' + basePath))
.isInstanceOf(IllegalArgumentException.class)
.hasCauseInstanceOf(InvalidPathException.class)
.hasMessageEndingWith("Invalid path '%s'", basePath);
}
}

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{
"fullyQualifiedName": "pkg.CompleteBugChecker",
"name": "OtherName",
"altNames": [
"Check"
],
"link": "https://error-prone.picnic.tech",
"tags": [
"Simplification"
],
"summary": "CompleteBugChecker summary",
"explanation": "Example explanation",
"severityLevel": "SUGGESTION",
"canDisable": false,
"suppressionAnnotations": [
"com.google.errorprone.BugPattern",
"org.junit.jupiter.api.Test"
]
}

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{
"fullyQualifiedName": "pkg.MinimalBugChecker",
"name": "MinimalBugChecker",
"altNames": [],
"link": "",
"tags": [],
"summary": "MinimalBugChecker summary",
"explanation": "",
"severityLevel": "ERROR",
"canDisable": true,
"suppressionAnnotations": [
"java.lang.SuppressWarnings"
]
}

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{
"fullyQualifiedName": "pkg.UndocumentedSuppressionBugPattern",
"name": "UndocumentedSuppressionBugPattern",
"altNames": [],
"link": "",
"tags": [],
"summary": "UndocumentedSuppressionBugPattern summary",
"explanation": "",
"severityLevel": "WARNING",
"canDisable": true,
"suppressionAnnotations": []
}