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SONARJAVA-5444 Handle case of Reader.of for try-with-resources #5231

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Merged
romainbrenguier merged 2 commits into from
Jul 3, 2025
Merged

SONARJAVA-5444 Handle case of Reader.of for try-with-resources #5231

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f66aa35
SONARJAVA-5444 add sample for Reader.of
romainbrenguier Jul 2, 2025
e1f6696
SONARJAVA-5444 Handle case of Reader.of for try-with-resources
romainbrenguier Jul 2, 2025
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63 changes: 49 additions & 14 deletions java-checks-test-sources/default/src/main/java/checks/TryWithResourcesCheckSample.java
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Original file line number Diff line number Diff line change
Expand Up @@ -3,8 +3,37 @@
import java.io.BufferedReader;
import java.io.FileReader;
import java.io.IOException;
import java.io.Reader;

class TryWithResourcesCheckSample {
String readerFactoryNonCompliant(String sequence) throws IOException {
char[] buf = new char[1024];
Reader reader = null;
try { // Noncompliant {{Change this "try" to a try-with-resources.}}
// ^^^
reader = Reader.of(sequence);
// ^^^^^^^^^^^^^^^^^^^<
reader.read(buf, 0, buf.length);
} catch (IOException e) {
throw new RuntimeException(e);
} finally {
if (reader != null) {
reader.close();
}
}
return String.valueOf(buf);
}

String readerFactoryCompliant(String sequence) {
char[] buf = new char[1024];
try (Reader reader = Reader.of(sequence)) { // Compliant
reader.read(buf, 0, buf.length);
} catch (IOException e) {
throw new RuntimeException(e);
}
return String.valueOf(buf);
}

String foo(String fileName) {
FileReader fr = null;
BufferedReader br = null;
Expand Down Expand Up @@ -32,7 +61,7 @@ String foo(String fileName) {
}
try { // compliant, no finally block so let's rely on unclosed resource rule
fr = new FileReader(fileName);
} catch (Exception e){
} catch (Exception e) {

}
try (
Expand All @@ -52,7 +81,7 @@ void newJustBeforeTryStatement() {
try { // Noncompliant {{Change this "try" to a try-with-resources.}}
// ^^^
a1.doSomething();
} finally {
} finally {
a1.close();
a2.close();
}
Expand All @@ -67,7 +96,7 @@ void newJustBeforeAndAfterTryStatement() {
a1 = new Auto();
// ^^^^^^^^^^<
a1.doSomething();
} finally {
} finally {
a1.close();
a2.close();
}
Expand All @@ -78,30 +107,33 @@ void methodBetweenNewAndTry() {
a.doSomething();
try {
a.doSomething();
} finally {
} finally {
a.close();
}
}

class B {}
class B {
}

void unknownNewBetweenNewAndTry() {
Auto a = new Auto();
B b = new B();
try {
a.doSomething();
} finally {
} finally {
a.close();
}
}

Auto passThrough(Auto a) { return a; }
Auto passThrough(Auto a) {
return a;
}

void newInsideMethodInvocation() {
Auto a = passThrough(new Auto()); // Compliant, we do not know what happens in the method
try {
a.doSomething();
} finally {
} finally {
a.close();
}
}
Expand All @@ -110,7 +142,7 @@ void newJustBeforeTryWithResource() {
Auto a1 = new Auto();
try (Auto a2 = new Auto()) {
a1.doSomething();
} finally {
} finally {
a1.close();
}
}
Expand All @@ -128,7 +160,7 @@ void enclosedTryWithFinallyStatements() {
} finally {
a2.close();
}
} finally {
} finally {
a1.close();
}
}
Expand All @@ -144,8 +176,9 @@ void enclosedTryStatements() {
try {
a2.doSomething();
a2.close();
} catch (Exception e) {}
} finally {
} catch (Exception e) {
}
} finally {
a1.close();
}
}
Expand All @@ -161,10 +194,12 @@ void method_with_while_continue(boolean a) {
}

static class Auto implements AutoCloseable {
public void doSomething() {}
public void doSomething() {
}

@Override
public void close() {}
public void close() {
}
}

}
8 changes: 7 additions & 1 deletion java-checks/src/main/java/org/sonar/java/checks/TryWithResourcesCheck.java
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Original file line number Diff line number Diff line change
Expand Up @@ -42,6 +42,11 @@ public class TryWithResourcesCheck extends IssuableSubscriptionVisitor implement
MethodMatchers.create().ofTypes("java.net.http.HttpClient").names("newHttpClient").addWithoutParametersMatcher().build()
);

private static final MethodMatchers AUTOCLOSEABLE_FACTORY_MATCHER =
MethodMatchers.create().ofSubTypes("java.io.Reader")
.names("of")
.addParametersMatcher("java.lang.CharSequence").build();

private final Deque<TryStatementTree> withinTry = new LinkedList<>();
private final Deque<List<Tree>> toReport = new LinkedList<>();

Expand Down Expand Up @@ -78,7 +83,8 @@ public void visitNode(Tree tree) {

private static boolean isNewAutocloseableOrBuilder(Tree tree, JavaFileScannerContext context) {
return (tree instanceof NewClassTree newClass && newClass.symbolType().isSubtypeOf("java.lang.AutoCloseable")) ||
(context.getJavaVersion().isJava21Compatible() && tree instanceof MethodInvocationTree mit && AUTOCLOSEABLE_BUILDER_MATCHER.matches(mit));
(context.getJavaVersion().isJava21Compatible() && tree instanceof MethodInvocationTree mit && AUTOCLOSEABLE_BUILDER_MATCHER.matches(mit))||
(tree instanceof MethodInvocationTree mit2 && AUTOCLOSEABLE_FACTORY_MATCHER.matches(mit2));
}

private static boolean isFollowedByTryWithFinally(Tree tree) {
Expand Down