Flag IO.print[ln]() in SystemOut.

#java25

PiperOrigin-RevId: 808172163

Author: kluever

core/src/main/java/com/google/errorprone/bugpatterns/SystemOut.java

@@ -37,19 +37,21 @@
 /** A {@link BugChecker}; see the associated {@link BugPattern} annotation for details. */
 @BugPattern(
     summary =
-        "Printing to standard output should only be used for debugging, not in production code",
+        "Production code should not print to standard out or standard error. Standard out and"
+            + " standard error should only be used for debugging.",
     severity = WARNING,
     tags = StandardTags.LIKELY_ERROR)
-public class SystemOut extends BugChecker
+public final class SystemOut extends BugChecker
     implements MethodInvocationTreeMatcher, MemberSelectTreeMatcher {
 
-  private static final Matcher<ExpressionTree> SYSTEM_OUT =
+  private static final Matcher<ExpressionTree> BAD_FIELDS =
       anyOf(
           staticField(System.class.getName(), "out"), //
           staticField(System.class.getName(), "err"));
 
-  private static final Matcher<ExpressionTree> PRINT_STACK_TRACE =
+  private static final Matcher<ExpressionTree> BAD_METHODS =
       anyOf(
+          staticMethod().onClass("java.lang.IO").namedAnyOf("print", "println"),
           staticMethod().onClass(Thread.class.getName()).named("dumpStack").withNoParameters(),
           instanceMethod()
               .onDescendantOf(Throwable.class.getName())
@@ -58,17 +60,11 @@ public class SystemOut extends BugChecker
 
   @Override
   public Description matchMemberSelect(MemberSelectTree tree, VisitorState state) {
-    if (SYSTEM_OUT.matches(tree, state)) {
-      return describeMatch(tree);
-    }
-    return NO_MATCH;
+    return BAD_FIELDS.matches(tree, state) ? describeMatch(tree) : NO_MATCH;
   }
 
   @Override
   public Description matchMethodInvocation(MethodInvocationTree tree, VisitorState state) {
-    if (PRINT_STACK_TRACE.matches(tree, state)) {
-      return describeMatch(tree);
-    }
-    return NO_MATCH;
+    return BAD_METHODS.matches(tree, state) ? describeMatch(tree) : NO_MATCH;
   }
 }

core/src/test/java/com/google/errorprone/bugpatterns/SystemOutTest.java

@@ -16,6 +16,8 @@
 
 package com.google.errorprone.bugpatterns;
 
+import static com.google.common.truth.TruthJUnit.assume;
+
 import com.google.errorprone.CompilationTestHelper;
 import org.junit.Test;
 import org.junit.runner.RunWith;
@@ -58,6 +60,27 @@ private void p(PrintStream ps) {}
         .doTest();
   }
 
+  @Test
+  public void positiveIoPrint() {
+    assume().that(Runtime.version().feature()).isAtLeast(25);
+    helper
+        .addSourceLines(
+            "Test.java",
+            """
+            class Test {
+              void main() {
+                // BUG: Diagnostic contains: SystemOut
+                IO.print("hello JDK 25");
+                // BUG: Diagnostic contains: SystemOut
+                IO.println();
+                // BUG: Diagnostic contains: SystemOut
+                IO.println("hello JDK 25");
+              }
+            }
+            """)
+        .doTest();
+  }
+
   @Test
   public void negative() {
     helper