Optimize VisitorState#getConstantExpression

By avoiding a second pass over the string.

Fixes #4586

FUTURE_COPYBARA_INTEGRATE_REVIEW=#4586 from PicnicSupermarket:sschroevers/optimize-getConstantExpression 45f3401
PiperOrigin-RevId: 711440462

Author: Stephan202

check_api/pom.xml

@@ -181,6 +181,22 @@
               </jdkToolchain>
             </configuration>
           </execution>
+          <execution>
+            <id>java23</id>
+            <goals>
+              <goal>compile</goal>
+            </goals>
+            <configuration>
+              <jdkToolchain>
+                <version>23</version>
+              </jdkToolchain>
+              <compileSourceRoots>
+                <compileSourceRoot>${basedir}/src/main/java23</compileSourceRoot>
+              </compileSourceRoots>
+              <!-- multiReleaseOutput requires setting release -->
+              <outputDirectory>${project.build.outputDirectory}/META-INF/versions/23</outputDirectory>
+            </configuration>
+          </execution>
           <execution>
             <id>java24</id>
             <configuration>
@@ -197,6 +213,17 @@
         </executions>
 
       </plugin>
+      <plugin>
+        <groupId>org.apache.maven.plugins</groupId>
+        <artifactId>maven-jar-plugin</artifactId>
+        <configuration>
+          <archive>
+            <manifestEntries>
+              <Multi-Release>true</Multi-Release>
+            </manifestEntries>
+          </archive>
+        </configuration>
+      </plugin>
     </plugins>
   </build>
 

check_api/src/main/java/com/google/errorprone/ConstantStringExpressions.java

@@ -0,0 +1,46 @@
+/*
+ * Copyright 2024 The Error Prone Authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.google.errorprone;
+
+import com.sun.tools.javac.util.Convert;
+import javax.lang.model.util.Elements;
+
+/**
+ * @see VisitorState#getConstantExpression(Object)
+ */
+final class ConstantStringExpressions {
+  private ConstantStringExpressions() {}
+
+  static String toConstantStringExpression(Object value, Elements elements) {
+    if (!(value instanceof CharSequence)) {
+      return elements.getConstantExpression(value);
+    }
+
+    // Don't escape single-quotes in string literals.
+    CharSequence str = (CharSequence) value;
+    StringBuilder sb = new StringBuilder("\"");
+    for (int i = 0; i < str.length(); i++) {
+      char c = str.charAt(i);
+      if (c == '\'') {
+        sb.append('\'');
+      } else {
+        sb.append(Convert.quote(c));
+      }
+    }
+    return sb.append('"').toString();
+  }
+}

check_api/src/main/java/com/google/errorprone/VisitorState.java

@@ -18,6 +18,7 @@
 
 import static com.google.common.base.Preconditions.checkArgument;
 import static com.google.common.base.Preconditions.checkNotNull;
+import static com.google.errorprone.ConstantStringExpressions.toConstantStringExpression;
 import static com.google.errorprone.util.ASTHelpers.getStartPosition;
 
 import com.google.common.annotations.VisibleForTesting;
@@ -757,27 +758,10 @@ private static final class SharedState {
 
   /**
    * Returns the Java source code for a constant expression representing the given constant value.
-   * Like {@link Elements#getConstantExpression}, but doesn't over-escape single quotes in strings.
+   * Like {@link Elements#getConstantExpression}, but (a) before JDK 23, doesn't over-escape single
+   * quotes in strings and (b) treats any {@link CharSequence} as a {@link String}.
    */
   public String getConstantExpression(Object value) {
-    String escaped = getElements().getConstantExpression(value);
-    if (value instanceof String) {
-      // Don't escape single-quotes in string literals
-      StringBuilder sb = new StringBuilder();
-      for (int i = 0; i < escaped.length(); i++) {
-        char c = escaped.charAt(i);
-        if (c == '\\' && i + 1 < escaped.length()) {
-          char next = escaped.charAt(++i);
-          if (next != '\'') {
-            sb.append(c);
-          }
-          sb.append(next);
-        } else {
-          sb.append(c);
-        }
-      }
-      return sb.toString();
-    }
-    return escaped;
+    return toConstantStringExpression(value, this.getElements());
   }
 }

check_api/src/main/java23/com/google/errorprone/ConstantStringExpressions.java

@@ -0,0 +1,31 @@
+/*
+ * Copyright 2024 The Error Prone Authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.google.errorprone;
+
+import javax.lang.model.util.Elements;
+
+/**
+ * @see VisitorState#getConstantExpression(Object)
+ */
+final class ConstantStringExpressions {
+  private ConstantStringExpressions() {}
+
+  static String toConstantStringExpression(Object value, Elements elements) {
+    return elements.getConstantExpression(
+        value instanceof CharSequence charSequence ? charSequence.toString() : value);
+  }
+}

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

@@ -73,7 +73,7 @@ public Description matchMethodInvocation(MethodInvocationTree tree, VisitorState
     MethodSymbol symbol = getSymbol(parent);
     String argReplacement =
         Streams.concat(
-                Stream.of(state.getConstantExpression(symbol.getSimpleName().toString())),
+                Stream.of(state.getConstantExpression(symbol.getSimpleName())),
                 Streams.zip(
                     symbol.getParameters().stream(),
                     parent.getArguments().stream(),

core/src/main/java/com/google/errorprone/bugpatterns/flogger/FloggerArgumentToString.java

@@ -352,7 +352,7 @@ Description unwrapArguments(
     if (!fixed) {
       return NO_MATCH;
     }
-    fix.replace(tree.getArguments().get(0), state.getConstantExpression(sb.toString()));
+    fix.replace(tree.getArguments().get(0), state.getConstantExpression(sb));
     return describeMatch(tree, fix.build());
   }
 

core/src/main/java/com/google/errorprone/bugpatterns/flogger/FloggerStringConcatenation.java

@@ -112,7 +112,7 @@ protected Void defaultAction(Tree tree, Void unused) {
         tree,
         SuggestedFix.replace(
             argument,
-            state.getConstantExpression(formatString.toString())
+            state.getConstantExpression(formatString)
                 + ", "
                 + formatArguments.stream().map(state::getSourceForNode).collect(joining(", "))));
   }

core/src/test/java/com/google/errorprone/VisitorStateTest.java

@@ -106,6 +106,8 @@ public void getConstantExpression() {
     assertThat(visitorState.getConstantExpression("hello \n world"))
         .isEqualTo("\"hello \\n world\"");
     assertThat(visitorState.getConstantExpression('\'')).isEqualTo("'\\''");
+    assertThat(visitorState.getConstantExpression(new StringBuilder("hello ' world")))
+        .isEqualTo("\"hello ' world\"");
   }
 
   // The following is taken from ErrorProneJavacPluginTest. There may be an easier way.