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Optimize VisitorState#getConstantExpression #4586

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31 changes: 14 additions & 17 deletions check_api/src/main/java/com/google/errorprone/VisitorState.java
Original file line number Diff line number Diff line change
Expand Up @@ -51,6 +51,7 @@
import com.sun.tools.javac.tree.JCTree.JCCompilationUnit;
import com.sun.tools.javac.tree.TreeMaker;
import com.sun.tools.javac.util.Context;
import com.sun.tools.javac.util.Convert;
import com.sun.tools.javac.util.Name;
import com.sun.tools.javac.util.Names;
import com.sun.tools.javac.util.Options;
Expand Down Expand Up @@ -770,24 +771,20 @@ private static final class SharedState {
* Like {@link Elements#getConstantExpression}, but doesn't over-escape single quotes in strings.
*/
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);
}
if (!(value instanceof CharSequence str)) {
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I added a second commit that enables a further optimization by accepting any CharSequence; this can be backed out if desired.

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Unfortunately we're not quite ready to start using Java > 11 features in non-test code internally. I can remove the instanceof pattern when importing this, I'm just leaving a note here in case you wonder why it disappears.

return getElements().getConstantExpression(value);
}

// Don't escape single-quotes in string literals.
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));
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Incidentally I recently learned that Convert.quote does the thing we'd want now, but only for JDK 23+: openjdk/jdk@144a08e

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Er, and as a result of that change Convert.quote(char) was replaced with Convert.quote(char, boolean), so this change doesn't work with the latest JDK EA builds.

I'm not sure what the best option is. We could use reflection or MR-JARs to call the method.

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Ah, nice catch! I haven't looked at the MR-JAR setup yet, but indeed reflection should work. TBD whether I'll find some time today for a new pass.

}
return sb.toString();
}
return escaped;
return sb.append('"').toString();
}
}
Original file line number Diff line number Diff line change
Expand Up @@ -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(),
Expand Down
Original file line number Diff line number Diff line change
Expand Up @@ -351,7 +351,7 @@ 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());
}

Expand Down
Original file line number Diff line number Diff line change
Expand Up @@ -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(", "))));
}
Expand Down
Original file line number Diff line number Diff line change
Expand Up @@ -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.
Expand Down
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