LexicalPreservingPrinter will remove comments when using ASTTransforms.wrapIntoResource #338
Description
Consider the following snippet:
String code =
"""
import java.nio.file.Files;
import java.io.File;
import java.io.BufferedWriter;
class A{
void f(File f){
// first comment
BufferedWriter writer = Files.newBufferedWriter(f.toPath());
// second comment
System.out.println(1);
// third comment
System.out.println(2);
}
}
""";
ParserConfiguration parserConfiguration = new ParserConfiguration();
parserConfiguration.setLanguageLevel(ParserConfiguration.LanguageLevel.BLEEDING_EDGE);
parserConfiguration.setSymbolResolver(new JavaSymbolSolver(new ReflectionTypeSolver()));
var parser = new JavaParser(parserConfiguration);
CompilationUnit cu = parser.parse(code).getResult().get();
LexicalPreservingPrinter.setup(cu);
var node = cu.findAll(VariableDeclarator.class).get(0);
var lvd = LocalVariableDeclaration.fromVariableDeclarator(node).get();
ASTTransforms.wrapIntoResource(lvd.getStatement().asExpressionStmt(), lvd.getVariableDeclarationExpr(), lvd.getScope());
System.out.println(cu);
System.out.println("------------------");
System.out.println(LexicalPreservingPrinter.print(cu));This will output:
import java.nio.file.Files;
import java.io.File;
import java.io.BufferedWriter;
class A {
void f(File f) {
// first comment
try (BufferedWriter writer = Files.newBufferedWriter(f.toPath())) {
// second comment
System.out.println(1);
// third comment
System.out.println(2);
}
}
}
------------------
import java.nio.file.Files;
import java.io.File;
import java.io.BufferedWriter;
class A{
void f(File f){
try (BufferedWriter writer = Files.newBufferedWriter(f.toPath())) {
System.out.println(1);
System.out.println(2);
}
}
}
Notice how the comments disappears if we print it with the LexicalPreservingPrinter, despite being there if we chose not to use it.
This affects all codemods that uses this transform, mainly those using the ResourceLeakFixer transform:
codeql:java/input-resource-leak, codeql:java/output-resource-leak, codeql:java/database-resource-leak, pixee:java/prevent-filewriter-leak-with-nio, pixee:java/resource-leak.