JavacTask.generate bug?

Jonathan Gibbons jonathan.gibbons at oracle.com
Tue Jun 15 15:18:32 PDT 2010


On 05/27/2010 04:56 PM, Jonathan Gibbons wrote:
> On 05/27/2010 04:49 PM, Joshua Maurice wrote:
>> On Thu, May 27, 2010 at 4:44 PM, Jonathan Gibbons 
>> <jonathan.gibbons at oracle.com <mailto:jonathan.gibbons at oracle.com>> wrote:
>>
>>     I don't know of any bugs in this area.     You could try setting
>>     -XDverboseCompilePolicy which is an undocumented option to trace
>>     the compiler's operation.
>>
>>     javac will stop generating files if an error is detected, but I
>>     don't see any error output coming from your test.
>>
>>     I'll not be able to look at this further until next week at the
>>     earliest. Sorry.
>>
>>     -- Jon
>>
>>
>>
>>
>>     On 05/27/2010 03:48 PM, Joshua Maurice wrote:
>>
>>         Silly question: is there a known bug in JavacTask.generate? I
>>         did a quick google search of the bug archives, and it did not
>>         come up. It seems that depending on the order of
>>         JavaFileObjects used to create the JavacTask, the fifth
>>         argument to javax.tools.JavaCompiler.getTask, it skips or
>>         does not skip generating files. Here's my stand alone example:
>>
>>
>>         import java.io.BufferedWriter;
>>         import java.io.File;
>>         import java.io.FileWriter;
>>         import java.io.IOException;
>>         import java.io.StringWriter;
>>         import java.util.Arrays;
>>         import java.util.Iterator;
>>         import java.util.List;
>>
>>         import javax.lang.model.element.Element;
>>         import javax.tools.DiagnosticCollector;
>>         import javax.tools.JavaCompiler;
>>         import javax.tools.JavaFileObject;
>>         import javax.tools.StandardJavaFileManager;
>>         import javax.tools.ToolProvider;
>>
>>         import com.sun.source.tree.CompilationUnitTree;
>>         import com.sun.source.util.JavacTask;
>>
>>         public class Foo {
>>            public static void main(String[] args) throws IOException {
>>                final File srcRoot = new File("C:/foo/src");
>>                final File tgtRoot = new File("C:/foo/tgt");
>>                writeToFile(new File(srcRoot + "/T3.java"), "public
>>         class T3 { public static final int C = 1; }\n");
>>                writeToFile(new File(srcRoot + "/T2.java"), "public
>>         class T2 extends T3 {}\n");
>>                writeToFile(new File(srcRoot + "/T1.java"), "public
>>         class T1 extends T2 {}\n");
>>                writeToFile(new File(srcRoot + "/Test.java"), "public
>>         class Test { public static final int D = T1.C; }\n");
>>
>>                final List<File> sourceFiles = Arrays.asList(new File[]{
>>                        new File(srcRoot, "/T2.java"),
>>                        new File(srcRoot, "/T1.java"),
>>                        new File(srcRoot, "/T3.java"),
>>                        new File(srcRoot, "/Test.java"),
>>                        });
>>
>>                final StringWriter compilerOutputStream = new
>>         StringWriter();
>>
>>                final List<String> compileOptions = Arrays.asList(new
>>         String[]{"-g", "-source", "1.6", "-Xlint:unchecked", "-d",
>>         tgtRoot.toString()});
>>                final JavaCompiler compiler =
>>         ToolProvider.getSystemJavaCompiler();
>>                DiagnosticCollector<JavaFileObject>
>>         diagnosticCollector = new DiagnosticCollector<JavaFileObject>();
>>                final StandardJavaFileManager fileManager =
>>         compiler.getStandardFileManager(diagnosticCollector, null, null);
>>                final Iterable<? extends JavaFileObject>
>>         sourceFileObjects =
>>         fileManager.getJavaFileObjectsFromFiles(sourceFiles);
>>                System.out.println("1- javac given java source
>>         JavaFileObjects " + sourceFileObjects);
>>                final JavaCompiler.CompilationTask task =
>>         compiler.getTask(compilerOutputStream, fileManager, null,
>>         compileOptions, null, sourceFileObjects);
>>                JavacTask javacTask = (JavacTask)task;
>>
>>                if (false) { //TOGGLE THIS
>>
>>                    final Iterable<? extends CompilationUnitTree>
>>         parsedTrees = javacTask.parse();
>>                    final Iterable<? extends Element> analyzedTrees =
>>         javacTask.analyze();
>>                    final Iterable<? extends JavaFileObject>
>>         generatedFiles = javacTask.generate();
>>
>>                    System.out.println("2- " + size(parsedTrees) + " "
>>         + size(analyzedTrees) + " " + size(generatedFiles));
>>
>>                    System.out.print("3-");
>>                    for (JavaFileObject f : generatedFiles)
>>                        System.out.print(" " + f);
>>                    System.out.println("");
>>                } else {
>>                    final boolean javacCallReturn = javacTask.call();
>>                    System.out.println("4- " + javacCallReturn);
>>                }
>>
>>                System.out.print("5-");
>>                for (File f : tgtRoot.listFiles())
>>                    System.out.print(" " + f);
>>                System.out.println("");
>>
>>                System.out.println("----");
>>                System.out.println(compilerOutputStream.toString());
>>            }
>>
>>            private static <E> int size(Iterable<E> x) {
>>                int n = 0;
>>                for (Iterator<E> iter = x.iterator(); iter.hasNext(); ++n)
>>                    iter.next();
>>                return n;
>>            }
>>
>>            private static void writeToFile(File f, String str) throws
>>         IOException  {
>>                f.getParentFile().mkdirs();
>>                BufferedWriter fout = new BufferedWriter(new
>>         FileWriter(f));
>>                try {
>>                    fout.write(str);
>>                    fout.flush();
>>                } finally {
>>                    fout.close();
>>                }
>>            }
>>         }
>>
>>
>>         When TOGGLE THIS is true, it calls "generate" on the
>>         JavacTask. The output on some execution on my computer is:
>>            1- javac given java source JavaFileObjects
>>         [C:\foo\src\T2.java, C:\foo\src\T1.java, C:\foo\src\T3.java,
>>         C:\foo\src\Test.java]
>>            2- 4 4 2
>>            3- C:\foo\tgt\T3.class C:\foo\tgt\Test.class
>>            5- C:\foo\tgt\T1.class C:\foo\tgt\T2.class
>>         C:\foo\tgt\T3.class C:\foo\tgt\Test.class
>>            ----
>>
>>         When TOGGLE THIS is false, it calls "call" on the JavacTask.
>>         The output on some execution on my computer is:
>>            1- javac given java source JavaFileObjects
>>         [C:\foo\src\T2.java, C:\foo\src\T1.java, C:\foo\src\T3.java,
>>         C:\foo\src\Test.java]
>>            4- true
>>            5- C:\foo\tgt\T1.class C:\foo\tgt\T2.class
>>         C:\foo\tgt\T3.class C:\foo\tgt\Test.class
>>            ----
>>
>>         When the order of file objects given to the JavacTask is
>>         altered, it starts to work. Ex:
>>                final List<File> sourceFiles = Arrays.asList(new File[]{
>>                        new File(srcRoot, "/Test.java"),
>>                        new File(srcRoot, "/T3.java"),
>>                        new File(srcRoot, "/T2.java"),
>>                        new File(srcRoot, "/T1.java"),
>>                        });
>>         gives output:
>>            1- javac given java source JavaFileObjects
>>         [C:\foo\src\Test.java, C:\foo\src\T3.java,
>>         C:\foo\src\T2.java, C:\foo\src\T1.java]
>>            2- 4 4 4
>>            3- C:\foo\tgt\Test.class C:\foo\tgt\T3.class
>>         C:\foo\tgt\T2.class C:\foo\tgt\T1.class
>>            5- C:\foo\tgt\T1.class C:\foo\tgt\T2.class
>>         C:\foo\tgt\T3.class C:\foo\tgt\Test.class
>>            ----
>>
>>         So, it appears as though I can work around this bug. I just
>>         have to create two different JavacTasks for each "javac task"
>>         aka "pom.xml", one to do the actual class file generation,
>>         done with the member function "call", and a second JavacTask
>>         invocation to get the analyzed parse trees to get the used
>>         types during compile (which I'm still working on figuring out
>>         how to do).
>>
>>         Finally:
>>            C:\Documents and Settings\jmaurice>javac -version
>>            javac 1.6.0_20
>>
>>
>> Using this new undocumented option, under the original code, except 
>> with TOGGLE THIS to true, after cleaning out the output folder, 
>> execution of the program prints:
>>
>> 1- javac given java source JavaFileObjects [C:\foo\src\T2.java, 
>> C:\foo\src\T1.java, C:\foo\src\T3.java, C:\foo\src\Test.java]
>> 2- 4 4 2
>> 3- C:\foo\tgt\T3.class C:\foo\tgt\Test.class
>> 5- C:\foo\tgt\T3.class C:\foo\tgt\Test.class
>> ----
>> [attribute T2]
>> [attribute T3]
>> [attribute T1]
>> [attribute Test]
>> [flow T2]
>> [flow T3]
>> [flow T1]
>> [flow Test]
>> [defer T2]
>> [desugar T3]
>> [defer T1]
>> [desugar Test]
>> [generate code T3]
>> [generate code Test]
>
>
> OK, you got my attention.  This needs to be investigated.   It looks 
> significant that T1 and T2 get deferred, then not generated.
>
> -- Jon

Joshua,

FWIW, I've recreated your issue using JDK 1.6, but your program works 
for me, using JDK7, using all 24 orderings of the 4 test files.  So it 
looks like the bug you encountered has already been fixed in JDK 7.

-- Jon


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