8198317: Enhance JavacTool.getTask for flexibility #1896

lgxbslgx · 2020-12-25T16:26:39Z

Hi all,

This little patch enhances the setting of Log in JavacTool.getTask.

Thank you for taking the time to review.

Best Regards.

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JDK-8198317: Enhance JavacTool.getTask for flexibility

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$ git fetch https://git.openjdk.java.net/jdk pull/1896/head:pull/1896
$ git checkout pull/1896

bridgekeeper · 2020-12-25T16:27:34Z

👋 Welcome back lgxbslgx! A progress list of the required criteria for merging this PR into master will be added to the body of your pull request. There are additional pull request commands available for use with this pull request.

openjdk · 2020-12-25T16:28:33Z

@lgxbslgx The following label will be automatically applied to this pull request:

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mlbridge · 2020-12-25T16:32:00Z

Webrevs

jonathan-gibbons

As a general rule, all changes should have an accompanying regression test, unless there is a good reason why not. The set of good reasons has a corresponding list of JBS labels, shown here: http://openjdk.java.net/guide/#noreg

The closest match here would be noreg-trivial but I don't think it is close enough to claim that. In other words, I think this change needs a corresponding new test. It is also not uncommon for small changes like this to more effort to write the test than fixing the underlying issue.

--

Unit test: insurance against having to writing a regression test later on
Regression test: the penalty for not writing a unit test in the first place

lgxbslgx · 2020-12-26T17:30:58Z

I submit a test case. But I don't satisfy with it, because it can't meet all the situations.
I try to use the reflect api locally to write a better test. Please see the code below. The code can't be compiled.

    @Test
    public void testLogSettingInJavacTool() throws Exception {
        Class<?> pwClass = Class.forName("java.io.PrintWriter");
        Field psOutField = pwClass.getDeclaredField("psOut");
        psOutField.setAccessible(true);
        Field outField = pwClass.getDeclaredField("out");
        outField.setAccessible(true);

        // Situation: out is null and the value is not set in the context.
        JavacTaskImpl task1 = (JavacTaskImpl) ToolProvider
                .getSystemJavaCompiler()
                .getTask(null, null, null, null, null, null);
        PrintWriter writer1 = task1.getContext().get(Log.errKey);
        PrintStream psOut1 = (PrintStream) psOutField.get(writer1);
        if (!System.err.equals(psOut1)) {
            throw new Error("The PrintWriter is set uncorrectly.");
        }

        // Situation: out is not null and out is a PrintWriter.
        PrintWriter expectedPW = new PrintWriter(System.out);
        JavacTaskImpl task2 = (JavacTaskImpl) ToolProvider
                .getSystemJavaCompiler()
                .getTask(expectedPW, null, null, null, null, null);
        PrintWriter writer2 = task2.getContext().get(Log.errKey);
        PrintStream psOut2 = (PrintStream) psOutField.get(writer2);
        if (!System.out.equals(psOut2) || expectedPW.equals(writer2)) {
            throw new Error("The PrintWriter is set uncorrectly.");
        }

        // Situation: out is not null and out is not a PrintWriter.
        OutputStreamWriter expectedOSW = new OutputStreamWriter(System.out);
        JavacTaskImpl task3 = (JavacTaskImpl) ToolProvider
                .getSystemJavaCompiler()
                .getTask(expectedOSW, null, null, null, null, null);
        PrintWriter writer3 = task3.getContext().get(Log.errKey);
        Writer out3 = (Writer) outField.get(writer3);
        if (!(out3 instanceof OutputStreamWriter) || !expectedOSW.equals(out3)) {
            throw new Error("The PrintWriter is set uncorrectly.");
        }
    }

The error information is shown below.

STDERR:
test: testLogSettingInJavacTool
Exception running test testLogSettingInJavacTool: java.lang.reflect.InaccessibleObjectException: Unable to make field private java.io.PrintStream java.io.PrintWriter.psOut accessible: module java.base does not "opens java.io" to unnamed module @2fd66ad3
java.lang.reflect.InaccessibleObjectException: Unable to make field private java.io.PrintStream java.io.PrintWriter.psOut accessible: module java.base does not "opens java.io" to unnamed module @2fd66ad3
	at java.base/java.lang.reflect.AccessibleObject.checkCanSetAccessible(AccessibleObject.java:357)
	at java.base/java.lang.reflect.AccessibleObject.checkCanSetAccessible(AccessibleObject.java:297)
	at java.base/java.lang.reflect.Field.checkCanSetAccessible(Field.java:177)
	at java.base/java.lang.reflect.Field.setAccessible(Field.java:171)
	at T8198317.testLogSettingInJavacTool(T8198317.java:63)
	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:78)
	at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.base/java.lang.reflect.Method.invoke(Method.java:567)
	at toolbox.TestRunner.runTests(TestRunner.java:89)
	at toolbox.TestRunner.runTests(TestRunner.java:73)
	at T8198317.main(T8198317.java:56)
	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:78)
	at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.base/java.lang.reflect.Method.invoke(Method.java:567)
	at com.sun.javatest.regtest.agent.MainActionHelper$AgentVMRunnable.run(MainActionHelper.java:298)
	at java.base/java.lang.Thread.run(Thread.java:831)

A better test case would be appreciated.

jonathan-gibbons · 2020-12-26T17:41:38Z

While it is acceptable practice for file manager tests to access the file manager internals, and more generally for javac tests to access the javac internals, it is less good to access the internals of other parts of the system (like PrintWriter in java.base), since future changes to those components could break this test as an unwelcome side effect.

How easy would it be to observe/verify the desired behavior by monitoring the output to the resulting PrintWriter object, e.g. by triggering some known diagnostic?

jonathan-gibbons

Any time that tests split a string into lines it is really important to ensure that it works on Windows as well as Linux/Mac platforms, because of the different line endings.

The code looks OK. Alternatively, if you are not concerned to check for the exact line ending sequence, you can use split("\\R") to split on any line ending sequence. Either way, it's worth checking the test runs on platforms with both kinds of typical line ending.

jonathan-gibbons · 2020-12-29T03:31:08Z

test/langtools/tools/javac/api/8198317/T8198317.java

+        ToolProvider.getSystemJavaCompiler()
+                .getTask(null, null, null, Arrays.asList("-XDrawDiagnostics", "-Xlint:serial"), null, files)
+                .call();
+        tb.checkEqual(expected, Arrays.asList(bais.toString().split(lineSeparator)));
+        System.setErr(prev);


Although not strictly necessary in this case, it is good practice to use try ... finally to reset values back to some previous value. In other words, the System.setErr(prev); should be in the finally clause.

jonathan-gibbons · 2020-12-29T03:34:21Z

test/langtools/tools/javac/api/8198317/T8198317.java

+        List<? extends JavaFileObject> files = Arrays.asList(new MemFile("Test.java", code));
+
+        // Situation: out is null and the value is not set in the context.
+        ByteArrayOutputStream bais = new ByteArrayOutputStream();


The variable name bais is "surprising". Is it a cut-n-paste from elsewhere? I was expecting to see baos as an acronym for "byte array output stream", bais suggests "byte array input stream".

Fixed. I used ByteArrayInputStream bais = new ByteArrayInputStream(); at the beginning. Then I identified the ByteArrayInputStream is not right and changed to use ByteArrayOutputStream. But I forgot to revise the variable name bais. Sorry for wasting the time at this careless detail.

jonathan-gibbons · 2020-12-29T03:43:14Z

Given that the langtools/tier1 pre-submit tests worked for Linux and Windows, you're OK on the "newline" front.

lgxbslgx · 2021-01-05T14:29:25Z

@jonathan-gibbons I updated the code according to your comments. Thank you for taking the time to review.

bridgekeeper · 2021-02-02T15:06:48Z

@lgxbslgx This pull request has been inactive for more than 4 weeks and will be automatically closed if another 4 weeks passes without any activity. To avoid this, simply add a new comment to the pull request. Feel free to ask for assistance if you need help with progressing this pull request towards integration!

bridgekeeper · 2021-03-02T17:05:39Z

@lgxbslgx This pull request has been inactive for more than 8 weeks and will now be automatically closed. If you would like to continue working on this pull request in the future, feel free to reopen it!

lahodaj · 2021-03-02T17:43:28Z

@lgxbslgx, could you please re-open this PR? Thanks!

lgxbslgx · 2021-04-06T05:12:27Z

@lahodaj sorry for the delay. I will assist you to completing the new PR.

8198317: Enhance JavacTool.getTask for flexibility

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openjdk bot added the rfr Pull request is ready for review label Dec 25, 2020

openjdk bot added the compiler compiler-dev@openjdk.org label Dec 25, 2020

jonathan-gibbons suggested changes Dec 25, 2020

View reviewed changes

Add a test case.

f73c405

Revise test.

e13c072

jonathan-gibbons reviewed Dec 29, 2020

View reviewed changes

Revise test code. Fix typo.

909140e

bridgekeeper bot closed this Mar 2, 2021

lahodaj mentioned this pull request Mar 8, 2021

8198317: Enhance JavacTool.getTask for flexibility #2871

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lgxbslgx deleted the JDK-8198317 branch April 30, 2021 08:54

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8198317: Enhance JavacTool.getTask for flexibility #1896

8198317: Enhance JavacTool.getTask for flexibility #1896

lgxbslgx commented Dec 25, 2020 •

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8198317: Enhance JavacTool.getTask for flexibility #1896

8198317: Enhance JavacTool.getTask for flexibility #1896

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