8278078: Cannot reference super before supertype constructor has been called #6642

asotona · 2021-12-01T16:32:55Z

Pull request #4376 (with fix of 8261006: 'super' qualified method references cannot occur in a static context) regressed compilation of all inner classes using .super pattern in their constructor argument to fail with:
error: cannot reference super before supertype constructor has been called

For example following source fragment cannot be compiled since that:

    class EnclClass { 
        class InnerClass extends Exception { 
            InnerClass() { 
                super(EnclClass.super.toString()); 
            } 
        } 
    }

This patch keeps throwing "cannot reference super" error for calls of .super and permits calls of .super

Plus it adds a new test.

Thanks,
Adam

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Issue

JDK-8278078: Cannot reference super before supertype constructor has been called

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Maurizio Cimadamore (@mcimadamore - Reviewer)

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… called

bridgekeeper · 2021-12-01T16:34:31Z

👋 Welcome back asotona! 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 · 2021-12-01T16:37:13Z

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mlbridge · 2021-12-01T16:42:41Z

Webrevs

mcimadamore

Looks good. For a qualified super call there are basically two cases:

qualifier is an interface name
qualifier is a class name

And there are three possible contexts:

a. constructors (this/super calls)
b. static
c. non-static

(in the JLS, (a) and (b) are the same, but javac deals with them differently).

Now, javac was correct with { b, c } x ( 1, 2 }, even before the problematic patch. It was also correct with (a, 2). But in the case of (a, 1) javac accepted the code even if that was, essentially, a reference to this before super.

The patch in 8261006 fixes this, but, while now javac rejects (a, 1), it also ends up rejecting (a, 2), which is a mistake.

Your patch seems to introduce a sharper distinction between handling of (1) and (2), so it looks good.

But I suggest that we test all possible combinations of { a, b, c } x { 1, 2 } - where for (a) we try both with super() and this() calls.

test/langtools/tools/javac/8278078/EclosingSuperTest.java

vicente-romero-oracle · 2021-12-01T17:46:50Z

yep the patch looks very sensible, modulo the tests proposed by Maurizio which will complete it

asotona · 2021-12-01T20:29:37Z

And there are three possible contexts:

a. constructors (this/super calls)
b. static
c. non-static

I'm actually not quite sure what the b. static and c. non-static contexts exactly mean in a context of this issue and how is it related with the bug subject "cannot reference super before supertype constructor has been called".

This only specifically failing case (constructor with super call to enclosing class) has been identified from the large regression compilation Corpus experiment.

I would prefer to track improvements in the actual test coverage as a separate issue, mainly to don't block this specific quick regression fix and have more time to design the test matrix more precisely.

Thanks,
Adam

mcimadamore · 2021-12-01T21:14:19Z

And there are three possible contexts:
a. constructors (this/super calls)
b. static
c. non-static

I'm actually not quite sure what the b. static and c. non-static contexts exactly mean in a context of this issue and how is it related with the bug subject "cannot reference super before supertype constructor has been called".

This only specifically failing case (constructor with super call to enclosing class) has been identified from the large regression compilation Corpus experiment.

I would prefer to track improvements in the actual test coverage as a separate issue, mainly to don't block this specific quick regression fix and have more time to design the test matrix more precisely.

It's ok to add more tests later. But at the very least I would like to see now a test which tries also this(Foo.super.m()) - because the two forms are very related.

Thanks, Adam

test/langtools/tools/javac/8278078/EnclosingSuperTest.java

extended set of compilation validation tests added set of negative tests that should result in compilation error

test/langtools/tools/javac/8278078/ValidThisAndSuperInConstructorArgTest.java

test/langtools/tools/javac/8278078/InvalidThisAndSuperInConstructorArgTest.java

openjdk · 2021-12-02T12:52:51Z

@asotona This change now passes all automated pre-integration checks.

ℹ️ This project also has non-automated pre-integration requirements. Please see the file CONTRIBUTING.md for details.

After integration, the commit message for the final commit will be:

8278078: Cannot reference super before supertype constructor has been called

Reviewed-by: mcimadamore

You can use pull request commands such as /summary, /contributor and /issue to adjust it as needed.

At the time when this comment was updated there had been 18 new commits pushed to the master branch:

b79554b: 8278130: Failure in jdk/javadoc/tool/CheckManPageOptions.java after JDK-8274639
ea905bd: 8277924: Small tweaks to foreign function and memory API
e002bfe: 8278049: G1: add precondition to set_remainder_to_point_to_start
16cfbc4: 8278071: typos in MemorySegment::set, MemorySegment::setAtIndex javadoc
84ca14d: 8277194: applications/runthese/RunThese30M.java crashes with jfrSymbolTable.cpp:305 assert(_instance != null)
103da8f: 8274639: Provide a way to disable warnings for cross-modular links
088b244: 8251216: Implement MD5 intrinsics on AArch64
a093cdd: 8276657: XSLT compiler tries to define a class with empty name
8198807: 8266435: WBMPImageReader.read() should not truncate the input stream
b226ab9: 8276141: XPathFactory set/getProperty method
... and 8 more: https://git.openjdk.java.net/jdk/compare/abaa073bcbdb202658c8a97401ffb098d71e0f16...master

As there are no conflicts, your changes will automatically be rebased on top of these commits when integrating. If you prefer to avoid this automatic rebasing, please check the documentation for the /integrate command for further details.

➡️ To integrate this PR with the above commit message to the master branch, type /integrate in a new comment.

mcimadamore · 2021-12-02T12:54:26Z

src/jdk.compiler/share/classes/com/sun/tools/javac/comp/Attr.java

@@ -4348,7 +4348,8 @@ public void visitSelect(JCFieldAccess tree) {
                if (env.info.isSelfCall &&
                        ((sym.name == names._this &&
                        site.tsym == env.enclClass.sym) ||
-                        sym.name == names._super && env.info.constructorArgs)) {
+                        sym.name == names._super && env.info.constructorArgs &&


Maybe for later - let's refactor this to:

if (sym.name == names._this) { if (site.tsym == env.enclClass.sym) { // error } } else if (sym.name == names._super && env.info.constructorArgs) { if (sitesym.isInterface() || site.tsym == env.enclClass.sym) { // error } }

The isSelfCall should imply that env.info.constructorArgs is true, probably no need to check twice.

asotona · 2021-12-02T15:27:39Z

/integrate

openjdk · 2021-12-02T15:29:38Z

Going to push as commit 8d9cb2e.
Since your change was applied there have been 23 commits pushed to the master branch:

65960f7: 8277753: Long*VectorTests.java fail with "bad AD file" on x86_32 after JDK-8276162
3889af3: 8277906: Incorrect type for IV phi of long counted loops after CCP
d2b16c8: 8276126: Dump time class transformation causes heap objects of non-boot classes to be archived
7696897: 8276837: [macos]: Error when signing the additional launcher
3d98ec1: 8273056: java.util.random does not correctly sample exponential or Gaussian distributions
b79554b: 8278130: Failure in jdk/javadoc/tool/CheckManPageOptions.java after JDK-8274639
ea905bd: 8277924: Small tweaks to foreign function and memory API
e002bfe: 8278049: G1: add precondition to set_remainder_to_point_to_start
16cfbc4: 8278071: typos in MemorySegment::set, MemorySegment::setAtIndex javadoc
84ca14d: 8277194: applications/runthese/RunThese30M.java crashes with jfrSymbolTable.cpp:305 assert(_instance != null)
... and 13 more: https://git.openjdk.java.net/jdk/compare/abaa073bcbdb202658c8a97401ffb098d71e0f16...master

Your commit was automatically rebased without conflicts.

openjdk · 2021-12-02T15:29:54Z

@asotona Pushed as commit 8d9cb2e.

💡 You may see a message that your pull request was closed with unmerged commits. This can be safely ignored.

8278078: cannot reference super before supertype constructor has been…

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openjdk bot added the rfr Pull request is ready for review label Dec 1, 2021

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vicente-romero-oracle reviewed Dec 1, 2021

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test/langtools/tools/javac/8278078/EclosingSuperTest.java Outdated Show resolved Hide resolved

fixed typo in test name

a396466

mcimadamore reviewed Dec 1, 2021

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test/langtools/tools/javac/8278078/EnclosingSuperTest.java Outdated Show resolved Hide resolved

fixed handling of <self>.super

1d09e71

extended set of compilation validation tests added set of negative tests that should result in compilation error

asotona changed the title ~~8278078: cannot reference super before supertype constructor has been called~~ 8278078: error: cannot reference super before supertype constructor has been called Dec 2, 2021

asotona changed the title ~~8278078: error: cannot reference super before supertype constructor has been called~~ 8278078: Cannot reference super before supertype constructor has been called Dec 2, 2021

mcimadamore reviewed Dec 2, 2021

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test/langtools/tools/javac/8278078/ValidThisAndSuperInConstructorArgTest.java Outdated Show resolved Hide resolved

test/langtools/tools/javac/8278078/InvalidThisAndSuperInConstructorArgTest.java Show resolved Hide resolved

aded copyright notice and method reference test

4bd9503

mcimadamore approved these changes Dec 2, 2021

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8278078: Cannot reference super before supertype constructor has been called #6642

8278078: Cannot reference super before supertype constructor has been called #6642

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8278078: Cannot reference super before supertype constructor has been called #6642

8278078: Cannot reference super before supertype constructor has been called #6642

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