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8043179: Lambda expression can mutate final field
(Description revised)
JDK-8043176 updated the JLS 16.1.10 to describe how within a lambda body, any variables that were DU before the lambda expression must not be considered DU at the start of the lambda block, because arbitrary code could have executed in the meantime:
No rule allows V to be definitely unassigned before a lambda body. This is by design: a variable that was definitely unassigned before the lambda body may end up being assigned to later on, so we cannot conclude that the variable will be unassigned when the body is executed.
This fix to Flow.AssignAnalyzer follows in a straightforward way: mark all variables as not DU before recursing into the lambda body.
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- JDK-8043179: Lambda expression can mutate final field
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I've updated this pull request to include a new unit test (apologies for omitting it previously).
Also there are a couple of changes to other unit tests which get broken because this change reflects changes to the JLS spec per JDK-8043176. I'm a little unclear on precisely what the new behavior is supposed to be, but in any case the actual behavior now makes a lot more sense: basically, everything that happens in a lambda is assumed to happen some indefinite time later in the future (same as if you were instantiating the equivalent local class), so the previous errors expected by T8024809/SelfInitializerInLambdaTestb.java regarding instance field initialization are no longer errors.
In summary:
- Added new unit test
LambdaMutateFinalField.javatesting JDK-8043179 directly. - Unit test
lambda/self_initializer/T8024809/SelfInitializerInLambdaTestb.javais now obsolete. Now it compiles successfully. - Unit test
lambda/lambdaExpression/EffectivelyFinal_neg.javastill works, but no longer generates a duplicate error. I think this is a good thing? The expected test output has been updated.
With the above changes now all javac tests should succeed.
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8043179: Lambda expression can mutate final field
Reviewed-by: vromero
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At the time when this comment was updated there had been 34 new commits pushed to the master branch:
- bf917ba6af9a69859f469a1e8056fbd32396cae4: 8304687: Move add_to_hierarchy
- 63d4afbeb17df4eff0f65041926373ee62a8a33a: 8304671: javac regression: Compilation with --release 8 fails on underscore in enum identifiers
- e2cfcfbfa90017b1b4ecbf6fb2f0f782c88456a3: 6817009: Action.SELECTED_KEY not toggled when using key binding
- af4d5600e37ec6d331e62c5d37491ee97cad5311: 8303951: Add asserts before record_method_not_compilable where possible
- c4338620b7651f4da03ce4cfddb9e5b053fddb6a: 6245410: javax.swing.text.html.CSS.Attribute: BACKGROUND_POSITION is not w3c spec compliant
- 91f407d6fe285c44bcc25c1acdf5dc0c43be0172: 8029301: Confusing error message for array creation method reference
- e73411a2354cf266ab7a5ddadfb6ea98d7eb4cd1: 8304376: Rename t1/t2 classes in com/sun/jdi/CLETest.java to avoid class duplication error in IDE
- a2d8f634de69d11d7beec5e853f710719497bfe3: 8288730: Add type parameter to Lookup::accessClass and Lookup::ensureInitialized
- 37774556da8a5aacf55884133ae936ed5a28eab2: 8302191: Performance degradation for float/double modulo on Linux
- 760c0128a4ef787c8c8addb26894c072ba8b2eb1: 8304683: Memory leak in WB_IsMethodCompatible
- ... and 24 more: https://git.openjdk.org/jdk/compare/42723dcb1862da598092bb499056940d78a8bdac...master
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Going to push as commit c00d0885ae3c99c0ebacec0bd7de7382ee954dc1.
Since your change was applied there have been 35 commits pushed to the master branch:
- 147f3473d4cb6e0bb9edda87d571ba5088fda4a2: 8219083: java/net/MulticastSocket/SetGetNetworkInterfaceTest.java failed in same binary run on windows x64
- bf917ba6af9a69859f469a1e8056fbd32396cae4: 8304687: Move add_to_hierarchy
- 63d4afbeb17df4eff0f65041926373ee62a8a33a: 8304671: javac regression: Compilation with --release 8 fails on underscore in enum identifiers
- e2cfcfbfa90017b1b4ecbf6fb2f0f782c88456a3: 6817009: Action.SELECTED_KEY not toggled when using key binding
- af4d5600e37ec6d331e62c5d37491ee97cad5311: 8303951: Add asserts before record_method_not_compilable where possible
- c4338620b7651f4da03ce4cfddb9e5b053fddb6a: 6245410: javax.swing.text.html.CSS.Attribute: BACKGROUND_POSITION is not w3c spec compliant
- 91f407d6fe285c44bcc25c1acdf5dc0c43be0172: 8029301: Confusing error message for array creation method reference
- e73411a2354cf266ab7a5ddadfb6ea98d7eb4cd1: 8304376: Rename t1/t2 classes in com/sun/jdi/CLETest.java to avoid class duplication error in IDE
- a2d8f634de69d11d7beec5e853f710719497bfe3: 8288730: Add type parameter to Lookup::accessClass and Lookup::ensureInitialized
- 37774556da8a5aacf55884133ae936ed5a28eab2: 8302191: Performance degradation for float/double modulo on Linux
- ... and 25 more: https://git.openjdk.org/jdk/compare/42723dcb1862da598092bb499056940d78a8bdac...master
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@vicente-romero-oracle @archiecobbs Pushed as commit c00d0885ae3c99c0ebacec0bd7de7382ee954dc1.
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