Add a check for nullness annotations in locations JSpecify does not recognize - #1787
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Inline comments:
In
`@nullaway/src/main/java/com/uber/nullaway/JSpecifyUnrecognizedAnnotationLocation.java`:
- Around line 470-476: Update the nullness annotation detection in
JSpecifyUnrecognizedAnnotationLocation to use the configured NullAway annotation
names instead of broad suffix matching, while preserving the TYPE_USE target
check and existing recognized annotations.
In
`@nullaway/src/test/java/com/uber/nullaway/JSpecifyUnrecognizedAnnotationLocationTest.java`:
- Line 826: Update both text blocks in
JSpecifyUnrecognizedAnnotationLocationTest so the backslash before u0065 is
escaped in each occurrence, including the field declaration and the
corresponding occurrence near the second test location; preserve the generated
source as the literal Unicode escape rather than allowing Java preprocessing to
convert it to Inner.
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nullaway/build.gradlenullaway/src/main/java/com/uber/nullaway/JSpecifyUnrecognizedAnnotationLocation.javanullaway/src/test/java/com/uber/nullaway/AndroidTest.javanullaway/src/test/java/com/uber/nullaway/JSpecifyUnrecognizedAnnotationLocationTest.javanullaway/src/test/java/com/uber/nullaway/NullAwayTestsBase.javanullaway/src/test/java/com/uber/nullaway/TypeUseAnnotationsTests.javanullaway/src/test/java/com/uber/nullaway/UnrecognizedAnnotationLocationInTestSourcesTest.javanullaway/src/test/java/com/uber/nullaway/UnsoundnessTests.javanullaway/src/test/java/com/uber/nullaway/jspecify/GenericsTests.javanullaway/src/test/java/com/uber/nullaway/jspecify/JSpecifyArrayTests.javanullaway/src/test/java/com/uber/nullaway/thirdpartylibs/GrpcTest.javanullaway/src/test/java/com/uber/nullaway/tools/SerializationTestHelper.javasample/build.gradle
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Inline comments:
In
`@nullaway/src/main/java/com/uber/nullaway/JSpecifyUnrecognizedAnnotationLocation.java`:
- Line 60: Remove the direct TokenKind import and avoid comparing against
token.kind() in a way that still exposes
com.sun.tools.javac.parser.Tokens.TokenKind. Update
JSpecifyUnrecognizedAnnotationLocation to use an API that abstracts the token
kind, preserving the existing annotation-location detection behavior without
requiring parser exports in consumer builds.
In
`@nullaway/src/test/java/com/uber/nullaway/JSpecifyUnrecognizedAnnotationLocationTest.java`:
- Around line 870-898: Merge the duplicated Arrays.java fixture coverage by
moving the method-parameter case from qualifiedInnerTypeInArrayIsReported into
outerTypeThroughArrayDimensions, preserving all existing assertions and the
shared recognized/invalid array and local-variable cases. Then remove
qualifiedInnerTypeInArrayIsReported and its duplicate fixture setup, leaving a
single test with the complete coverage.
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The // LocalAsyncCache.java:197
@Nullable V value = future.getNow(null);
// LocalAsyncCache.java:511
@Nullable CompletableFuture<V> future = asyncCache.cache().computeIfAbsent(
key, function, /* recordStats= */ true, /* recordLoad= */ false);Both annotate a local variable's root type, which JSpecify does not recognize. The specification illustrates that location with cc @ben-manes: whether the two are deliberate and worth keeping for a human reader, or were meant for somewhere else, is a call for caffeine. spring-framework and spring-boot fail on master at |
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- Complexity 3292 3430 +138
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This looks quite cool! One quick high-level point (more detailed review to follow). I'm open to shipping this as part of NullAway, but if we do that, the default level will have to be SUGGESTION, plus using this further trick to avoid reporting anything at the SUGGESTION level. Without the trick, users didn't like the new messages in their build logs from |
How about "experimental mode => WARNING, regular mode => SUGGESTION"? I am afraid, nobody would ever manually configure "warning" level, so people won't really benefit from the check if it ships with SUGGESTION by default. I checked that similar ErrorProne checks ship with WARNING by default. I think the case is different from With "unrecognized annotation" the case is different: it detects clear warnings. The specification explicitly ignores nullability annotations in certain positions while users have that. Most likely it means they have a false sense of security regarding "this is nullable" except the annotation is ignored and nothing shows that. |
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That's a fair point. We can experiment and try it your suggested way (experimental mode => WARNING, regular mode => SUGGESTION), if you can figure out how to tweak the level based on a command-line. We'd still want the SUGGESTION mode trick to turn it off completely by default I think. Due to behavior of other checkers, and possible documentation purposes, we probably want warning on annotations on locals to be configurable, possibly off by default. IntelliJ ended up adding a setting for this; see https://youtrack.jetbrains.com/issue/IDEA-374631. |
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It might have been for Spotbugs to avoid |
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I agree there might be reasons for not wanting the inspections, so I went with your suggestion+trick approach. I've also added an option to silence the check for local variable root types: One thing worth knowing about the trick: it does not keep the check quiet in a build that promotes suggestions. Measured with a check at SUGGESTION carrying the same gate:
So it covers the case it was added for — someone upgrades NullAway, asks for nothing, sees nothing — and does not cover caffeine, which sets That job needs a decision either way, since the check can find something else in caffeine later. |
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I ran this check over Apache Calcite, on the branch that replaces the Checker Framework with NullAway and JSpecify (apache/calcite#5213), built from Two locations account for all of them:
None of the other 15 locations the specification lists occurs in Calcite. The four Error Prone checks that overlap with this one — The result that argues for the check: 40 of the 161 were introduced by the migration branch itself, and all 40 are local variables. I established the split two ways, by So the check catches the mistake while it is being made, not only the backlog it inherits. That is the case I would not have been able to make from the backlog alone: a project migrating to JSpecify reproduces the habits of the tool it is leaving, and nothing in the existing check set reports it. Every one of the 161 carries a suggested fix, so the whole set goes in one pass: Calcite codebase uncovered a new issue (which I already fixed): The fix now removes the annotation together with the blanks that followed it, so |
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Thanks for this significant contribution! This is a pretty substantial amount of code. Honestly, I don't know if I'll be able to fully review all the logic and tests. But, given the new check is off by default, and is well tested, I'm open to accepting it without that full review, after making a couple of passes. I have some initial comments below.
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…ecognize JSpecify defines the locations where `@Nullable` and `@NonNull` carry meaning and states that an annotation anywhere else has none. Nothing reports one. An author who writes `@Nullable int count` or `List<@nullable ?> values` gets no diagnostic and a false sense of safety, and the specification asks source-analysis tools to offer exactly this diagnostic. Error Prone's own checks reach 4 of the 17 locations the specification lists: NullablePrimitive, NullableWildcard, NullableTypeParameter and NullableOnContainingClass. Measured on the Apache Calcite branch that moves from the Checker Framework to NullAway and JSpecify (apache/calcite#5213), those four reach none of the 161 annotations in unrecognized locations that branch carries, because all 161 sit on the root type of a local variable or of a cast. JSpecifyUnrecognizedAnnotationLocation reports those 17 locations and two more the specification's catch-all reaches: a constructor's result type and a method reference's root type. One check rather than a set of per-construct checks, because the rule is about position: everything not listed as recognized is unrecognized. That is what separates `(List<@nullable String>) o`, which is clean, from `(@nullable String) o`, which is not, and each per-construct check would have to re-derive that a type argument inside an unrecognized root is still recognized. One check is also one severity and one `@SuppressWarnings` name. It reads org.jspecify.annotations.Nullable and .NonNull by qualified name and no other annotation. Reading any annotation named `Nullable` was rejected: the Checker Framework reads its own on a local variable's and a cast's root type, and IntelliJ reads JetBrains' on a local, so telling those users the annotation has no meaning where their own tool reads it would be wrong. The check ships at SUGGESTION and reports nothing there, not even a note, so upgrading NullAway without asking for it changes nothing; -Xep:JSpecifyUnrecognizedAnnotationLocation:WARN or :ERROR turns it on. Error Prone cannot ship a plugin check off outright (google/error-prone#5387). -XepOpt:...:CheckLocalVariableRootType=false silences the one location a codebase arriving from JetBrains' annotations carries in bulk; IntelliJ added the same switch in IDEA-374631. It is one key per location rather than one list, because ErrorProneFlags holds one value per key and two convention plugins appending to a shared list would leave whichever ran last, silently. Fixes move the annotation to a wildcard or type parameter bound, onto the last name of a qualified type, and after an array's element type, so `@Nullable Bounds.Inner` and `@Nullable String[]` become `Bounds.@nullable Inner` and `String @nullable []` rather than losing it. They remove it where no single recognized form expresses the intent. The changelog entry is one line, matching the house format. Note that this repository has never carried an `Unreleased` section: every one of the twelve commits that touched CHANGELOG.md is a dedicated "Release notes for X" pull request, so entries are curated at release rather than written per change. Fold the section into the release notes or drop it if that flow is preferred. What a reader needs beyond the check's name -- that it ships at SUGGESTION, reports nothing there, and is raised with -Xep:JSpecifyUnrecognizedAnnotationLocation:WARN -- belongs in the release paragraph above the bullet list, which is written at release time. Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
The check is worth nothing to this repository unless this repository is subject to it. Two of its own sources turned out not to be. buildWithNullAway now compiles NullAway's main sources with the check at ERROR alongside NullAway, and the sample project runs it at WARN. Both are above the check's SUGGESTION default, at which it reports nothing. NullAwayTestsBase.makeTestHelperWithArgs builds every test helper from a ScannerSupplier carrying NullAway and the location check, and appends -Xep:JSpecifyUnrecognizedAnnotationLocation:WARN, so the snippets the test suite compiles are checked too. AndroidTest, GrpcTest, SerializationTestHelper and UnsoundnessTests built their own helpers and now go through it. UnrecognizedAnnotationLocationInTestSourcesTest fails if that wiring is lost, which nothing else would notice: a test whose sources stopped being checked still passes. Building both ways found one real defect and one deliberate case. GenericsTests.nestedGenericTypes wrote `@Nullable Wrapper<String>.Fn<String>`, which annotates the outer `Wrapper` rather than the `Fn` the test means to make nullable; the JSpecify-correct `Wrapper<String>.@nullable Fn<String>` passes every assertion that test already made. A source in JSpecifyArrayTests annotates an unrecognized location on purpose and now says so with `@SuppressWarnings` on the declaration. Because the helpers are built from a ScannerSupplier rather than from NullAway alone, Error Prone no longer requires a `// BUG:` marker to match a diagnostic naming NullAway; any diagnostic containing the marker text answers it. Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Both predate the location check and are unrelated to it; they are here because putting these files under the check is what surfaced them. AndroidTest was the only Java source in the repository spelling the verb `initialise`; about 70 others spell it `initializ*`. A reader who greps `initializeAndroid` in the one test class about Android finds nothing. GrpcTest.ioGrpcMetadataAsMapPossitiveTest carries a typo that a failure report prints verbatim and that defeats a grep for its correctly spelled sibling, ioGrpcMetadataAsAccessPathPositiveTest, two methods below. Each method is reached by name in one file only: the 16 occurrences of `initialiseAndroidCoreClasses` are all in AndroidTest, and JUnit discovers the Grpc test by @test rather than by name. The 90 `initialisedField` occurrences under nullaway/src/test/resources and sample-app are a different identifier in compiled test-data sources, with expected-diagnostic markers pinned to them, and are left alone. Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
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Caffeine is ready for activating the checker: ben-manes/caffeine#2008 |
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Spring Framework passes the new check with no issues. |
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I checked junit-framework, and it requires not changes as well |
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Sorry, this is not a complete review, I'm just working through this when I have some time and adding comments. Will look more later and will likely have more comments.
| // until the walk out to the enclosing construct has finished. A construct on the way out may | ||
| // suppress the classification altogether, because an annotation reachable through two | ||
| // TreePaths is classified on one of them. The two differ in whether an unrecognized enclosing |
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Again, don't get the point about being reachable through two paths
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Same answer as on the Javadoc above: the comment no longer talks about paths, it says what javac does. c81527be.
| // location replaces them. A primitive names the most specific location there is, so nothing | ||
| // outside it improves on the phrase. A wildcard's fix moves the annotation to a bound, and a | ||
| // location that covers what is nested inside it leaves the annotation just as meaningless | ||
| // there. |
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I can't follow this either. Is this about finding the best fix location, so the suggested fix is a good one?
We may need to write some examples somewhere, or point to specific test cases.
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It decides which phrase to report, and the fix follows from that. The comment now gives the cases instead of the rule:
(@Nullable int) xreports the primitive rather than the cast, because no fix moves the annotation either way —annotatedPrimitiveInAnonymousSupertypeIsReportedOnce.(List<@Nullable ?>) oreports the wildcard and moves the annotation to a bound, whereo instanceof List<@Nullable ?>reports the operand and removes it —wildcardTakesAnEnclosingLocationThatCoversNestedTypes.
| ? UnrecognizedLocation.PRIMITIVE_TYPE | ||
| : underlyingType instanceof WildcardTree ? UnrecognizedLocation.WILDCARD : null; | ||
| // Walk out to the declaration or expression the type usage belongs to. Along the way, nested | ||
| // records whether a recognized nesting step (a type argument, an array component, or a bound) |
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Is a "recognized nesting step" any nesting of types? Or are there some kinds of type nesting that are unrecognized?
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There are, and the coined term was hiding them. nested is now belowRootType, and the comment names the three steps that set it: a type argument, an array component, a bound. Crossing a union or an intersection is not one; see the reply on line 413.
| : underlyingType instanceof WildcardTree ? UnrecognizedLocation.WILDCARD : null; | ||
| // Walk out to the declaration or expression the type usage belongs to. Along the way, nested | ||
| // records whether a recognized nesting step (a type argument, an array component, or a bound) | ||
| // was crossed, and qualifierAnchor records the name whose qualifier the annotation landed on. |
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So is qualifierAnchor only non-null for declarations? So it might be null, e.g., for a cast expression?
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No, it has nothing to do with declarations. qualifierAnchor is set whenever the annotation stands in front of a qualified name and the walk has not yet gone below a root type, a cast included.
It survives to the end only where no construct took the annotation first. So (@Nullable Outer.Inner) o is reported as a cast, while the field List<@Nullable Outer.Inner> f is reported as an outer type. outerTypeIsReportedUnderEveryConstructThatDoesNotCoverNestedTypes has both rows.
| // An alternative of a union type and a member of an intersection type are in the same | ||
| // location as the type that contains them, so crossing one is not a nesting step. |
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Ah, ok, so there are in fact unrecognized nesting types. What does it mean that an alternative is in the same location as the containing type?
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The opposite of a nesting step, in fact. Each alternative of catch (@Nullable A | B e) is a root type of the exception parameter, and each member of (@Nullable A & B) o is a root type of the cast, so crossing one leaves belowRootType alone and the enclosing construct still names the location. unionAndIntersectionMembersAreReported pins both.
Review of classifyTypeUsage could not follow its comments. They leaned on terms the file never defined, "a recognized nesting step" and "an annotation reachable through two TreePaths", and gave no example of either. The word "anchor" carried two meanings within twenty lines: the tree a fix is built against, and the enclosing construct a type usage belongs to. Define each term where it is used and give it an example the tests already cover: what UnrecognizedLocation.coversNestedTypes changes, which steps put an annotation below a construct's root type, why a union alternative is not one of them, and which of the type usage and the construct around it names the location when both are unrecognized. Say what javac does that lets one annotation arrive through two TreePaths, and name the two constructs it happens for. Rename the local `nested` to `belowRootType` and the method `anchorLocation` to `enclosingLocation`, leaving "anchor" to mean the fix target alone. Behavior is unchanged; no diagnostic, message, or fix moves.
A sweep for the defect the previous commit fixed found four more places. "Root type" reaches the user in four diagnostic phrases and appears twenty times in the file, with no definition anywhere. It is JSpecify's own term for the whole type a construct names, so the class comment now defines it and names the type components that sit inside one. "A second view of" was a third name for what the file elsewhere calls one subtree under two parents, and what classifyTypeUsage now calls two TreePaths reaching one annotation. Say the latter in all three places. "Obstacle" was a coinage for what destinationIsOccupied is named after. Say that an annotation occupies the destination. Add an example to ARRAY_CREATION, where `new @nullable String[5]` is recognized and `new String @nullable [5]` is not, to OUTER_TYPE, to TypeUsage.anchor, to buildFix's annotationCount, and to destinationIsOccupied, whose Javadoc had the densest rule in the file and no worked case. Every example is one the tests already cover.
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Thanks, I think I'm understanding the structure/logic better now. A couple more questions
| * @param declarationLocation the location to report if the declared root type is unrecognized, or | ||
| * {@code null} if the declaration is a recognized location | ||
| */ | ||
| private void checkAnnotationsOnDeclaration( |
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JSpecify's @Nullable and @NonNull both have @Target(TYPE_USE) only. So can they really appear on declarations and still pass javac checks? I skimmed through the tests and didn't see any cases trying this for classes or methods (e.g., @Nullable class Foo { ... }).
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They can. JLS 9.6.4.1 makes a TYPE_USE annotation applicable in type declarations and type parameter declarations as well as in type contexts, so javac accepts @Nullable class Foo {}, and the same for an interface, an enum, a record, and an annotation interface. It also accepts one on a constructor and on an enum constant. What it rejects is a method with no type to annotate: @Nullable void m() {} fails with annotation interface not applicable to this kind of declaration. I checked all of these on javac 21.
The tests are there, spread over four methods:
declarationsAndSupertypesexpectson a class declarationfor@Nullable class Declarations;annotationInterfaceDeclarationIsReportedfor@Nullable @interface Marked;aConstructorIsReportedAsItsResultTypefor a constructor;anAnnotatedEnumConstantIsReportedAsItsTypefor an enum constant.
A method is the one declaration with no test. Its annotation lands on the return type, a recognized location, unless the return type is void, and javac rejects that form.
The example contrasted `(List<@nullable ?>) o` with `o instanceof List<@nullable ?>`, and a wildcard is unrecognized on its own, so the reader could not tell which of the two reports the flag causes. A type argument is recognized under a cast and reported under `instanceof`, so `o instanceof List<@nullable String>` shows the flag alone. The test row pins that `instanceof` case. The cast case is already in annotationsInRecognizedLocationsAreNotReported.
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Thank you for this! I think it'll be a great help to the community.
It seems the Caffeine integration test is still failing; is that expected? I'm ok with landing this one either way, just wanted to check.
JSpecify does not recognize a nullness annotation on the root type of a local variable, so `@Nullable V value = cache().compute(...)` makes no claim about nullness even though it reads like one. NullAway's new `JSpecifyUnrecognizedAnnotationLocation` check reports each of them: ```text A nullness annotation on the root type of a local variable has no meaning under JSpecify. ``` The build promotes every Error Prone suggestion to a warning (`allSuggestionsAsWarnings`) and CI compiles with `-Werror`, so the 53 annotations left in caffeine, jcache and simulator fail the build as soon as the check is released. ben-manes#2008 removed the first two, and the `Build caffeine with snapshot` job of uber/NullAway#1787 is red on the rest today. Drop the annotation, and let `var` carry the declaration wherever the local allows it, which is 43 of the 53. The null checks, the nested type-use annotations such as `(K k, @nullable V currentValue) ->`, and `@Var` stay where they are. Ten declarations keep an explicit type for reasons that have nothing to do with nullness: five have no initializer, `WindowTinyLfuPolicy.evictFromWindow` initializes from `null`, which javac cannot infer a type from, and the four reads of `lvElement` in `MpscGrowableArrayQueue` are declared `Object` on purpose, since `var` there infers `E` and makes the `(E) e` casts that follow redundant. `.claude/rules/errorprone.md` warned that `var` widens an inferred `@Nullable` type to non-null, and told the reader to give the local an explicit `@Nullable`-typed declaration, which is the annotation this check reports. The bullet was written against NullAway 0.13.8 and no longer holds: its own example, `values.stream().reduce(...).orElse(null)` assigned to a local and returned as `@Nullable T`, compiles clean under 0.14.2-SNAPSHOT both with `var` and with an explicit type, as do the 43 locals converted here. Remove it. Every Java compile task in the four modules, tests and the specialized suites included, builds against a NullAway snapshot carrying the check and reports nothing. The jcache and simulator suites pass; the caffeine `@CacheSpec` matrix is left to CI.
JSpecify does not recognize a nullness annotation on the root type of a local variable, so `@Nullable V value = cache().compute(...)` makes no claim about nullness even though it reads like one. NullAway's new `JSpecifyUnrecognizedAnnotationLocation` check reports each of them: ```text A nullness annotation on the root type of a local variable has no meaning under JSpecify. ``` The build promotes every Error Prone suggestion to a warning (`allSuggestionsAsWarnings`) and CI compiles with `-Werror`, so the 53 annotations left in caffeine, jcache and simulator fail the build as soon as the check is released. #2008 removed the first two, and the `Build caffeine with snapshot` job of uber/NullAway#1787 is red on the rest today. Drop the annotation, and let `var` carry the declaration wherever the local allows it, which is 43 of the 53. The null checks, the nested type-use annotations such as `(K k, @nullable V currentValue) ->`, and `@Var` stay where they are. Ten declarations keep an explicit type for reasons that have nothing to do with nullness: five have no initializer, `WindowTinyLfuPolicy.evictFromWindow` initializes from `null`, which javac cannot infer a type from, and the four reads of `lvElement` in `MpscGrowableArrayQueue` are declared `Object` on purpose, since `var` there infers `E` and makes the `(E) e` casts that follow redundant. `.claude/rules/errorprone.md` warned that `var` widens an inferred `@Nullable` type to non-null, and told the reader to give the local an explicit `@Nullable`-typed declaration, which is the annotation this check reports. The bullet was written against NullAway 0.13.8 and no longer holds: its own example, `values.stream().reduce(...).orElse(null)` assigned to a local and returned as `@Nullable T`, compiles clean under 0.14.2-SNAPSHOT both with `var` and with an explicit type, as do the 43 locals converted here. Remove it. Every Java compile task in the four modules, tests and the specialized suites included, builds against a NullAway snapshot carrying the check and reports nothing. The jcache and simulator suites pass; the caffeine `@CacheSpec` matrix is left to CI.
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Why
JSpecify defines the locations where
@Nullableand@NonNullcarry meaning and states that an annotation anywhere else has none.@Nullable int countandList<@Nullable ?> valuesread as claims about nullness and are not, so an author who writes one holds a false sense of safety and nothing says otherwise. The specification asks source-analysis tools to offer exactly this diagnostic.Error Prone's existing checks reach 4 of the 17 locations the specification lists. Compiling one file that holds an example of each through the default checks reports
NullablePrimitiveon the primitive type,NullableWildcardon the wildcard,NullableTypeParameteron the type parameter, andNullableOnContainingClasson the outer type qualifying an inner type. The 13 they do not reach are the local variable root type, cast root type,instanceoftype, pattern type, object creation, array creation, supertype, thrown type, exception parameter, receiver parameter, class declaration, enum constant, and annotation interface member return.Measured on a real migration: the Apache Calcite branch that replaces the Checker Framework with NullAway and JSpecify (apache/calcite#5213) carries 161 annotations in unrecognized locations, all of them local variable root types (141) and cast root types (20). The four existing checks reach none of the 161. 40 of the 161 were introduced by the migration branch itself, established both by
git blameagainst the branch's commit range and by comparing each line against the merge base. So the check catches the mistake while it is being made, not only the backlog a project inherits. Every one carries a suggested fix:-XepPatchChecks:JSpecifyUnrecognizedAnnotationLocationmakes 161 replacements across 74 files and the rebuild reports zero.What
JSpecifyUnrecognizedAnnotationLocationreports the 17 unrecognized locations the specification lists, and two more its catch-all reaches: the result type of a constructor, whichNullableConstructoralready reports, and the root type of a method reference, which nothing else reaches.It reads
org.jspecify.annotations.Nullableandorg.jspecify.annotations.NonNullby their qualified names and no other annotation. Reading any annotation namedNullablewas rejected: the tools that define the others read them in some of these very locations. The Checker Framework reads its@Nullableon the root type of a local variable and of a cast; IntelliJ reads JetBrains' on a local variable. Telling those users the annotation has no meaning where their own tool does read it would be wrong. Supporting another annotation is left to a flag on this check.It is one check rather than a documented set of per-construct checks because JSpecify's rule is about position, not about constructs: everything not listed as recognized is unrecognized. That is what separates
(List<@Nullable String>) o, which is clean, from(@Nullable String) o, which is not, andnew ArrayList<@Nullable String>()fromnew @Nullable ArrayList<String>(). Each per-construct check has to re-derive that a type argument inside an unrecognized root is still recognized. One check is also one severity and one@SuppressWarnings("JSpecifyUnrecognizedAnnotationLocation"), where a documented set costs N flags and N suppression names and grows silently as locations are covered.The check ships at
SUGGESTIONand reports nothing there, not even a note, so a user who upgrades NullAway without asking for it sees no change.-Xep:JSpecifyUnrecognizedAnnotationLocation:WARNor:ERRORturns it on. Error Prone cannot ship a plugin check turned off outright (google/error-prone#5387), and this is how close to off a default can get.-XepOpt:JSpecifyUnrecognizedAnnotationLocation:CheckLocalVariableRootType=falsesilences the root type of a local variable, the one location a codebase arriving from JetBrains' annotations carries in bulk; IntelliJ added the same switch in IDEA-374631. It reports by default, so that switching the check on reports every location the specification lists.Fixes move the annotation to the bound of a wildcard or type parameter, onto the last name of a qualified type, and after the element type of an array, so
@Nullable Bounds.Innerand@Nullable String[]becomeBounds.@Nullable InnerandString @Nullable []rather than losing the annotation. They remove it where no single recognized form expresses the intent, such as a lower-bounded wildcard or an intersection bound, and where a nullness annotation already stands at the destination.Running the check over NullAway's own sources found one real defect, fixed here:
GenericsTests.nestedGenericTypeswrote@Nullable Wrapper<String>.Fn<String>, which annotates the outerWrapperrather than theFnthe test means to make nullable. The JSpecify-correctWrapper<String>.@Nullable Fn<String>passes every assertion that test already made. One test source inJSpecifyArrayTestsannotates an unrecognized location on purpose and now says so with@SuppressWarnings.Verification
66 tests in
JSpecifyUnrecognizedAnnotationLocationTestestablish one diagnostic per location, that the recognized locations nested inside unrecognized ones stay unreported, a fix per fix shape, and exact report counts for the annotations two tree paths reach, which a// BUG:marker cannot tell apart from one reported once;UnrecognizedAnnotationLocationInTestSourcesTest(new) fails if the harness stops running the check over the sources every other test compiles.Scope
A construct the check cannot name is left alone rather than reported under the specification's catch-all, so the failure mode is a missed diagnostic rather than a wrong one.
A codebase still on the Checker Framework's or JetBrains' annotations gets no diagnostic until it has switched. That is the narrowing working as intended; the follow-up is a flag on this check that maps another annotation onto JSpecify's.
The severity is per check rather than per location, so a build cannot take
@Nullable Outer.Inner, which contradicts a property the specification calls intrinsic, as an error while leaving another location a warning.Description.Builder.overrideSeveritywould express that and is@RestrictedApi: "Overriding the severity for individual Descriptions causes any command line options to be ignored, which is potentially very confusing." Measured: with it, a user who writes-Xep:JSpecifyUnrecognizedAnnotationLocation:WARNgets errors anyway. A build that wants the strict reading of the outer type has it fromNullableOnContainingClass, which reports it as an error today.CheckLocalVariableRootTypeis the only location switch, and it is one key per location rather than one list of locations becauseErrorProneFlagsholds one value per key: two convention plugins each appending to a shared list would leave whichever ran last, silently.Build caffeine with snapshotis red on two@Nullableon local variable root types inLocalAsyncCache. @ben-manes has said caffeine can switch those tovar, so this branch needs no change for that job.