Add JSpecifyExperimental configuration flag by msridhar · Pull Request #1648 · uber/NullAway

msridhar · 2026-07-24T00:52:13Z

Adds a new boolean CLI flag, JSpecifyExperimental.

When enabled, it enables both experimental JSpecify features:

JSpecifyJDKModels
HandleWildcardGenerics

The existing individual flags continue to work independently. The plan is to encourage users to test with JSpecifyExperimental enabled to shake out more bugs before enabling these features by default in JSpecify mode.

Added a regression test confirming that JSpecifyExperimental enables both underlying options.

Summary by CodeRabbit

New Features
- Added a new experimental JSpecify flag; when enabled, it automatically turns on wildcard generic handling and enhanced JSpecify JDK model support.
Tests
- Added a new unit test to verify the experimental option enables both related behaviors.

msridhar · 2026-07-24T00:52:14Z

This change is part of the following stack:

Fix handling of reference to method with @Nullable parameter from library model #1642
- Enable JSpecify JDK models (under a flag) #1641
  - Enable JSpecify JDK models for regression tests #1646
    - Fix bug with lambdas assigned to locals with a wildcard in their type #1647
      - Add JSpecifyExperimental configuration flag #1648 ◀
        
        Enable inference failure warnings in experimental mode, and fix related bug in library models #1649

_{Change managed by git-spice.}

codecov · 2026-07-24T01:03:39Z

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 88.17%. Comparing base (78055dd) to head (c4cfd1f).
⚠️ Report is 1 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff            @@
##             master    #1648   +/-   ##
=========================================
  Coverage     88.17%   88.17%           
  Complexity     3064     3064           
=========================================
  Files           105      105           
  Lines         10301    10304    +3     
  Branches       2079     2079           
=========================================
+ Hits           9083     9086    +3     
  Misses          576      576           
  Partials        642      642

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coderabbitai · 2026-07-24T01:46:42Z

Walkthrough

Adds NullAway:JSpecifyExperimental to ErrorProneCLIFlagsConfig. When enabled, it activates wildcard-generic handling and JSpecify JDK models. A test verifies both settings.

Possibly related PRs

uber/NullAway#1646: Adds related JSpecify JDK model configuration and test wiring.

Suggested reviewers: lazaroclapp

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly matches the main change: adding the new JSpecifyExperimental configuration flag.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

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Create PR with unit tests
Commit unit tests in branch add-jspecify-experimental

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lazaroclapp

Approved with suggestion!

coderabbitai

Actionable comments posted: 1

🤖 Prompt for all review comments with AI agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Inline comments:
In `@nullaway/src/test/java/com/uber/nullaway/ErrorProneCLIFlagsConfigTest.java`:
- Around line 89-101: Add a test case alongside
jspecifyExperimentalEnablesExperimentalFeatures using JSpecifyExperimental=true
with JSpecifyJDKModels=false and HandleWildcardGenerics=false, then assert
isJSpecifyJDKModels() and handleWildcardGenerics() both return false, confirming
explicit per-feature flags override the experimental fallback.

🪄 Autofix (Beta)

Fix all unresolved CodeRabbit comments on this PR:

Push a commit to this branch (recommended)
Create a new PR with the fixes

ℹ️ Review info

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Run ID: ece69863-f5ec-42ca-a113-7e5a2b35f267

📥 Commits

Reviewing files that changed from the base of the PR and between 4276a87 and e39330a.

📒 Files selected for processing (2)

nullaway/src/main/java/com/uber/nullaway/ErrorProneCLIFlagsConfig.java
nullaway/src/test/java/com/uber/nullaway/ErrorProneCLIFlagsConfigTest.java

coderabbitai · 2026-07-24T14:34:30Z

+  @Test
+  public void jspecifyExperimentalEnablesExperimentalFeatures() {
+    ErrorProneCLIFlagsConfig config =
+        new ErrorProneCLIFlagsConfig(
+            ErrorProneFlags.fromMap(
+                Map.of(
+                    "NullAway:AnnotatedPackages", "foo",
+                    "NullAway:JSpecifyMode", "true",
+                    "NullAway:JSpecifyExperimental", "true")));
+
+    assertTrue(config.isJSpecifyJDKModels());
+    assertTrue(config.handleWildcardGenerics());
+  }


🎯 Functional Correctness | 🟡 Minor | ⚡ Quick win

Cover explicit per-feature overrides.

This test only verifies the experimental true fallback. Add a case with JSpecifyExperimental=true, JSpecifyJDKModels=false, and HandleWildcardGenerics=false, asserting both accessors remain false. This protects the contract that the individual flags continue to override the umbrella flag.

🤖 Prompt for AI Agents

Verify each finding against current code. Fix only still-valid issues, skip the rest with a brief reason, keep changes minimal, and validate. In `@nullaway/src/test/java/com/uber/nullaway/ErrorProneCLIFlagsConfigTest.java` around lines 89 - 101, Add a test case alongside jspecifyExperimentalEnablesExperimentalFeatures using JSpecifyExperimental=true with JSpecifyJDKModels=false and HandleWildcardGenerics=false, then assert isJSpecifyJDKModels() and handleWildcardGenerics() both return false, confirming explicit per-feature flags override the experimental fallback.

msridhar mentioned this pull request Jul 24, 2026

Enable inference failure warnings in experimental mode, and fix related bug in library models #1649

Merged

msridhar force-pushed the supplier-assigned-lambda-returning-null branch from c0a7b38 to 974105a Compare July 24, 2026 01:45

msridhar force-pushed the add-jspecify-experimental branch from a9e1661 to 2191a1c Compare July 24, 2026 01:45

lazaroclapp approved these changes Jul 24, 2026

View reviewed changes

Comment thread nullaway/src/main/java/com/uber/nullaway/ErrorProneCLIFlagsConfig.java Outdated

msridhar force-pushed the supplier-assigned-lambda-returning-null branch from 974105a to ccd037a Compare July 24, 2026 04:02

msridhar force-pushed the add-jspecify-experimental branch from 2191a1c to faaed55 Compare July 24, 2026 04:02

msridhar force-pushed the supplier-assigned-lambda-returning-null branch from ccd037a to 7aaa8e3 Compare July 24, 2026 04:28

msridhar force-pushed the add-jspecify-experimental branch from faaed55 to 4276a87 Compare July 24, 2026 04:28

msridhar force-pushed the supplier-assigned-lambda-returning-null branch from 7aaa8e3 to 1c4dc6d Compare July 24, 2026 14:12

Base automatically changed from supplier-assigned-lambda-returning-null to master July 24, 2026 14:27

msridhar added 2 commits July 24, 2026 07:28

Add JSpecifyExperimental configuration flag

fd9b284

apply Lazaro's suggestion

e39330a

msridhar force-pushed the add-jspecify-experimental branch from 4276a87 to e39330a Compare July 24, 2026 14:31

coderabbitai Bot reviewed Jul 24, 2026

View reviewed changes

msridhar enabled auto-merge (squash) July 24, 2026 14:39

msridhar added 2 commits July 24, 2026 08:39

Empty commit for CI

eb4ad80

Empty commit for CI

c4cfd1f

msridhar merged commit a7f21cc into master Jul 24, 2026
12 checks passed

msridhar deleted the add-jspecify-experimental branch July 24, 2026 16:48

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Add JSpecifyExperimental configuration flag - #1648

Add JSpecifyExperimental configuration flag#1648
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