[java] NullAway added

[mk868]

User description

🔗 Related Issues

Related issue: #14291
Original PR (auto-closed): #14421

💥 What does this PR do?

Introduce the NullAway nullness analyzer to Selenium’s Java builds to simplify the process of adding JSpecify annotations and easily reveal inconsistencies.
This is a recreation of the original PR #14421 which was automatically closed.
I intentionally omitted the GitHub CI configuration to run NullAway analysis locally to simplify addition of the JSpecify annotations.
After applying all JSpecify annotations, we can enable verification in GitHub CI - it's too early for that right now, because it will only cause build failures.

By default, the NullAway plugin is disabled, to enable it, set the //java:nullaway_level flag:

• --//java:nullaway_level=WARN
• --//java:nullaway_level=ERROR

For example:

bazel build //java/... --//java:nullaway_level=WARN

🔧 Implementation Notes

Used NullAway parameters:

• -Xep:NullAway:WARN - report problems as warnings
• -Xep:NullAway:ERROR - report problems as errors and stop compilation when an error occurs - good for CI/CD
• -XepOpt:NullAway:AnnotatedPackages=org.openqa.selenium - analyze this package (including subpackages)

I also updated org.checkerframework:checker-qual to version 3.49.2 because there was a conflict with version 3.21.2.

💡 Additional Considerations

Once all classes are properly and consistently annotated with JSpecify, we can add the configuration to GitHub CI to ensure nullness correctness for newly added code.

🔄 Types of changes

• New feature (non-breaking change which adds functionality and tests!)

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PR Type

Enhancement

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Description

• Integrates NullAway static analyzer for Java nullness checking

• Adds configurable build flag (--//java:nullaway_level) with WARN/ERROR levels

• Updates checker-qual dependency from 3.21.2 to 3.49.2

• Creates custom java_library wrapper with conditional NullAway plugin injection

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Diagram Walkthrough

flowchart LR
  A["Build flag configuration"] --> B["java_library wrapper"]
  B --> C["Conditional NullAway plugin"]
  C --> D["Nullness analysis"]
  E["Dependency updates"] --> D

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File Walkthrough

	Relevant files
Enhancement	java_library.bzl Add custom java_library wrapper with NullAway support        java/private/java_library.bzl Creates new java_library wrapper function Implements conditional NullAway plugin injection based on build flags Configures NullAway javacopts for WARN and ERROR levels Sets annotated packages to org.openqa.selenium +49/-0    export.bzl Switch to custom java_library wrapper                                        java/private/export.bzl Removes direct import of java_library from contrib_rules_jvm Imports custom java_library from local wrapper module +1/-1      library.bzl Update library imports to use wrapper                                        java/private/library.bzl Removes java_library import from contrib_rules_jvm Imports custom java_library from wrapper module +1/-1
Configuration changes	BUILD.bazel Configure NullAway plugin and build flags                                java/BUILD.bazel Defines nullaway java_plugin with uber.nullaway dependency Creates nullaway_level string flag with NONE/WARN/ERROR values Adds config_setting rules for WARN and ERROR levels +35/-0
Dependencies	MODULE.bazel Add NullAway and update checker-qual dependencies                MODULE.bazel Adds com.uber.nullaway:nullaway:0.12.10 dependency Updates org.checkerframework:checker-qual from 3.21.2 to 3.49.2 +2/-0      maven_install.json Regenerate Maven dependency lockfile                                          java/maven_install.json Updates artifact hashes for new dependencies Adds NullAway artifact with transitive dependencies Updates checker-qual to 3.49.2 with new packages Adds dataflow-nullaway dependency +100/-6

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[qodo-merge-pro]

PR Compliance Guide 🔍

Below is a summary of compliance checks for this PR:

Security Compliance
🟢	No security concerns identified No security vulnerabilities detected by AI analysis. Human verification advised for critical code.
Ticket Compliance
🟡	🎫 #14291 🔴 Add JSpecify Nullness annotations across Selenium’s Java codebase so IDEs and static analyzers understand nullability of parameters and return values. ⚪ Ensure tooling/CI can surface nullness issues, improving developer feedback and avoiding NullPointerExceptions. Improve Kotlin interoperability by providing explicit nullability information.
Codebase Duplication Compliance
⚪	Codebase context is not defined Follow the guide to enable codebase context checks.
Custom Compliance
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Compliance status legend

🟢 - Fully Compliant
🟡 - Partial Compliant
🔴 - Not Compliant
⚪ - Requires Further Human Verification
🏷️ - Compliance label

[qodo-merge-pro]

PR Code Suggestions ✨

Explore these optional code suggestions:

Category	Suggestion	Impact
Possible issue	Fix incorrect Bazel select concatenation Reverse the order of concatenation for plugins and javacopts to be select({...}) + list. The current order list + select({...}) is invalid in Bazel and will cause build failures. java/private/java_library.bzl [38-49] # global place for NullAway plugin use _java_library( name = name, deps = deps, srcs = srcs, exports = exports, tags = tags, visibility = visibility, - plugins = plugins + nullaway_plugins, - javacopts = javacopts + nullaway_javacopts, + plugins = nullaway_plugins + plugins, + javacopts = nullaway_javacopts + javacopts, **kwargs ) Apply / Chat Suggestion importance[1-10]: 9 __ Why: The suggestion correctly identifies a critical issue in Bazel's handling of select concatenation; list + select({...}) is not a valid operation for rule attributes and will cause the build to fail, whereas select({...}) + list is the correct pattern. This fix is essential for the functionality introduced in the PR to work correctly.	High
High-level	Consider a toolchain-based implementation Instead of wrapping the java_library rule to add the NullAway plugin, consider using a custom java_toolchain. This approach better separates tooling configuration from build definitions, aligning with Bazel best practices and improving maintainability. Examples: java/private/java_library.bzl [6-49] def java_library( name, deps = [], srcs = [], exports = [], tags = [], visibility = None, javacopts = [], plugins = [], **kwargs): ... (clipped 34 lines) Solution Walkthrough: Before: # In java/private/java_library.bzl load("@contrib_rules_jvm//java:defs.bzl", _java_library = "java_library") def java_library(name, plugins=[], javacopts=[], **kwargs): nullaway_plugins = select({ "//java:use_nullaway_level_warn": ["//java:nullaway"], "//java:use_nullaway_level_error": ["//java:nullaway"], ... }) nullaway_javacopts = select({ "//java:use_nullaway_level_warn": ["-Xep:NullAway:WARN", ...], "//java:use_nullaway_level_error": ["-Xep:NullAway:ERROR", ...], ... }) _java_library( name = name, plugins = plugins + nullaway_plugins, javacopts = javacopts + nullaway_javacopts, **kwargs ) After: # In a new file, e.g., java/toolchains/BUILD.bazel java_toolchain( name = "selenium_java_toolchain_impl", # ... standard toolchain attributes plugins = ["//java:nullaway"], ) # In WORKSPACE or MODULE.bazel register_toolchains("//java/toolchains:selenium_java_toolchain") # The java_library wrapper is removed, and build files use the # standard java_library rule. The toolchain is selected via # Bazel flags, not config_setting in every library. # The --//java:nullaway_level flag would now control which toolchain is active. Suggestion importance[1-10]: 7 __ Why: This is a valid and significant architectural suggestion that proposes a more idiomatic Bazel approach, improving long-term maintainability by separating tooling from build logic.	Medium
Learned best practice	Make annotated packages configurable Avoid hard-coding AnnotatedPackages; expose it as a build setting so different modules can specify their own annotated packages, keeping configuration accurate and reusable. java/private/java_library.bzl [26-36] +# In java/BUILD.bazel +string_flag( + name = "nullaway_annotated_packages", + build_setting_default = "org.openqa.selenium", +) +config_setting( + name = "use_nullaway_annotated_packages_default", + flag_values = {":nullaway_annotated_packages": "org.openqa.selenium"}, +) + +# In java/private/java_library.bzl +load("//java:defs.bzl", "nullaway_annotated_packages") # or read via select on flag nullaway_javacopts = select({ "//java:use_nullaway_level_warn": [ "-Xep:NullAway:WARN", - "-XepOpt:NullAway:AnnotatedPackages=org.openqa.selenium", + "-XepOpt:NullAway:AnnotatedPackages=$(location //java:nullaway_annotated_packages)", ], "//java:use_nullaway_level_error": [ "-Xep:NullAway:ERROR", - "-XepOpt:NullAway:AnnotatedPackages=org.openqa.selenium", + "-XepOpt:NullAway:AnnotatedPackages=$(location //java:nullaway_annotated_packages)", ], "//conditions:default": [], }) Apply / Chat Suggestion importance[1-10]: 6 __ Why: Relevant best practice - Make concurrency and lifecycle code robust by correctly computing timeouts and ensuring deterministic configuration; avoid hard-coding scope-specific settings and prefer configurable parameters to keep API/documentation accurate and consistent.	Low
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[diemol]

Thank you. Let's get this in and enable a GH workflow when more coverage has been put in place.