Java 9: Missing strict dependency is erroneously reported

[davido]

Description of the problem / feature request:

Bazel built with Java 9 from HEAD, with this PR applied, is reporting missing strict dependency. The reported missing dependency is in place.

Bugs: what's the simplest, easiest way to reproduce this bug? Please provide a minimal example if possible.

• Apply this PR on HEAD
• Build Bazel with Java 9 with this command:

$ bazel --host_javabase=/usr/lib64/jvm/java-9-openjdk build \
  --javacopt='--release 9' \
  --java_toolchain=@bazel_tools//tools/jdk:toolchain_jdk9 \
  src:bazel

• Clone bazel_printy test repository
• Try to build printy_lib rule with Bazel built with java 9

Expected: build is successful

Actual: build is failing:

$ bazel build :printy_lib
INFO: Analysed target //:printy_lib (0 packages loaded).
INFO: Found 1 target and 0 test targets...
ERROR: /home/davido/projects/bazel_printy/BUILD:9:1: Building libprinty_lib.jar (1 source file) failed (Exit 1)
src/main/java/org/gerritcon/mv2016/Printy.java:22: error: [strict] Using type com.google.common.base.Joiner from an indirect dependency (TOOL_INFO: "@guava//jar"). See command below **
    System.out.println(Joiner.on(' ').join(argv));
                       ^
 ** Please add the following dependencies: 
  @guava//jar  to //:printy_lib 
 ** You can use the following buildozer command: 
buildozer 'add deps @guava//jar ' //:printy_lib 

Target //:printy_lib failed to build
Use --verbose_failures to see the command lines of failed build steps.
INFO: Elapsed time: 0.481s, Critical Path: 0.32s
FAILED: Build did NOT complete successfully

Note, that printy_lib already depends on guava:

https://github.com/davido/bazel_printy/blob/master/BUILD#L9-L14

What operating system are you running Bazel on?

Linux, Java 9.

Related:

#4709

Known workarounds:

All is fine if I build Bazel with Java 8.

[cushon]

This is effectively a duplicate of #3410.

In particular, see:

• google/error-prone-javac@9901a45

• bazel/tools/jdk/default_java_toolchain.bzl

  Line 32 in 9b79b00

  # TODO(cushon): override the javac in the JDK.

[davido]

@cushon Thanks for the pointers. What is your recommendation to fix strict dependency problem when #4795 (or equivalent) is merged and we sorted out Java 9 gRpc issue? Do we really need to patch javac in Java 9 for strict dependencies to work properly?

[davido]

I'm asking, because for now, strict dependency is the last unresolved issue for building Bazel and Gerrit Code Review eco-system with Java 9 (Bazel, Gerrit, JGit and Gitiles). With the disabled strict java deps feature I was able to build Bazel and use built Bazel with Java 9 and successfully build gerrit, see this CL pending for review: [1] and friends.

There are two known workarounds for this problem:

• Pass --strict_java_deps=OFF to diable strict java deps feature
• Dynamically detect the Java runtime and disable that feature, because we do know, it doesn't work: [2]

• [1] https://gerrit-review.googlesource.com/#/c/gerrit/+/147234
• [2] http://paste.openstack.org/show/697836

[davido]

Thanks for the fix. It works now. I see, that the custom javac is used now

"--patch-module=java.compiler=$(location //third_party/java/jdk/langtools:java_compiler_jar)",
"--patch-module=jdk.compiler=$(location //third_party/java/jdk/langtools:jdk_compiler_jar)"

Where are those files are coming from?