Cannot make alternative java_toolchain work (to activate all error prone warnings)

[davido]

On most recent Bazel version (d019651) I'm, trying to implement alternative java_toolchain and activate all error prone warnings, as described in this comment: [1]:

$ bazel build --java_toolchain //tools:error_prone_warnings_toolchain java/com/google/gerrit/extensions:extension-api-javadoc
DEBUG: /home/davido/.cache/bazel/_bazel_davido/5c01f4f713b675540b8b424c5c647f63/external/bazel_skylib/lib/versions.bzl:98:7: 
Current Bazel is not a release version, cannot check for compatibility.
DEBUG: /home/davido/.cache/bazel/_bazel_davido/5c01f4f713b675540b8b424c5c647f63/external/bazel_skylib/lib/versions.bzl:99:7: Make sure that you are running at least Bazel 0.14.0.
ERROR: /home/davido/projects/gerrit2/java/com/google/gerrit/extensions/BUILD:49:1: every rule of type java_doc implicitly depends upon the target '@local_jdk//:jdk-default', but this target could not be found because of: no such target '@local_jdk//:jdk-default': target 'jdk-default' not declared in package '' (did you mean 'jre-default'?) defined by /home/davido/.cache/bazel/_bazel_davido/5c01f4f713b675540b8b424c5c647f63/external/local_jdk/BUILD.bazel
ERROR: Analysis of target '//java/com/google/gerrit/extensions:extension-api-javadoc' failed; build aborted: Analysis failed
INFO: Elapsed time: 0.085s
INFO: 0 processes.
FAILED: Build did NOT complete successfully (0 packages loaded)

javadoc.bzl is here: [2] and the reproducer is here: [3].

• [1] Feature request: Setting default javacopts for all java_library rules in workspace #3427 (comment)
• [2] https://github.com/GerritCodeReview/gerrit/blob/master/tools/bzl/javadoc.bzl#L75-L77
• [3] https://gerrit-review.googlesource.com/c/gerrit/+/194045

[cushon]

https://github.com/GerritCodeReview/gerrit/blob/a194115149152c5a99a29188f25358d8a5533844/tools/bzl/javadoc.bzl#L76

Don't depend on @local_jdk directly; use @bazel_tools//tools/jdk:current_java_runtime to get the configured JDK instead (see #5594).

e.g.:

diff --git a/tools/bzl/javadoc.bzl b/tools/bzl/javadoc.bzl
index 34ae9d2c2f..8f2316c696 100644
--- a/tools/bzl/javadoc.bzl
+++ b/tools/bzl/javadoc.bzl
@@ -36,7 +36,7 @@ def _impl(ctx):
         "rm -rf %s" % dir,
         "mkdir %s" % dir,
         " ".join([
-            ctx.file._javadoc.path,
+            "%s/bin/javadoc" % ctx.attr._jdk[java_common.JavaRuntimeInfo].java_home,
             "-Xdoclint:-missing",
             "-protected",
             "-encoding UTF-8",
@@ -67,14 +67,10 @@ java_doc = rule(
         "pkgs": attr.string_list(),
         "title": attr.string(),
         "external_docs": attr.string_list(),
-        "_javadoc": attr.label(
-            default = Label("@local_jdk//:bin/javadoc"),
-            single_file = True,
-            allow_files = True,
-        ),
         "_jdk": attr.label(
-            default = Label("@local_jdk//:jdk-default"),
+            default = Label("@bazel_tools//tools/jdk:current_java_runtime"),
             allow_files = True,
+            providers = [java_common.JavaRuntimeInfo],
         ),
     },
     outputs = {"zip": "%{name}.zip"},

[davido]

Thank you! It works like a charm:

$ bazel build --java_toolchain //tools:error_prone_warnings_toolchain java/com/google/gerrit/extensions:extension-api-javadoc
DEBUG: /home/davido/.cache/bazel/_bazel_davido/5c01f4f713b675540b8b424c5c647f63/external/bazel_skylib/lib/versions.bzl:98:7: 
Current Bazel is not a release version, cannot check for compatibility.
DEBUG: /home/davido/.cache/bazel/_bazel_davido/5c01f4f713b675540b8b424c5c647f63/external/bazel_skylib/lib/versions.bzl:99:7: Make sure that you are running at least Bazel 0.14.0.
INFO: Analysed target //java/com/google/gerrit/extensions:extension-api-javadoc (1 packages loaded).
INFO: Found 1 target...
Target //java/com/google/gerrit/extensions:extension-api-javadoc up-to-date:
  bazel-bin/java/com/google/gerrit/extensions/extension-api-javadoc.zip
INFO: Elapsed time: 8.688s, Critical Path: 6.34s
INFO: 4 processes: 1 remote cache hit, 3 linux-sandbox.
INFO: Build completed successfully, 5 total actions