Feedback on Bazel

[ulfjack]

Hi all,

I ran some builds with Bazel and I have some observations that I wanted to share.

1. Bazel downloads a ton of third-party jar files, with sequential version numbers; not sure why that is but it definitely looks wrong
2. There are lots of warnings about duplicate jars on the classpath (maybe overlaps with 1). See below for an example.
3. There are lots of warnings about 'ambiguous' priorities. See below for an example.
4. Build doesn't work with Java 11. Running bazel build -s //module487 --host_java_toolchain=@bazel_tools//tools/jdk:toolchain_java11 --java_toolchain=@bazel_tools//tools/jdk:toolchain_java11 results in very unusual error messages.

warning: some runtime JAR files in the classpath have an incompatible version. Consider removing them from the classpath
warning: runtime JAR files in the classpath should have the same version. These files were found in the classpath:
    /mnt/ssd/cas/work/build-aafe24f3-3055-4101-92cb-c1f609f8e54c/external/com_github_jetbrains_kotlin/lib/kotlin-stdlib.jar (version 1.3)
    /mnt/ssd/cas/work/build-aafe24f3-3055-4101-92cb-c1f609f8e54c/external/com_github_jetbrains_kotlin/lib/kotlin-stdlib-jdk7.jar (version 1.3)
    /mnt/ssd/cas/work/build-aafe24f3-3055-4101-92cb-c1f609f8e54c/external/com_github_jetbrains_kotlin/lib/kotlin-stdlib-jdk8.jar (version 1.3)
    /mnt/ssd/cas/work/build-aafe24f3-3055-4101-92cb-c1f609f8e54c/external/maven/v1/https/jcenter.bintray.com/org/jetbrains/kotlin/kotlin-stdlib-common/1.4.21/kotlin-stdlib-common-1.4.21.jar (version 1.4)
    /mnt/ssd/cas/work/build-aafe24f3-3055-4101-92cb-c1f609f8e54c/external/maven/v1/https/jcenter.bintray.com/org/jetbrains/kotlin/kotlin-stdlib/1.4.21/kotlin-stdlib-1.4.21.jar (version 1.4)
    /mnt/ssd/cas/work/build-aafe24f3-3055-4101-92cb-c1f609f8e54c/external/maven/v1/https/jcenter.bintray.com/org/jetbrains/kotlin/kotlin-stdlib-jdk7/1.3.40/kotlin-stdlib-jdk7-1.3.40.jar (version 1.3)
    /mnt/ssd/cas/work/build-aafe24f3-3055-4101-92cb-c1f609f8e54c/external/maven/v1/https/jcenter.bintray.com/org/jetbrains/kotlin/kotlin-stdlib-jdk8/1.3.40/kotlin-stdlib-jdk8-1.3.40.jar (version 1.3)
    /mnt/ssd/cas/work/build-aafe24f3-3055-4101-92cb-c1f609f8e54c/external/maven/v1/https/jcenter.bintray.com/org/jetbrains/kotlin/kotlin-reflect/1.3.31/kotlin-reflect-1.3.31.jar (version 1.3)
    /mnt/ssd/cas/work/build-aafe24f3-3055-4101-92cb-c1f609f8e54c/external/com_github_jetbrains_kotlin/lib/kotlin-script-runtime.jar (version 1.3)
    /mnt/ssd/cas/work/build-aafe24f3-3055-4101-92cb-c1f609f8e54c/external/com_github_jetbrains_kotlin/lib/kotlin-reflect.jar (version 1.3)

INFO: From Merging compiled Android resources for //module62:module62:
Feb 15, 2021 11:03:12 PM com.google.devtools.build.android.AndroidDataMerger doMerge
WARNING: 
...
CONFLICT: string-fi/abc_searchview_description_query is provided with ambiguous priority from:
	 bazel-out/k8-fastbuild/bin/external/maven/_aar/unzipped/resources/androidx_appcompat_appcompat/res/values-fi/values-fi.xml (with value Hakukysely)
	 bazel-out/k8-fastbuild/bin/external/com_android_support_appcompat_v7_28_0_0/_aar/unzipped/resources/com_android_support_appcompat_v7_28_0_0/res/values-fi/values-fi.xml (with value Hakulauseke)
...