Bazel coverage with --combined_report=lcov fails #6450
Description
Description of the problem / feature request:
Running bazel coverage --combined_report=lcov //... results in a NullPointerException
> bazel coverage --combined_report=lcov //...
INFO: Using default value for --instrumentation_filter: "//src/main/java/com/chris[/:]".
INFO: Override the above default with --instrumentation_filter
Internal error thrown during build. Printing stack trace: java.lang.NullPointerException
at com.google.devtools.build.lib.bazel.coverage.BazelCoverageReportModule$1.getArgs(BazelCoverageReportModule.java:108)
at com.google.devtools.build.lib.bazel.coverage.CoverageReportActionBuilder.generateCoverageReportAction(CoverageReportActionBuilder.java:244)
at com.google.devtools.build.lib.bazel.coverage.CoverageReportActionBuilder.createCoverageActionsWrapper(CoverageReportActionBuilder.java:192)
at com.google.devtools.build.lib.bazel.coverage.BazelCoverageReportModule$1.createCoverageReportActionsWrapper(BazelCoverageReportModule.java:93)
at com.google.devtools.build.lib.analysis.BuildView.createResult(BuildView.java:436)
It appears that the default value of --coverage_report_generator causes this. Running it with --coverage_report_generator="@bazel_tools//tools/test/LcovMerger/java/com/google/devtools/lcovmerger:Main" works; though it should be pointed out that there are some SEVERE logs.
> bazel coverage --combined_report=lcov --coverage_report_generator="@bazel_tools//tools/test/LcovMerger/java/com/google/devtools/lcovmerger:Main" //...
INFO: Using default value for --instrumentation_filter: "//src/main/java/com/chris[/:]".
INFO: Override the above default with --instrumentation_filter
INFO: Analysed 5 targets (23 packages loaded).
INFO: Found 3 targets and 2 test targets...
INFO: LCOV coverage report is located at /home/chris.rice/.cache/bazel/_bazel_chris.rice/1baebf64cb080dc7a8e39a79a89b8741/execroot/__main__/bazel-out/_coverage/_coverage_report.dat
and execpath is bazel-out/_coverage/_coverage_report.dat
INFO: From CoverageReport _coverage/_coverage_report.dat:
Oct 19, 2018 8:57:48 AM com.google.devtools.lcovmerger.Main getTracefiles
INFO: Found 2 tracefiles.
Oct 19, 2018 8:57:48 AM com.google.devtools.lcovmerger.Main parseFiles
SEVERE: Parsing file bazel-out/k8-fastbuild/testlogs/src/test/java/com/chris/foo/FooTest/coverage.dat
Oct 19, 2018 8:57:48 AM com.google.devtools.lcovmerger.Main parseFiles
SEVERE: Parsing file bazel-out/k8-fastbuild/testlogs/src/test/java/com/chris/hello/HelloWorldTest/coverage.dat
Oct 19, 2018 8:57:48 AM com.google.devtools.lcovmerger.Main getGcovInfoFiles
SEVERE: No gcov info file found.
INFO: Elapsed time: 6.037s, Critical Path: 5.47s
INFO: 15 processes: 10 linux-sandbox, 5 worker.
INFO: Build completed successfully, 35 total actions
//src/test/java/com/chris/foo:FooTest PASSED in 0.7s
/home/chris.rice/.cache/bazel/_bazel_chris.rice/1baebf64cb080dc7a8e39a79a89b8741/execroot/__main__/bazel-out/k8-fastbuild/testlogs/src/test/java/com/chris/foo/FooTest/coverage.dat
//src/test/java/com/chris/hello:HelloWorldTest PASSED in 0.6s
/home/chris.rice/.cache/bazel/_bazel_chris.rice/1baebf64cb080dc7a8e39a79a89b8741/execroot/__main__/bazel-out/k8-fastbuild/testlogs/src/test/java/com/chris/hello/HelloWorldTest/coverage.dat
Bugs: what's the simplest, easiest way to reproduce this bug? Please provide a minimal example if possible.
Clone this repo: https://github.com/chris-rice-lr/bazel_combined_report_repro and run
bazel coverage --combined_report=lcov //...
Running
bazel coverage --combined_report=lcov --coverage_report_generator="@bazel_tools//tools/test/LcovMerger/java/com/google/devtools/lcovmerger:Main" //...
will result in a single .dat file as expected
What operating system are you running Bazel on?
Fedora 28
What's the output of bazel info release?
> bazel info release
Starting local Bazel server and connecting to it...
release 0.18.0- (@non-git)
If bazel info release returns "development version" or "(@Non-Git)", tell us how you built Bazel.
I used the COPR repo: https://copr.fedorainfracloud.org/coprs/vbatts/bazel/
What's the output of git remote get-url origin ; git rev-parse master ; git rev-parse HEAD ?
> git remote get-url origin ; git rev-parse master ; git rev-parse HEAD
git@github.com:chris-rice-lr/bazel_combined_report_repro.git
3b2b00c761c46fe8ea6a86deed47c8f10607ded3
3b2b00c761c46fe8ea6a86deed47c8f10607ded3
Have you found anything relevant by searching the web?
This thread helped. It showed that running with --coverage_report_generator set correctly made it work. https://groups.google.com/forum/#!searchin/bazel-discuss/combined_report%7Csort:date/bazel-discuss/itJkJ2T4mWw/qNKGEk_uFAAJ