Customize gcovr reports

[sdarwin]

Coverage reports are being generated on pull requests at https://github.com/boostorg/url . For example, in boostorg/url#649 it shows:

GCOVR code coverage report https://649.url.prtest.cppalliance.org/gcovr/index.html
LCOV code coverage report https://649.url.prtest.cppalliance.org/genhtml/index.html
Coverage Diff https://649.url.prtest.cppalliance.org/gcovr/coverage_diff.txt

The GCOVR report is created by running this command:

gcovr -p --html-details --exclude '.*/test/.*' --exclude '.*/extra/.*' --filter ".*/url/.*" --html --output $BOOST_CI_SRC_FOLDER/gcovr/index.html

However that requires the C++ source code to be available and to have been built so it's useful to have a more complete script. This example script https://github.com/CPPAlliance/ci-automation/blob/master/scripts/jenkins.sh will build everything from scratch.

Run jenkins.sh in an ubuntu 22.04 container. gcovr html output will be generated in:

./url_job_folder/gcovr/

and json files, discussed in the other github issue, will be here:

./url_job_folder/json/
./url/json/

Goals:

The aim of the project is to make the html more closely resemble the earlier codecov design before their recent updates.

Codecov results: https://app.codecov.io/github/CPPAlliance/http_proto/tree/develop/include/boost/http_proto . Vinnie will comment further about what's correct or incorrect in those webpages.

Methods:

• gcovr html is already customizable to a certain extent. For example, css may be replaced: --html-css <css>. See https://gcovr.com/en/stable/manpage.html

• Add preprocessing or postprocessing steps in a new custom script.

• If the gcovr executable itself has to be modified to enable customization to take place, consider submitting pull requests directly to https://github.com/gcovr/gcovr

cc @vinniefalco @gregnewman

[sdarwin]

@gregnewman, the current script is running these commands:

gcovr --html-details

and

gcovr --json-summary

If the html reports are only minimally customized I had been imagining gcovr --html-details would continue to be used, modifying the output in various ways.

However, for the most flexibility in the design it is possible to replace that step. Instead of --html-details run --json-summary. That produces plain json data. Create html pages from scratch based on the data.

Here's an example of a webpage that generates javascript charts based on benchmark statistics which have been include in a textarea field https://github.com/boostorg/json/blob/develop/bench/results.html

[sdarwin]

The latest script is lcov-jenkins-gcc-13.sh. Also, documentation and files may be found in https://github.com/cppalliance/ci-automation/tree/master/scripts

Vinnie requested that branch coverage be disabled. I added the flags --exclude-unreachable-branches --exclude-throw-branches which reduces branch coverage, however doesn't eliminate it. And, I opened a GitHub Issue with gcovr. It's unlikely to be fixed though. How about this solution: since the templates and the css will be modified, display the "yellow" "warning" color of incomplete branch coverage as "green" instead, or whatever the success color is. It will visually appear to be well covered code. Probably leave the small informational drop-down menus to the left which display the per-branch coverage or non-coverage, as long as it's all "green", then it looks fine.

@rbbeeston

[vinniefalco]

LOL not a bad idea Sam :)