Switch from relative to absolute pathing for coverage reports

[jdw-creare]

Short reason: To help with certain deployments that use podpac as a submodule, working around a limitation in the coverage tool.

Long reason:

• SonarQube ingests an XML report, which we name coverage.xml
• We generate coverage.xml by first running the tests with the coverage run command, which outputs a binary report (coverage.bin), then by converting that binary report to XML with the coverage xml command.
• SonarQube needs to be able to find the sources referenced in the report. It runs on a different machine, so it works best and makes sense to send SonarQube a coverage report with relative paths in this XML report.
• Configuration for the coverage tool is done in pyproject.toml. Every repo has its own choices about which folders contain source and which ones should be ignored, so it makes sense to keep this configuration on a per-repo basis.
• The coverage command can be configured to use absolute or relative paths by this file. There is not (that I have found) any way to override this at the command line. The choice of absolute or relative paths applies to all coverage subcommands, notably run, combine, and xml.
• So, when you run coverage run with relative paths, coverage xml must be run at the same working directory, or coverage xml won't find the source and will fail. (I don't know why coverage xml requires access to the source files)
• That's not a problem at all when scanning an individual repository. Since SonarQube requires relative paths, it makes sense to just configure coverage to always use relative paths.
• In certain deployments, we structure the repository as follows:

root_project_repo
└podpac (as submodule)
└ogc (as submodule)
└other repos (as submodules)

For those repos, we wish to compute coverage, and combine them into one summary XML report. We have to run coverage run in each submodule separately, to use each repo's coverage settings from its pyproject.toml. That's not a problem - coverage combine will combine binary coverage reports. But if we use relative paths, then each call to coverage xml has to occur with the same working directory as the initial coverage run, or coverage xml won't find the source files it needs. That's incompatible with running coverage run several times with different working directories.

So the solution I lean toward is to run coverage run and coverage xml with absolute paths. SonarQube requires relative paths. It's pretty easy to convert an absolute path to a relative path in an XML file by using sed. So there's a required sed command for each CI job, to get it back to relative paths.

An alternative would be to generate one XML report for each submodule, and then stitch them together later. That's a much more involved level of text postprocessing, so I prefer this solution.

Since this is all a workaround for a limitation in coverage, if someone finds a better workaround, or if there is an improvement to the coverage tool so that we don't need to do this, we should switch back to relative paths.

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[scranford1]

Looks good to me, thanks @jdw-creare.

[jdw-creare]

Thanks Sam!