Files
Marc Schier ea0f266b66 Move build and test to the Azure DevOps managed pool and replace Codecov with an in-pipeline coverage gate (#4122)
# Description

Moves the all-target-framework build, the cross-platform test matrix and
the Native AoT run from GitHub Actions onto the Azure DevOps
`netstandard` Managed DevOps Pool, and replaces Codecov with a coverage
gate that runs inside the pipeline.

## 1. CI backend switch

One conceptual switch decides who owns that work. It is checked into
source in **two places that must be flipped together**:

| File | Setting | Default |
| --- | --- | --- |
| `azure-pipelines.yml` | `parameters.ciBuildBackend` | `ado` |
| `.github/workflows/buildandtest.yml` | `env.CI_BUILD_BACKEND` | `ado`
|

Setting both to `actions` restores the previous behaviour exactly.

Azure Pipelines gains what it was missing to take the work over:

- A **Linux all-TFM `sln.yml` leg**, replacing `build-all-tfm-linux`.
`sln.yml` gets a `configurations` parameter so this leg builds `Release`
only instead of doubling the managed-pool job count.
- A **Linux agent in the `net10.0` `testfastpr` matrix**, replacing the
ubuntu `build-and-test` job.
- **Native AoT and Code Coverage now gate pull requests** instead of
running only on Schedule/Manual. The coverage stage drops its
`testdebug` dependency, which is Schedule/Manual-only and would
otherwise have skipped coverage on every PR.
- On a PR, Windows builds the .NET Framework TFMs and Linux the modern
ones — mirroring the split the GitHub Actions jobs used — so all seven
TFMs stay covered without fanning every TFM across both pools.

Two things are deliberately **not** covered by the switch:

- **macOS** stays on GitHub-hosted runners, because Managed DevOps Pools
provide no macOS image.
- **`master378` and `develop/*`** keep running the GitHub Actions jobs,
since Azure Pipelines only builds `master`/`main` from this file.

GitHub Actions does not expose the `env` context to job-level `if:`
conditions, so the switch is resolved once in the existing `discover`
job and re-exported as job outputs.

A new **`build-and-test summary`** job gives branch protection one
stable check to require, instead of the generated matrix job names. It
treats an intentionally skipped job as success but still fails on a real
failure or cancellation.

The `paths:` allow-list was moved off the `pull_request` trigger and
into `discover`. A workflow filtered out by `paths` never reports its
checks, and a required check that never reports leaves a PR permanently
*"Expected — waiting for status to be reported"*. That would have made
the routine "ratchet the coverage floor" PR (which touches only
`coverage-thresholds.json` and docs) unmergeable.

## 2. Coverage gate replacing Codecov

Codecov is removed entirely — `codecov.yml`, both uploads, the badge,
and the token usage. `.azurepipelines/check-coverage.ps1` runs at the
end of the `Code Coverage` stage against the Cobertura report
ReportGenerator already merges, driven by `coverage-thresholds.json`:

| Check | Behaviour |
| --- | --- |
| Project floor | **Blocking** — total line and branch rates against an
absolute floor. |
| Patch coverage | **Blocking on PRs** — changed lines must reach
`patch.target`, tolerating `patch.threshold` percentage points (the same
semantics `codecov/patch` had). |
| Baseline delta | **Advisory** — reports the change against the
recorded baseline, never fails. |

The project rate is recomputed from the per-line data rather than read
off the Cobertura root element, so the `ignore` globs carried over from
`codecov.yml` apply to the project floor as well as to the changed-lines
gate — otherwise samples and generated code would count towards one gate
but not the other.

`testcc.yml` gains an explicit `checkout: self` with `fetchDepth: 0`,
because the default shallow clone cannot diff against the base branch.

## Follow-up actions for maintainers

Two items cannot be automated from source:

1. **Enable the `/azp run` gate.** In the Azure DevOps portal: pipeline
→ **More actions** → **Triggers** → **Pull request validation** →
**Require a team member's comment before building a pull request**,
scoped to *Only on pull requests from non-team members*. This makes
Copilot-authored and outside-contributor PRs wait for a maintainer's
`/azp run`, mirroring the approval GitHub Actions already requires. The
documentation added here describes the workflow and the
private-org-membership gotcha; **the setting itself still has to be
switched on.**
2. **Update branch protection and secrets.** Drop the `codecov/project`
and `codecov/patch` required checks, require `build-and-test summary`
and the ADO coverage check instead, and remove `CODECOV_TOKEN` from the
GitHub repository secrets and the ADO variable group.

Also note the thresholds in `coverage-thresholds.json` are seeded from
the last Codecov reading (73.61 %) with headroom, because the
in-pipeline number had not been observed yet. The first full `Code
Coverage` run on master should confirm it and the floors should be
tightened then — the gate prints the exact figure it computes.

## Related Issues

_No tracking issue; this is CI infrastructure work requested directly._

## Checklist

- [x] I have signed the
[CLA](https://opcfoundation.org/license/cla/ContributorLicenseAgreementv1.0.pdf)
and read the
[CONTRIBUTING](https://github.com/OPCFoundation/UA-.NETStandard/blob/master/CONTRIBUTING.md)
doc.
- [x] I have added tests that prove my fix is effective or that my
feature works and increased code coverage.
- No product code changed, so there are no unit tests to add. The new
logic was verified with purpose-built harnesses instead:
- All 8 branch/event/backend combinations of the `discover` switch,
confirming `master378` and `develop/*` are untouched and that `actions`
restores the old behaviour.
- 12 scenarios for `check-coverage.ps1`: the project floor, the patch
gate, ignore globs applying to *both* gates, three path-normalization
shapes, and the advisory delta.
- 14 path-relevance cases confirming the in-job filter matches the
retired `paths:` allow-list exactly.
- End-to-end against a **real** ReportGenerator report: correctly
resolved `src/Opc.Ua.PubSub/DependencyInjection/PubSubBuilder.cs`, found
exactly the four modified tracked lines and reported 50 % patch coverage
(2 covered, 2 uncovered).
- [x] I have added all necessary documentation.
- New **Continuous integration** section in `docs/DeveloperGuide.md`, a
CI note in `CONTRIBUTING.md`, and links from `docs/README.md`. Also
corrected the CI matrix description, which claimed the PR gate ran net48
+ **net8.0** — it runs net48 + **net10.0**.
- [x] I have verified that my changes do not introduce (new) build or
analyzer warnings.
- `dotnet build src/Opc.Ua.Server` → 0 warnings, 0 errors. No product
code changed.
- [ ] I ran **all** tests locally using the **UA.slnx** solution against
at least .net **framework** and .net **10**, and all passed.
- Not applicable — no product code changed. `Opc.Ua.Server.Tests` was
run on net10.0 during development (3480 passed; the single
`ServerFluentApiHostingTests` failure is pre-existing and reproduces on
master).
- [ ] I fixed **all** failing and flaky tests in the CI pipelines and
**all** CodeQL warnings.
- [x] I have addressed **all** PR feedback received.
- A review pass over this branch flagged the `paths:`-filter deadlock
described above; it is fixed in `1926e240e`.

---------

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
Copilot-Session: 181ba7ea-c72f-42d7-a737-00a3faadaa17
Copilot-Session: 26aa55a2-5731-4a4c-b61c-df2f7a785eca
2026-07-31 21:06:25 +00:00
..