<!--- Please read this! Before opening a new issue, make sure to search for keywords in the issues filtered by the "regression" or "type::bug" label: - https://gitlab.com/gitlab-org/gitlab/issues?label_name%5B%5D=regression - https://gitlab.com/gitlab-org/gitlab/issues?label_name%5B%5D=type::bug and verify the issue you're about to submit isn't a duplicate. ---> ### Summary `GET /projects/:id/pipelines` passes the raw request `params` hash to `Ci::PipelinesFinder` instead of `declared_params`, so any query parameter whose name matches a finder option is honored even though the endpoint does not declare or document it. Two of those options, `iids` and `ids`, bypass the finder's child pipeline filter, which contradicts the endpoint's own description: "By default, child pipelines are not included in the results. To return child pipelines, set `source` to `parent_pipeline`." `iids` already returns child pipelines this way. Since https://gitlab.com/gitlab-org/gitlab/-/merge_requests/265592 merged, which exempts `ids` lookups from the child filter, `ids` does too. The finder options `pipeline_schedules` and `merge_request_event_first` reach the finder through the same path. During review of the fix, the Pipeline Execution group confirmed the `iids` behavior was not designed but has been public for years, and decided to declare and document `iids` and `ids` rather than drop them, because removing them would silently change responses for existing callers. This bug was identified in https://gitlab.com/gitlab-org/gitlab/-/merge_requests/265592#note_4102377165. <!--Summarize the bug encountered concisely.--> ### Steps to reproduce 1. Pick a child pipeline in a public project through the documented filter: ```shell curl "https://gitlab.com/api/v4/projects/278964/pipelines?source=parent_pipeline&per_page=1" ``` 2. Request it through the undeclared `iids` parameter, using the `iid` from the previous response: ```shell curl "https://gitlab.com/api/v4/projects/278964/pipelines?iids[]=<child_iid>" ``` 3. Request the default list and confirm no child pipelines appear: ```shell curl "https://gitlab.com/api/v4/projects/278964/pipelines?per_page=2" ``` <!--Describe how one can reproduce the issue - this is very important. Please use an ordered list.--> ### Example Project https://gitlab.com/gitlab-org/gitlab (project ID 278964). Any project with parent-child pipelines reproduces it. <!--If possible, please create an example project here on GitLab.com that exhibits the problematic behavior, and link to it here in the bug report. If you are using an older version of GitLab, this will also determine whether the bug is fixed in a more recent version.--> ### What is the current _bug_ behavior? Step 2 returns the child pipeline, even though `iids` is not a declared parameter of this endpoint and the response is documented to exclude child pipelines unless `source=parent_pipeline` is set. `?ids[]=<child_id>` behaves the same way since https://gitlab.com/gitlab-org/gitlab/-/merge_requests/265592 merged. Neither parameter appears in the endpoint description, the REST docs, or the OpenAPI document. <!--Describe what actually happens.--> ### What is the expected _correct_ behavior? `iids` and `ids` are declared optional parameters of `GET /projects/:id/pipelines`, documented in the endpoint description, `doc/api/pipelines.md`, and the OpenAPI document, and both forms of passing them (`iids[]=1&iids[]=2` and `iids=1,2`) work as they do on the issues and merge requests endpoints. The docs state that child pipelines are returned when requested by `iids` or `ids`. Responses for existing requests do not change. <!--Describe what you should see instead.--> ### Relevant logs and/or screenshots <!--Paste any relevant logs - please use code blocks (```) to format console output, logs, and code as it's tough to read otherwise.--> ### Output of checks <!--If you are reporting a bug on GitLab.com, uncomment below--> <!--This bug happens on GitLab.com--> <!--and uncomment below if you have /label privileges--> <!--/label ~"reproduced on GitLab.com"--> <!--or follow up with an issue comment of `@gitlab-bot label ~"reproduced on GitLab.com"` if you do not--> #### Results of GitLab environment info <!--Input any relevant GitLab environment information if needed.--> <details> <summary>Expand for output related to GitLab environment info</summary> <pre> (For installations with omnibus-gitlab package run and paste the output of:\\\ \\\`sudo gitlab-rake gitlab:env:info\\\`)\\\ \\\ (For installations from source run and paste the output of:\\\ \\\`sudo -u git -H bundle exec rake gitlab:env:info RAILS_ENV=production\\\`) </pre> </details> #### Results of GitLab application Check <!--Input any relevant GitLab application check information if needed.--> <details> <summary>Expand for output related to the GitLab application check</summary> <pre> (For installations with omnibus-gitlab package run and paste the output of:\\\ \`sudo gitlab-rake gitlab:check SANITIZE=true\`)\ \ (For installations from source run and paste the output of:\\\ \`sudo -u git -H bundle exec rake gitlab:check RAILS_ENV=production SANITIZE=true\`)\ \ (we will only investigate if the tests are passing) </pre> </details> ### Possible fixes Declare `iids` and `ids` as `Array[Integer]` with `CommaSeparatedToIntegerArray.coerce` in `lib/api/ci/pipelines.rb`, update the endpoint `detail`, `doc/api/pipelines.md`, and the regenerated OpenAPI document, and keep passing the raw `params` hash to the finder so no existing response changes. Implemented in https://gitlab.com/gitlab-org/gitlab/-/merge_requests/267392. Switching the endpoint to `declared_params` was considered and rejected: it would also stop honoring `pipeline_schedules` and `merge_request_event_first`, which `doc/development/api_styleguide.md` treats as a breaking change to REST v4. Those two remain undeclared. If they should be closed off, that is a separate decision for the group. <!--If you can, link to the line of code that might be responsible for the problem.--> ### Patch release information for backports If the bug fix needs to be backported in a [patch release](https://handbook.gitlab.com/handbook/engineering/releases/patch-releases) to a version under [the maintenance policy](https://docs.gitlab.com/policy/maintenance/), please follow the steps on the [patch release runbook for GitLab engineers](https://gitlab.com/gitlab-org/release/docs/-/blob/master/general/patch/engineers.md). Refer to the [internal "Release Information" dashboard](https://dashboards.gitlab.net/d/delivery-release_info/delivery3a-release-information?orgId=1) for information about the next patch release, including the targeted versions, expected release date, and current status. #### High-severity bug remediation To remediate high-severity issues requiring an [internal release](https://handbook.gitlab.com/handbook/engineering/releases/internal-releases/) for single-tenant SaaS instances, refer to the [internal release process for engineers](https://gitlab.com/gitlab-org/release/docs/-/blob/master/general/internal-releases/engineers.md?ref_type=heads). <!--If you don't have /label privileges, follow up with an issue comment of `@gitlab-bot label ~"type::bug"`-->