## Summary Feature specs (Capybara, headless Chrome) checked the browser console only when an example fails while passing specs never looked for errors. This is different from how we've configured jest, where errors are induce a failures (with some exceptions). In https://gitlab.com/gitlab-org/gitlab/-/merge_requests/255207 we've configured the JavaScript-enabled example to fail on an unexpected SEVERE console message, so JS errors are discovered as they appear please baseline allowlist, `spec/support/browser_console_allowlist.yml`, with 50 known errors across about 200 spec files. This issue is the catalogue of those errors, with links to the CI jobs that showed them and a suggested fix for each. Every entry is a real error that the application logs today in the test environment. Each one needs an owner to either fix it or open a tracked issue and add the URL to the allowlist entry. ## How we got here GitLab migrates its frontend from Vue 2 to Vue 3 page by page, behind feature flags, on the `@vue/compat` build. On 2026-09-11 the Vue 3 migration of the merge request Rapid Diffs page (https://gitlab.com/gitlab-org/gitlab/-/merge_requests/252389) merged and was reverted within hours (https://gitlab.com/gitlab-org/gitlab/-/merge_requests/255026). Replying to a diff discussion broke the discussion list under Vue 3 **in test**. <details> <summary>Which tests failed?</summary> The failing feature specs were `spec/features/merge_request/user_comments_on_whitespace_hidden_diff_spec.rb` and `user_sees_avatar_on_diff_notes_spec.rb`, in jobs https://gitlab.com/gitlab-org/gitlab/-/jobs/16446513687 and https://gitlab.com/gitlab-org/gitlab/-/jobs/16446513695. The cause is in https://gitlab.com/gitlab-org/gitlab/-/issues/628791: the optimistic reply placeholder note has no `author`, and `noteable_note.vue` throws `TypeError: Cannot read properties of undefined (reading 'id')`. Fixes: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/255283 (minimal, skips the placeholder) and https://gitlab.com/gitlab-org/gitlab/-/merge_requests/255075 (renders it). </details> **The important finding was not the bug but why nobody saw it earlier.** Under Vue 2 the same code had thrown the same error for a long time. The feature specs passed and logged the error to the browser console on every run. Nothing read the console of a passing spec. To measure how common this was, a "reveal" merge request (https://gitlab.com/gitlab-org/gitlab/-/merge_requests/255199, not meant to merge) made every feature spec fail on any SEVERE console message and ran the full RSpec suite. After some noise filtering (https://gitlab.com/gitlab-org/gitlab/-/pipelines/2843079787) it showed about 1,400 failed examples in about 190 files. About 500 of those examples carried an application error, in roughly 50 distinct signatures. Three more merge requests came out of this work: - https://gitlab.com/gitlab-org/gitlab/-/merge_requests/255205 (merged) installs a Vue 3 error handler in non-production builds, so Vue 3 recovers from a component error the way production and Vue 2 do. - https://gitlab.com/gitlab-org/gitlab/-/merge_requests/255209 re-applies the Rapid Diffs migration on top of it. - https://gitlab.com/gitlab-org/gitlab/-/merge_requests/255198 adds a full-mount Jest spec for the Rapid Diffs bug class. One Vue 3-only error found by the reveal run has its own issue: https://gitlab.com/gitlab-org/gitlab/-/issues/628844 (merge request list filtering throws `No match for` from vue-router 4). ## What Vue 2 hides and Vue 3 exposes When a component throws during render, Vue 2 catches the error, calls `console.error`, and renders the component blank. The page keeps working. This is the same in every build. Vue 3 asks whether an `errorHandler` is installed. In production GitLab installs a Sentry handler, so Vue 3 also recovers and renders a comment node. In the development build, used by feature specs and by GDK (the local environment), no handler was installed, so Vue 3 rethrew. The throw unwinds through the parent's patch before the vnode tree is updated, and every later update fails with `Cannot set properties of null (setting '__vnode')`. The component tree is dead until reload. https://gitlab.com/gitlab-org/gitlab/-/merge_requests/255205 removes this difference. For this catalogue: entries marked "Vue 3 only" fail under Vue 3 but not under Vue 2. Everything else fails the same way under both versions and is not a migration problem. It is a pre-existing bug that the console check now makes visible. Vue 2 emits `[Vue warn]` messages with `console.error` (SEVERE). Vue 3 emits them with `console.warn` (not SEVERE). So prop-validation warnings fail specs only in Vue 2 jobs. ## What the console check does now In https://gitlab.com/gitlab-org/gitlab/-/merge_requests/255207, `spec/support/capybara.rb` runs `raise_if_unexpected_browser_console_output` after every `:js` example. Before, it ran only when the example had already failed. `BROWSER_CONSOLE_ERROR_FILTER` in `spec/support/helpers/browser_console_helpers.rb` ignores messages that come from the test environment, not from the application: failed HTTP requests (Chrome logs every 4xx and 5xx as SEVERE, and many specs assert on those responses), Content Security Policy violations (no network in CI: Snowplow, Zuora, OneTrust, Sentry envelope, media), the ArkoseLabs and Google Tag Manager scripts, the `[Sentry stub]` logger, the missing web manifest, the GraphQL explorer's embedded fonts, the `user_counts` request after logout, skipped view transitions, blocked `beforeunload` prompts, and the ActionCable WebSocket handshake. `spec/support/browser_console_allowlist.yml` lists known application errors. Each entry has a `pattern` (regexp), `specs` (the spec files it applies to; required, so an entry never hides the same error on another page), optional `vue` (2 or 3) and optional `issue` (full URL). A message is allowed only if the pattern matches, the running spec file is listed, and the Vue version matches. A validator spec, `spec/support_specs/browser_console_allowlist_spec.rb`, checks keys, regexps, URLs, and that every listed spec file exists, so entries die with the specs they reference. The baseline was generated from the traces of five pipelines: https://gitlab.com/gitlab-org/gitlab/-/pipelines/2843011566, https://gitlab.com/gitlab-org/gitlab/-/pipelines/2843079787, https://gitlab.com/gitlab-org/gitlab/-/pipelines/2843143467, https://gitlab.com/gitlab-org/gitlab/-/pipelines/2843157294 and https://gitlab.com/gitlab-org/gitlab/-/pipelines/2843200407. With it, every Vue 2 system job of the merge request passes. After the merge request merges, a new console error in a feature spec fails that spec. The author then fixes the error or adds an allowlist entry with an issue link. ## How to read the catalogue below One heading per allowlist entry, grouped into four categories: Vue 3-only crashes; uncaught JavaScript errors under both Vue versions; Vue warnings; and data or API problems (Apollo cache warnings, GraphQL errors, failed requests the application logs itself). Each entry lists the failed examples and spec files it covered across the five pipelines, representative CI jobs (the console output is under "Unexpected browser console output" in each failure), the bundle the message came from, a sample of the message, and a likely cause with a suggested fix. Causes marked "Hypothesis" have not been verified in code. To take an entry: fix it or open an issue, then add `issue: <url>` to the entry in `spec/support/browser_console_allowlist.yml`. When the error is fixed, delete the entry. The validator fails if a listed spec file no longer exists. -------- :robot: Below, there information about the errors collected, for agent consumption: ## Catalogue Counts are failed examples and spec files across the five pipelines. Job links open the CI job; the console output is under "Unexpected browser console output" in each failure. "Hypothesis" marks a cause that is not verified in code. ### A. Vue 3-only crashes These fail only in the `rspec system pg17 vue3` jobs. They are the migration blockers. #### `Uncaught Error: No match for` (Vue 3 only) - 40 examples, 16 spec files: `spec/features/merge_requests/user_filters_by_*_spec.rb`, `user_sorts_merge_requests_spec.rb`, `filters_generic_behavior_spec.rb`, `spec/features/groups/merge_requests_spec.rb`, `spec/features/issuables/sorting_list_spec.rb`, `spec/features/user_sorts_things_spec.rb`, `ee/spec/features/merge_requests/user_filters_by_approvers_spec.rb` - Jobs: [rspec system pg17 vue3 2/32](https://gitlab.com/gitlab-org/gitlab/-/jobs/16462296276), [rspec system pg17 vue3 7/32](https://gitlab.com/gitlab-org/gitlab/-/jobs/16462296281) - Source: `main.chunk.js`, thrown by vue-router 4 (`@gitlab/vue-router-vue3` 4.5.1) when a location resolves to no route record. The merge request list creates its router with a single `/` route (`app/assets/javascripts/merge_requests/list/index.js`). - Tracked: https://gitlab.com/gitlab-org/gitlab/-/issues/628844 - Suggested fix: make the filter and sort handlers push a location that resolves against the `/` route, or register the route shape vue-router 4 needs. Verify with the flag for the merge request list page and `VUE_VERSION=3` Jest. - Fix MR: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/255285 (keeps component-less routes matchable in the Vue Router compat layer) #### `Cannot set properties of null (setting '__vnode')`, `Cannot read properties of null (reading 'type')` (Vue 3 only) - 5 + 2 examples, spec files: `spec/features/merge_request/user_comments_on_whitespace_hidden_diff_spec.rb`, `user_sees_avatar_on_diff_notes_spec.rb`, `batch_comments_spec.rb` - Jobs: [rspec system pg17 vue3 3/32](https://gitlab.com/gitlab-org/gitlab/-/jobs/16462296277), [rspec system pg17 vue3 23/32](https://gitlab.com/gitlab-org/gitlab/-/jobs/16462296297) - Source: Vue runtime, after the Rapid Diffs reply placeholder crash (next entry). These are the cascade, not separate bugs. `batch_comments_spec.rb` is a fifth affected example that https://gitlab.com/gitlab-org/gitlab/-/merge_requests/255075 does not list. - Fix: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/255075 (placeholder branch in Rapid Diffs `discussion_notes.vue`). https://gitlab.com/gitlab-org/gitlab/-/merge_requests/255205 stops the cascade in development builds. - Fix MRs: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/255283 (minimal: skip placeholder replies) or https://gitlab.com/gitlab-org/gitlab/-/merge_requests/255075 (render the placeholder). https://gitlab.com/gitlab-org/gitlab/-/merge_requests/255205 is merged, so the development build now recovers like production. #### `Cannot read properties of undefined (reading 'id')` (Vue 2 form of the same crash) - 5 examples, same 3 spec files as above - Jobs: [rspec system pg17 10/32](https://gitlab.com/gitlab-org/gitlab/-/jobs/16462296252), [rspec system pg17 26/32](https://gitlab.com/gitlab-org/gitlab/-/jobs/16462296268) - Sample: `[Vue warn]: Error in render: "TypeError: Cannot read properties of undefined (reading 'id')" found in ---> <TimelineEntryItem> at rapid_diffs/app/discussions/timeline_entry_item.vue` - Tracked: https://gitlab.com/gitlab-org/gitlab/-/issues/628791. Fix: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/255075. - Fix MRs: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/255283 (minimal) or https://gitlab.com/gitlab-org/gitlab/-/merge_requests/255075 (render the placeholder) ### B. Uncaught JavaScript errors, both Vue versions Code outside Vue's error boundary (init scripts, DOM listeners, promise chains) or errors Vue 2 swallows. Not migration related; each is a latent bug in production too (Sentry receives the Vue ones). #### `Uncaught ReferenceError: _this\d+ is not defined` - 70 examples, 9 spec files: `ee/spec/features/{projects,groups}/analytics/dashboards_spec.rb`, `…/duo_and_sdlc_trends_dashboard_spec.rb`, `ee/spec/features/groups/analytics/visualizations_spec.rb`, `ee/spec/features/groups/contribution_analytics_spec.rb`, `ee/spec/features/groups/security/compliance_dashboards_spec.rb`, `ee/spec/features/explore/{analytics,system}_dashboards_spec.rb` - Jobs: [rspec-ee system clickhouse25](https://gitlab.com/gitlab-org/gitlab/-/jobs/16462296315), [rspec-ee system pg17 4/16](https://gitlab.com/gitlab-org/gitlab/-/jobs/16462296378) - Source: `main.chunk.js` (line 258837 in the first run), so shared code loaded on every page but triggered by the analytics dashboards. - Hypothesis: `_this12` is a Babel-generated alias for `this` used before its declaration, typically an arrow function inside a class field or a `switch` case that Babel hoists. Find the module by mapping `main.chunk.js:258837` with the job's source map, then remove the `this` capture. Largest single crash class in the list. - Fix MR: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/255292 (merged; Babel arrow-function transform on gridstack) #### `Uncaught ParametersMissing: Route missing required keys: id` - 20 examples, 3 spec files: `spec/features/projects/pages/user_adds_domain_spec.rb`, `user_edits_lets_encrypt_settings_spec.rb`, `user_edits_settings_spec.rb` - Jobs: [rspec system pg17 12/32](https://gitlab.com/gitlab-org/gitlab/-/jobs/16462296254), [rspec system pg17 19/32](https://gitlab.com/gitlab-org/gitlab/-/jobs/16462296261) - Source: `main.chunk.js`. A generated JavaScript route helper (`~/lib/utils/path_helpers`) called without the `id` parameter on the Pages domain settings pages. - Hypothesis: the Pages settings app calls a `*_path` helper for a domain that does not exist yet (new domain form). Guard the call or pass the id. - Fix MR: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/255305 #### `Uncaught RangeError: Invalid time value` - 14 examples, 6 spec files: `spec/features/projects/branches_spec.rb`, `spec/features/projects/branches/user_{views_branches,deletes_branch}_spec.rb`, `spec/features/protected_branches_spec.rb`, `ee/spec/features/projects/protected_branches_spec.rb`, `spec/features/projects/members/member_leaves_project_spec.rb` - Jobs: [rspec system pg17 3/32](https://gitlab.com/gitlab-org/gitlab/-/jobs/16462296245), [rspec system pg17 11/32](https://gitlab.com/gitlab-org/gitlab/-/jobs/16462296253) - Source: `main.chunk.js`. `Date.prototype.toISOString` (or `Intl` formatting) on an invalid date. - Hypothesis: a timestamp attribute on the branches page is empty or in a format `new Date()` rejects (for example a `data-*` attribute with a localized string). Find with the source map; parse defensively or fix the attribute. - Fix MR: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/255309 #### `Cannot read properties of null (reading 'text')` - 27 examples, 12 spec files: notes and GFM autocomplete specs (`spec/features/work_items/issues/{gfm_autocomplete,notes_on_issues,user_comments_on_issue}_spec.rb`, `spec/features/projects/milestones/gfm_autocomplete_spec.rb`, `spec/features/merge_request/user_{comments_on_merge_request,suggests_changes_on_diff}_spec.rb`, `spec/features/issuables/markdown_references/jira_spec.rb`, `ee/spec/features/groups/wiki_spec.rb`, `ee/spec/features/projects/feature_flags/feature_flag_issues_spec.rb`, `spec/features/work_items/issues/design_management/user_views_design_spec.rb`, `spec/features/work_items/detail/work_item_detail_spec.rb`, `spec/features/milestones/user_creates_milestone_spec.rb`) - Jobs: [rspec system pg17 8/32](https://gitlab.com/gitlab-org/gitlab/-/jobs/16462296250), [rspec system pg17 9/32](https://gitlab.com/gitlab-org/gitlab/-/jobs/16462296251) - Source: `vendor.dll.bundle.js`, so a dependency, most likely the autocomplete library (`@gitlab/at.js` / Tribute) reading `.text` of a null selection or node. - Hypothesis: autocomplete fires on a textarea whose selection or caret node is null after the note is submitted and the field is cleared. Guard in the wrapper (`app/assets/javascripts/gfm_auto_complete.js`) or upgrade the library. #### `Cannot read properties of null (reading 'containsElement')` - 16 examples, 7 spec files: `spec/features/incidents/incident_timeline_events_spec.rb`, `spec/features/{groups,projects}/service_accounts*_spec.rb`, `spec/features/profiles/user_updates_comment_template_spec.rb`, `ee/spec/features/groups/user_updates_comment_template_spec.rb`, `ee/spec/features/groups/settings/work_items/custom_status_configuration_spec.rb` - Jobs: [rspec system pg17 30/32](https://gitlab.com/gitlab-org/gitlab/-/jobs/16462296272), [rspec system pg17 vue3 10/32](https://gitlab.com/gitlab-org/gitlab/-/jobs/16462296284) - Source: `main.chunk.js`. `containsElement` is the API of the markdown editor's content editor (Tiptap/ProseMirror wrapper) or the `GlDisclosureDropdown` outside-click handler. - Hypothesis: a handler runs after the editor or dropdown instance is destroyed (form submitted, drawer closed) and dereferences a null ref. All affected pages have a form in a drawer or modal. Null-guard the handler or unbind it on destroy. - Fix MR: https://gitlab.com/gitlab-org/gitlab-services/design.gitlab.com/-/merge_requests/6362 (`@gitlab/ui`, `GlDisclosureDropdown.handleAutoClose`; also reported as https://gitlab.com/gitlab-org/gitlab/-/work_items/629489). Released in `@gitlab/ui` 137.2.5, merged into GitLab by https://gitlab.com/gitlab-org/gitlab/-/merge_requests/256414 on 2026-09-21. #### `Cannot read properties of null (reading 'appendChild')` - 6 examples, 4 spec files: `spec/features/projects/labels/user_{edits_labels,removes_labels,sees_breadcrumb_links}_spec.rb`, `spec/features/projects/active_tabs_spec.rb` - Jobs: [rspec system pg17 10/32](https://gitlab.com/gitlab-org/gitlab/-/jobs/16462296252), [rspec system pg17 29/32](https://gitlab.com/gitlab-org/gitlab/-/jobs/16462296271) - Source: `main.chunk.js`. - Hypothesis: an init script on the labels pages mounts into a container that the page no longer renders (`document.querySelector(...)` returns null). Guard the mount or delete the script. - Fix MR: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/255311 #### `Cannot read properties of undefined (reading 'filter')` - 12 examples, 4 spec files: `spec/features/projects/clusters_spec.rb`, `spec/features/projects/clusters/{gcp,user}_spec.rb`, `spec/features/clusters/create_agent_spec.rb` - Jobs: [rspec system pg17 19/32](https://gitlab.com/gitlab-org/gitlab/-/jobs/16462296261), [rspec system pg17 vue3 15/32](https://gitlab.com/gitlab-org/gitlab/-/jobs/16462296289) - Source: `vendor.dll.bundle.js`. - Hypothesis: a component on the clusters pages filters a list prop that is `undefined` while a GraphQL query is loading. Default the prop to `[]`. Note that most certificate-based cluster pages are unreachable in production; check whether the code is still live before fixing. - Fix MR: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/255315 #### `Cannot read properties of undefined (reading 'map')` and `(reading 'emitsOptions')` - 13 + 6 examples, 1 spec file: `ee/spec/features/admin/admin_dev_ops_reports_spec.rb` - Jobs: [rspec-ee system pg17 12/16](https://gitlab.com/gitlab-org/gitlab/-/jobs/16462296386), [rspec-ee system pg17 vue3 15/16](https://gitlab.com/gitlab-org/gitlab/-/jobs/16462296405) - Source: `pages.admin.dev_ops_report.show` and `pages.admin.application_settings.*` commons chunks. - Hypothesis: the DevOps adoption page maps over `data.nodes` before the query resolves (`map`), and a tab component reads `emitsOptions` of a `null` component instance, which points at a `<component :is>` receiving `null` while switching tabs. Default the data, and guard the dynamic component. - Fix MR: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/255322 #### `Cannot instantiate GlTabsBehavior without an element` - 5 examples, 2 spec files: `spec/features/projects/show/repository_actions_spec.rb`, `spec/features/admin/admin_disables_git_access_protocol_spec.rb` - Jobs: [rspec system pg17 22/32](https://gitlab.com/gitlab-org/gitlab/-/jobs/16462296264), [rspec system pg17 vue3 14/32](https://gitlab.com/gitlab-org/gitlab/-/jobs/16462296288) - Source: `pages.projects.show.chunk.js`. `GlTabsBehavior` (`app/assets/javascripts/tabs/index.js`) is constructed on the project page when the Git clone instructions tabs are not rendered (empty project, or SSH disabled). - Fix: only instantiate when the element exists. - Fix MR: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/255313 #### `Cannot add property 5, object is not extensible` - 2 examples, 1 spec file: `spec/features/projects/ci/editor_spec.rb` - Jobs: [rspec system pg17 28/32](https://gitlab.com/gitlab-org/gitlab/-/jobs/16462642137), [rspec system pg17 vue3 21/32](https://gitlab.com/gitlab-org/gitlab/-/jobs/16462642162) - Source: `vendor.dll.bundle.js`, in the pipeline editor branch switcher. - Hypothesis: code pushes into a frozen array, typically an Apollo cache result (Apollo freezes results in development) used as a mutable list. Copy before mutating. - Fix MR: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/255316 #### `$toolpop.show is not a function` - 4 examples, 2 spec files: `spec/features/work_items/issues/notes_on_issues_spec.rb`, `ee/spec/features/work_items/epics/referencing_epics_spec.rb` - Jobs: [rspec system pg17 19/32](https://gitlab.com/gitlab-org/gitlab/-/jobs/16462296261), [rspec system pg17 vue3 27/32](https://gitlab.com/gitlab-org/gitlab/-/jobs/16462296301) - Source: the issuable reference popover (`app/assets/javascripts/issuable/popover/index.js`). Cross-reference notes render issue and epic links, and hovering one mounts the popover with `new (Vue.extend(PopoverComponent))({ propsData: { show: true } }).$mount()`. In the default job the frame is in a `.vue3-` commons chunk, so the popover runs under `@vue/compat` in both jobs. - Root cause: under `@vue/compat`, that app's `globalProperties.constructor` is the `Vue.extend()` subclass. The vendored bootstrap-vue factory `createNewChildComponent` in `@gitlab/ui` builds the tooltip helper from it, so the popover component's props are merged into the helper and its `show` prop shadows the helper's `show()` method. Same bug as the Sentry report https://gitlab.com/gitlab-org/gitlab/-/work_items/629440. A `this.$toolpop` guard would hide the error and the popover. - Fix MR: https://gitlab.com/gitlab-org/gitlab-services/design.gitlab.com/-/merge_requests/6361 (`@gitlab/ui`). No GitLab change is needed; the entry clears with the next `@gitlab/ui` bump. #### `Cannot read properties of undefined (reading 'clientWidth')` - 9 examples, 3 spec files: `spec/features/{groups,projects}/service_accounts*_spec.rb` - Jobs: [rspec system pg17 12/32](https://gitlab.com/gitlab-org/gitlab/-/jobs/16462296254), [rspec system pg17 16/32](https://gitlab.com/gitlab-org/gitlab/-/jobs/16462296258) - Sample: `[Vue warn]: Error in callback for watcher "items" (Promise/async) … found in ---> <GlBreadcrumb>` - Source: `@gitlab/ui` `GlBreadcrumb`. The `items` watcher measures a ref that is gone because the breadcrumb was unmounted while the promise was pending. - Suggested fix: in `@gitlab/ui`, guard the measurement after `await`; in GitLab, avoid remounting the breadcrumb on the service accounts page. #### `Cannot read properties of null (reading 'value')` - 2 examples, 1 spec file: `ee/spec/features/groups/group_settings_spec.rb` (seat control settings) - Jobs: [rspec-ee system pg17 9/16](https://gitlab.com/gitlab-org/gitlab/-/jobs/16462296383), [rspec-ee system pg17 vue3 9/16](https://gitlab.com/gitlab-org/gitlab/-/jobs/16462296399) - Source: `pages.groups.edit.chunk.js`. - Hypothesis: a settings init script reads `.value` of an input that is not rendered when seat control is hidden. Guard the query. - Fix MR: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/255319 #### `Cannot read properties of null (reading 'before')` - 3 examples, 1 spec file: `spec/features/markdown/math_spec.rb` - Jobs: [rspec system pg17 8/32](https://gitlab.com/gitlab-org/gitlab/-/jobs/16462296250), [rspec system pg17 vue3 16/32](https://gitlab.com/gitlab-org/gitlab/-/jobs/16462296290) - Source: `main.chunk.js`, math rendering (`app/assets/javascripts/behaviors/markdown/render_math.js`). - Hypothesis: `element.parentNode.before(...)` where the math node was already detached (rendered twice). Guard `parentNode`. - Fix MR: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/255328 #### `Cannot read properties of undefined (reading 'focus')` and `(reading 'getValue')` - 2 + 2 examples, 1 spec file: `spec/features/projects/files/template_selector_menu_spec.rb` - Jobs: [rspec system pg17 16/32](https://gitlab.com/gitlab-org/gitlab/-/jobs/16462296258), [rspec system pg17 vue3 10/32](https://gitlab.com/gitlab-org/gitlab/-/jobs/16462296284) - Source: lazy chunks of the source editor (Monaco). - Hypothesis: the template selector calls `editor.focus()` / `editor.getValue()` before the editor instance is created or after it is disposed. Await the editor promise. - Fix MRs: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/255321 (edit mode tabs), https://gitlab.com/gitlab-org/gitlab/-/merge_requests/255539 (commit changes modal) #### `Cannot destructure property 'boardList' of 'object null'` - 3 examples, 1 spec file: `ee/spec/features/boards/new_issue_spec.rb` - Jobs: [rspec-ee system pg17 vue3 14/16](https://gitlab.com/gitlab-org/gitlab/-/jobs/16462296404), [rspec-ee system pg17 es9 1/16](https://gitlab.com/gitlab-org/gitlab/-/jobs/16462296456) - Source: `vendor.dll.bundle.js` (Apollo update function). - Hypothesis: a mutation `update` callback destructures `data.boardList` from a `null` mutation result (the mutation returned errors). Guard the result. - Fix MR: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/255325 (merged) #### `Cannot read properties of null (reading 'namespace')` - 1 example, 1 spec file: `spec/features/work_items/issues/user_interacts_with_awards_spec.rb` - Jobs: [rspec system pg17 12/32](https://gitlab.com/gitlab-org/gitlab/-/jobs/16462296254), [rspec system pg17 vue3 19/32](https://gitlab.com/gitlab-org/gitlab/-/jobs/16462296293) - Hypothesis: an Apollo cache read for `workItem.namespace` returns null after an award mutation. Guard the read. - Fix MR: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/255326 (merged) #### `Uncaught TypeError` (other), `Uncaught Error` (other) - 13 + 1 examples, 12 spec files, for example `spec/features/admin/runners/admin_manages_runners_spec.rb`, `spec/features/dashboard/issues_spec.rb`, `spec/features/work_items/issues/list/filtered_search/dropdown_{assignee,author}_spec.rb`, `ee/spec/features/admin/geo/admin_geo_replication_nav_spec.rb`, `ee/spec/features/dashboards/environments_spec.rb`, `spec/features/groups/work_items_spec.rb` - Jobs: [rspec system pg17 23/32](https://gitlab.com/gitlab-org/gitlab/-/jobs/16462296265), [rspec system pg17 32/32](https://gitlab.com/gitlab-org/gitlab/-/jobs/16462296274), [rspec system pg17 11/32](https://gitlab.com/gitlab-org/gitlab/-/jobs/16462296253) - Samples: `Cannot read properties of null (reading 'hide')` (a dropdown hidden after unmount), `The resource that you are attempting to access does not exist or you don't have permission` (a GraphQL error surfaced as an uncaught rejection) - These two entries are catch-alls. Split them into specific entries when taking one; the job console output has the exact message per spec. ### C. Vue warnings Vue 2 emits these with `console.error`, so they fail Vue 2 jobs only. Each is a cheap fix. #### `[Vue warn]: Invalid prop: type check failed for prop` - 140 examples, 35 spec files. Props seen: `text` (GlBreadcrumbItem receives a Number, and Null), `token` (access tokens `NewToken`, Null), `publicKey` (IdentityVerificationArkoseApp, Undefined), `hasDependencyPaths` (dependency list, Undefined), `target`, `value` (TimezoneDropdown, Undefined), `licenses`, `containerType` (DuoAgenticChatBlockedStateView), `dateTitle` (MrWidgetAuthor, Null), `placeholder` - Jobs: [rspec system pg17 3/32](https://gitlab.com/gitlab-org/gitlab/-/jobs/16462296245), [rspec system pg17 8/32](https://gitlab.com/gitlab-org/gitlab/-/jobs/16462296250) - Suggested fix: per component, either pass the right type (`String(id)`), make the prop optional with a default, or accept `null`. Jest already ignores these warnings globally (`spec/frontend/environment.js`), so they never fail unit tests; consider mirroring that ignore in the feature spec filter if the list is not worth fixing. - Fix MRs: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/255394 (`token`, `value`, `dateTitle`; the `text` warning is `SimpleCopyButton` under `NewToken`, not `GlBreadcrumbItem`), https://gitlab.com/gitlab-org/gitlab/-/merge_requests/255395 (`hasDependencyPaths`, `licenses`), https://gitlab.com/gitlab-org/gitlab/-/merge_requests/255396 (`target`), https://gitlab.com/gitlab-org/gitlab/-/merge_requests/255397 (`containerType`), https://gitlab.com/gitlab-org/gitlab/-/merge_requests/255398 (`publicKey`, spec helper only). `placeholder` was not found in the traces. #### `[Vue warn]: Invalid prop: custom validator check failed for prop "items"` - 1 example, `ee/spec/features/projects/google_cloud/artifact_registry_spec.rb`. `GlBreadcrumb` items validator; a breadcrumb item lacks `text` or `href`. - Jobs: [rspec-ee system pg17 14/16](https://gitlab.com/gitlab-org/gitlab/-/jobs/16462296388) - Fix MR: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/255392 #### `[Vue warn]: Write operation failed: computed value is readonly` - 31 examples, 7 spec files: incidents (`spec/features/incidents/*_spec.rb`, `ee/spec/features/incidents/*_spec.rb`), `spec/features/abuse_report_spec.rb` - Jobs: [rspec system pg17 2/32](https://gitlab.com/gitlab-org/gitlab/-/jobs/16462296244), [rspec system pg17 9/32](https://gitlab.com/gitlab-org/gitlab/-/jobs/16462296251) - Source: `vendor.dll.bundle.js`. A component assigns to a computed property without a setter, likely a `v-model` bound to a computed on the incident details or timeline form. - Fix: add a setter or bind to a data property. - Fix MR: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/255393 (Pinia `syncWithVuex` copied the Vuex `discussions` key onto a Pinia getter) #### `[Vue warn]: Failed to resolve directive: gl-tooltip` - 21 examples, 1 spec file: `spec/features/user_settings/granular_personal_access_tokens/tokens_table_spec.rb` - Jobs: [rspec system pg17 24/32](https://gitlab.com/gitlab-org/gitlab/-/jobs/16462296266) - Fix: register `GlTooltipDirective` in the component that uses `v-gl-tooltip` in the tokens table. - Fix MR: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/255388 #### `[Vue warn]: Injection "newReleasePath" not found`, `Property or method "newReleasePath" is not defined` - 1 + 2 examples: `spec/features/projects/releases/user_views_releases_spec.rb` (and `ee/spec/features/user_sees_active_nav_items_spec.rb` for a second property) - Jobs: [rspec system pg17 3/32](https://gitlab.com/gitlab-org/gitlab/-/jobs/16462296245) - Fix: provide `newReleasePath` in the releases index app (`app/assets/javascripts/releases/`), or give the inject a default. - Fix MR: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/255389 #### `[Vue warn]: Avoid using non-primitive value as key`, `Duplicate keys detected` - 1 + 1 examples: `ee/spec/features/merge_request/user_edits_merge_request_blocking_mrs_spec.rb` (`BlockingMrInputRoot`), `ee/spec/features/merge_request/user_sets_approvers_spec.rb` (`MrRulesHiddenInputs`) - Jobs: [rspec-ee system pg17 4/16](https://gitlab.com/gitlab-org/gitlab/-/jobs/16462296378), [rspec-ee system pg17 12/16](https://gitlab.com/gitlab-org/gitlab/-/jobs/16463080529) - Fix: use `item.id` as the `:key`, and make hidden-input keys unique per rule. - Fix MR: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/255390 #### `[Vue warn]: Error in render: … (reading 'value')`, `Error in data(): … (reading 'scanModes')` - 1 + 1 examples: `ee/spec/features/user_sees_active_nav_items_spec.rb`, in `ConfigurationForm` at `ee/app/assets/javascripts/security_configuration/api_fuzzing/components/` - Jobs: [rspec-ee system pg17 16/16](https://gitlab.com/gitlab-org/gitlab/-/jobs/16462642257) - Hypothesis: the API fuzzing configuration form is mounted with an empty `apiFuzzingCiConfiguration` on the nav spec's page. Default the data or do not mount the form without configuration. - Fix MR: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/255391 ### D. Data and API problems The application logs these itself. Some are test-data gaps rather than frontend bugs. #### `Missing field 'humanTimeEstimate' while writing result` - 62 examples, 9 spec files: boards sidebar specs in CE and EE (`spec/features/boards/*_spec.rb`, `ee/spec/features/boards/*_spec.rb`, `spec/features/groups/board_sidebar_spec.rb`) - Jobs: [rspec system pg17 8/32](https://gitlab.com/gitlab-org/gitlab/-/jobs/16462296250), [rspec system pg17 10/32](https://gitlab.com/gitlab-org/gitlab/-/jobs/16462296252) - Source: Apollo cache write. A board mutation or subscription returns an `Issue` without `humanTimeEstimate`, but a query fragment in the cache expects it. - Fix: add `humanTimeEstimate` to the mutation's response fragment (or remove it from the query fragment). Largest data entry; one fix covers 9 files. - Cause found: not a mutation fragment. The board drawer sync `mapWorkItemWidgetsToIssuableFields` wrote `undefined` for `humanTimeEstimate`, because the detail widgets fragment no longer selects time tracking (commit 3b47290ed135). Boards never read the field. - Fix MR: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/255556 (drops the unused fields from the board fragment; the mapper keeps cached values when a widget has no data) #### `Missing field 'html'`, `Missing field '<other>'` (`errors`, `commit`, `pipelines`, `browseArtifactsPath`) - 19 + 9 examples: `spec/features/projects/active_tabs_spec.rb` (repository tree `html`), `spec/features/projects/pipelines/pipelines_spec.rb`, `spec/features/projects/jobs/user_browses_jobs_spec.rb`, `spec/features/environments/environments_folder_spec.rb`, `ee/spec/features/work_items/detail/change_type_action_spec.rb` - Jobs: [rspec system pg17 29/32](https://gitlab.com/gitlab-org/gitlab/-/jobs/16462296271), [rspec system pg17 9/32](https://gitlab.com/gitlab-org/gitlab/-/jobs/16462296251) - Fix: same class as above; align the fragments per query. - Fix MRs: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/255572 (`html`: the readme resolver now always returns the field; the blob JSON omits it for a README without a rich viewer), https://gitlab.com/gitlab-org/gitlab/-/merge_requests/255571 (`pipelines`, `commit`, `browseArtifactsPath`: CI `subscribeToMore` handlers returned the partial cache read, which Apollo rewrote; the jobs subscription now shares the query fragment), https://gitlab.com/gitlab-org/gitlab/-/merge_requests/255570 (`errors`: the environments delete resolver returned the `cache.evict` boolean instead of its payload; the traced field for `environments_folder_spec.rb` is `errors`, not `commit`), https://gitlab.com/gitlab-org/gitlab/-/merge_requests/255573 (`change_type_action_spec.rb`: the convert mutation did not pass `useWorkItemFeatures`; the exact field was not in the traces and a local run did not reproduce it) #### `GraphQL execution errors for query 'runners'`, `'mergeRequest'`, `for subscription 'mergeChecksState'`, `Unhandled GraphQL subscription error: Unauthorized subscription` - 20 + 3 + 1 + 1 examples: `spec/features/projects/ci/editor_spec.rb` (runners), `spec/features/work_items/issues/notes_on_issues_spec.rb` (mergeRequest), `ee/spec/features/merge_request/user_sees_approve_via_custom_role_spec.rb` (subscriptions) - Jobs: [rspec system pg17 28/32](https://gitlab.com/gitlab-org/gitlab/-/jobs/16462642137), [rspec system pg17 19/32](https://gitlab.com/gitlab-org/gitlab/-/jobs/16462296261), [rspec-ee system pg17 vue3 1/16](https://gitlab.com/gitlab-org/gitlab/-/jobs/16462642258) - Hypothesis: the pipeline editor queries `runners` without the permission the spec user has; the issue page queries `mergeRequest` for a reference that is not a merge request; the custom-role spec user is not authorized for the `mergeChecksState` subscription. Either give the spec user the permission, or make the frontend not issue the query when the user cannot see the data. - Fix MR: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/255562 (`runners`: the job assistant drawer queried the admin-only root `runners` field on every page load; it now queries the project's runners, only while open, only with `read_runners`) - `mergeRequest` and the custom-role subscriptions did not reproduce locally. A probe in `Subscriptions::BaseSubscription` logged `allowed=true` for every subscription in `user_sees_approve_via_custom_role_spec.rb`, and `notes_on_issues_spec.rb` produced no GraphQL error. Both need the error payload from CI (the console shows only `Object`); the reveal branch with a console probe is the next step. #### `[gitlab] Error: Request failed with status code 408` - 13 examples, 11 spec files: `spec/features/search/user_searches_for_*_spec.rb`, `ee/spec/features/search/*` - Jobs: [rspec system pg17 10/32](https://gitlab.com/gitlab-org/gitlab/-/jobs/16462296252), [rspec system pg17 14/32](https://gitlab.com/gitlab-org/gitlab/-/jobs/16462296256) - The search page's count requests time out (408) in the test environment; the frontend logs each with `logError`. - Suggested fix: the search app should treat a 408 on a count request as "count unavailable" without logging an error, or the specs should stub the counts. - Fix MR: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/255552 (408 is `SearchController#render_timeout`, on purpose; the count and aggregation actions no longer log it) #### `PipelineUsageApp: error fetching subscriptionPermissions query`, `Error sending the query 'subscriptionPermissions'` - 11 + 2 examples: `ee/spec/features/ci/ci_minutes_spec.rb`, `ee/spec/features/profiles/usage_quotas/usage_quotas_spec.rb`, `spec/features/groups/usage_quotas/storage_tab_spec.rb`, `ee/spec/features/user_sees_active_nav_items_spec.rb` - Jobs: [rspec-ee system pg17 1/16](https://gitlab.com/gitlab-org/gitlab/-/jobs/16462296375), [rspec system pg17 vue3 2/32](https://gitlab.com/gitlab-org/gitlab/-/jobs/16462296276) - Sample: `ServerParseError: Unexpected token '<', "<!DOCTYPE "... is not valid JSON` - The `subscriptionPermissions` query goes to the CustomersDot GraphQL endpoint, which does not exist in the test environment, so the request returns an HTML page. - Suggested fix: skip the query when CustomersDot is not configured, or stub the endpoint in these specs. - Fix MR: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/255561 (the proxy answers 404 outside GitLab.com; gon now carries the `cdot_graphql_proxy` SaaS flag, the six callers skip the query, and the 404 is JSON). `user_sees_active_nav_items_spec.rb` has no CustomersDot caller; that attribution looks wrong. #### `[gitlab] Error: bad request: error building search request` (Zoekt), `Error: failed to parse query` (Elasticsearch) - 2 + 1 examples: `ee/spec/features/search/zoekt/search_spec.rb`, `ee/spec/features/search/elastic/project_search_spec.rb` - Jobs: [rspec-ee system pg17 15/16](https://gitlab.com/gitlab-org/gitlab/-/jobs/16462296389), [rspec-ee system pg17 12/16](https://gitlab.com/gitlab-org/gitlab/-/jobs/16462296386) - The specs search for a query the backend rejects (regexp with a missing argument). The frontend logs the backend error. - Suggested fix: decide whether the frontend should show this as a user-facing message instead of logging it; the specs may intend to test the invalid-query path. - Fix MR: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/255558 (Zoekt 4xx is now `InvalidQueryError`; the results app shows the Zoekt message and no longer logs or reports it) #### `Refused to apply style from '…/page_bundles/error_tracking_index.css'` - 3 examples, 3 spec files: `spec/features/error_tracking/*_spec.rb` - Jobs: [rspec system pg17 12/32](https://gitlab.com/gitlab-org/gitlab/-/jobs/16462296254) - The error tracking page links a page bundle stylesheet that is not compiled, so the server answers with HTML. Fix: remove the dead `page_specific_stylesheet` or add the bundle. - Fix MR: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/255551 (removes the call; adds a haml-lint check `PageSpecificStyle` so a dangling stylesheet name fails lint) #### Bare `Object` and empty console errors - `\d+:\d+ Object$`: 24 examples, `spec/features/projects/ci/editor_spec.rb`, `spec/features/work_items/issues/notes_on_issues_spec.rb`, `ee/spec/features/merge_request/user_sees_approve_via_custom_role_spec.rb`. Jobs: [rspec system pg17 19/32](https://gitlab.com/gitlab-org/gitlab/-/jobs/16462296261). A `console.error(someObject)` call with no message text, in a groups analytics commons chunk; it accompanies the GraphQL execution errors above. - `\d+:\d+\s*$` (empty message): 44 examples, 11 spec files, all registration and identity verification flows (`ee/spec/features/registrations/**`, `ee/spec/features/users/identity_verification_spec.rb`, `ee/spec/features/groups/analytics/cycle_analytics/charts_spec.rb`, `ee/spec/features/projects/pipelines/pipelines_spec.rb`). Jobs: [rspec-ee system pg17 1/16](https://gitlab.com/gitlab-org/gitlab/-/jobs/16462296375). Source: `pages.users.identity_verification.show` chunk. A `console.error()` with an empty or non-string argument. - Suggested fix: find the two `console.error` call sites with the source map and log a message with the object. These entries cannot be narrowed further until the message says something. - Bare `Object`: vue-apollo prints each `graphQLErrors` entry after the `GraphQL execution errors` line. No separate call site; fixed with the entries above. - Empty message: `init_arkose_labs.js`. The script load rejection had no handler while the payload request was pending, so the browser reported an unhandled rejection whose value is a DOM Event. Confirmed with a local console probe. Fix MR: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/255568. ## References - Console check and baseline allowlist: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/255207 - Reveal merge request (not meant to merge): https://gitlab.com/gitlab-org/gitlab/-/merge_requests/255199 - Reveal pipelines: https://gitlab.com/gitlab-org/gitlab/-/pipelines/2843011566, https://gitlab.com/gitlab-org/gitlab/-/pipelines/2843079787 - Baseline pipelines of the console check MR: https://gitlab.com/gitlab-org/gitlab/-/pipelines/2843143467, https://gitlab.com/gitlab-org/gitlab/-/pipelines/2843157294, https://gitlab.com/gitlab-org/gitlab/-/pipelines/2843200407 - Rapid Diffs placeholder crash: https://gitlab.com/gitlab-org/gitlab/-/issues/628791, fix https://gitlab.com/gitlab-org/gitlab/-/merge_requests/255075 - Original Rapid Diffs migration and revert: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/252389, https://gitlab.com/gitlab-org/gitlab/-/merge_requests/255026 - Failing jobs that started this: https://gitlab.com/gitlab-org/gitlab/-/jobs/16446513687, https://gitlab.com/gitlab-org/gitlab/-/jobs/16446513695 - Non-production Vue 3 error handler: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/255205 - Rapid Diffs migration re-applied on top of it: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/255209 - Full-mount Jest spec for the Rapid Diffs bug class: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/255198 - Merge request list router error under Vue 3: https://gitlab.com/gitlab-org/gitlab/-/issues/628844 - Vue 3 migration (Code Review) epic: https://gitlab.com/groups/gitlab-org/-/work_items/23167 <!-- claude session=0ae9bc86-b4fd-49f7-9175-f982bae78bac posted=2026-09-14T07:31:31Z --> <!-- claude session=cea8c5fe-0580-4dce-947a-0262456690fe posted=2026-09-15T07:35:30Z --> <!-- claude session=0ae9bc86-b4fd-49f7-9175-f982bae78bac posted=2026-09-15T07:41:15Z --> <!-- claude session=2a10c1fb-c8d2-432c-b36a-629ee12c11a2 posted=2026-09-15T09:57:20Z --> <!-- claude session=0ba4ef87-1982-46ae-bd56-ccc6020846df posted=2026-09-18T09:17:40Z --> <!-- claude session=7e77c27d-5d47-47c3-91f5-6b107a4fd323 posted=2026-09-21T10:19:06Z -->