[scheduler-premium] Dependencies - Arrows and terminals for SS, FF and SF by rita-codes · Pull Request #23524 · mui/mui-x

rita-codes · 2026-09-07T15:40:16Z

Closes #23394. Part of #22853.

Renders the Start-to-Start, Finish-to-Finish and Start-to-Finish dependencies on the timeline and lets users create them by gesture. The engine side (per-type formulas, lag) stays in #23393: until it lands, a non-FS dependency is drawn and described but not enforced.

What is covered

Model. SchedulerDependencyType widens to the four types, the minimum the rendering needs. The rest of the model work (lag, lagUnit, validation) belongs to [scheduler] Dependencies: SS/FF/SF and lag in the auto-scheduling engine #23393 with the engine formulas that consume it, and is not touched here. Helpers getDependencyEdges(type) and getDependencyType(sourceSide, targetSide). A dependency with an unknown type is ignored with a dev warning.
Arrows. Each type connects the edges it constrains. Routing works in a canonical frame where the source exits to the right: SF is FS mirrored, SS is FF mirrored. Two routers: the existing one for opposite edges (elbow, S detour when backward) and a new one for same edges (wraps around the outermost anchor, detours below the events at the same height). The arrowhead always enters horizontally, also at the timeline edges.
Terminals on both edges. The dragged edge and the dropped edge define the type. Terminals are drop targets themselves; dropping on the event body targets the start edge, so FS and SS need no aiming. Same behavior as Bryntum's DependencyCreation.
Gesture feedback. The hovered target shows its terminals and the one the drop would use grows in green; the provisional line snaps to that edge. The delete button of a selected arrow sits on the side the arrow comes from, and the terminal under it steps aside while the selection lasts.
Duplicates. Two dependencies of different types between the same events are allowed; a duplicate of the same type is rejected.
Accessibility. One sentence per dependency on the successor: "Cannot start until A finishes", "Cannot start until A starts", "Cannot finish until A finishes", "Cannot finish until A starts".

Also

The arrow geometry module is split into anchor resolver, routing and hit-area (pure move, first commit), each with its own tests.
The arrow path string is built lazily and the terminal leaf is memoized: a gesture transition re-renders only the terminals involved.
The experiments demo is a release day with every type and arrow shape once.

Out of scope

Violated-dependency styling (open question in the issue; Bryntum never renders that state).
Same-lane back-to-back SS/FF links overlap the other endpoint by a few pixels, like adjacent FS events already do.
Lag ([scheduler] Dependencies: SS/FF/SF and lag in the auto-scheduling engine #23393), the arrow editor ([scheduler] Dependencies: arrow editor (type + lag) and immediate cascade on create/edit #23395), the public API flip and docs ([scheduler] Dependencies: public API flip and docs #23420).

How to test

/x/react-scheduler/experiments/, section "Timeline dependency arrows": one dependency of each type in the data, hover an event for its terminals, drag from either edge onto another event or one of its terminals, select an arrow to delete it.

Pure move: the anchor resolver, the orthogonal routing and the hit-area helpers get a module each, so the routing changes for the new dependency types are reviewable on their own. Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01EBYMarDHeuysLnbKifmMaP

Widens SchedulerDependencyType to the four PDM types (the rendering is the consumer; lag stays with the engine work) and routes the arrows in a canonical frame: StartToStart and StartToFinish mirror the anchors around the events area, leaving one router for opposite edges (the existing one) and one for same edges. The arrow path is now built lazily, like the hit-area, so a row re-measure does not rebuild the strings of off-screen arrows. Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01EBYMarDHeuysLnbKifmMaP

…ions Every event gets a terminal on both edges, and the terminals are drop targets themselves: the dragged edge and the dropped edge resolve the dependency type (the event body targets the start edge). While a gesture hovers a target, its terminals are revealed by state so the user can pick the edge. Duplicate detection now includes the type, the delete button sits on the side the arrow comes from, and the successor description carries one sentence per type. Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01EBYMarDHeuysLnbKifmMaP

While the gesture hovers a target, the terminal of the edge the drop would use (the hovered terminal, or the start edge over the event body) carries data-dependency-drop-target and grows in the creation color, like Bryntum's active terminal. Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01EBYMarDHeuysLnbKifmMaP

- Let the pointer through the terminals while a dependency is selected, so the delete button under the target's edge terminal stays reachable. - Compare the revealed terminal set element by element: the two terminals of an appearance are culled separately and the set can grow on scroll. - Drop the hover reveal of the source's other terminal at gesture start. - Memoize the terminal leaf on primitive props so a gesture transition only re-renders the gesture's terminals. - Ignore and warn about dependencies with an unknown type instead of throwing. - Tests for the start terminal placement and clamp, the multi-resource gesture, the provisional line anchor, the StartToFinish edge cases and a FinishToFinish multi-resource fan-out; stale comments, dead code and duplicated CSS cleaned up. Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01EBYMarDHeuysLnbKifmMaP

One dataset where every dependency has a business reason and each type and arrow shape appears once, restricted to working hours so it fits the viewport. Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01EBYMarDHeuysLnbKifmMaP

…rminals-for-ssffsf

code-infra-dashboard · 2026-09-07T15:46:00Z

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docs/data/scheduler/experiments/TimelineDependencyArrows.js

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Moves the resolver tests out of the geometry suite, shares the fixtures through dependencyGeometryTestUtils, and pins the edge points per lane and row, the row obstacles, the unmeasured rows and the precomputed positions directly. Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01EBYMarDHeuysLnbKifmMaP

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01EBYMarDHeuysLnbKifmMaP

…rminals-for-ssffsf

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01EBYMarDHeuysLnbKifmMaP

…rminals-for-ssffsf

…ion build The shared fixtures import test/utils, which the declaration build (rootDir src) cannot follow; the tests folder is excluded from it. Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01EBYMarDHeuysLnbKifmMaP

…sffsf' of github.com:rita-codes/mui-x into 23394-scheduler-dependencies-arrows-and-terminals-for-ssffsf

…meline edges The same-height branch of the same-edges router kept the raw anchors as its endpoints, so a target ending at the timeline end (or starting at its start for the mirrored types) lost its entry segment and the arrowhead pointed up. The stubs now ride over the events like the other branches, and an invariant test over the whole type matrix pins that every route ends horizontally into its target edge. Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01EBYMarDHeuysLnbKifmMaP

Hiding every terminal while a dependency is selected made a press on a visible terminal fall through to whatever sits beneath it. Only the selected arrow's target-edge terminal, the one the button covers, steps aside now. Also: the routing invariant test checks the exit direction and orthogonality, the fixtures shared by the dependency tests live in one place, and a few dead bits and stale comments from the review go. Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01EBYMarDHeuysLnbKifmMaP

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01EBYMarDHeuysLnbKifmMaP

…rminals-for-ssffsf

github-actions · 2026-09-17T07:16:25Z

This pull request has conflicts, please resolve those before we can evaluate the pull request.

flaviendelangle

PR review

One non-blocking finding: an unknown dependency type can crash the timeline when that dependency is selected. All 251 executed dependency tests passed; browser tests were not run.

Bugs (1)

1. 🟠 Guard the selected dependency’s type before resolving its edges

Location: EventTimelinePremiumDependencyTerminals.tsx:362

: { eventId: selected.target, side: getDependencyEdges(selected.type).target };

Unknown types are filtered out of active arrows, but selectedModel still returns them. The selection cleanup also does not check the type. This lookup therefore returns undefined, and reading .target crashes rendering.

Failure scenario: Select a valid arrow, then refresh dependencies with the same ID and an unknown type. A local reproduction confirmed the TypeError at this line.

Fix: Guard unsupported types before resolving the selected dependency’s edges, clear their selection, and add a regression test for this update.

Tests (0)

No findings.

Simplifications (0)

No findings.

Docs (0)

No findings.

Verdict

Approve after nits - guard the selected-dependency lookup against malformed type updates.

🤖 Review generated with Codex

…ependencies-arrows-and-terminals-for-ssffsf # Conflicts: # packages/x-scheduler-internals-premium/src/event-timeline-premium-selectors/eventTimelinePremiumDependencySelectors.ts # packages/x-scheduler-premium/src/event-timeline-premium/content/timeline-dependency-arrows/dependencyArrowGeometry.test.ts # packages/x-scheduler-premium/src/event-timeline-premium/content/timeline-dependency-arrows/dependencyArrowGeometry.ts # packages/x-scheduler-premium/src/event-timeline-premium/tests/dependencyTestUtils.tsx

…ows-and-terminals-for-ssffsf' into 23394-scheduler-dependencies-arrows-and-terminals-for-ssffsf

…ependencies-arrows-and-terminals-for-ssffsf

… whose type becomes unknown Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

…rminals-for-ssffsf

rita-codes · 2026-09-17T09:31:41Z

Good catch, thanks. The store effect that clears the selection only checked the endpoints, so it missed the "unknown type" case this PR introduced in the active-list selector.

Fixed in d7009e6 by extracting an isDependencyActive predicate (supported type + valid endpoints) shared by the active-list selector and the selection cleanup, so anything the arrows drop can no longer stay selected. Added a store test and a timeline test reproducing the TypeError on the same-id / unknown-type update.

rita-codes and others added 6 commits September 7, 2026 13:02

rita-codes self-assigned this Sep 7, 2026

rita-codes added type: new feature Expand the scope of the product to solve a new problem. scope: scheduler Changes related to the scheduler. labels Sep 7, 2026

rita-codes changed the title ~~[scheduler-premium] Dependencies - Arrows and terminals for SS, FF and SF~~ [DRAFT][scheduler-premium] Dependencies - Arrows and terminals for SS, FF and SF Sep 7, 2026

Merge branch 'master' into 23394-scheduler-dependencies-arrows-and-te…

a1cc47f

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rita-codes added the plan: Premium Impact at least one Premium user. label Sep 7, 2026

rita-codes and others added 11 commits September 8, 2026 12:02

[scheduler] Point the localeText TODOs at the public flip issue

8265a7f

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01EBYMarDHeuysLnbKifmMaP

Merge branch 'master' into 23394-scheduler-dependencies-arrows-and-te…

0a65cc5

…rminals-for-ssffsf

[scheduler] Trim the comments added with the dependency types

50b8e45

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01EBYMarDHeuysLnbKifmMaP

Merge branch 'master' into 23394-scheduler-dependencies-arrows-and-te…

f256e06

…rminals-for-ssffsf

Merge branch '23394-scheduler-dependencies-arrows-and-terminals-for-s…

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…sffsf' of github.com:rita-codes/mui-x into 23394-scheduler-dependencies-arrows-and-terminals-for-ssffsf

[scheduler] Point every public flip TODO at its issue

bed0082

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01EBYMarDHeuysLnbKifmMaP

Merge branch 'master' into 23394-scheduler-dependencies-arrows-and-te…

d812940

…rminals-for-ssffsf

rita-codes changed the title ~~[DRAFT][scheduler-premium] Dependencies - Arrows and terminals for SS, FF and SF~~ [scheduler-premium] Dependencies - Arrows and terminals for SS, FF and SF Sep 8, 2026

rita-codes marked this pull request as ready for review September 8, 2026 14:48

rita-codes mentioned this pull request Sep 8, 2026

[scheduler] Dependencies: public API flip and docs #23420

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rita-codes requested a review from flaviendelangle September 8, 2026 15:19

Merge branch 'master' into 23394-scheduler-dependencies-arrows-and-te…

74b3555

…rminals-for-ssffsf

rita-codes mentioned this pull request Sep 16, 2026

[scheduler-premium] Dependencies - Auto-scheduling engine (FS) #23439

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github-actions Bot added the PR: out-of-date The pull request has merge conflicts and can't be merged. label Sep 17, 2026

flaviendelangle approved these changes Sep 17, 2026

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rita-codes added 2 commits September 17, 2026 11:20

Merge remote-tracking branch 'origin/23394-scheduler-dependencies-arr…

7f1441c

…ows-and-terminals-for-ssffsf' into 23394-scheduler-dependencies-arrows-and-terminals-for-ssffsf

github-actions Bot removed the PR: out-of-date The pull request has merge conflicts and can't be merged. label Sep 17, 2026

rita-codes and others added 3 commits September 17, 2026 11:23

Merge remote-tracking branch 'upstream/master' into 23394-scheduler-d…

6ba3e28

…ependencies-arrows-and-terminals-for-ssffsf

[scheduler-premium] Apply review: clear the selection of a dependency…

d7009e6

… whose type becomes unknown Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

Merge branch 'master' into 23394-scheduler-dependencies-arrows-and-te…

34b6667

…rminals-for-ssffsf

rita-codes merged commit e8e61f8 into mui:master Sep 17, 2026
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rita-codes mentioned this pull request Sep 17, 2026

[scheduler-premium] Dependencies - SS/FF/SF and lag in the auto-scheduling engine #23623

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[scheduler-premium] Dependencies - Arrows and terminals for SS, FF and SF - #23524

[scheduler-premium] Dependencies - Arrows and terminals for SS, FF and SF#23524
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Bugs (1)

1. 🟠 Guard the selected dependency’s type before resolving its edges

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