[ENG-1547] Relation creation via drag handle (Obsidian) by trangdoan982 · Pull Request #909 · DiscourseGraphs/discourse-graph

trangdoan982 · 2026-03-23T21:53:47Z

https://www.loom.com/share/ee0d603ff9db4025a1c8f857f2b01aec

Summary

Clicking an existing persisted relation arrow now shows the relation type dropdown at the arrow midpoint
Selecting a new type updates the arrow visuals (color, label) and persists the change to relations.json in-place (preserving id, created, author, etc.)
Added updateRelationType() helper to relationsStore.ts
Handles edge cases: same-type re-selection dismisses without changes, Escape/click-outside closes without modifying, dropdown doesn't re-open after creation or edit flows

Test plan

Create a relation via drag handles — existing flow still works, dropdown closes after selection
Select a new type — arrow updates (color, label) and relations.json type field updated in-place
Escape/click outside — dropdown closes, arrow disappear
Relation Overlay updated correctly after relation is created

🤖 Generated with Claude Code

linear · 2026-03-23T21:53:51Z

ENG-1547 Implement relation creation via drag handles in tldraw (Obsidian)

supabase · 2026-03-23T21:53:57Z

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Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

mdroidian

CI is failing.
This PR is ~50% over the line change limit. I understand this might be required (or ideal) in this case, that being said, would you mind creating a Loom video walking through this code and code choices?

The biggest concern I have doing a quick review was the code possibly not being as DRY as possible. I worry we might be duplicating work, specifically in the relation/arrow drag handling logic and potential relations checking.

apps/obsidian/src/components/canvas/overlays/RelationTypeDropdown.tsx

apps/obsidian/src/components/canvas/overlays/DragHandleOverlay.tsx

trangdoan982 · 2026-04-06T17:12:27Z

@mdroidian video explain file structure here: https://youtu.be/BBAKm1G-zXM

devin-ai-integration · 2026-04-09T04:13:21Z

apps/obsidian/src/components/canvas/shapes/DiscourseRelationShape.tsx

    targetNodeTypeId: string,
    relationTypeId: string,
  ): boolean {
-    const plugin = this.options.plugin;
-
-    // Check direct connection (source -> target)
-    const directConnection = plugin.settings.discourseRelations.some(
-      (relation) =>
-        relation.relationshipTypeId === relationTypeId &&
-        relation.sourceId === sourceNodeTypeId &&
-        relation.destinationId === targetNodeTypeId,
-    );
-
-    if (directConnection) return true;
-
-    // Check reverse connection (target -> source)
-    // This handles bidirectional relations where the complement is used
-    const reverseConnection = plugin.settings.discourseRelations.some(
-      (relation) =>
-        relation.relationshipTypeId === relationTypeId &&
-        relation.sourceId === targetNodeTypeId &&
-        relation.destinationId === sourceNodeTypeId,
-    );
-
-    return reverseConnection;
+    return isValidRelationConnection({
+      discourseRelations: this.options.plugin.settings.discourseRelations,
+      relationTypeId,
+      sourceNodeTypeId,
+      targetNodeTypeId,
+    });
  }


(Refers to lines 1117-1128)

📝 Info: isValidNodeConnection method is now dead code

The isValidNodeConnection method on DiscourseRelationUtil (DiscourseRelationShape.tsx:1117-1128) was refactored to delegate to the new isValidRelationConnection utility. However, its only call site in onHandleDrag was changed to call isValidRelationConnection directly (DiscourseRelationShape.tsx:349). A search confirms isValidNodeConnection has no remaining callers anywhere in the codebase. It could be removed to reduce confusion.

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devin-ai-integration · 2026-04-09T04:15:19Z

apps/obsidian/src/components/canvas/DiscourseRelationTool.ts

(Refers to lines 139-143)

📝 Info: Dead code: unreachable !target branch in DiscourseRelationTool

At line 139, the check if (!target) is unreachable because target was already validated as non-null at line 110 (if (!target || target.type !== 'discourse-node')), which returns early if null. This means this.createArrowShape() on line 140 can never be called from this branch. This is a pre-existing issue (not introduced by this PR), but since the surrounding code was modified by the refactoring, it's worth noting.

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mdroidian

Nothing blocking approval from me, but this looks like a good candidate for a small DRY follow-up later. DragHandleOverlay seems to reimplement part of the existing relation-arrow flow that already lives in DiscourseRelationTool / DiscourseRelationUtil.onHandleDrag, especially around > arrow creation, end-handle binding updates, and finalization/reification. Not suggesting we hold this PR for it, just flagging it as a worthwhile cleanup > target.

There was a couple interesting Devin comments that might be worth looking at as well.

mdroidian · 2026-04-09T03:52:07Z

apps/obsidian/src/components/canvas/overlays/RelationTypeDropdown.tsx

+  );
+
+  // Auto-dismiss if arrow is deleted
+  useEffect(() => {


This is worrisome. What case is this handling that cannot be handled directly via a user event? EG: on escape and on clickoutside are already handled.

mdroidian · 2026-04-09T04:01:59Z

apps/obsidian/src/components/canvas/overlays/RelationTypeDropdown.tsx

+  );
+
+  // Handle click outside
+  useEffect(() => {


Could the click/escape be handled with onBlur on the dropdown itself?

drag handle works

0ebe9ce

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trangdoan982 force-pushed the eng-1547-implement-relation-creation-via-drag-handles-in-tldraw branch from 75c8668 to 0ebe9ce Compare March 26, 2026 03:47

fix: reset isDragging on early returns and use e.currentTarget for hover

a61f515

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

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trangdoan982 added 2 commits March 27, 2026 15:03

format and lint

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format

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address PR comment + fix z-position

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trangdoan982 changed the title ~~[ENG-1547] Add relation type editing via click on existing arrows~~ [ENG-1547] Relation creation via drag handle (Obsidian) Mar 27, 2026

trangdoan982 requested a review from mdroidian March 27, 2026 19:43

some updates naming etc

5dae9f7

mdroidian requested changes Mar 27, 2026

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address PR comments

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trangdoan982 mentioned this pull request Mar 28, 2026

[ENG-1546] Relation creation via drag handles (Roam) #923

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trangdoan982 added 2 commits April 6, 2026 12:41

dry as much as possible

6873ad4

further DRY and styling fixes

ad197b1

trangdoan982 requested a review from mdroidian April 6, 2026 17:05

prettier

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devin-ai-integration bot reviewed Apr 9, 2026

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mdroidian approved these changes Apr 9, 2026

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trangdoan982 commented Apr 6, 2026

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trangdoan982 commented Mar 23, 2026 •

edited

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