[devin-ai-integration]

What and why

The drawio rendering form (#1668) exports a view as an editable diagrams.net / draw.io file whose semantic cells carry the element's qualified name. This adds the way back: read a draw.io file the user edited and write the geometry into the model as DiagramLayout metadata (Layout, Route, Canvas, Style, Note, Picture) through the existing model-edit path, so the positions land in the .sysml text as reviewable metadata Layout about … lines, exactly as a drag in the VS Code panel does.

Reader (internal/ir/view/drawio_import.go): ReadDrawio parses <mxfile> with encoding/xml, accepting both the uncompressed <diagram><mxGraphModel> form the writer emits and the compressed form draw.io desktop saves (<diagram> text = base64 → raw deflate → percent-decoded XML). Multi-page files: the page whose cells' view attribute names the requested view, a typed *DrawioViewError on none or several. Container-relative geometry is resolved to absolute coordinates (a Layout is absolute). Malformed input yields a typed *DrawioFileError, never a panic.

Matcher and diff (internal/ir/view/drawio_import_diff.go): Rendering.ImportDrawio renders the view, writes it with the writer under the same options, and diffs the edited file against that baseline cell by cell. Nodes and ports pair by fqn (and ordinal, when a view draws the same element twice, as a tree does an inherited member); edges by the names of their ends + kind + ordinal — the writer's e<i> ids are an order, not an identity; notes and pictures by position. Only a cell that differs from what the writer would emit now becomes an edit: moved/resized/collapsed node → Layout, re-routed edge → Route (a straightened edge clears it), restyled cell → Style, resized page → Canvas, moved note/picture → Note/Picture. Positions equal within 0.5 px are unchanged, so an untouched export imports zero edits — and the routes the writer computes itself never become annotations unless the user moved them.

Reported, not imported: cells with no fqn the export did not write (shapes drawn in draw.io — nothing creates model elements), semantic cells the file no longer holds (nothing deletes elements), fqns matching no element (renamed or gone), moved edge labels (a Route places a line, not its label; label positions have no annotation yet) and a port moved along its owner's border (ports are drawn there by the renderer).

Edits (internal/check/edit/drawio.go): DrawioOperations turns an import into Operations for the existing SetLayout/SetRoute/SetCanvas/SetStyle and the new SetNote/SetPicture (also on the LSP's applyModelEdit and the MCP's apply_model_edit). A member drawn under a node of another element — a part of the usage's type, an inherited state — is named by the path a Layout resolves through (Loop::sensor::waterOut, not Pump::waterOut), so moving one inheritor moves that one.

Fixed on the way, each with its regression test: a member drawn under an inheriting node was placed and coloured by the first Layout about its declaration rather than the one naming it as that node's (inheritedGeometryOf); a Layout about the declaring body's start grew a start in every body inheriting it, at the same absolute place; a filter verdict, and the resolver's kept enumeration of a filtered expose, reached while the about index was still being built were cached (a view exposing P::*[@Tag] and annotating one of its elements in its own body never exposed it); the edit refused a Layout about a member drawn under an exposed usage as "not exposed".

Surfaces. sysml <model…> -import-diagram <file.drawio> [-view <name>] [-dry-run] prints the planned edits and what is reported; with -dry-run a unified diff per document and no write, otherwise the changed documents are staged beside themselves and swapped in as one set (a failure restores every original; a symlinked model is edited where the link points; an unchanged document is left alone). LSP opensysml/importDiagram {textDocument, path or content, view, inline, dryRun} answers the same WorkspaceEdit the panel's edits produce, pinned to the documents the view was rendered from (stale when they moved). MCP import_diagram wraps it (file under the workspace root or inline content; apply writes, otherwise a dry run) with its catalog row and man page. VS Code opensysml.importDiagram ("Import layout from draw.io…") opens a file picker and applies the WorkspaceEdit, so undo works. %render has no REPL twin that writes a file, so the REPL grows no meta-command; the CLI applies through repl.Session.ApplyModelEdit.

develop merged in (merge commits, no rebase), last at b173793: #1677's edge routing (routed edges carry edgeStyle=none, exit/entry anchors and their bends as waypoints; an untouched routed export still imports zero edits; no golden re-recorded; the draw.io desktop fixture saved again by draw.io desktop 32.6.1 against the routed export), #1671/#1659 at 14e53c0 (clean), and #1676's go.lsp.dev 1.0 migration with #1660 at b173793, which conflicted in internal/frontend/lsp/{modeledit.go,modeledit_cross_document_test.go,server.go}: the import request was ported to the 1.0 handler shape (decodeParams, (any, error), []protocol.DocumentChange) and the MCP round trip accepts the pinned-document entries ApplyEdit now lists. A second merge, at a57a863, brought in #1681–#1687: #1687's inOrder wrapper in internal/frontend/lsp/server.go (the import handler now sits inside the ordered chain, under CancelHandler), and #1683's draw.io writer follow-ups, whose paragraph on fqn in docs/project/view-rendering-forms.md was taken as develop has it with this branch's start/done clause re-applied; no golden moved. #1688 (fix/view-layout-sibling-gap, head 9806ff4, 34 draw.io goldens re-recorded for a 50 px grid gap) dry-merges clean on this head: six goldens are touched by both (action, mixed, state, state-entry, typed-action, typed-state) and merge textually without conflict, since this branch only adds fqn attributes and #1688 only moves geometry; the round-trip test reads the goldens as both export and expected import, so whichever lands second re-runs go test ./internal/ir/view ./internal/check/edit -run Drawio on the merged tree before merging. A third merge, at eb96507 and then ade0359 (clean, no conflicts), brought #1688 and #1689 in. #1688's 50 px grid gap moved the layout golden (the loop now at (50, 170), was (40, 160)), so two tests that had hard-coded the old geometry were re-derived rather than re-numbered: TestDrawioImportMovedNodeIsALayout reads the loop's exported geometry and TestImportDiagramPortsRoundTripSilently the exported bends; the compressed draw.io desktop fixture layout-desktop.drawio was saved again by draw.io desktop 32.6.1 against the new export (tank dragged from (266, 262) to (430, 262)), as it was after #1677. Referee baselines re-recorded with pilot-apijson-diff -update and pilot-diff -update (never by hand), and every moved object is accounted for: in both baselines provenance.inputs[examples].digest moved (bdb2697a… → 710f0a45…) because this branch's self-model edit adds the opensysml.importDiagram line to examples/self-model/surfaces.sysml — a first re-record on develop eb96507 moved that digest and the recording date alone, no count or scorecard row; and provenance.inputs[opensysml-libraries].digest moved (ac6a1e3b… → 29a3bf0f…) because #1689 changed DocumentQueries.sysml and the stdlib snapshot without re-recording, which is why bare develop ade0359 fails the same two provenance tests. #1689's library change is also the only source of row movement, all in the api-json baseline: pilotLibraryElements +198 in total (examples +77, manual-examples +121 — the two roots whose models load the OpenSysML Libraries), properties.presentEqual −68 / presentDifferent +68 in the same two roots, and the scorecard rows InvocationExpression.input (368/96 → 334/130) and InvocationExpression.parameter (382/98 → 348/132). The pilot-differential baseline moved only the two digests and the date. When develop's own re-record for #1689 lands, this branch takes develop's two baseline files and re-runs both -update flags on top.

How it was verified

• TestDrawioImportUntouchedGoldenIsNoEdit: every one of the 35 .drawio.golden fixtures imported as is yields zero edits and nothing reported.
• Mutation tests over the layout fixture (a placed view with a Layout, a Route, a Canvas, a Style and notes): moved node → absolute Layout; move under half a pixel → no edit; resized node keeps its height; nested child resolves to its container's offset and a port keeps its relative geometry; re-routed edge → Route with the waypoints; straightened edge → clear; recoloured node → Style with the fill; resized page → Canvas; moved note → Note; moved picture → Picture with its Origin; a renamed fqn, a deleted cell and a hand-drawn shape are reported without an edit.
• TestDrawioRoundTrip (internal/check/edit): for every golden, the untouched export imports nothing; a move, a container move, a resize, a re-route, a recolour each import as exactly that edit, are applied through Apply, and the re-exported drawio draws the mutated cell as the file had it (cells found by identity, since ids renumber); an edge no Route steers (specialization, typing, containment) is reported rather than imported.
• TestReadDrawioCompressedDesktopSave: the compressed save draw.io desktop 32.6.1 wrote (testdata/layout-desktop.drawio) reads and imports as the one Layout of the dragged tank, re-parented to the page by the app.
• Surfaces: TestImportDiagram* in cmd/sysml (dry-run diff and no write, write and idempotent re-import, -import-diagram '' and flag misuse refused, symlinked model edited through the link while an unchanged sibling keeps its inode and mtime), TestImportDiagramAnswersTheLayoutsAsAWorkspaceEdit (LSP), TestImportDiagramRoundTripsARenderedView and TestImportDiagramReadsFilesUnderTheRootAlone (MCP; dry run, apply, the file re-read, a path outside the root refused), the catalog gates (TestRegisteredToolsMatchTheCatalog, TestTheCatalogIsWellFormed, TestEverySysmlFlagIsClassifiedForMCP), TestUnifiedDiffInsertionRanges, VS Code manifest tests (npm test, 420 passing, npm run typecheck).
• go build ./..., go vet ./..., gofmt -l . empty, go test ./... (all packages), make lint (staticcheck, gosec), make man-check, make docs (strict), python3 scripts/changelog.py check, on the tree with develop b173793 merged.

MCP over stdio, as recorded

sysml-mcp -stdio -root /tmp/mcpx over a workspace holding one plant.sysml (Plant::Loop with parts pump and spare, view loopView { expose Loop; render asInterconnectionDiagram; }); request bodies abridged to what matters.

→ {"method":"initialize","params":{"protocolVersion":"2025-06-18",...},"id":1}
→ {"method":"notifications/initialized"}
→ {"method":"tools/call","params":{"name":"render_view","arguments":{"path":"plant.sysml","view":"Plant::loopView","form":"drawio"}},"id":2}
← artifact: 1846 bytes of uncompressed draw.io; the cell with fqn="Plant::Loop::pump" has `<mxGeometry x="16" y="82" width="54" height="37"/>`
   (edit: the pump's y 82 → 152, as a drag in draw.io would)
→ {"method":"tools/call","params":{"name":"import_diagram","arguments":{"path":"plant.sysml","content":"<?xml version=\"1.0\" …"}},"id":3}
← Plant::loopView: 3 edits planned, 0 refused, edits to 1 documents
   Layout about Plant::Loop
   Layout about Plant::Loop::pump
   Layout about Plant::Loop::spare
→ {"method":"tools/call","params":{"name":"import_diagram","arguments":{"path":"plant.sysml","content":"…","apply":true}},"id":4}
← Plant::loopView: 3 edits planned, 0 refused, edits to 1 documents, written

plant.sysml afterwards:

	view loopView {
		expose Loop;
		render asInterconnectionDiagram;
		metadata DiagramLayout::Layout about Plant::Loop { x = 40; y = 40; width = 189; height = 135; }
		metadata DiagramLayout::Layout about Plant::Loop::pump { x = 56; y = 192; width = 54; height = 37; }
		metadata DiagramLayout::Layout about Plant::Loop::spare { x = 150; y = 122; width = 63; height = 37; }
	}

Two notes from a reviewer's independent run. A Style the import writes reads metadata DiagramLayout::Style about PumpStation::station::pump { … } beside a hand-written Layout about station::tank: the editor spells the target as the operation names it, and both the panel's setStyle (from nodes[].fqn) and the import pass the qualified name the rendering reports, so this is the form develop already writes; both spellings resolve to the same element. The CLI has no -inline: -import-diagram writes view-local annotations only (the panel's default), while the LSP request and MCP tool take inline; the CLI reference says so.

Three edits for one drag: the view had no Layout yet, so the auto-placed container and its other child are pinned where the export drew them, else re-exporting would lay them out afresh around the moved pump. Importing the same file again plans nothing.

Checklist

• make test and make lint pass locally
• Tests added or updated for the change
• Documentation extended where it already covers the surface (see CONTRIBUTING.md)
• Changelog entry added as changes/unreleased/<slug>.<section>.md, not as an edit to CHANGELOG.md
• baselines regenerated and make docs-counts run if a gate count moved (no gate count moved)
• No internal work-item labels (waves, slices, F4, K5) in the body, docs, or changelog

[devin-ai-integration]

I'll fix CI failures and address comments from users with write access. I'll skip comments containing "(aside)".

• Disable automatic comment, CI, and merge conflict monitoring

[devin-ai-integration]

Heads-up for the matcher: the draw.io writer is about to put fqn on an edge's <object> too (branch fix/drawio-unrouted-edges), for edges that are declarations of their own — connection, binding, association, flow, succession, transition, require/assume/assert/frame/event, import, dependency, derive, refine, expose, satisfy, verify, allocate, include, perform, exhibit — e.g. <object id="e0" label="" fqn="PumpStation::station::fluid" kind="connection" …>. Edges drawn from a member's declaration (composition, reference, typing, specialization, …) still carry no fqn. So the import can prefer fqn when present and fall back to endpoint names + kind + ordinal otherwise. Same branch also rounds waypoints to a thousandth of a pixel and adds exact exit*/entry* anchors (plus a notice) on edges the router found no path for.