Enable no-throw-literal in oxlint: 13 bare-literal throws in litegraph, plus one legitimate re-throw to exempt

## Problem

`throw 'target node is null'` produces a value with no `.stack` and no `instanceof Error`. Sentry
groups these badly, `catch (e) { e.message }` returns `undefined`, and nothing upstream can tell a
thrown string from a rejected value. oxlint ships `no-throw-literal` and this repo has it switched
off, so 14 such sites sit in `src/` today. Thirteen are bare literals that should become
`new Error(...)`. The fourteenth is a legitimate re-throw and must be exempted, not converted.

Enable the rule and fix the sites. Everything here is pre-existing on `main` and unrelated to any
open branch.

GitHub issue: https://github.com/Comfy-Org/ComfyUI_frontend/issues/15635 — unassigned, no labels.
That issue's line numbers were measured on `feature/ecs-migration` and have drifted. The numbers
below are re-measured on `origin/main` and are the ones to work from.

## Provenance

* **Found by:** lint-coverage sweep of ComfyUI_frontend, then re-verified against `origin/main` for
this ticket · 2026-08-22
* **How:** `oxlint -A all -D no-throw-literal src` executed at `origin/main` `a08a7598aa`, then every
one of the 14 reported sites opened and read
* **Why now:** the fix is one config line plus 13 mechanical conversions, and it closes a rule gap
that neither linter covers today
* **Lane rationale:** mechanical — the rule name, the exact site list and the fix shape are all
known; nothing here needs a decision
* **Dedup identity:** `fe-oxlint-no-throw-literal`. Linear dedupe run 2026-08-22 found no existing
ticket; the only prior art is BE-582 / BE-1982, which are unrelated oxlint adoption work
* **Confidence:** verified — every site below was opened and read

## Evidence

Measured with oxlint 1.77.0 at `origin/main` `a08a7598aa`:

```
npx --no-install oxlint -A all -D no-throw-literal src
```

The run reports **14 findings**. Thirteen are bare literals to convert; the fourteenth is a
legitimate re-throw to exempt. Both controls were run first, so the instrument is known live in
both directions: `-D no-console` on a litegraph file reports findings and exits 1, `-D no-debugger`
on the same file reports nothing and exits 0.

Thirteen bare-literal throws to convert:

| Site | What is there |
| --- | --- |
| `src/lib/litegraph/src/ContextMenu.ts:364` | `throw 'ContextMenu submenu needs options'` |
| `src/lib/litegraph/src/LiteGraphGlobal.ts:412` | `throw 'Cannot register a simple object, it must be a class with a prototype'` |
| `src/lib/litegraph/src/LiteGraphGlobal.ts:456` | `` throw `node type not found: ${String(type)}` `` |
| `src/lib/litegraph/src/LGraphNode.ts:2093` | `throw "LiteGraph addWidget('combo',...) requires to pass values in options: ..."` |
| `src/lib/litegraph/src/LGraphNode.ts:2904` | `if (!nodeById) throw 'target node is null'` |
| `src/lib/litegraph/src/LGraphNode.ts:2908` | `if (!target_node) throw 'target node is null'` |
| `src/lib/litegraph/src/LGraphNode.ts:3226` | `if (!target) throw 'Target Node not found'` |
| `src/lib/litegraph/src/LGraph.ts:992` | `throw 'LiteGraph: max number of nodes in a graph reached'` |
| `src/lib/litegraph/src/LGraphCanvas.ts:1708` | `if (!node) throw 'no node for color'` |
| `src/lib/litegraph/src/LGraphCanvas.ts:1770` | `if (!node) throw 'no node passed'` |
| `src/lib/litegraph/src/LGraphCanvas.ts:1950` | `throw 'Error validating LiteGraph canvas: Canvas element not found'` |
| `src/lib/litegraph/src/LGraphCanvas.ts:1992` | `` throw `Element supplied for LGraphCanvas must be a element, you passed a ${element.localName}` `` |
| `src/lib/litegraph/src/LGraphCanvas.ts:1994` | `throw "This browser doesn't support Canvas"` |

The fourteenth is **not** a defect and must not be converted:

* `src/platform/cloud/subscription/components/CreditsTile.vue:451` — `if (lastError) throw lastError`.
`lastError` is declared `let lastError: unknown` at `:441` and assigned from `catch (error)` at
`:448`. This is a deliberate re-throw of a caught error inside a coalescing refresh loop
(`refreshLatestCredits`, `:436-452`). Converting it to `new Error(...)` would destroy the original
error and its stack. oxlint flags it only because it cannot prove an `unknown` is an `Error`.

### The 13-vs-14 count, settled

The count was disputed. It was settled by opening every site at `origin/main` `a08a7598aa`, and
**13 is the number of conversions**. Two separate counting errors produced the competing 14:

1. **`CreditsTile.vue` does exist on `main`.** A claim that it does not, and that only
`browser_tests/tests/dialogs/creditsTile.spec.ts` exists, is wrong.
`git ls-tree -r --name-only origin/main | grep -i creditstile` returns three paths, including
`src/platform/cloud/subscription/components/CreditsTile.vue`. The file was opened at `:436-459`
and reads exactly as described below.
2. **A text search for bare literals returns 14, but one of them is a comment.** Grepping
`throw[[:space:]]+['"`]` across `src/` at `origin/main` returns 14 lines. The fourteenth is
`src/stores/widgetStore.ts:28`, which is the comment
`// throw "Cannot convert undefined or null to object" and break app init.` inside a guard's
explanatory block. It is not a throw. Opened and confirmed.

So both roads arrive at 13 conversions: oxlint reports 14 findings of which one
(`CreditsTile.vue:451`) is a correct re-throw, and the text search finds 14 candidate lines of which
one (`widgetStore.ts:28`) is a comment. Do not re-litigate this; the numbers below are the ones to
work from.

Config state at `origin/main` `a08a7598aa`:

* `.oxlintrc.json` has no `no-throw-literal` entry, so the rule is off. The `eslint` plugin is
already enabled in its `plugins` array, so no new dependency is needed.
* eslint does not configure `no-throw-literal` or `@typescript-eslint/only-throw-error` either, so
the rule is genuinely uncovered rather than enforced elsewhere.
* `oxlint -A all -D typescript/only-throw-error src` reports nothing, so that rule is not an
available alternative in this oxlint version. Use `no-throw-literal`.

Litegraph already imports and throws `NullGraphError` and uses `new Error(...)` in the majority of
its throw sites, so the 13 above are the inconsistent minority, not the local convention.

Attribution: `git blame` is not usable here. Local clones of this repo are shallow, so every line
older than the graft collapses onto a single unrelated commit. Use
`GET /repos/Comfy-Org/ComfyUI_frontend/commits?path=` if you need the real author.

## Acceptance criteria

- [ ] `"no-throw-literal": "error"` added to the `rules` block of `.oxlintrc.json`
- [ ] All 13 litegraph sites converted to `throw new Error(...)`, preserving the existing message
text verbatim
- [ ] `CreditsTile.vue:451` left as `throw lastError`, with a
`// oxlint-disable-next-line no-throw-literal` comment and a one-line reason. This repo already
uses `oxlint-disable` comments (e.g. `src/utils/graphTraversalUtil.test.ts:1`), so the
mechanism is established
- [ ] `npx oxlint src` exits 0 with no `no-throw-literal` findings after the change
- [ ] Any existing test that catches one of these throws and asserts on the caught **string** is
updated to assert on `error.message`. Search for the message text before converting each site;
the PR states how many such call sites were found (including zero)
- [ ] `pnpm lint`, `pnpm typecheck` and `pnpm test:unit` pass. Note that `vue-tsc` OOMs at Node's
2GB default and exits 134 while a grep filtered for `error TS` returns nothing — run it as
`NODE_OPTIONS=--max-old-space-size=8192 vue-tsc --noEmit` and report the exit code

## Out of scope

1. Enabling `no-throw-literal` in eslint as well — one linter is enough, and oxlint is the one that
already loads the `eslint` plugin
2. Any other oxlint rule currently off in `.oxlintrc.json`
3. Introducing new typed error classes, or changing which error type any site throws beyond
`Error`
4. `src/scripts/*` and `src/extensions/core/*` — both are in `.oxlintrc.json`'s `ignorePatterns`
(`:12-13`) and are therefore not scanned. Do not un-ignore them here; that is a separate
decision with a much larger blast radius
5. Changing any thrown message string

## Working notes

Everything needed is above; you do not need any other context to finish this.

* Base off `main`. Do not target `feature/ecs-migration`, and do not merge anything.
* This is a pnpm workspace with **eight** `node_modules` directories. If only the root one is
present, vitest dies at `Failed to resolve import "clsx"` at *every* commit, which turns any
before/after comparison into noise. Run `vitest run src/lib/litegraph/src/LLink.test.ts` as a
positive control before trusting any red result.
* `oxlint` exit codes are ambiguous in both directions: it exits 0 when findings are warning-level,
and exits 1 both for real errors **and** when every input path is ignored
(`No files found to lint`). Read the output, not just `$?`.

---

Original issue text as filed on 2026-08-22 (superseded by the section above, preserved in full)

The body above replaces this text. It was re-measured against `origin/main` `a08a7598aa`; the line numbers below were measured on `feature/ecs-migration` and have drifted. The count is now settled at 13 conversions plus one exemption (see "The 13-vs-14 count, settled" above). Nothing from the original has been deleted.

`no-throw-literal` is available in oxlint and switched off. Turning it on flags 14 sites in `src/`, all pre-existing. Two of them are bugs that were found by hand during ECS review last week, which is the point of filing this.

## Why it matters

`throw 'target node is null'` produces a value with no `.stack` and no `instanceof Error`. Sentry groups these badly, `catch (e) { e.message }` gives `undefined`, and nothing upstream can tell a thrown string from a rejected value.

## Measured

oxlint 1.77.0, at `5002fae1b1`:

```
$ npx --no-install oxlint -A all -D no-throw-literal src
```

| Count | Scope |
| --- | --- |
| 13 | `src/lib/litegraph/` |
| 1 | `src/platform/cloud/subscription/components/CreditsTile.vue` |
| **14** | **total** |

Sites in litegraph:

```
src/lib/litegraph/src/LGraphCanvas.ts:1716, :1778, :1958, :2000, :2002
src/lib/litegraph/src/LGraphNode.ts:2237, :3050, :3054, :3349
src/lib/litegraph/src/LiteGraphGlobal.ts:412, :456
src/lib/litegraph/src/LGraph.ts:1153
src/lib/litegraph/src/ContextMenu.ts:364
```

Count is identical at `6532665db9` (the `feature/ecs-migration` merge base) and at `5002fae1b1`, so this is entirely pre-existing and not introduced by #14246.

## Current config state

- eslint: `no-throw-literal` and `@typescript-eslint/only-throw-error` are **not configured at all** (621 rules configured, 117 enabled, 504 off, per `eslint --print-config`).
- oxlint: rule exists in the bundled `eslint` plugin, not listed in `.oxlintrc.json`, so it is off.

No new dependency is needed. This is one line in `.oxlintrc.json` plus 14 fixes.

## Suggested

Add `"no-throw-literal": "error"` to `.oxlintrc.json` and convert the 14 sites to `throw new Error(...)`. Litegraph already has `NullGraphError` and uses `new Error(...)` in the majority of its throws, so the 13 there are the inconsistent minority, not the convention.

Worth checking whether any caller depends on catching the string value before converting.