I have reproduced the issue on the latest CLI version.
Yes, I am on the latest version
I have searched existing posts and this report is not a duplicate.
Yes, this isn’t a duplicate
In which of these areas are you experiencing a problem?
Extension
Expected behavior
shopify app dev to run extensions-only app locally for updates
Actual behavior
Fails with “Error updating app preview”
Reproduction steps
New extensions-only app. Try to deploy or run locally and will fail
Verbose output
won’t allow the full --verbose output with character limits
> bbs-checkout-extensions@1.0.0 dev
> shopify app dev
╭─ info ─────────────────────────────────────────────────────────────────╮
│ │
│ Using shopify.app.toml for default values: │
│ │
│ • Org: The Pages Media │
│ • App: BBS Checkout Extensions │
│ • Dev store: │
│ the-pages-media-checkout-extensions.myshopify.com │
│ • Update URLs: Yes │
│ │
│ You can pass `--reset` to your command to reset your app │
│ configuration. │
│ │
╰────────────────────────────────────────────────────────────────────────╯
10:34:25 │ app-preview │ Preparing app preview on
the-pages-media-checkout-extensions.myshopify.com
10:34:25 │ graphiql │ GraphiQL server started on port
3457
10:34:25 │ proxy │ Proxy server started on port 63048
10:34:25 │ update-selected-size │ Building function
update-selected-size...
10:34:25 │ update-selected-size │ Building GraphQL types...
10:34:25 │ upsell-multiple │ Build successful
10:34:25 │ conditional-banner │ Build successful
10:34:25 │ upsell-single-item │ Build successful
10:34:25 │ countdown-timer │ Build successful
10:34:25 │ banner │ Build successful
10:34:26 │ update-selected-size │ (node:48741) [DEP0040]
DeprecationWarning: The `punycode` module is deprecated. Please use a
userland alternative instead.
10:34:26 │ update-selected-size │ (Use `node --trace-deprecation ...`
to show where the warning was created)
10:34:26 │ update-selected-size │ Bundling JS function...
10:34:26 │ update-selected-size │ Running javy...
10:34:26 │ update-selected-size │ Done!
10:34:27 │ app-preview │ ❌ Error
10:34:27 │ app-preview │ └ Cannot read properties of null
(reading '0')
──────────────────────────────────────────────────────────────────
│ (d) Dev status │ (a) App info │ (s) Store info │ (q) Quit
❌ Error updating app preview
╭─ error ────────────────────────────────────────────────────────────────╮
│ │
│ Failed to start app preview. │
│ │
╰────────────────────────────────────────────────────────────────────────╯
Operating system
macOS Sequoia 15.6.1
CLI version
3.87.0 and tested 3.87.1
Shell
warp
Nodejs version
22.4.1
What language and version are you using in your application?
Default - didn’t even make it that far