fix(item-sliding, segment-button): read props after frameworks assign them

[ShaneK]

Issue number: resolves #31388

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What is the current behavior?

Currently, ion-item-sliding reads side off each ion-item-options in connectedCallback. It only waits for the option first if the element has a componentOnReady method, and the custom elements build doesn't add one, so it reads straight away and every option comes back as the default end. In v9 React that means side="start" options can't be swiped open.

There's the same problem in ion-segment-button, where the check that stops a button tied to an ion-segment-content from being disabled also runs in connectedCallback, before contentId or disabled exist.

Both come from @ionic/react v9 going through @lit/react, which assigns element props in a useLayoutEffect after React commits the DOM.

What is the new behavior?

Now updateOptions waits for every ion-item-options through the componentOnReady helper before reading side. The helper waits a frame in the custom elements build, which is after the props land, and is unchanged in the lazy build. That also drops the repo's only eslint-disable custom-rules/no-component-on-ready-method, since bypassing the helper was the bug.

The ion-segment-button check moved to componentWillLoad, and it now also requires the parent segment to be enabled. A disabled ion-segment pushes disabled onto its buttons through updateState, which is why the check used to run first, and without the new condition the fix force-enables every button inside <ion-segment disabled>.

Does this introduce a breaking change?

• Yes
• No

Other information

I swept every core component with a connectedCallback for this pattern and only these two break, the rest self-heal through a @Watch or an existing await. Only ion-radio-group drifts, cosmetically, and I left it alone.

The real fix isn't in core. If @stencil/react-output-target passed serializable props through React.createElement the way the v8 wrapper did, they'd be set before insertion and none of this would reach connectedCallback late. Could be worth trying to fix there for later.

Current Dev Build

9.0.1-dev.11787248963.10a00c73

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Project	Deployment	Actions	Updated (UTC)
ionic-framework	Ready	Preview	Aug 20, 2026 6:02pm

[thetaPC]

LGTM