id	summary	reporter	owner	description	type	status	priority	milestone	component	version	severity	resolution	keywords	cc	focuses
65450	Site Editor crashes on block style variation detail route for `core/column`	kimjiwoon		"When opening the Site Editor style variation detail screen for a `core/column` block style variation, the editor crashes with:

```text
TypeError: Cannot read properties of undefined (reading 'map')
```

This reproduces with the default Twenty Twenty-Five theme, so it does not appear to be caused by a custom theme implementation.

**Environment**
- WordPress: 7.0
- Theme: Twenty Twenty-Five 1.5
- Browser: Chromium-based browser
- Context: Site Editor → Styles → Blocks → Column → Style variation

**Steps To Reproduce**
1. Activate Twenty Twenty-Five 1.5.
2. Open the Site Editor.
3. Navigate to a `core/column` block style variation detail route, for example:

```text
/wp-admin/site-editor.php?p=%2Fstyles&section=%2Fblocks%2Fcore%252Fcolumn%2Fvariations%2Fsection-1
```

4. Observe the JavaScript error.

**Actual Result**
The Site Editor crashes and logs:

```text
TypeError: Cannot read properties of undefined (reading 'map')
    at Dwe (.../wp-includes/js/dist/editor.min.js:149:7185)
```

**Expected Result**
The style variation detail screen should render without crashing.

If the Style Book has no standalone preview example for `core/column`, the editor should either:

- fall back to a suitable parent/container example, or
- render an empty/unsupported preview state gracefully, without throwing.

**Technical Notes**
The error appears to come from the Style Book preview flow.

In the unminified editor build, `applyBlockVariationsToExamples()` assumes `examples` is defined:

```js
function applyBlockVariationsToExamples(examples, variation) {
    if (!variation) {
        return examples;
    }
    return examples.map((example) => {
        // ...
    });
}
```

For `core/column` variation routes, the filtered Style Book example set appears to be missing or undefined, likely because `core/column` is primarily a nested child block and does not have a standalone Style Book example.

The same route pattern works for `core/group`, but fails for `core/column`.

**Additional Reproduction**
A custom block style variation for `core/column` produces the same error, while the same variation on `core/group` renders normally. This suggests the issue is tied to `core/column` Style Book preview handling rather than a specific theme JSON style declaration."	defect (bug)	closed	normal		Editor	7.0	normal	reported-upstream