diff --git a/.changeset/tidy-trees-stay.md b/.changeset/tidy-trees-stay.md new file mode 100644 index 0000000000..65bf7de619 --- /dev/null +++ b/.changeset/tidy-trees-stay.md @@ -0,0 +1,5 @@ +--- +'svelte': patch +--- + +fix: preserve dynamic element connections during hydration diff --git a/packages/svelte/src/internal/client/dom/blocks/svelte-element.js b/packages/svelte/src/internal/client/dom/blocks/svelte-element.js index 84217c57e3..adca73b181 100644 --- a/packages/svelte/src/internal/client/dom/blocks/svelte-element.js +++ b/packages/svelte/src/internal/client/dom/blocks/svelte-element.js @@ -71,6 +71,7 @@ export function element(node, get_tag, is_svg, render_fn, get_namespace, locatio branches.ensure(next_tag, (anchor) => { if (next_tag) { + var is_hydrating = hydrating; element = hydrating ? /** @type {Element} */ (element) : create_element(next_tag, ns); if (DEV && location) { @@ -123,7 +124,8 @@ export function element(node, get_tag, is_svg, render_fn, get_namespace, locatio // we do this after calling `render_fn` so that child effects don't override `nodes.end` /** @type {Effect & { nodes: EffectNodes }} */ (active_effect).nodes.end = element; - anchor.before(element); + // we only move the node if we are not hydrating since a claimed element is already in place + if (!is_hydrating) anchor.before(element); } if (hydrating) { diff --git a/packages/svelte/tests/hydration/samples/dynamic-element-child-mismatch/_config.js b/packages/svelte/tests/hydration/samples/dynamic-element-child-mismatch/_config.js new file mode 100644 index 0000000000..cdd8f4484b --- /dev/null +++ b/packages/svelte/tests/hydration/samples/dynamic-element-child-mismatch/_config.js @@ -0,0 +1,10 @@ +import { test } from '../../test'; + +export default test({ + server_props: { condition: false }, + props: { condition: true }, + + snapshot(target) { + return { element: target.querySelector('div'), sibling: target.querySelector(':scope > p') }; + } +}); diff --git a/packages/svelte/tests/hydration/samples/dynamic-element-child-mismatch/_expected.html b/packages/svelte/tests/hydration/samples/dynamic-element-child-mismatch/_expected.html new file mode 100644 index 0000000000..5f68a45e48 --- /dev/null +++ b/packages/svelte/tests/hydration/samples/dynamic-element-child-mismatch/_expected.html @@ -0,0 +1,2 @@ +
client
after
diff --git a/packages/svelte/tests/hydration/samples/dynamic-element-child-mismatch/main.svelte b/packages/svelte/tests/hydration/samples/dynamic-element-child-mismatch/main.svelte new file mode 100644 index 0000000000..839a06981f --- /dev/null +++ b/packages/svelte/tests/hydration/samples/dynamic-element-child-mismatch/main.svelte @@ -0,0 +1,9 @@ + + +client
{:else}server{/if} +after
diff --git a/packages/svelte/tests/runtime-browser/assert.js b/packages/svelte/tests/runtime-browser/assert.js index 249c5ad33d..9fdb917048 100644 --- a/packages/svelte/tests/runtime-browser/assert.js +++ b/packages/svelte/tests/runtime-browser/assert.js @@ -128,6 +128,7 @@ function normalize_children(node) { * id_prefix?: string; * props?: Props; * compileOptions?: Partial