refactor(runtime-tags): make the show hide edge repair inert on the end

DylanPiercey · DylanPiercey · commit e45bdf8fc42e · 2026-07-30T14:41:59.000-07:00
Hiding a `&lt;show&gt;` mapped an owner's end onto the sibling before the range
while its start moved to the reference node after it. That pair is only
unreachable by an invariant; if it ever fired the owner's start would
follow its end and the range would swallow later siblings. Pass the end
through unchanged so a match is a no-op instead.
diff --git a/.sizes.json b/.sizes.json
@@ -7,8 +7,8 @@
     {
       "name": "*",
       "total": {
-        "min": 27219,
-        "brotli": 10116
+        "min": 27187,
+        "brotli": 10109
       }
     },
     {
diff --git a/.sizes/dom.js b/.sizes/dom.js
@@ -1,4 +1,4 @@
-// size: 27219 (min) 10116 (brotli)
+// size: 27187 (min) 10109 (brotli)
 //#region packages/runtime-tags/dist/dom.mjs
 let empty = [],
   rest = Symbol(),
@@ -1865,12 +1865,11 @@ function _show(nodeAccessor, startNodeAccessor, endNodeAccessor) {
       display
         ? inDom ||
           (insertBranchBefore(range, parentNode, onlyChild ? null : referenceNode),
-          onlyChild ||
-            fixBranchEdges(scope.F, referenceNode, range.S.previousSibling, range.S, range.K))
+          onlyChild || fixBranchEdges(scope.F, referenceNode, range.K, range.S, range.K))
         : inDom &&
           (onlyChild
             ? ((range.S = parentNode.firstChild), (range.K = parentNode.lastChild))
-            : fixBranchEdges(scope.F, range.S, range.K, referenceNode, range.S.previousSibling),
+            : fixBranchEdges(scope.F, range.S, range.K, referenceNode, range.K),
           tempDetachBranch(range));
     }
   );
diff --git a/packages/runtime-tags/src/__tests__/fixtures/branch-edge-hidden-show-body/sizes.json b/packages/runtime-tags/src/__tests__/fixtures/branch-edge-hidden-show-body/sizes.json
@@ -1,8 +1,8 @@
 {
   "dom": {
     "template.marko.page.mjs": {
-      "min": 9053,
-      "brotli": 3995
+      "min": 9021,
+      "brotli": 3992
     }
   },
   "html": {
diff --git a/packages/runtime-tags/src/__tests__/fixtures/branch-edge-nested-control-flow/sizes.json b/packages/runtime-tags/src/__tests__/fixtures/branch-edge-nested-control-flow/sizes.json
@@ -1,8 +1,8 @@
 {
   "dom": {
     "template.marko.page.mjs": {
-      "min": 9238,
-      "brotli": 4065
+      "min": 9206,
+      "brotli": 4063
     }
   },
   "html": {
diff --git a/packages/runtime-tags/src/__tests__/fixtures/branch-edge-resume-leading-show/sizes.json b/packages/runtime-tags/src/__tests__/fixtures/branch-edge-resume-leading-show/sizes.json
@@ -1,8 +1,8 @@
 {
   "dom": {
     "template.marko.page.mjs": {
-      "min": 7243,
-      "brotli": 3200
+      "min": 7211,
+      "brotli": 3195
     }
   },
   "html": {
diff --git a/packages/runtime-tags/src/__tests__/fixtures/show-tag-empty-body/sizes.json b/packages/runtime-tags/src/__tests__/fixtures/show-tag-empty-body/sizes.json
@@ -1,8 +1,8 @@
 {
   "dom": {
     "template.marko.page.mjs": {
-      "min": 4702,
-      "brotli": 2209
+      "min": 4670,
+      "brotli": 2204
     }
   },
   "html": {
diff --git a/packages/runtime-tags/src/__tests__/fixtures/show-tag-for-body-only-child/sizes.json b/packages/runtime-tags/src/__tests__/fixtures/show-tag-for-body-only-child/sizes.json
@@ -1,8 +1,8 @@
 {
   "dom": {
     "template.marko.page.mjs": {
-      "min": 4698,
-      "brotli": 2200
+      "min": 4666,
+      "brotli": 2197
     }
   },
   "html": {
diff --git a/packages/runtime-tags/src/__tests__/fixtures/show-tag-hidden/sizes.json b/packages/runtime-tags/src/__tests__/fixtures/show-tag-hidden/sizes.json
@@ -1,8 +1,8 @@
 {
   "dom": {
     "template.marko.page.mjs": {
-      "min": 4700,
-      "brotli": 2200
+      "min": 4668,
+      "brotli": 2202
     }
   },
   "html": {
diff --git a/packages/runtime-tags/src/__tests__/fixtures/show-tag-if-body-empties/sizes.json b/packages/runtime-tags/src/__tests__/fixtures/show-tag-if-body-empties/sizes.json
@@ -1,8 +1,8 @@
 {
   "dom": {
     "template.marko.page.mjs": {
-      "min": 7061,
-      "brotli": 3136
+      "min": 7029,
+      "brotli": 3132
     }
   },
   "html": {
diff --git a/packages/runtime-tags/src/__tests__/fixtures/show-tag-if-body-toggle/sizes.json b/packages/runtime-tags/src/__tests__/fixtures/show-tag-if-body-toggle/sizes.json
@@ -1,8 +1,8 @@
 {
   "dom": {
     "template.marko.page.mjs": {
-      "min": 4702,
-      "brotli": 2209
+      "min": 4670,
+      "brotli": 2204
     }
   },
   "html": {
diff --git a/packages/runtime-tags/src/__tests__/fixtures/show-tag-in-for/sizes.json b/packages/runtime-tags/src/__tests__/fixtures/show-tag-in-for/sizes.json
@@ -1,8 +1,8 @@
 {
   "dom": {
     "template.marko.page.mjs": {
-      "min": 4895,
-      "brotli": 2276
+      "min": 4863,
+      "brotli": 2273
     }
   },
   "html": {
diff --git a/packages/runtime-tags/src/__tests__/fixtures/show-tag-interactive-body/sizes.json b/packages/runtime-tags/src/__tests__/fixtures/show-tag-interactive-body/sizes.json
@@ -1,8 +1,8 @@
 {
   "dom": {
     "template.marko.page.mjs": {
-      "min": 4851,
-      "brotli": 2265
+      "min": 4819,
+      "brotli": 2262
     }
   },
   "html": {
diff --git a/packages/runtime-tags/src/__tests__/fixtures/show-tag-nested/sizes.json b/packages/runtime-tags/src/__tests__/fixtures/show-tag-nested/sizes.json
@@ -1,8 +1,8 @@
 {
   "dom": {
     "template.marko.page.mjs": {
-      "min": 4769,
-      "brotli": 2230
+      "min": 4737,
+      "brotli": 2226
     }
   },
   "html": {
diff --git a/packages/runtime-tags/src/__tests__/fixtures/show-tag-only-child-interactive/sizes.json b/packages/runtime-tags/src/__tests__/fixtures/show-tag-only-child-interactive/sizes.json
@@ -1,8 +1,8 @@
 {
   "dom": {
     "template.marko.page.mjs": {
-      "min": 4847,
-      "brotli": 2264
+      "min": 4815,
+      "brotli": 2262
     }
   },
   "html": {
diff --git a/packages/runtime-tags/src/__tests__/fixtures/show-tag-only-child/sizes.json b/packages/runtime-tags/src/__tests__/fixtures/show-tag-only-child/sizes.json
@@ -1,8 +1,8 @@
 {
   "dom": {
     "template.marko.page.mjs": {
-      "min": 4717,
-      "brotli": 2211
+      "min": 4685,
+      "brotli": 2206
     }
   },
   "html": {
diff --git a/packages/runtime-tags/src/__tests__/fixtures/show-tag/sizes.json b/packages/runtime-tags/src/__tests__/fixtures/show-tag/sizes.json
@@ -1,8 +1,8 @@
 {
   "dom": {
     "template.marko.page.mjs": {
-      "min": 4700,
-      "brotli": 2200
+      "min": 4668,
+      "brotli": 2202
     }
   },
   "html": {
diff --git a/packages/runtime-tags/src/__tests__/fixtures/show-text-prefix-placeholder/sizes.json b/packages/runtime-tags/src/__tests__/fixtures/show-text-prefix-placeholder/sizes.json
@@ -1,8 +1,8 @@
 {
   "dom": {
     "template.marko.page.mjs": {
-      "min": 4857,
-      "brotli": 2275
+      "min": 4825,
+      "brotli": 2271
     }
   },
   "html": {
diff --git a/packages/runtime-tags/src/dom/control-flow.ts b/packages/runtime-tags/src/dom/control-flow.ts
@@ -559,7 +559,7 @@ export function _show(
           fixBranchEdges(
             scope[AccessorProp.ClosestBranch],
             referenceNode,
-            range[AccessorProp.StartNode].previousSibling!,
+            range[AccessorProp.EndNode],
             range[AccessorProp.StartNode],
             range[AccessorProp.EndNode],
           );
@@ -572,14 +572,15 @@ export function _show(
         range[AccessorProp.StartNode] = parentNode.firstChild!;
         range[AccessorProp.EndNode] = parentNode.lastChild!;
       } else {
-        // A resumed owner can begin or end at this range, and the reference
-        // node always trails it, so collapse the owner onto that.
+        // The reference node always trails this range, so an owner can begin
+        // at it but never end there; passing the end through unchanged keeps
+        // that a no-op rather than a range whose start follows its end.
         fixBranchEdges(
           scope[AccessorProp.ClosestBranch],
           range[AccessorProp.StartNode],
           range[AccessorProp.EndNode],
           referenceNode,
-          range[AccessorProp.StartNode].previousSibling!,
+          range[AccessorProp.EndNode],
         );
       }
       tempDetachBranch(range);
diff --git a/packages/runtime-tags/src/dom/scope.ts b/packages/runtime-tags/src/dom/scope.ts
@@ -116,6 +116,10 @@ export function removeAndDestroyBranch(branch: BranchScope) {
 // marker, or hidden), enclosing branches whose start/end landed on the old
 // range's edges must adopt the new edges; without owned boundary nodes this
 // replaces the padding markers that used to pin those edges.
+//
+// Start above the branch that already owns the new range: `ParentBranch` for a
+// range that is itself a branch, `ClosestBranch` for one that is not (a
+// `<show>` range, or content rendered into a plain child scope).
 export function fixBranchEdges(
   branch: BranchScope | undefined,
   oldStart: ChildNode,

Original file line number	Diff line number	Diff line change
`@@ -7,8 +7,8 @@`
`7`	`7`	`{`
`8`	`8`	`"name": "*",`
`9`	`9`	`"total": {`
`10`		`- "min": 27219,`
`11`		`- "brotli": 10116`
	`10`	`+ "min": 27187,`
	`11`	`+ "brotli": 10109`
`12`	`12`	`}`
`13`	`13`	`},`
`14`	`14`	`{`
Original file line number	Diff line number	Diff line change
`@@ -1,8 +1,8 @@`
`1`	`1`	`{`
`2`	`2`	`"dom": {`
`3`	`3`	`"template.marko.page.mjs": {`
`4`		`- "min": 9053,`
`5`		`- "brotli": 3995`
	`4`	`+ "min": 9021,`
	`5`	`+ "brotli": 3992`
`6`	`6`	`}`
`7`	`7`	`},`
`8`	`8`	`"html": {`