fix(registry): keep file tree names on one line

layers/registry/app/components/SkillFileTreeNode.vue

@@ -1,7 +1,7 @@
 <script setup lang="ts">
 import type { SkillFileTreeNode as TreeNode } from '../utils/skill-file-tree'
 import { formatByteSize } from '../utils/skill-context-cost'
-import { fileIcon, isInlineRenderable } from '../utils/skill-file-tree'
+import { fileIcon, isInlineRenderable, splitFileLabel } from '../utils/skill-file-tree'
 
 const props = defineProps<{
   node: TreeNode
@@ -55,6 +55,8 @@ function onFileClick(event: MouseEvent) {
   emit('select', props.node.path)
 }
 
+const label = computed(() => splitFileLabel(props.node.name))
+
 const inlineRenderable = computed(() =>
   props.node.kind === 'file' && !!props.node.asset && isInlineRenderable(props.node.asset.type),
 )
@@ -68,22 +70,29 @@ const inlineRenderable = computed(() =>
         class="tree-row"
         :aria-expanded="open"
         :aria-controls="`${idPrefix}-${node.path}`"
+        :title="node.path"
         @click="open = !open"
       >
-        <UIcon
-          name="i-lucide-chevron-right"
-          class="size-3 text-muted transition-transform shrink-0"
-          :class="{ 'rotate-90': open }"
-          aria-hidden="true"
-        />
         <SkillFileIcon
           :name="open ? 'default-folder-opened' : 'default-folder'"
           class="size-4 shrink-0"
         />
-        <span class="tree-label">{{ node.name }}</span>
+        <span
+          class="tree-label"
+          :style="{ '--label-tail': `${label.tail.length}ch` }"
+        >
+          <span class="tree-label-head">{{ label.head }}</span>
+          <span v-if="label.tail">{{ label.tail }}</span>
+        </span>
         <span
           class="tree-size"
         >{{ folderFileCount }} {{ folderFileCount === 1 ? 'file' : 'files' }}</span>
+        <UIcon
+          name="i-lucide-chevron-right"
+          class="size-3 text-muted transition-transform shrink-0"
+          :class="{ 'rotate-90': open }"
+          aria-hidden="true"
+        />
       </button>
       <ul
         v-show="open"
@@ -122,12 +131,17 @@ const inlineRenderable = computed(() =>
         :title="node.path"
         @click="onFileClick"
       >
-        <span class="tree-spacer" aria-hidden="true" />
         <SkillFileIcon
           :name="fileIcon(node.name)"
           class="size-4 shrink-0"
         />
-        <span class="tree-label">{{ node.name }}</span>
+        <span
+          class="tree-label"
+          :style="{ '--label-tail': `${label.tail.length}ch` }"
+        >
+          <span class="tree-label-head">{{ label.head }}</span>
+          <span v-if="label.tail">{{ label.tail }}</span>
+        </span>
         <span
           v-if="node.asset?.size"
           class="tree-size"
@@ -142,12 +156,17 @@ const inlineRenderable = computed(() =>
         :title="node.path"
         @click="onFileClick"
       >
-        <span class="tree-spacer" aria-hidden="true" />
         <SkillFileIcon
           :name="fileIcon(node.name)"
           class="size-4 shrink-0"
         />
-        <span class="tree-label">{{ node.name }}</span>
+        <span
+          class="tree-label"
+          :style="{ '--label-tail': `${label.tail.length}ch` }"
+        >
+          <span class="tree-label-head">{{ label.head }}</span>
+          <span v-if="label.tail">{{ label.tail }}</span>
+        </span>
         <span
           v-if="node.asset?.size"
           class="tree-size"
@@ -161,12 +180,17 @@ const inlineRenderable = computed(() =>
         class="tree-row file"
         :title="node.path"
       >
-        <span class="tree-spacer" aria-hidden="true" />
         <SkillFileIcon
           :name="fileIcon(node.name)"
           class="size-4 shrink-0"
         />
-        <span class="tree-label">{{ node.name }}</span>
+        <span
+          class="tree-label"
+          :style="{ '--label-tail': `${label.tail.length}ch` }"
+        >
+          <span class="tree-label-head">{{ label.head }}</span>
+          <span v-if="label.tail">{{ label.tail }}</span>
+        </span>
         <span
           v-if="node.asset?.size"
           class="tree-size"
@@ -185,13 +209,14 @@ const inlineRenderable = computed(() =>
 .tree-children {
   list-style: none;
   margin: 0;
-  padding-left: 0.875rem;
+  padding-left: 0.375rem;
   border-left: 1px dashed var(--ui-border);
-  margin-left: 0.4375rem;
+  /* Puts the guide line under the parent folder icon. */
+  margin-left: 0.9375rem;
 }
 .tree-row {
   display: flex;
-  align-items: flex-start;
+  align-items: center;
   gap: 0.375rem;
   width: 100%;
   padding: 0.25rem 0.5rem;
@@ -217,21 +242,25 @@ const inlineRenderable = computed(() =>
   background: var(--ui-bg-muted);
   font-weight: 500;
 }
-.tree-spacer {
-  width: 0.75rem;
-  flex-shrink: 0;
-}
 .tree-size {
   flex-shrink: 0;
   font-size: 0.6875rem;
   font-variant-numeric: tabular-nums;
   color: var(--ui-text-muted);
 }
-/* The explorer column is narrow, so long names wrap instead of hiding the
-   part that tells two files apart. */
 .tree-label {
-  min-width: 0;
+  display: flex;
   flex: 1;
-  overflow-wrap: anywhere;
+  min-width: 0;
+  white-space: nowrap;
+  container-type: inline-size;
+}
+/* The tree is monospace. Rounding the head down to whole characters puts the
+   ellipsis flush against the tail, with no part-character gap between them. */
+.tree-label-head {
+  min-width: 0;
+  max-width: round(down, calc(100cqw - var(--label-tail)), 1ch);
+  overflow: hidden;
+  text-overflow: ellipsis;
 }
 </style>

layers/registry/app/utils/skill-file-tree.ts

@@ -173,3 +173,26 @@ export function highlightLangFromPath(path: string): string {
 export function isInlineRenderable(type: 'markdown' | 'code' | 'image' | 'data' | 'other'): boolean {
   return type === 'markdown' || type === 'code' || type === 'data'
 }
+
+const LABEL_SPLIT_MIN = 17
+const LABEL_TAIL_MIN = 6
+const LABEL_TAIL_MAX = 12
+const LABEL_TAIL_FALLBACK = 8
+const LABEL_BOUNDARY = /[-_. ]/g
+
+/**
+ * Splits a long file name so the tree can truncate its middle and keep its
+ * end. Names like `setup-v1.md` and `setup-v2.md` then stay apart in a narrow
+ * column. The tail starts after a separator when one gives a tail of 6 to 12
+ * characters, so a word is not cut in half.
+ */
+export function splitFileLabel(name: string): { head: string, tail: string } {
+  if (name.length < LABEL_SPLIT_MIN)
+    return { head: name, tail: '' }
+  const cut = [...name.matchAll(LABEL_BOUNDARY)]
+    .map(match => match.index + 1)
+    .reverse()
+    .find(index => name.length - index >= LABEL_TAIL_MIN && name.length - index <= LABEL_TAIL_MAX)
+    ?? name.length - LABEL_TAIL_FALLBACK
+  return { head: name.slice(0, cut), tail: name.slice(cut) }
+}

test/unit/skill-file-tree.test.ts

@@ -1,6 +1,6 @@
 import type { SkillFileTreeNode } from '../../layers/registry/app/utils/skill-file-tree'
 import { describe, expect, it } from 'vitest'
-import { buildSkillFileTree } from '../../layers/registry/app/utils/skill-file-tree'
+import { buildSkillFileTree, splitFileLabel } from '../../layers/registry/app/utils/skill-file-tree'
 
 function file(path: string, type: 'markdown' | 'code' = 'markdown') {
   return { path, size: 100, type }
@@ -55,3 +55,18 @@ describe('skill file tree', () => {
     expect(tree.at(-1)).toMatchObject({ kind: 'file', asset: { path: 'SKILL.md', size: 7900 } })
   })
 })
+
+describe('splitFileLabel', () => {
+  it('keeps a short name whole', () => {
+    expect(splitFileLabel('SKILL.md')).toEqual({ head: 'SKILL.md', tail: '' })
+  })
+
+  it('starts the kept tail at a word boundary', () => {
+    expect(splitFileLabel('package-lock.json')).toEqual({ head: 'package-', tail: 'lock.json' })
+    expect(splitFileLabel('shipreel.example.yml')).toEqual({ head: 'shipreel.', tail: 'example.yml' })
+  })
+
+  it('keeps the last eight characters when no boundary fits', () => {
+    expect(splitFileLabel('abcdefghijklmnopqrstuvwxyz.md')).toEqual({ head: 'abcdefghijklmnopqrstu', tail: 'vwxyz.md' })
+  })
+})