Add missing-file detection with click-to-replace

Rows pointing at a lora that's no longer on disk (moved, renamed, or
deleted) now render red with a warning marker instead of only logging
to the console at generation time. The missing row's name is
click-to-replace: clicking it reopens the folder browser to swap in a
working file in place.

Detection reuses the existing /tree endpoint - its full paths are
flattened into a set of valid loras, and a row is flagged when its
lora isn't in that set. Fails safe (flags nothing until the list is
known / if the fetch fails) and tolerates path-separator differences
across OSes.

Documents the feature in the README with a screenshot and promotes it
out of the roadmap.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

README.md

@@ -20,6 +20,7 @@ The node in its default state, right after adding it to the canvas:
 - **Native quick-edit dialogs** — click any strength or priority number to get ComfyUI's own auto-selected value-entry dialog (matches the interaction rgthree's nodes use)
 - **Toggle-all / delete-all** — bulk controls in the header row, column-aligned with the per-row toggle and trash icons
 - **Auto-growing node** — the node resizes itself to fit your lora list; shrink it manually below that and the list scrolls internally instead of spilling out
+- **Missing-file detection** — if a row points at a lora that's no longer on disk (moved, renamed, or deleted since the workflow was saved), the row is flagged in red with a ⚠ marker, and its name becomes click-to-replace so you can swap in a working file without rebuilding the row
 
 A populated stack — drag handle, priority number, toggle, name, strength stepper, and trash icon, all column-aligned with the header row's toggle-all and delete-all controls:
 
@@ -33,6 +34,10 @@ Connect `clip` and every row gains an independent second stepper — the header
 
 ![Clip connected, showing the header split into Model and Clip columns with a second stepper per row](docs/screenshot-clip-optional.png)
 
+If a row's lora file goes missing — moved, renamed, or deleted since the workflow was saved — that row is flagged in red with a ⚠ marker instead of silently failing at generation time. Click the highlighted name to reopen the folder browser and pick a replacement in place:
+
+![A lora stack with one row flagged red because its lora file is missing from disk](docs/screenshot-missing-file.png)
+
 ## Install
 
 **Via git clone (recommended):**
@@ -95,7 +100,6 @@ Planned features, roughly in the order they're likely to land:
 **Self-contained (no external services needed):**
 - Search/filter box in the Add Lora popup — type to filter instead of scrolling through folders
 - Duplicate detection — block re-adding a lora that's already in the stack, with a clear message, since there's no real use case for having the same file twice
-- Missing-file detection — if a saved workflow references a lora that's been moved or deleted, highlight that row (rather than only printing to the console), and offer a way to search for it
 
 **Trigger words, suggested strength, and CivitAI metadata (one combined feature):**
 - A clickable info icon after the lora name, showing trigger words and CivitAI metadata for that lora

js/ultimate_lora_loader.js

@@ -43,6 +43,21 @@ if (!document.getElementById(STYLE_ID)) {
       border-color: #6d5aa8;
     }
 
+    /* Missing on disk - wins over enabled-highlight's background/border so a
+       broken row reads as broken whether it's toggled on or off. */
+    .fll-row.missing,
+    .fll-row.missing.enabled-highlight {
+      background: #3a2323;
+      border-color: #c0392b;
+    }
+    .fll-name.fll-name-missing {
+      color: #ff8a80;
+      cursor: pointer;
+    }
+    .fll-name.fll-name-missing:hover {
+      text-decoration: underline;
+    }
+
     /* --- Toggle switch (replaces checkbox) --- */
     .fll-toggle-switch {
       position: relative;
@@ -397,6 +412,46 @@ let _treeCache = null;
 let _treeCacheTime = 0;
 const TREE_CACHE_MS = 15000; // refresh at most every 15s so new files show up reasonably fast
 
+// Flat set of every valid lora path the backend reports (the exact strings
+// get_filename_list("loras") returns, which is what an entry's `lora` field
+// stores). Stays null until the first successful tree fetch so we never flag
+// rows as "missing" before we actually know what's on disk.
+let validLoraPaths = null;
+
+function _normLora(p) {
+  // Normalize separators so a workflow saved on one OS doesn't read as
+  // "missing" on another; the flag is purely cosmetic so being lenient here
+  // only ever avoids false positives.
+  return String(p).replace(/\\/g, "/");
+}
+
+// Walk the nested tree collecting every value in every __full_paths__ map -
+// those values are the full relative paths, i.e. the source of truth for
+// what's installed. Rebuilt on each tree fetch so added/removed files show up.
+function _rebuildValidLoraPaths(tree) {
+  const set = new Set();
+  (function walk(node) {
+    if (!node || typeof node !== "object") return;
+    const fp = node.__full_paths__;
+    if (fp) {
+      for (const k in fp) set.add(_normLora(fp[k]));
+    }
+    for (const key in node) {
+      if (key === "__files__" || key === "__full_paths__") continue;
+      walk(node[key]);
+    }
+  })(tree);
+  validLoraPaths = set;
+}
+
+// True only when we have a loaded list AND this lora isn't in it. Unknown
+// (list not loaded yet / fetch failed) -> false, so we fail safe toward
+// "not missing" rather than lighting up every row red on a transient hiccup.
+function isLoraMissing(loraName) {
+  if (!validLoraPaths || !loraName) return false;
+  return !validLoraPaths.has(_normLora(loraName));
+}
+
 async function fetchLoraTree(force = false) {
   const now = Date.now();
   if (!force && _treeCache && now - _treeCacheTime < TREE_CACHE_MS) {
@@ -407,6 +462,7 @@ async function fetchLoraTree(force = false) {
     const data = await res.json();
     _treeCache = data;
     _treeCacheTime = now;
+    _rebuildValidLoraPaths(data);
     return data;
   } catch (e) {
     console.error("[UltimateLoraLoader] Failed to fetch lora tree", e);
@@ -571,7 +627,7 @@ function openLoraBrowser(x, y, onSelect) {
 // Node widget
 // ---------------------------------------------------------------------------
 
-function makeRow(entry, { onChange, onRemove, showClipStrength, onDragStart, onDragOver, onDrop, onDragEnd, onPriorityChange, currentPriority }) {
+function makeRow(entry, { onChange, onRemove, onReplace, showClipStrength, onDragStart, onDragOver, onDrop, onDragEnd, onPriorityChange, currentPriority }) {
   const row = document.createElement("div");
   row.className = rowClassName(entry);
   // Row itself isn't draggable - only the dedicated drag handle icon
@@ -660,8 +716,23 @@ function makeRow(entry, { onChange, onRemove, showClipStrength, onDragStart, onD
   const name = document.createElement("div");
   name.className = "fll-name";
   const shortName = entry.lora.split("/").pop();
-  name.textContent = shortName;
-  name.title = entry.lora;
+  const missing = isLoraMissing(entry.lora);
+  name.textContent = missing ? "⚠ " + shortName : shortName;
+  if (missing) {
+    name.classList.add("fll-name-missing");
+    name.title = `File not found on disk:\n${entry.lora}\n\nClick to choose a replacement.`;
+    // Click-to-replace: reopen the same folder browser and swap this row's
+    // lora in place. Cheap stand-in for the roadmap's "click-to-search"
+    // until a real search box exists.
+    name.onclick = (e) => {
+      e.stopPropagation();
+      if (!onReplace) return;
+      const rect = name.getBoundingClientRect();
+      openLoraBrowser(rect.left, rect.bottom + 4, (loraPath) => onReplace(loraPath));
+    };
+  } else {
+    name.title = entry.lora;
+  }
 
   const STRENGTH_STEP = 0.05;
 
@@ -855,6 +926,7 @@ function rowClassName(entry) {
   let cls = "fll-row";
   if (!entry.enabled) cls += " disabled";
   if (entry.enabled) cls += " enabled-highlight";
+  if (isLoraMissing(entry.lora)) cls += " missing";
   return cls;
 }
 
@@ -1074,6 +1146,11 @@ app.registerExtension({
               render();
               resizeNode();
             },
+            onReplace: (loraPath) => {
+              entry.lora = loraPath;
+              persist();
+              render();
+            },
             showClipStrength,
             currentPriority: idx + 1,
             onPriorityChange: (rawPriority) => {
@@ -1373,6 +1450,13 @@ app.registerExtension({
       render();
       syncWidth();
 
+      // Fetch the on-disk lora list so missing-file highlighting can light up
+      // once we know what actually exists. The paint above happens first and
+      // flags nothing (validLoraPaths is null until this resolves); this
+      // re-render applies red highlighting to any rows pointing at files that
+      // are no longer present.
+      fetchLoraTree().then(() => render());
+
       // restore size sanity on load (also re-syncs width once ComfyUI has
       // finished laying out the node on the canvas, in case initial
       // node.size wasn't final yet at widget-creation time). Also retry