Changesets: staged deletes of gone records count as done, name stale ops

A web changeset with a staged record delete could not be applied after
the record was deleted elsewhere (e.g. with the CLI), and the error only
said "record N does not exist", so it was hard to find the operation to
remove. A delete of a record that is already gone is now a no-op with a
warning. Other operations that no longer apply fail with their number and
summary (op_summary in the API), and the Changes page marks that row and
offers to remove it from the error.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

internal/web/static/assets/pages/changes.js

@@ -44,18 +44,33 @@ async function draftPanel(d) {
   const applyBtn = h("button", { class: "primary", disabled: true }, "Apply changes");
   const forceBox = h("label", { class: "check small hidden" }, h("input", { type: "checkbox" }), "Overwrite files changed outside Jarl");
   const ops = d.ops || [];
+  const removeOp = async (seq) => {
+    try {
+      const cs = await api("DELETE", "/changesets/" + d.id + "/ops/" + seq);
+      useDraft(cs);
+      rerender();
+    } catch (e) { toast(e.message, "err", 8000); }
+  };
   const opsTable = table([
     { label: "#", render: (o) => String(o.seq) },
     { label: "Change", render: (o) => o.summary || o.op, tdClass: "mono small" },
     { label: "Added", render: (o) => time(o.added_at) },
-    { label: "", render: (o) => h("button", { class: "small", title: "Remove this operation from the changeset", onclick: async () => {
-      try {
-        const cs = await api("DELETE", "/changesets/" + d.id + "/ops/" + o.seq);
-        useDraft(cs);
-        rerender();
-      } catch (e) { toast(e.message, "err", 8000); }
-    } }, "Remove"), tdClass: "actions-cell" },
+    { label: "", render: (o) => h("button", { class: "small", title: "Remove this operation from the changeset", onclick: () => removeOp(o.seq) }, "Remove"), tdClass: "actions-cell" },
   ], ops);
+  // failedOp marks the operation that no longer applies and says how to
+  // get past it.
+  const failedOp = (err) => {
+    const i = ops.findIndex((o) => o.seq === err.op);
+    const rows = opsTable.querySelectorAll("tbody tr");
+    if (i < 0 || !rows[i]) return errorBox({ message: err.message, details: err });
+    rows[i].classList.add("op-failed");
+    return h("div", { class: "msg err" },
+      h("div", null, h("strong", null, "Operation " + err.op + " can't be applied: "), err.message),
+      h("div", { class: "mono small" }, ops[i].summary || ops[i].op),
+      h("div", { style: { marginTop: "8px" } },
+        h("button", { class: "small", onclick: () => removeOp(err.op) }, "Remove operation " + err.op),
+        " ", h("span", { class: "muted small" }, "It is marked in the list above. Then check the rest again.")));
+  };
   const runPreview = async () => {
     try {
       const p = await get("/changesets/" + d.id + "/preview");
@@ -64,7 +79,7 @@ async function draftPanel(d) {
       const drift = (p.drift || []);
       forceBox.classList.toggle("hidden", drift.length === 0);
       mount(preview,
-        p.error ? errorBox({ message: p.error.message, details: p.error }) : null,
+        p.error ? (p.error.op ? failedOp(p.error) : errorBox({ message: p.error.message, details: p.error })) : null,
         valid ? h("div", { class: "msg ok" }, "Valid. named-checkconf accepts the new configuration.", (p.serials || []).length ? " Serials: " + p.serials.map((s) => s.zone.replace(/\.$/, "") + " " + s.old + "→" + s.new).join(", ") : "") : null,
         !p.error && !valid ? h("div", { class: "msg err" }, "This changeset can't be applied yet:") : null,
         problemsList(p.problems),