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>

CHANGELOG.md

@@ -6,6 +6,17 @@ All notable changes to Jarl are documented here. The format follows
 
 ## [Unreleased]
 
+### Fixed
+
+- A changeset with a staged record delete could not be applied after that
+  record was deleted elsewhere (e.g. with the CLI), and it was hard to see
+  which operation to remove: the error only said "record 832 does not
+  exist". A staged delete of a record that is already gone now counts as
+  done (with a warning), and the other operations that no longer apply
+  (an edit or disable of a deleted record, a change to an object changed
+  since) are named with their number and summary. The Changes page marks
+  that operation and offers to remove it right in the error.
+
 ### Added
 
 - Prometheus metrics at `/metrics` ([docs/metrics.md](docs/metrics.md)),

docs/api.md

@@ -149,6 +149,14 @@ honours `If-Match: <version>`, and batch operations take `base_version`. If
 the object changed in the meantime the request fails with 409. Staged
 operations record the version they were staged against automatically.
 
+**Stale changesets.** When an object a staged operation needs was changed
+or deleted after it was staged (from the CLI, say), preview and apply fail
+on that operation: the error has `op` (its number in the changeset),
+`op_summary` and a message saying what happened; remove the operation
+(`DELETE /changesets/{id}/ops/{seq}`) or stage it again. A staged delete of
+a record that is already gone is not an error: it counts as done, with a
+warning.
+
 ## Resources
 
 `{zone}` is a zone ID or name (`root` for the root zone). Add `?view=NAME`

internal/engine/errors.go

@@ -25,15 +25,21 @@ const (
 
 // Error is an engine error with details for the caller.
 type Error struct {
-	Kind     ErrorKind          `json:"code"`
+	Kind    ErrorKind `json:"code"`
-	Message  string             `json:"message"`
+	Message string    `json:"message"`
-	OpSeq    int                `json:"op,omitempty"` // the operation that failed
+	OpSeq   int       `json:"op,omitempty"` // the operation that failed
-	Problems []validate.Problem `json:"problems,omitempty"`
+	// OpSummary describes that operation, so people can find it in the
-	Check    []CheckMessage     `json:"check,omitempty"`
+	// changeset (record IDs mean little to them).
-	Diff     string             `json:"diff,omitempty"`
+	OpSummary string             `json:"op_summary,omitempty"`
+	Problems  []validate.Problem `json:"problems,omitempty"`
+	Check     []CheckMessage     `json:"check,omitempty"`
+	Diff      string             `json:"diff,omitempty"`
 }
 
 func (e *Error) Error() string {
+	if e.OpSeq > 0 && e.OpSummary != "" {
+		return fmt.Sprintf("operation %d (%s): %s", e.OpSeq, e.OpSummary, e.Message)
+	}
 	if e.OpSeq > 0 {
 		return fmt.Sprintf("operation %d: %s", e.OpSeq, e.Message)
 	}

internal/engine/ops.go

@@ -120,7 +120,7 @@ func applyOp(st *model.State, op model.Op, c *applyCtx) error {
 		err = errf(KindBadRequest, "unknown operation %q", op.Kind)
 	}
 	if e, ok := AsError(err); ok && e.OpSeq == 0 {
-		e.OpSeq = op.Seq
+		e.OpSeq, e.OpSummary = op.Seq, op.Summary
 	}
 	return err
 }
@@ -457,7 +457,7 @@ func applyRecordCreate(st *model.State, op model.Op, c *applyCtx) error {
 func applyRecordUpdate(st *model.State, op model.Op, c *applyCtx) error {
 	r := st.Records[op.ID]
 	if r == nil {
-		return errf(KindNotFound, "record %d does not exist", op.ID)
+		return errf(KindConflict, "the record (ID %d) no longer exists: it was deleted after this change was staged; remove this operation from the changeset", op.ID)
 	}
 	if err := checkVersion(op, r.Version, recordLabel(r)); err != nil {
 		return err
@@ -533,7 +533,10 @@ func applyRecordDelete(st *model.State, op model.Op, c *applyCtx) error {
 	if op.ID != 0 {
 		r := st.Records[op.ID]
 		if r == nil {
-			return errf(KindNotFound, "record %d does not exist", op.ID)
+			// Deleted since this was staged (by someone else, or the
+			// CLI): what the operation wanted is done.
+			c.warn("%s: the record was already deleted outside this changeset, so there was nothing to delete", strings.TrimPrefix(op.Summary, "delete "))
+			return nil
 		}
 		if err := checkVersion(op, r.Version, recordLabel(r)); err != nil {
 			return err

internal/engine/stale_test.go

@@ -0,0 +1,51 @@
+package engine
+
+import (
+	"strings"
+	"testing"
+
+	"jarl/internal/model"
+)
+
+// Records deleted or changed after a change to them was staged (in the
+// CLI while a web UI changeset is open, say).
+func TestStaleChangeset(t *testing.T) {
+	env := newEnv(t)
+	setupZone(env)
+	env.submit(env.admin, rec("example.com", "one", "A", "192.0.2.51"), rec("example.com", "two", "A", "192.0.2.52"), rec("example.com", "three", "A", "192.0.2.53"))
+	st := env.state()
+	one, two, three := findRec(st, "one.example.com.", "A"), findRec(st, "two.example.com.", "A"), findRec(st, "three.example.com.", "A")
+
+	// Two deletes staged; one of the records is deleted elsewhere first.
+	cs, err := env.e.CreateChangeset(env.ctx, env.admin, "web", "")
+	if err != nil {
+		t.Fatal(err)
+	}
+	if _, err := env.e.Stage(env.ctx, cs.ID, []Request{NewRequest(OpRecordDelete, one.ID, nil), NewRequest(OpRecordDelete, two.ID, nil)}, env.admin); err != nil {
+		t.Fatal(err)
+	}
+	env.submit(env.admin, NewRequest(OpRecordDelete, one.ID, nil))
+	res, err := env.e.Apply(env.ctx, cs.ID, env.admin, ApplyOptions{})
+	if err != nil {
+		t.Fatalf("apply after the record was deleted elsewhere: %v", err)
+	}
+	if len(res.Warnings) != 1 || !strings.Contains(res.Warnings[0], "one.example.com. A 192.0.2.51: the record was already deleted") {
+		t.Errorf("warnings = %q", res.Warnings)
+	}
+	if st := env.state(); st.Records[two.ID] != nil {
+		t.Error("two was not deleted")
+	}
+
+	// A staged edit of a record deleted elsewhere names the operation.
+	cs, _ = env.e.CreateChangeset(env.ctx, env.admin, "web", "")
+	env.e.Stage(env.ctx, cs.ID, []Request{NewRequest(OpRecordUpdate, three.ID, RecordInput{Data: model.Ptr("192.0.2.54")})}, env.admin)
+	env.submit(env.admin, NewRequest(OpRecordDelete, three.ID, nil))
+	p, err := env.e.Preview(env.ctx, cs.ID, env.admin)
+	if err != nil || p.Error == nil || p.Error.OpSeq != 1 || !strings.HasPrefix(p.Error.OpSummary, "change three.example.com. A 192.0.2.53") {
+		t.Fatalf("preview = %+v, %v", p, err)
+	}
+	_, err = env.e.Apply(env.ctx, cs.ID, env.admin, ApplyOptions{})
+	if ee, ok := AsError(err); !ok || ee.Kind != KindConflict || !strings.Contains(err.Error(), "operation 1 (change three.example.com. A") || !strings.Contains(err.Error(), "remove this operation") {
+		t.Errorf("apply = %v", err)
+	}
+}

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 () => {
+    { label: "", render: (o) => h("button", { class: "small", title: "Remove this operation from the changeset", onclick: () => removeOp(o.seq) }, "Remove"), tdClass: "actions-cell" },
-      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" },
   ], 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),

internal/web/static/assets/style.css

@@ -154,6 +154,8 @@ td.actions-cell { white-space: nowrap; text-align: right; width: 1%; }
 tr.editing td { background: var(--accent-soft); }
 tr.pending-add td { background: var(--add); }
 tr.pending-change td, tr.pending-disable td, tr.pending-enable td { background: var(--warn-soft); }
+tr.op-failed td { background: var(--err-soft); }
+tr.op-failed td:first-child { box-shadow: inset 3px 0 0 var(--err); }
 tr.pending-delete td { background: var(--del); text-decoration: line-through; color: var(--muted); }
 tr.disabled td:not(.actions-cell), tr.disabled td strong { color: var(--muted); }
 /* Disabled records: hatched, so they stand out from live and pending rows. */