Keep a flow's runs when the flow goes

A run record is a record of what ran, so deleting a flow no longer sweeps its
history: `_forget_runs` is gone from the flow-delete path, and `DELETE /runs/{id}`
is the only thing that removes a run one at a time. The in-flight guard stays —
that is about work, not history.

`DELETE /runs?flow=` is the counterpart to the list's flow filter and what a
reseed needs, sharing the four statements with the single-run delete and
refusing the same way while a run of that flow is still going.

A run whose flow is gone reads as one: `useFlowInputs` reports the 404 rather
than an empty declaration set, so the run page says "flow deleted", explains it,
and disables Retry, which the route would refuse anyway.

frontend/src/client/core/OpenAPI.ts

@@ -48,7 +48,7 @@ export const OpenAPI: OpenAPIConfig = {
 	PASSWORD: undefined,
 	TOKEN: undefined,
 	USERNAME: undefined,
-	VERSION: '0.1.4+dev',
+	VERSION: '0.1.5+dev',
 	WITH_CREDENTIALS: false,
 	interceptors: {
 		request: new Interceptors(),

frontend/src/client/types.gen.ts

@@ -1830,6 +1830,12 @@ export type RunsReadRunsData = {
 
 export type RunsReadRunsResponse = (Array<fluksio__api__routes__runs__RunRow>);
 
+export type RunsDeleteRunsData = {
+    flow: string;
+};
+
+export type RunsDeleteRunsResponse = (Message);
+
 export type RunsReadOverviewResponse = (Array<FlowRunsRow>);
 
 export type RunsExportMetricsData = {
@@ -1860,6 +1866,17 @@ export type RunsExportRunsData = {
 
 export type RunsExportRunsResponse = (unknown);
 
+export type RunsReadMetricNamesData = {
+    flow?: (string | null);
+    group?: (string | null);
+    ids?: string;
+    since?: (string | null);
+    status?: (string | null);
+    until?: (string | null);
+};
+
+export type RunsReadMetricNamesResponse = (Array<(string)>);
+
 export type RunsReadRunData = {
     runId: string;
 };

frontend/src/components/Runs/RunDetail.tsx

@@ -23,6 +23,7 @@ import { OpenInDashboard } from "./OpenInDashboard"
 import {
   CARD,
   downloadArtifact,
+  FLOW_GONE,
   isLive,
   NO_CURVE,
   paramText,
@@ -42,7 +43,7 @@ export function RunDetail({ id }: { id: string }) {
   const cancel = useCancelRun()
   const retry = useRetryRun()
   const names = useMetricNames(id)
-  const declared = useFlowInputs(run?.flow)
+  const { declared, gone } = useFlowInputs(run?.flow)
   const [metric, setMetric] = useState("")
 
   if (isPending || !run) return <Skeleton className="h-96 w-full rounded-lg" />
@@ -96,6 +97,14 @@ export function RunDetail({ id }: { id: string }) {
             ran the working copy
           </span>
         )}
+        {gone && (
+          <span
+            className="rounded-full border border-border px-2 py-0.5 text-muted-foreground text-xs"
+            data-testid="flow-gone"
+          >
+            flow deleted
+          </span>
+        )}
 
         <div className="ml-auto flex items-center gap-2">
           <OpenInDashboard flow={run.flow} ids={[run.id]} />
@@ -115,7 +124,8 @@ export function RunDetail({ id }: { id: string }) {
               size="sm"
               className="h-8"
               onClick={() => retry.mutate(run.id)}
-              disabled={retry.isPending}
+              // There is no flow left to run it against; the route would 404.
+              disabled={retry.isPending || gone}
               data-testid="retry-run"
             >
               <RotateCcw className="size-3.5" />
@@ -126,6 +136,7 @@ export function RunDetail({ id }: { id: string }) {
       </header>
 
       {reason && <p className="text-muted-foreground text-sm">{reason}</p>}
+      {gone && <p className="text-muted-foreground text-sm">{FLOW_GONE}</p>}
 
       <section className={cn(CARD, "grid gap-4 sm:grid-cols-2 lg:grid-cols-4")}>
         <Fact label="Submitted">{ago(String(run.created_at ?? ""))}</Fact>
@@ -157,7 +168,9 @@ export function RunDetail({ id }: { id: string }) {
         <h2 className="font-medium text-sm">Inputs</h2>
         {fed.length === 0 ? (
           <p className="text-muted-foreground text-sm">
-            This flow declares no inputs, so there was nothing to choose.
+            {gone
+              ? "The run carried no parameters of its own, and its flow is gone, so what it took from the flow cannot be read back."
+              : "This flow declares no inputs, so there was nothing to choose."}
           </p>
         ) : (
           <dl className="grid gap-x-6 gap-y-1 sm:grid-cols-2 lg:grid-cols-3">

frontend/src/components/Runs/RunsScreen.tsx

@@ -721,7 +721,7 @@ function ParamDiff({ rows }: { rows: RunRow[] }) {
   // ponytail: only when the picks share one flow — spanning flows would mean a
   // declaration lookup per flow, and a sweep comparison never does.
   const one = rows.every((run) => run.flow === rows[0].flow)
-  const declared = useFlowInputs(one ? rows[0].flow : undefined)
+  const { declared } = useFlowInputs(one ? rows[0].flow : undefined)
   const varying = varyingKeys(rows)
   // Not a parameter, but it is part of what produced the number, and in a
   // sweep it is often the only thing that moved.

frontend/src/components/Runs/queries.ts

@@ -2,7 +2,7 @@ import { useMutation, useQuery, useQueryClient } from "@tanstack/react-query"
 import { useNavigate } from "@tanstack/react-router"
 import { useMemo } from "react"
 
-import { OpenAPI, RunsService } from "@/client"
+import { ApiError, OpenAPI, RunsService } from "@/client"
 import { flowQueryOptions } from "@/components/Flow/queries"
 import { apiToken } from "@/lib/portal"
 
@@ -176,8 +176,12 @@ export async function downloadArtifact(digest: string, name: string) {
   URL.revokeObjectURL(url)
 }
 
+/** The server saying a thing is not there, rather than failing to answer. */
+const isMissing = (error: unknown) =>
+  error instanceof ApiError && error.status === 404
+
 /**
- * What a flow declares it can be given, by input name.
+ * What a flow declares it can be given, by input name — and whether it is gone.
  *
  * A batch flow's inputs *are* its parameters — a run supplies values for the
  * ones it names and takes the flow's own for the rest — so this is what turns
@@ -185,15 +189,21 @@ export async function downloadArtifact(digest: string, name: string) {
  *
  * The declarations are the flow's *current* ones, while a run carries the
  * `flow_version` it was submitted against. An input added since is shown on an
- * older run as a default it never actually received.
+ * older run as a default it never actually received. And the flow may not be
+ * there at all: deleting one leaves its runs standing, so `gone` is an ordinary
+ * answer here rather than a fault, and the screen says so instead of drawing a
+ * run that declares nothing.
  */
 export function useFlowInputs(flow: string | undefined) {
-  const { data } = useQuery({
+  const { data, error } = useQuery({
     ...flowQueryOptions(flow ?? ""),
     enabled: Boolean(flow),
+    // A flow that is gone stays gone; asking three more times only delays it.
+    retry: (count: number, failure: unknown) =>
+      !isMissing(failure) && count < 3,
   })
   const inputs = data?.definition.inputs
-  return useMemo(
+  const declared = useMemo(
     () =>
       new Map<string, unknown>(
         (inputs ?? [])
@@ -202,6 +212,7 @@ export function useFlowInputs(flow: string | undefined) {
       ),
     [inputs],
   )
+  return { declared, gone: isMissing(error) }
 }
 
 /**
@@ -267,13 +278,17 @@ export async function cancelThenDelete(runId: string) {
  * Why a finished run can have nothing to draw.
  *
  * A cache hit replays no emissions, so a restored node's curve is read back
- * from the run that recorded it. Deleting that run — deleting its flow does —
- * takes the curve with it, and then a reused run has a result and nothing to
- * draw. Said out loud rather than left as an empty chart, which reads as a fault.
+ * from the run that recorded it. Deleting that run takes the curve with it, and
+ * then a reused run has a result and nothing to draw. Said out loud rather than
+ * left as an empty chart, which reads as a fault.
  */
 export const NO_CURVE =
   "No curve was recorded. A node restored from the cache is read back from the run that produced it, so this draws nothing once that run has been deleted — its outputs are still on the result."
 
+/** Why a run can name a flow that is not there any more. */
+export const FLOW_GONE =
+  "The flow this ran has been deleted. The run is kept as the record of what ran, but there is nothing left to retry it against."
+
 /** A run id, short enough for a table cell. The tail is the random half. */
 export const shortId = (id: string) => id.slice(-8)