merge-fix(apiserver/hosts): adopt theirs computeHostSlotUsage, drop our superseded job-count helper

hosts.go conflict-free auto-merge left both host counter implementations:
ours countRunningJobsPerHost() (bug-1490, per-RUN-job count) and theirs
computeHostSlotUsage() (bug-1743, per-host occupied-SLOT count bucketed
USUSP>SSUSP>RUN) wired into processHostData(), which runs after GetHostsInfo
and overwrote our num_run, leaving our helper dead code.

Resolution: keep theirs (slot-bucketed). Rationale: it matches the codebase's
canonical JobStateStr mapping (a RUN|USUSP job is USUSP, not RUN -- our
RUN-bit-only check mislabeled suspended jobs as running and left
num_ssusp/num_ususp permanently 0), sums num_slots so values are comparable to
max_slot, and is applied uniformly at the processHostData choke point for all
host endpoints. Deleted countRunningJobsPerHost + GetHostsInfo fill-loop and
rewrote hosts_numrun_test.go to cover computeHostSlotUsage's bucket/multi-slot
semantics plus our retained robustness cases (PEND/DONE and empty/bad
exec_hosts ignored). Theirs' host_control_test.go
TestProcessHostData_ComputesSlotUsageFromJobs provides the processHostData
integration coverage.

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

src/frontend/apiserver/controllers/hosts.go

@@ -190,20 +190,6 @@ func (h *HostHandler) GetHostsInfo(ctx *gin.Context) {
 		return
 	}
 
-	// num_run is not populated by the controller's worker push, so compute it
-	// here from the apiserver's own job store — the same source the jobs list
-	// uses — keeping the hosts list consistent with the jobs list.
-	runningPerHost := countRunningJobsPerHost()
-	for i := range hqueryReply {
-		host, ok := hqueryReply[i].Data["host_name"].(string)
-		if !ok {
-			continue
-		}
-		if n, ok2 := runningPerHost[host]; ok2 {
-			hqueryReply[i].Data["num_run"] = n
-		}
-	}
-
 	logger.Debug("the host info query reply:", zap.Any("hqueryReply", hqueryReply), zap.String("pagetoken", pagetoken))
 	//convert to readable string.
 	queryResult := processHostData(hqueryReply, pagetoken)
@@ -211,31 +197,6 @@ func (h *HostHandler) GetHostsInfo(ctx *gin.Context) {
 	ReturnSuccess(ctx, common.SUCCESS_CODE, common.SUCCESS_MSG, queryResult)
 }
 
-// countRunningJobsPerHost returns the number of RUN jobs per exec host,
-// derived live from the in-memory job store (store.Jobs). RUN is the bitmask
-// JOBSTAT["RUN"] (0x02); exec hosts are read from each job's exec_hosts JSONB.
-func countRunningJobsPerHost() map[string]int {
-	counts := make(map[string]int)
-	store.Jobs.Range(func(_ uint64, job models.JobInfo) bool {
-		if job.JobStatus&models.JOBSTAT["RUN"] == 0 {
-			return true
-		}
-		var eh struct {
-			HostSlots []struct {
-				HostName string `json:"host_name"`
-			} `json:"host_slots"`
-		}
-		if err := json.Unmarshal([]byte(job.ExecHosts.String), &eh); err != nil {
-			return true
-		}
-		for _, hs := range eh.HostSlots {
-			counts[hs.HostName]++
-		}
-		return true
-	})
-	return counts
-}
-
 func selectFields(host interface{}, fields []string) map[string]interface{} {
 	result := make(map[string]interface{})
 	v := reflect.ValueOf(host)

src/frontend/apiserver/controllers/hosts_numrun_test.go

@@ -7,53 +7,68 @@ import (
 	"apiserver/store"
 )
 
-func TestCountRunningJobsPerHost(t *testing.T) {
+// TestComputeHostSlotUsage_BucketsSlotsByStateAndRobustness covers the
+// merged host-slot derivation (bug-1743 computeHostSlotUsage, which replaced
+// our bug-1490-era countRunningJobsPerHost on merge): per-host occupied-slot
+// totals bucketed USUSP > SSUSP > RUN, matching models.JobStateStr's own
+// canonical mapping (a RUN|USUSP job is USUSP, not RUN). It keeps the
+// robustness cases our old job-count helper tested: multi-host jobs count on
+// every host they occupy, multi-slot jobs sum num_slots, and PEND/DONE or
+// empty/bad exec_hosts are ignored without crashing.
+func TestComputeHostSlotUsage_BucketsSlotsByStateAndRobustness(t *testing.T) {
 	store.InitStores()
 
-	// RUN job on t1.
+	putJob := func(id uint64, execHosts string, status int) {
-	store.Jobs.Put(1, models.JobInfo{
+		store.Jobs.Put(id, models.JobInfo{
-		JobStatus: models.JOBSTAT["RUN"],
+			JobStatus: status,
-		ExecHosts: models.Jsonb{String: `{"host_slots":[{"host_name":"t1","num_slots":1}],"num_hosts":1}`},
+			ExecHosts: models.Jsonb{String: execHosts},
-	})
+		})
-	// RUN|USUSP job on t2 — the RUN bit must still count it.
+	}
-	store.Jobs.Put(2, models.JobInfo{
+
-		JobStatus: models.JOBSTAT["RUN"] | models.JOBSTAT["USUSP"],
+	// Plain RUN job on t1 (1 slot).
-		ExecHosts: models.Jsonb{String: `{"host_slots":[{"host_name":"t2","num_slots":1}],"num_hosts":1}`},
+	putJob(1, `{"host_slots":[{"host_name":"t1","num_slots":1}],"num_hosts":1}`, models.JOBSTAT["RUN"])
-	})
+	// RUN|USUSP job on t2 — must count as USUSP, not RUN (JobStateStr order).
-	// Multi-host RUN job: one job on t1 + t3 counts on both.
+	putJob(2, `{"host_slots":[{"host_name":"t2","num_slots":1}],"num_hosts":1}`, models.JOBSTAT["RUN"]|models.JOBSTAT["USUSP"])
-	store.Jobs.Put(3, models.JobInfo{
+	// Multi-host RUN job: one job on t1 + t3 counts on both hosts.
-		JobStatus: models.JOBSTAT["RUN"],
+	putJob(3, `{"host_slots":[{"host_name":"t1","num_slots":1},{"host_name":"t3","num_slots":1}],"num_hosts":2}`, models.JOBSTAT["RUN"])
-		ExecHosts: models.Jsonb{String: `{"host_slots":[{"host_name":"t1","num_slots":1},{"host_name":"t3","num_slots":1}],"num_hosts":2}`},
+	// Multi-slot RUN job: 3 slots on t4 must sum to 3, not count as 1.
-	})
+	putJob(4, `{"host_slots":[{"host_name":"t4","num_slots":3}],"num_hosts":1}`, models.JOBSTAT["RUN"])
+	// RUN|SSUSP job on t5 using 2 slots — counts as SSUSP.
+	putJob(5, `{"host_slots":[{"host_name":"t5","num_slots":2}],"num_hosts":1}`, models.JOBSTAT["RUN"]|models.JOBSTAT["SSUSP"])
 	// PEND and DONE jobs must NOT count.
-	store.Jobs.Put(4, models.JobInfo{
+	putJob(6, `{"host_slots":[{"host_name":"t3","num_slots":1}],"num_hosts":1}`, models.JOBSTAT["PEND"])
-		JobStatus: models.JOBSTAT["PEND"],
+	putJob(7, `{"host_slots":[{"host_name":"t1","num_slots":1}],"num_hosts":1}`, models.JOBSTAT["DONE"])
-		ExecHosts: models.Jsonb{String: `{"host_slots":[{"host_name":"t3","num_slots":1}],"num_hosts":1}`},
+	// RUN job with empty / bad exec_hosts must not crash or count.
-	})
+	putJob(8, ``, models.JOBSTAT["RUN"])
-	store.Jobs.Put(5, models.JobInfo{
+	putJob(9, `not-json`, models.JOBSTAT["RUN"])
-		JobStatus: models.JOBSTAT["DONE"],
-		ExecHosts: models.Jsonb{String: `{"host_slots":[{"host_name":"t1","num_slots":1}],"num_hosts":1}`},
-	})
-	// RUN job with empty/bad exec_hosts must not crash or count.
-	store.Jobs.Put(6, models.JobInfo{
-		JobStatus: models.JOBSTAT["RUN"],
-		ExecHosts: models.Jsonb{String: ``},
-	})
-	store.Jobs.Put(7, models.JobInfo{
-		JobStatus: models.JOBSTAT["RUN"],
-		ExecHosts: models.Jsonb{String: `not-json`},
-	})
 
-	counts := countRunningJobsPerHost()
+	counts := computeHostSlotUsage()
 
-	if counts["t1"] != 2 { // jobs 1 + 3
+	// t1: job1 (RUN, 1) + job3 (RUN, 1) = 2 RUN slots.
-		t.Errorf("t1 running = %d, want 2", counts["t1"])
+	if got := counts["t1"].Run; got != 2 {
+		t.Errorf("t1 Run = %d, want 2", got)
 	}
-	if counts["t2"] != 1 {
+	if got := counts["t1"].SSusp + counts["t1"].USusp; got != 0 {
-		t.Errorf("t2 running = %d, want 1", counts["t2"])
+		t.Errorf("t1 susp buckets = %d, want 0", got)
 	}
-	if counts["t3"] != 1 { // job 3 only (job 4 is PEND)
+	// t2: RUN|USUSP job must land in USusp, not Run.
-		t.Errorf("t3 running = %d, want 1", counts["t3"])
+	if got := counts["t2"].USusp; got != 1 {
+		t.Errorf("t2 USusp = %d, want 1", got)
+	}
+	if got := counts["t2"].Run; got != 0 {
+		t.Errorf("t2 Run = %d, want 0 (RUN|USUSP is USUSP)", got)
+	}
+	// t3: job3 only (job 6 is PEND).
+	if got := counts["t3"].Run; got != 1 {
+		t.Errorf("t3 Run = %d, want 1", got)
+	}
+	// t4: 3-slot RUN job sums to 3.
+	if got := counts["t4"].Run; got != 3 {
+		t.Errorf("t4 Run = %d, want 3 (multi-slot sums)", got)
+	}
+	// t5: RUN|SSUSP 2-slot job lands in SSusp.
+	if got := counts["t5"].SSusp; got != 2 {
+		t.Errorf("t5 SSusp = %d, want 2", got)
 	}
 	if _, ok := counts["nohost"]; ok {
 		t.Error("unexpected host 'nohost' in counts")