The plans verb: what the last merges produced and where each stands (hq ADR 0162)

The mesh's seat answers plans — the recent plans with their tier, what each waits for and since when,
or one plan whole given its id — so the console reads a merge's progress where it reads everything
else, instead of a person reading the daemon's log.

cmd/mesh-controller/release_plan.go

@@ -2,6 +2,7 @@ package main
 
 import (
 	"context"
+	"flag"
 	"fmt"
 	"sort"
 	"strings"
@@ -524,3 +525,63 @@ func openPlans(plans []inventory.Plan) ([]inventory.Plan, int) {
 	}
 	return open, late
 }
+
+
+// plansCommand says what the last merges produced and where each stands; given an id, one plan
+// tier by tier with every module's state.
+func plansCommand(ctx context.Context, args []string) error {
+	set := flag.NewFlagSet("plans", flag.ContinueOnError)
+	limit := set.Int("n", 10, "how many to show")
+	positionals, err := parseAround(set, args)
+	if err != nil {
+		return err
+	}
+	open, err := openStores(ctx)
+	if err != nil {
+		return err
+	}
+	defer open.Close()
+	inv := open.inventory
+	now := time.Now()
+	if len(positionals) == 1 {
+		p, err := inv.PlanByID(ctx, positionals[0])
+		if err != nil {
+			return err
+		}
+		fmt.Printf("%s — %s\n", p.ID, planLine(p, now))
+		for i, tier := range p.Tiers {
+			marker := " "
+			if i == p.Tier && p.Open() {
+				marker = ">"
+			}
+			fmt.Printf("%s tier %d\n", marker, i)
+			for _, m := range tier {
+				s := p.Modules[m]
+				state := "not yet asked"
+				if s != nil && s.State != "" {
+					state = s.State
+					if s.Commit != "" {
+						state += " from " + short(s.Commit)
+					}
+					if s.Why != "" {
+						state += ": " + s.Why
+					}
+				}
+				fmt.Printf("    %-22s %s\n", m, state)
+			}
+		}
+		return nil
+	}
+	plans, err := inv.RecentPlans(ctx, *limit)
+	if err != nil {
+		return err
+	}
+	if len(plans) == 0 {
+		fmt.Println("no merge has produced a plan yet")
+		return nil
+	}
+	for _, p := range plans {
+		fmt.Printf("%-28s %s\n", p.ID, planLine(p, now))
+	}
+	return nil
+}