Seed player_meta on auto-migration to prevent player_meta-less stragglers

The !setup confirm path seeds the canonical player_meta row (commit
667f87f), but the auto-migration path (ensureDnDCharacterForCombat) writes
a confirmed dnd_character without touching the legacy layer. Commands that
trigger it — !rest, !cast, !abilities, !skills — derive the adventure char
via a bare loadAdvCharacter that is nil when player_meta is absent, and
autoBuildCharacter tolerates a nil char. So a brand-new player whose
first-ever adventure action is one of those gets a confirmed character with
no player_meta, which then fails every legacy-layer command (expeditions,
arena, world boss, town, duels) with "sql: no rows" — the same state
@camcast was found in.

Fix: ensurePlayerMetaSeed guarantees the seed row (+ tier-0 equipment)
exists at the fresh auto-migration point. Conditional on player_meta being
absent, so it's idempotent and never duplicates a legacy player's gear
(createAdvCharacter's equipment insert has no conflict guard).

Regression tests cover both the straggler repro (first-ever !rest seeds
player_meta + loads cleanly) and idempotency (no equipment duplication).

Claude-Session: https://claude.ai/code/session_017mEwUmmS7aQTP2NQXj6rUa

internal/plugin/adventure_character.go

@@ -1,6 +1,9 @@
 package plugin
 
 import (
+	"database/sql"
+	"errors"
+	"strings"
 	"time"
 
 	"gogobee/internal/db"
@@ -536,6 +539,41 @@ func createAdvCharacter(userID id.UserID, displayName string) error {
 	return tx.Commit()
 }
 
+// ensurePlayerMetaSeed guarantees the canonical player_meta seed row (and tier-0
+// equipment) exists for userID, creating it only when absent. The auto-migration
+// path (ensureDnDCharacterForCombat) writes a confirmed dnd_character without
+// touching the legacy layer; without this, a brand-new player whose first-ever
+// action auto-migrates — e.g. !rest or !cast before !setup — ends up with a
+// player_meta-less character that fails every legacy-layer command with
+// "sql: no rows" (the camcast straggler). Conditional on absence and thus
+// idempotent: legacy players who already have player_meta keep their equipment
+// untouched — createAdvCharacter's tier-0 equipment insert has no conflict guard
+// and would otherwise duplicate their gear.
+func ensurePlayerMetaSeed(userID id.UserID) error {
+	d := db.Get()
+	var one int
+	err := d.QueryRow(`SELECT 1 FROM player_meta WHERE user_id = ?`, string(userID)).Scan(&one)
+	if err == nil {
+		return nil // already seeded
+	}
+	if !errors.Is(err, sql.ErrNoRows) {
+		return err
+	}
+	return createAdvCharacter(userID, localpartOf(userID))
+}
+
+// localpartOf returns the mxid localpart (between @ and :) as a display-name
+// fallback — matches Base.DisplayName's offline behavior. The seed's display
+// name is overlaid by later player_meta upserts; this is just a sane default
+// for a character born without a Matrix client in reach.
+func localpartOf(userID id.UserID) string {
+	s := string(userID)
+	if i := strings.Index(s, ":"); i > 0 {
+		return s[1:i]
+	}
+	return strings.TrimPrefix(s, "@")
+}
+
 // saveAdvCharacter persists every mutable AdventureCharacter field to
 // player_meta. Phase L5h: the legacy adventure_characters UPDATE has been
 // retired — the row is now read-only after createAdvCharacter seeds it,

internal/plugin/dnd_combat.go

@@ -1,6 +1,7 @@
 package plugin
 
 import (
+	"fmt"
 	"log/slog"
 	"time"
 
@@ -305,6 +306,13 @@ func ensureDnDCharacterForCombat(userID id.UserID, char *AdventureCharacter) (*D
 	c := autoBuildCharacter(userID, char)
 	c.AutoMigrated = true
 	c.PendingSetup = false
+	// Seed the canonical player_meta row before handing back a confirmed
+	// character. Auto-migration otherwise mints a player_meta-less character
+	// (the camcast straggler) that fails every legacy-layer command with
+	// "sql: no rows". No-op for legacy players who already have the row.
+	if err := ensurePlayerMetaSeed(userID); err != nil {
+		return nil, false, fmt.Errorf("seed player_meta: %w", err)
+	}
 	if err := SaveDnDCharacter(c); err != nil {
 		return nil, false, err
 	}

internal/plugin/player_meta_seed_test.go

@@ -0,0 +1,81 @@
+package plugin
+
+import (
+	"testing"
+
+	"gogobee/internal/db"
+
+	"maunium.net/go/mautrix/id"
+)
+
+// TestAutoMigrationSeedsPlayerMeta guards the camcast straggler regression: a
+// brand-new player whose first-ever adventure action auto-migrates a character
+// (e.g. !rest before !setup) must come out with a canonical player_meta seed,
+// or every legacy-layer command (expeditions, arena, world boss, town…) fails
+// with "sql: no rows". Before the ensurePlayerMetaSeed guard this produced a
+// confirmed dnd_character with zero player_meta rows.
+func TestAutoMigrationSeedsPlayerMeta(t *testing.T) {
+	setupEmptyTestDB(t)
+	uid := id.UserID("@fresh-automigrant:example.org")
+
+	p := &AdventurePlugin{euro: &EuroPlugin{}}
+	p.Sink = &captureSink{}
+
+	// First-ever adventure action for a player with no character at all.
+	if err := p.handleDnDShortRest(MessageContext{Sender: uid}); err != nil {
+		t.Fatalf("handleDnDShortRest: %v", err)
+	}
+
+	d := db.Get()
+	var dndRows, pmRows, equipRows, pending int
+	d.QueryRow(`SELECT COUNT(*) FROM dnd_character WHERE user_id=?`, string(uid)).Scan(&dndRows)
+	d.QueryRow(`SELECT COUNT(*) FROM player_meta WHERE user_id=?`, string(uid)).Scan(&pmRows)
+	d.QueryRow(`SELECT COUNT(*) FROM adventure_equipment WHERE user_id=?`, string(uid)).Scan(&equipRows)
+	d.QueryRow(`SELECT COALESCE(MAX(pending_setup),-1) FROM dnd_character WHERE user_id=?`, string(uid)).Scan(&pending)
+
+	if dndRows != 1 {
+		t.Fatalf("expected 1 auto-migrated dnd_character, got %d", dndRows)
+	}
+	if pending != 0 {
+		t.Errorf("auto-migrated character should be confirmed (pending_setup=0), got %d", pending)
+	}
+	if pmRows != 1 {
+		t.Errorf("player_meta not seeded for auto-migrant: got %d rows, want 1 (camcast straggler regression)", pmRows)
+	}
+	// createAdvCharacter seeds tier-0 gear in all five slots.
+	if equipRows != len(allSlots) {
+		t.Errorf("tier-0 equipment not seeded: got %d rows, want %d", equipRows, len(allSlots))
+	}
+
+	// The character must now load through the legacy layer that camcast choked on.
+	if _, err := loadAdvCharacter(uid); err != nil {
+		t.Errorf("loadAdvCharacter after auto-migration: %v (this is the exact failure camcast hit)", err)
+	}
+}
+
+// TestEnsurePlayerMetaSeedIdempotent proves the guard never duplicates a legacy
+// player's equipment — createAdvCharacter's tier-0 insert has no conflict guard,
+// so the seed must be conditional on player_meta being absent.
+func TestEnsurePlayerMetaSeedIdempotent(t *testing.T) {
+	setupEmptyTestDB(t)
+	uid := id.UserID("@legacy:example.org")
+
+	// Seed once (fresh), then again (should be a no-op).
+	if err := ensurePlayerMetaSeed(uid); err != nil {
+		t.Fatalf("first seed: %v", err)
+	}
+	if err := ensurePlayerMetaSeed(uid); err != nil {
+		t.Fatalf("second seed: %v", err)
+	}
+
+	d := db.Get()
+	var pmRows, equipRows int
+	d.QueryRow(`SELECT COUNT(*) FROM player_meta WHERE user_id=?`, string(uid)).Scan(&pmRows)
+	d.QueryRow(`SELECT COUNT(*) FROM adventure_equipment WHERE user_id=?`, string(uid)).Scan(&equipRows)
+	if pmRows != 1 {
+		t.Errorf("player_meta rows = %d, want 1 (no duplication)", pmRows)
+	}
+	if equipRows != len(allSlots) {
+		t.Errorf("equipment rows = %d, want %d (guard must not re-insert gear)", equipRows, len(allSlots))
+	}
+}