Avoid rewriting unchanged retained waits

src/V2/Models/WorkflowRun.php

@@ -217,8 +217,7 @@ public function waits(): HasMany
             ConfiguredV2Models::resolve('run_wait_model', WorkflowRunWait::class),
             'workflow_run_id',
         )
-            ->orderBy('position')
-            ->orderBy('wait_id');
+            ->inDisplayOrder();
     }
 
     public function timelineEntries(): HasMany

src/V2/Models/WorkflowRunWait.php

@@ -5,6 +5,7 @@
 namespace Workflow\V2\Models;
 
 use Carbon\CarbonInterface;
+use Illuminate\Database\Eloquent\Builder;
 use Illuminate\Database\Eloquent\Model;
 use Illuminate\Database\Eloquent\Relations\BelongsTo;
 use Illuminate\Support\Carbon;
@@ -38,6 +39,53 @@
         'resolved_at' => UtcScheduleTimestamp::class,
     ];
 
+    /**
+     * @param string $key
+     */
+    public function originalIsEquivalent($key): bool
+    {
+        if (parent::originalIsEquivalent($key)) {
+            return true;
+        }
+
+        if (! array_key_exists($key, $this->original)) {
+            return false;
+        }
+
+        if ($key === 'payload' && ($this->getCasts()[$key] ?? null) === 'array') {
+            // MySQL normalizes JSON object key order. Lists and scalar types
+            // still carry meaning, so compare those without coercion.
+            return self::canonicalPayload($this->getAttribute($key))
+                === self::canonicalPayload($this->getOriginal($key));
+        }
+
+        if (in_array($key, ['opened_at', 'deadline_at', 'resolved_at'], true)
+            && ($this->getCasts()[$key] ?? null) === UtcScheduleTimestamp::class) {
+            $current = $this->getAttribute($key);
+            $original = $this->getOriginal($key);
+
+            // PostgreSQL can return a zero-fraction timestamp without its
+            // trailing digits. Its instant has not changed.
+            return $current instanceof CarbonInterface
+                && $original instanceof CarbonInterface
+                && $current->equalTo($original);
+        }
+
+        return false;
+    }
+
+    public function scopeInDisplayOrder(Builder $query): Builder
+    {
+        $status = $query->getQuery()
+            ->getGrammar()
+            ->wrap($this->qualifyColumn('status'));
+
+        return $query->orderByRaw(
+            "CASE {$status} WHEN 'open' THEN 0 WHEN 'resolved' THEN 1 WHEN 'cancelled' THEN 2 ELSE 99 END",
+        )->orderBy($this->qualifyColumn('position'))
+            ->orderBy($this->qualifyColumn('wait_id'));
+    }
+
     public function run(): BelongsTo
     {
         return $this->belongsTo(
@@ -93,4 +141,17 @@
             ? Carbon::parse($value)
             : null;
     }
+
+    private static function canonicalPayload(mixed $value): mixed
+    {
+        if (! is_array($value)) {
+            return $value;
+        }
+
+        if (! array_is_list($value)) {
+            ksort($value);
+        }
+
+        return array_map(self::canonicalPayload(...), $value);
+    }
 }

src/V2/Support/RunWaitProjector.php

@@ -144,6 +144,7 @@ public static function project(WorkflowRun $run, ?array $waits = null): array
         $seen = [];
         $projected = [];
         $existing = $waitModel::query()->where('workflow_run_id', $run->id)->get()->keyBy('id');
+        $positions = self::chronologicalPositions($waits);
 
         foreach (array_values($waits) as $position => $wait) {
             $waitId = self::waitId($wait, $position);
@@ -161,7 +162,7 @@ public static function project(WorkflowRun $run, ?array $waits = null): array
                     'workflow_run_id' => $run->id,
                     'workflow_instance_id' => $run->workflow_instance_id,
                     'wait_id' => $waitId,
-                    'position' => $position,
+                    'position' => $positions[$waitId],
                     'kind' => self::stringValue($wait['kind'] ?? null) ?? 'unknown',
                     'sequence' => self::intValue($wait['sequence'] ?? null),
                     'status' => self::stringValue($wait['status'] ?? null) ?? 'unknown',
@@ -296,13 +297,41 @@ private static function projectedRows(WorkflowRun $run): EloquentCollection
         /** @var EloquentCollection<int, WorkflowRunWait> $waits */
         $waits = $waitModel::query()
             ->where('workflow_run_id', $run->id)
-            ->orderBy('position')
-            ->orderBy('wait_id')
+            ->inDisplayOrder()
             ->get();
 
         return $waits;
     }
 
+    /**
+     * Keep stored order independent of status. Otherwise closing one open
+     * wait and opening the next rewrites every retained row twice.
+     *
+     * @param list<array<string, mixed>> $waits
+     * @return array<string, int>
+     */
+    private static function chronologicalPositions(array $waits): array
+    {
+        $ordered = [];
+
+        foreach (array_values($waits) as $position => $wait) {
+            $ordered[] = [
+                'id' => self::waitId($wait, $position),
+                'opened_at' => self::timestamp($wait['opened_at'] ?? null)?->getTimestampMs() ?? PHP_INT_MAX,
+            ];
+        }
+
+        usort($ordered, static fn (array $left, array $right): int =>
+            ($left['opened_at'] <=> $right['opened_at']) ?: ($left['id'] <=> $right['id']));
+        $positions = [];
+
+        foreach ($ordered as $position => $wait) {
+            $positions[$wait['id']] = $position;
+        }
+
+        return $positions;
+    }
+
     /**
      * @param EloquentCollection<int, WorkflowRunWait> $projected
      * @param list<array<string, mixed>> $canonical

tests/Fixtures/V2/TestRetainedSignalWritesWorkflow.php

@@ -0,0 +1,24 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Tests\Fixtures\V2;
+
+use Workflow\V2\Attributes\Signal;
+use function Workflow\V2\signal;
+
+use Workflow\V2\Workflow;
+
+#[Signal('advance')]
+final class TestRetainedSignalWritesWorkflow extends Workflow
+{
+    public function handle(int $count): array
+    {
+        $values = [];
+        for ($index = 0; $index < $count; $index++) {
+            $values[] = signal('advance');
+        }
+
+        return $values;
+    }
+}