Fix cost-tracker SELECT against canonical schema (v0.15.1)

The cost-preview probe in get_avg_tokens_for_stages() referenced
input_tokens/output_tokens/timestamp, which don't exist. Canonical
columns are prompt_tokens/completion_tokens/created_at. Empty-result
fallback was masking the failure functionally, but the wpdb debug
notice was visibly leaking to every admin visit of the AI Models tab.

Adds regression tests that assert $wpdb->last_error after the call,
so the next schema drift won't be masked the same way.

Bug present since v0.11.0 (2026-04-23).

Agent-Session: engineer-prautoblogger cost-tracker-schema-mismatch

CHANGELOG.md

@@ -5,6 +5,13 @@ All notable changes to PRAutoBlogger will be documented in this file.
 Format follows [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project uses [Semantic Versioning](https://semver.org/).
 
+## [0.15.1] - 2026-05-14
+
+### Fixed
+- Cost preview in AI Models settings tab no longer prints a WordPress database
+  error notice; query now uses canonical column names (`prompt_tokens`,
+  `completion_tokens`, `created_at`). Bug present since v0.11.0 (2026-04-23).
+
 ## [0.14.0] - 2026-04-26
 ## [0.15.0] - 2026-04-26
 

includes/core/class-cost-tracker.php

@@ -235,19 +235,19 @@ class PRAutoBlogger_Cost_Tracker {
 			);
 		}
 
-		$cutoff_time   = time() - ( $days * DAY_IN_SECONDS );
+		$cutoff_datetime = gmdate( 'Y-m-d H:i:s', time() - ( $days * DAY_IN_SECONDS ) );
 		$stage_list      = implode( ',', array_map( array( $wpdb, 'prepare' ), array_fill( 0, count( $stages ), '%s' ), $stages ) );
 		$table_name      = $wpdb->prefix . 'prautoblogger_generation_log';
 
 		// phpcs:ignore WordPress.DB.PreparedSQL.InterpolatedNotPrepared -- Prepared stage list via array_map + prepare
 		$query = $wpdb->prepare(
-			"SELECT AVG(input_tokens) as avg_input,
+			"SELECT AVG(prompt_tokens) as avg_prompt,
-                    AVG(output_tokens) as avg_output,
+                    AVG(completion_tokens) as avg_completion,
                     COUNT(*) as sample_count
              FROM $table_name
              WHERE stage IN ( $stage_list )
-             AND timestamp >= %d",
+             AND created_at >= %s",
-			$cutoff_time
+			$cutoff_datetime
 		);
 
 		// phpcs:ignore WordPress.DB.PreparedSQL.NotPrepared -- phpcs pragma above
@@ -262,8 +262,8 @@ class PRAutoBlogger_Cost_Tracker {
 		}
 
 		return array(
-			'avg_prompt_tokens'      => (float) ( $result['avg_input'] ?? 0 ),
+			'avg_prompt_tokens'      => (float) ( $result['avg_prompt'] ?? 0 ),
-			'avg_completion_tokens'  => (float) ( $result['avg_output'] ?? 0 ),
+			'avg_completion_tokens'  => (float) ( $result['avg_completion'] ?? 0 ),
 			'sample_size'            => (int) ( $result['sample_count'] ?? 0 ),
 		);
 	}

prautoblogger.php

@@ -9,7 +9,7 @@
  * Plugin Name:       PRAutoBlogger
  * Plugin URI:        https://peptiderepo.com/prautoblogger
  * Description:       Monitors social media for trending topics, generates SEO-friendly blog posts using AI, and publishes them on a daily schedule with full cost tracking and self-improvement metrics.
- * Version:           0.15.0
+ * Version:           0.15.1
  * Requires at least: 6.0
  * Requires PHP:      7.4
  * Author:            PeptideRepo
@@ -35,7 +35,7 @@ if ( ! defined( 'ABSPATH' ) ) {
 | Defined here so every file in the plugin can reference paths, versions,
 | and limits without magic strings.
 */
-define( 'PRAUTOBLOGGER_VERSION', '0.15.0' );
+define( 'PRAUTOBLOGGER_VERSION', '0.15.1' );
 define( 'PRAUTOBLOGGER_DB_VERSION', '1.1.0' );
 define( 'PRAUTOBLOGGER_PLUGIN_FILE', __FILE__ );
 define( 'PRAUTOBLOGGER_PLUGIN_DIR', plugin_dir_path( __FILE__ ) );

tests/unit/Core/CostTrackerTest.php

@@ -113,4 +113,139 @@ class CostTrackerTest extends BaseTestCase {
         // If we get here without exception, the method worked.
         $this->assertTrue( true );
     }
+
+    /**
+     * Regression: get_avg_tokens_for_stages must return the documented zero
+     * shape when there is no generation history, without leaving a $wpdb
+     * error behind.
+     *
+     * Load-bearing: asserting $wpdb->last_error === '' alongside the shape
+     * is what would have caught the v0.11.0 column-name drift. The empty-
+     * result fallback silently masked the failure from shape-only tests.
+     */
+    public function test_get_avg_tokens_returns_zero_shape_when_no_history(): void {
+        $captured_query = '';
+        $this->wpdb->method( 'prepare' )->willReturnCallback(
+            function ( $sql, ...$args ) use ( &$captured_query ) {
+                $captured_query = $sql;
+                return $sql; // Simulate prepared SQL passthrough.
+            }
+        );
+        // Empty result row — fallback branch.
+        $this->wpdb->method( 'get_row' )->willReturn( null );
+
+        $tracker = new \PRAutoBlogger_Cost_Tracker();
+        $result  = $tracker->get_avg_tokens_for_stages( [ 'analysis' ], 30 );
+
+        $this->assertSame(
+            [
+                'avg_prompt_tokens'     => 0.0,
+                'avg_completion_tokens' => 0.0,
+                'sample_size'           => 0,
+            ],
+            $result
+        );
+        $this->assertSame( '', $this->wpdb->last_error, 'wpdb->last_error must be empty after the query' );
+
+        // Schema-drift guard: query must reference canonical columns, not the
+        // pre-v0.15.1 names that don't exist on wp_prautoblogger_generation_log.
+        $this->assertStringContainsString( 'prompt_tokens', $captured_query );
+        $this->assertStringContainsString( 'completion_tokens', $captured_query );
+        $this->assertStringContainsString( 'created_at', $captured_query );
+        $this->assertStringNotContainsString( 'input_tokens', $captured_query );
+        $this->assertStringNotContainsString( 'output_tokens', $captured_query );
+        // The bug query had `AND timestamp >= %d`; canonical query uses
+        // `AND created_at >= %s`. Guard against the column reference, not the
+        // bare word (a SQL comment in future code could legitimately mention
+        // "timestamp" in prose).
+        $this->assertStringNotContainsString( 'timestamp >=', $captured_query );
+    }
+
+    /**
+     * Regression: with seeded rows the method returns real averages and the
+     * canonical SELECT aliases (avg_prompt / avg_completion) are extracted
+     * correctly.
+     */
+    public function test_get_avg_tokens_returns_real_averages_with_seeded_rows(): void {
+        $this->wpdb->method( 'prepare' )->willReturnCallback(
+            static function ( $sql ) {
+                return $sql;
+            }
+        );
+        // Simulate three rows averaged: prompt_tokens=100, completion_tokens=50.
+        $this->wpdb->method( 'get_row' )->willReturn(
+            [
+                'avg_prompt'     => '100.0000',
+                'avg_completion' => '50.0000',
+                'sample_count'   => '3',
+            ]
+        );
+
+        $tracker = new \PRAutoBlogger_Cost_Tracker();
+        $result  = $tracker->get_avg_tokens_for_stages( [ 'analysis' ], 30 );
+
+        $this->assertSame( 100.0, $result['avg_prompt_tokens'] );
+        $this->assertSame( 50.0, $result['avg_completion_tokens'] );
+        $this->assertSame( 3, $result['sample_size'] );
+        $this->assertSame( '', $this->wpdb->last_error );
+    }
+
+    /**
+     * Regression: the days cutoff must be a MySQL DATETIME string (compared
+     * against the canonical created_at column), not a unix int. Captured via
+     * the prepare() callback so we can inspect the bound parameter.
+     */
+    public function test_get_avg_tokens_respects_days_cutoff_as_datetime(): void {
+        $captured_args = [];
+        $this->wpdb->method( 'prepare' )->willReturnCallback(
+            function ( $sql, ...$args ) use ( &$captured_args ) {
+                $captured_args = $args;
+                return $sql;
+            }
+        );
+        $this->wpdb->method( 'get_row' )->willReturn( null );
+
+        $tracker = new \PRAutoBlogger_Cost_Tracker();
+        $tracker->get_avg_tokens_for_stages( [ 'analysis' ], 30 );
+
+        // Exactly one bound param: the DATETIME cutoff.
+        $this->assertCount( 1, $captured_args );
+        $this->assertIsString( $captured_args[0], 'Cutoff must be a DATETIME string, not a unix int' );
+        $this->assertMatchesRegularExpression(
+            '/^\d{4}-\d{2}-\d{2} \d{2}:\d{2}:\d{2}$/',
+            $captured_args[0]
+        );
+    }
+
+    /**
+     * Regression: the stage filter is propagated into the SQL. Calling with
+     * a single stage should result in exactly one prepared %s placeholder
+     * for the IN ( … ) list.
+     */
+    public function test_get_avg_tokens_filters_by_stage(): void {
+        $stage_prepare_calls = 0;
+        $main_query          = '';
+        $this->wpdb->method( 'prepare' )->willReturnCallback(
+            function ( $sql, ...$args ) use ( &$stage_prepare_calls, &$main_query ) {
+                // The method calls $wpdb->prepare twice in two distinct shapes:
+                //  1. per-stage placeholder prep (sql='%s', single arg)
+                //  2. the main SELECT (sql contains 'SELECT', many tokens)
+                if ( strpos( $sql, 'SELECT' ) !== false ) {
+                    $main_query = $sql;
+                } else {
+                    ++$stage_prepare_calls;
+                }
+                return $sql;
+            }
+        );
+        $this->wpdb->method( 'get_row' )->willReturn( null );
+
+        $tracker = new \PRAutoBlogger_Cost_Tracker();
+        $tracker->get_avg_tokens_for_stages( [ 'analysis' ], 30 );
+
+        $this->assertSame( 1, $stage_prepare_calls, 'One stage → one per-stage prepare() call' );
+        $this->assertStringContainsString( 'stage IN', $main_query );
+        $this->assertStringContainsString( 'wp_prautoblogger_generation_log', $main_query );
+        $this->assertSame( '', $this->wpdb->last_error );
+    }
 }