Support table and column comments

src/Schema.php

@@ -31,6 +31,8 @@
 use function strncasecmp;
 use function strtolower;
 
+use const PREG_SET_ORDER;
+
 /**
  * Implements the SQLite Server specific schema, supporting SQLite 3.3.0 or higher.
  *
@@ -155,8 +157,11 @@ protected function loadTableSchema(string $name): TableSchemaInterface|null
 
         $table->name($name);
         $table->fullName($name);
+        $table->createSql($this->getCreateTableSql($name));
+        $this->findTableComment($table);
 
         if ($this->findColumns($table)) {
+            $this->findComments($table);
             $this->findConstraints($table);
 
             return $table;
@@ -294,12 +299,7 @@ protected function loadTableUniques(string $tableName): array
      */
     protected function loadTableChecks(string $tableName): array
     {
-        $sql = $this->db->createCommand(
-            'SELECT `sql` FROM `sqlite_master` WHERE name = :tableName',
-            [':tableName' => $tableName],
-        )->queryScalar();
-
-        $sql = ($sql === false || $sql === null) ? '' : (string) $sql;
+        $sql = $this->getCreateTableSql($tableName);
 
         $code = (new SqlTokenizer($sql))->tokenize();
         $pattern = (new SqlTokenizer('any CREATE any TABLE any()'))->tokenize();
@@ -741,6 +741,85 @@ protected function getCacheTag(): string
         return md5(serialize(array_merge([self::class], $this->generateCacheKey())));
     }
 
+    /**
+     * @throws Exception
+     * @throws InvalidConfigException
+     * @throws Throwable
+     */
+    private function findTableComment(TableSchemaInterface $tableSchema): void
+    {
+        $sql = $tableSchema->getCreateSql() ?? '';
+
+        if (preg_match('#^[^(]+?((?:\s*--[^\n]*|\s*/\*.*?\*/)+)\s*\(#', $sql, $matches) === 1) {
+            $comment = $this->filterComment($matches[1]);
+            $tableSchema->comment($comment);
+        }
+    }
+
+    /**
+     * @throws Exception
+     * @throws InvalidConfigException
+     * @throws Throwable
+     */
+    private function findComments(TableSchemaInterface $tableSchema): void
+    {
+        $sql = $tableSchema->getCreateSql() ?? '';
+
+        if (!preg_match('#^(?:[^(]*--[^\n]*|[^(]*/\*.*?\*/)*[^(]*\((.*)\)[^)]*$#s', $sql, $matches)) {
+            return;
+        }
+
+        $columnsDefinition = $matches[1];
+
+        $identifierPattern = '(?:([`"])([^`"]+)\1|\[([^\]]+)\]|([a-zA-Z_]\w*))';
+        $notCommaPattern = "(?:[^,]|\([^()]+\)|'[^']+')*?";
+        $commentPattern = '(?:\s*--[^\n]*|\s*/\*.*?\*/)';
+
+        $pattern = "#$identifierPattern\s*$notCommaPattern,?($commentPattern+)#";
+
+        if (preg_match_all($pattern, $columnsDefinition, $matches, PREG_SET_ORDER)) {
+            foreach ($matches as $match) {
+                $columnName = ($match[2] ?: $match[3]) ?: $match[4];
+                $comment = $this->filterComment($match[5] ?: $match[6]);
+
+                $tableSchema->getColumn($columnName)?->comment($comment);
+            }
+        }
+    }
+
+    private function filterComment(string $comment): string
+    {
+        preg_match_all('#--([^\n]*)|/\*(.*?)\*/#', $comment, $matches, PREG_SET_ORDER);
+
+        $lines = [];
+
+        foreach ($matches as $match) {
+            $lines[] = trim($match[1] ?: $match[2]);
+        }
+
+        return implode("\n", $lines);
+    }
+
+    /**
+     * Returns the `CREATE TABLE` SQL string.
+     *
+     * @param string $name The table name.
+     *
+     * @throws Exception
+     * @throws InvalidConfigException
+     * @throws Throwable
+     * @return string The `CREATE TABLE` SQL string.
+     */
+    private function getCreateTableSql(string $name): string
+    {
+        $sql = $this->db->createCommand(
+            'SELECT `sql` FROM `sqlite_master` WHERE `name` = :tableName',
+            [':tableName' => $name],
+        )->queryScalar();
+
+        return (string)$sql;
+    }
+
     /**
      * @throws Throwable
      */

tests/SchemaTest.php

@@ -359,4 +359,24 @@ public function testNotConnectionPDO(): void
 
         $schema->refreshTableSchema('customer');
     }
+
+    public function testTableComment(): void
+    {
+        $db = $this->getConnection(true);
+        $schema = $db->getSchema();
+        $table = $schema->getTableSchema('comment');
+
+        $this->assertSame("Table comment\nsecond line\nthird line", $table->getComment());
+    }
+
+    public function testColumnComments(): void
+    {
+        $db = $this->getConnection(true);
+        $schema = $db->getSchema();
+        $table = $schema->getTableSchema('comment');
+
+        $this->assertSame('primary key', $table->getColumn('id')->getComment());
+        $this->assertSame('USD', $table->getColumn('price')->getComment());
+        $this->assertSame("Column comment\nsecond line\nthird line", $table->getColumn('name')->getComment());
+    }
 }

tests/Support/Fixture/sqlite.sql

@@ -15,6 +15,7 @@ DROP TABLE IF EXISTS "negative_default_values";
 DROP TABLE IF EXISTS "animal";
 DROP TABLE IF EXISTS "default_pk";
 DROP TABLE IF EXISTS "notauto_pk";
+DROP TABLE IF EXISTS "comment";
 DROP VIEW IF EXISTS "animal_view";
 DROP TABLE IF EXISTS "T_constraints_4";
 DROP TABLE IF EXISTS "T_constraints_3";
@@ -173,6 +174,17 @@ CREATE TABLE "timestamp_default" (
   timestamp_text TEXT NOT NULL DEFAULT CURRENT_TIMESTAMP
 ); -- STRICT
 
+CREATE TABLE `comment` -- Table comment
+-- second line
+/* third line */
+(
+    `id` integer PRIMARY KEY AUTOINCREMENT NOT NULL, -- primary key
+    price decimal(10,2), -- USD
+    `name` varchar(100) DEFAULT 'Pan, Peter' -- Column comment
+    -- second line
+    /* third line */
+);
+
 CREATE VIEW "animal_view" AS SELECT * FROM "animal";
 
 INSERT INTO "animal" ("type") VALUES ('yiiunit\data\ar\Cat');