Add support for multiline string sqls.

Author: codrin-mares

lib/activerecord/cte/string_cte_parser.rb

@@ -110,29 +110,33 @@ module StringCteParser
       #   ASS (too many letters)
       AS_KEYWORD = /AS/i.freeze
 
-      # Matches the SQL expression inside parentheses (greedy match for everything inside)
+      # Matches the SQL expression inside parentheses (greedy match for everything inside, including newlines)
+      # Using [\s\S] to match any character including newlines (equivalent to . with DOTALL flag)
       # Examples that MATCH:
       #   (SELECT * FROM posts) → captures "SELECT * FROM posts"
       #   (SELECT id, name FROM users WHERE active = true) → captures "SELECT id, name FROM users WHERE active = true"
       #   (SELECT * FROM posts WHERE views > (SELECT AVG(views) FROM posts)) → captures "SELECT * FROM posts WHERE views > (SELECT AVG(views) FROM posts)"
+      #   (SELECT *\n  FROM posts\n  WHERE views > 100) → captures "SELECT *\n  FROM posts\n  WHERE views > 100"
       # Examples that DON'T match:
       #   SELECT * FROM posts (no parentheses)
       #   (SELECT * FROM posts (missing closing paren)
       #   SELECT * FROM posts) (missing opening paren)
-      EXPRESSION_PATTERN = /\((.+)\)/.freeze
+      EXPRESSION_PATTERN = /\(([\s\S]+)\)/.freeze
 
       # Complete CTE string pattern: optional whitespace + table_name + whitespace + AS + whitespace + (expression) + optional whitespace
+      # Uses multiline mode to handle strings with newlines
       # Examples that MATCH:
       #   "popular_posts AS (SELECT * FROM posts WHERE views_count > 100)"
       #   "  `user stats`   AS   (SELECT COUNT(*) FROM users)  "
       #   '"complex_table" as (SELECT * FROM posts)'
       #   "table_2023 AS (SELECT id FROM posts WHERE created_at > '2023-01-01')"
+      #   "multiline_cte AS (\n  SELECT *\n  FROM posts\n  WHERE active = true\n)"
       # Examples that DON'T match:
       #   "popular_posts (SELECT * FROM posts)" (missing AS)
       #   "popular_posts AS SELECT * FROM posts" (missing parentheses)
       #   "AS (SELECT * FROM posts)" (missing table name)
       #   "123_table AS (SELECT * FROM posts)" (invalid table name)
-      CTE_STRING_PATTERN = /\A\s*#{TABLE_NAME_PATTERN}\s+#{AS_KEYWORD}\s+#{EXPRESSION_PATTERN}\s*\z/i.freeze
+      CTE_STRING_PATTERN = /\A\s*#{TABLE_NAME_PATTERN}\s+#{AS_KEYWORD}\s+#{EXPRESSION_PATTERN}\s*\z/im.freeze
 
       # ---------------------------------------------------------------------------
       # Main parsing method that converts a CTE string into an Arel::Nodes::As node

test/activerecord/cte_test.rb

@@ -326,4 +326,70 @@ def test_string_cte_with_underscores_and_numbers
     popular_posts = Post.where("views_count > 100")
     assert_equal popular_posts.to_a, popular_posts_from_cte
   end
+
+  def test_string_cte_with_multiline_expressions
+    # Test multiline CTE expressions with complex formatting
+    multiline_cte = <<~SQL.strip
+      filtered_tracker_issue_extras AS (
+        SELECT tie.scheduled_in_external_sprint_ids,
+              tie.tracker_project_issue_id
+        FROM tracker_issue_extras tie
+        JOIN repo_issues ri
+          ON ri.tracker_project_issue_id = tie.tracker_project_issue_id
+        WHERE ri.primary_committer_id = ANY(ARRAY[1]::bigint[])
+          AND ri.repo_id               = ANY(ARRAY[2, 3, 1]::bigint[])
+      )
+    SQL
+
+    # This should parse successfully without raising an error
+    assert_nothing_raised do
+      Post.with(multiline_cte).to_sql
+    end
+
+    # Test with newlines in different positions
+    cte_with_newlines = "popular_posts AS (\n  SELECT *\n  FROM posts\n  WHERE views_count > 100\n)"
+    assert_nothing_raised do
+      Post.with(cte_with_newlines).to_sql
+    end
+
+    # Test with complex nested subqueries and multiline formatting
+    complex_multiline_cte = <<~SQL.strip
+      complex_analysis AS (
+        SELECT
+          p.id,
+          p.title,
+          (SELECT COUNT(*)
+           FROM comments c
+           WHERE c.post_id = p.id
+             AND c.created_at > '2023-01-01') as recent_comments,
+          CASE
+            WHEN p.views_count > 1000 THEN 'popular'
+            WHEN p.views_count > 100 THEN 'moderate'
+            ELSE 'low'
+          END as popularity
+        FROM posts p
+        WHERE p.published_at IS NOT NULL
+      )
+    SQL
+
+    assert_nothing_raised do
+      Post.with(complex_multiline_cte).to_sql
+    end
+  end
+
+  def test_string_cte_with_user_provided_multiline_example
+    # Test the specific multiline example provided by the user
+    user_multiline_cte = "filtered_tracker_issue_extras AS (\n  SELECT tie.scheduled_in_external_sprint_ids,\n        tie.tracker_project_issue_id\n  FROM tracker_issue_extras tie\n  JOIN repo_issues ri\n    ON ri.tracker_project_issue_id = tie.tracker_project_issue_id\n  WHERE ri.primary_committer_id = ANY(ARRAY[[1]]::bigint[])\n    AND ri.repo_id               = ANY(ARRAY[[2, 3, 1]]::bigint[])\n)\n"
+
+    # This should parse successfully without raising an error
+    result = Post.with(user_multiline_cte).to_sql
+
+    # The table name gets quoted by PostgreSQL, so check for quoted version
+    assert result.include?("WITH \"filtered_tracker_issue_extras\" AS"), "Should include WITH clause with user's table name (quoted)"
+    assert result.include?("tie.scheduled_in_external_sprint_ids"), "Should include specific column from user's example"
+    assert result.include?("tracker_issue_extras tie"), "Should include table alias from user's example"
+    assert result.include?("JOIN repo_issues ri"), "Should include JOIN clause from user's example"
+    assert result.include?("ARRAY[[1]]::bigint[]"), "Should preserve complex array syntax"
+    assert result.include?("ARRAY[[2, 3, 1]]::bigint[]"), "Should preserve complex array with multiple values"
+  end
 end