From d909bf2b604b7ae2f6c6aafa90e6fc746293177a Mon Sep 17 00:00:00 2001
From: Devin <devinpadron28@gmail.com>
Date: Thu, 8 Oct 2026 08:00:35 -0400
Subject: [PATCH] fix(python): emit Alembic op.execute SQL as an escaped string
 literal

PythonGenerator.generateMigration wrapped each statement in """...""".
SQL from TypeORM usually ends in a quoted identifier, so the line ended
in four quotes (DROP TABLE "user"""") and most generated migrations
failed with "SyntaxError: unterminated string literal".

Emit JSON.stringify(sql) instead. Each JSON escape (\" \\ \n \t \uXXXX)
means the same in a Python string literal, so the SQL reaches
op.execute unchanged.

The new test runs the generated migration in python3 under a stub
alembic.op and checks it records exactly the input SQL (quoted
identifier, backslash, newlines, and the downgrade path). It is skipped
when python3 is not installed.

fixes #148
---
 src/lib/generators/python.ts       |  4 +--
 test/lib/generators/python.test.ts | 47 ++++++++++++++++++++++++++++++
 2 files changed, 49 insertions(+), 2 deletions(-)

diff --git a/src/lib/generators/python.ts b/src/lib/generators/python.ts
index 2f92a9e..564193f 100644
--- a/src/lib/generators/python.ts
+++ b/src/lib/generators/python.ts
@@ -319,10 +319,10 @@ export class PythonGenerator extends BaseGenerator {
     const filename = `${timestamp}_${name}.py`;
 
     const upStatements = upSql
-      .map((sql) => `    op.execute("""${sql}""")`)
+      .map((sql) => `    op.execute(${JSON.stringify(sql)})`)
       .join("\n");
     const downStatements = (downSql || [])
-      .map((sql) => `    op.execute("""${sql}""")`)
+      .map((sql) => `    op.execute(${JSON.stringify(sql)})`)
       .join("\n");
 
     const content = `"""${name}"""
diff --git a/test/lib/generators/python.test.ts b/test/lib/generators/python.test.ts
index 4f37da3..dc5fbb4 100644
--- a/test/lib/generators/python.test.ts
+++ b/test/lib/generators/python.test.ts
@@ -1,4 +1,5 @@
 import { expect, describe, test, beforeAll } from "@jest/globals";
+import { spawnSync } from "child_process";
 import { PythonGenerator } from "../../../src/lib/generators/python";
 import { GeneratorConfig, Entity, Relationship } from "../../../src/lib/types";
 
@@ -567,4 +568,50 @@ describe("PythonGenerator", () => {
       expect(files).toEqual([]);
     });
   });
+
+  describe("migration generation (cli#148)", () => {
+    const hasPython = spawnSync("python3", ["--version"]).status === 0;
+
+    // Run the migration under a stub alembic.op that records each statement.
+    const runMigration = `
+import json, sys, types
+calls = []
+alembic = types.ModuleType("alembic")
+alembic.op = types.SimpleNamespace(execute=calls.append)
+sys.modules["alembic"] = alembic
+exec(sys.stdin.read())
+upgrade()
+downgrade()
+print(json.dumps(calls))
+`;
+
+    (hasPython ? test : test.skip)(
+      "writes a migration Python runs with the SQL unchanged",
+      async () => {
+        const upSql = [
+          // ends in a quoted identifier
+          'ALTER TABLE "task" DROP COLUMN "title"',
+          // backslash
+          String.raw`ALTER TABLE "task" ALTER COLUMN "path" SET DEFAULT 'C:\tmp'`,
+          // newlines
+          'CREATE TABLE "note" (\n  "id" SERIAL NOT NULL\n)',
+        ];
+        const downSql = ['DROP TABLE "user"'];
+        const files = await generator.generateMigration({
+          entities: [],
+          relationshipMap: {},
+          upSql,
+          downSql,
+        });
+
+        expect(files).toHaveLength(1);
+        const result = spawnSync("python3", ["-c", runMigration], {
+          input: files[0].content,
+          encoding: "utf8",
+        });
+        expect(result.stderr).toBe("");
+        expect(JSON.parse(result.stdout)).toEqual([...upSql, ...downSql]);
+      }
+    );
+  });
 });