Cursor rule

1---
2description: Backend Java production code, Spring Boot controllers/services/repositories, controller return values, imports, schema ERD pointer
3globs: backend/src/main/**/*.java
4alwaysApply: false
5---
6# Backend Code Rules
7 
8Use this rule when writing or modifying backend production Java code. For backend tests, use `backend-testing.mdc`; for database migrations, use `db-migration.mdc`.
9 
10## Commands
11 
12Run backend verification from the repo root:
13 
14```bash
15CURSOR_DEV=true nix develop -c pnpm backend:verify
16```
17 
18When no database migration is involved, this is faster:
19 
20```bash
21CURSOR_DEV=true nix develop -c pnpm backend:test_only
22```
23 
24## Relational Schema
25 
26The `docs/database-erd.md` Mermaid diagram documents tables, foreign keys, and key columns. After Flyway migrations change the schema, regenerate it with the `database-erd` skill:
27 
28```bash
29CURSOR_DEV=true nix develop -c pnpm export:database-erd
30```
31 
32## Controller Return Values
33 
34- Prefer returning entities, or other types already used as API bodies, from controllers when the JSON shape fits.
35- Narrow the serialized surface with `@JsonIgnore`, `@JsonView`, and similar mechanisms already used in the codebase.
36- Introduce a response DTO only when necessary, such as a different wire shape, aggregating multiple sources, or decoupling from persistence without overloading the entity.
37 
38## Import Style
39 
40- Always use import statements at the top of files.
41- Do not use inline fully qualified class names in code.
42- Use fully qualified names only when there is a naming conflict between classes with the same simple name from different packages.
43 
44Avoid:
45 
46```java
47ObjectMapper mapper = new com.odde.doughnut.configs.ObjectMapperConfig().objectMapper();
48List<com.theokanning.openai.completion.chat.ChatMessage> messages = ...;
49```
50 
51Prefer:
52 
53```java
54import com.odde.doughnut.configs.ObjectMapperConfig;
55import com.theokanning.openai.completion.chat.ChatMessage;
56 
57ObjectMapper mapper = new ObjectMapperConfig().objectMapper();
58List<ChatMessage> messages = ...;
59```
60