Compound primary key gives error "Diesel only supports tables with primary keys."

[SamuelMarks]

Setup

Versions

• Rust: 1.91.0-nightly (51ff89506 2025-09-02)
• Diesel: 2.2.12
• Database: PostgreSQL
• Operating System macOS 15.6.1

Feature Flags

• diesel:

Problem Description

What are you trying to accomplish?

What is the expected output?

What is the actual output?

Are you seeing any additional errors?

Steps to reproduce

$ diesel migration generate create_repo_and_history

Then in up.sql add:

CREATE TABLE repo_tbl
(
    "id"           INTEGER PRIMARY KEY,
    -- other columns omitted for gh issue
);

CREATE TABLE repo_history_tbl
(
    "commit"         CHAR(40),
    repo             INTEGER REFERENCES repo_tbl ("id"),
    -- other columns omitted for gh issue
    created_at       TIMESTAMP NOT NULL DEFAULT current_timestamp,
    PRIMARY KEY (repo, "commit")
);

Then:

$ diesel migration run
Diesel only supports tables with primary keys. Table `repo_history_tbl` has no primary key

Checklist

• I have already looked over the issue tracker and the discussion forum for similar possible closed issues.

• This issue can be reproduced on Rust's stable channel. (Your issue will be
  closed if this is not the case)
• This issue can be reproduced without requiring a third party crate

EDIT: Also tried this approach, which failed with same error:

"id" TEXT GENERATED ALWAYS AS (repo || '@' || "commit") STORED PRIMARY KEY

[weiznich]

I converted this to a discussion as I'm not able to reproduce this locally. Given that it seems like this might be an issue with your local environment instead of an issue in diesel.

Diesel uses the following SQL query to load the primary keys for a given table. You can check if that locally returns the expected result:

select column_name from information_schema.key_column_usage where constraint_name in (select t.constraint_name from information_schema.table_constraints as t where t.constraint_type = 'PRIMARY KEY') and table_name = 'repo_history_tbl' and table_schema = 'public' order by ordinal_position;

[SamuelMarks]

Thanks yeah this is a weird one. I DROP DATABASE and tried again and wasn't able to replicate.