sqlite3 foreign keys which don't name columns can't be inferred

[habnabit]

Setup

Versions

• Rust: rustc 1.25.0-nightly (616b66dca 2018-02-02)
• Diesel: diesel 1.1.0
• Database: sqlite3 3.16.0 2016-11-04 19:09:39 0e5ffd9123d6d2d2b8f3701e8a73cc98a3a7ff5f
• Operating System macOS 10.12.6 (16G1114)

Feature Flags

• diesel: sqlite postgres

Problem Description

Running diesel print-schema fails, with very terse output:

$ RUST_BACKTRACE=full RUST_LOG=trace diesel print-schema
Unexpected null for non-null column

Steps to reproduce

sqlite> .schema accounts
CREATE TABLE accounts (
  id INTEGER PRIMARY KEY AUTOINCREMENT,
  account TEXT NOT NULL,
  data_center_id INTEGER NOT NULL,
  auth_key BLOB NOT NULL,
  UNIQUE (account, data_center_id),
  FOREIGN KEY (data_center_id) REFERENCES data_centers
);
sqlite> .schema data_centers
CREATE TABLE data_centers (
  id INTEGER PRIMARY KEY
);

This produces:

sqlite> PRAGMA FOREIGN_KEY_LIST('accounts');
id          seq         table         from            to          on_update   on_delete   match
----------  ----------  ------------  --------------  ----------  ----------  ----------  ----------
0           0           data_centers  data_center_id  -NULL-      NO ACTION   NO ACTION   NONE

to is NULL because REFERENCES data_centers doesn't name any columns; it's implicitly the same as REFERENCES data_centers(id). I'm pretty sure this is due to the pragma_foreign_key_list pseudo-table doesn't expect a NULL.

diesel/diesel_infer_schema/infer_schema_internals/src/sqlite.rs

Lines 27 to 38 in 07319d3

	table! {
	pragma_foreign_key_list {
	id -> Integer,
	seq -> Integer,
	_table -> VarChar,
	from -> VarChar,
	to -> VarChar,
	on_update -> VarChar,
	on_delete -> VarChar,
	_match -> VarChar,
	}
	}

Checklist

• I have already looked over the issue tracker for similar issues.