MySQL migration: ADD COLUMN workspaces TEXT NOT NULL has no DEFAULT — fails on populated tables under strict mode

[TYRMars]

Summary

The MySQL migration adds the workspaces column as TEXT NOT NULL with no DEFAULT, then backfills existing rows in a separate UPDATE. On a pre-existing populated projects table under strict SQL mode (MySQL 8 default STRICT_TRANS_TABLES), the ALTER TABLE … ADD COLUMN … TEXT NOT NULL itself errors because TEXT has no implicit default — so the migration fails before the backfill ever runs.

Details

• crates/harness-store/src/mysql.rs:120-130:

  sqlx::query("ALTER TABLE projects ADD COLUMN workspaces TEXT NOT NULL")
      .execute(pool).await?;
  // Backfill so the NOT NULL constraint is satisfied for legacy rows.
  sqlx::query("UPDATE projects SET workspaces = '[]' WHERE workspaces IS NULL OR workspaces = ''")
      .execute(pool).await?;

The SQLite path does this safely with a default: sqlite.rs:120 ADD COLUMN workspaces TEXT NOT NULL DEFAULT '[]'. The MySQL path omits the DEFAULT, so the ADD COLUMN can't satisfy existing rows and aborts under strict mode (the backfill UPDATE is a no-op anyway since it runs after).

Impact

Breaks idempotent re-migration / upgrade on MySQL deployments that pre-date the workspaces column and have existing project rows. Severity: medium (MySQL only; depends on sql_mode, but strict is the MySQL 8 default).

Suggested fix

Add a default on the MySQL ADD COLUMN: ADD COLUMN workspaces TEXT NOT NULL DEFAULT ('[]') (expression default required for TEXT/BLOB in MySQL 8), or add the column as nullable, backfill, then MODIFY to NOT NULL.