Function run 

pub fn run(
    config: &Config,
    db_name: Option<&str>,
    opts: GenerateOptions,
) -> Result<(), CliError>

Runs drizzle generate: diffs the schema files against the newest snapshot.json in the migrations folder and writes <out>/<tag>/migration.sql plus snapshot.json.

After a git merge leaves several open heads in the snapshot history, the diff runs against the merged state of every branch instead (see drizzle_migrations::history::load_merge_base) and the new snapshot’s prevIds lists every head, as drizzle-kit does.

Prints a note and writes nothing when the schema has no tables or indexes or nothing changed. With --custom, writes a migration.sql holding only a comment and no snapshot, so the next diff ignores it. Also rewrites migrations.js when bundling is enabled. Does not connect to the database.

Ambiguous renames are asked about on a terminal and otherwise answered from --hints / --hints-file; renames are never inferred (see renames).

Errors

Returns CliError if db_name does not match the config, the folder still uses the legacy meta/_journal.json layout (run drizzle up), no schema files are found or they have parse errors, merged migration branches conflict (unless --ignore-conflicts or --fix-conflicts), a conflicting migration folder cannot be deleted, the hints are invalid (CliError::InvalidHints) or leave a rename question unanswered without a terminal (CliError::MissingHints), a prompt is aborted, the diff fails, or the migration folder cannot be written (including when its tag already exists).