Crate migrate_guard 

Detect and auto-renumber colliding sqlx migration version numbers across git branches.

sqlx assigns a migration’s version at author time, so two branches that both add NNNN_*.sql at the same NNNN merge cleanly, then fail at test time with UNIQUE constraint failed: _sqlx_migrations.version. migrate-guard catches this before merge and renumbers your topic branch above the global max. A collision is one version claimed by two different files — the same file seen on multiple branches is not a collision.

As a CLI

The cargo migrate-guard subcommand runs at your repo root, configured by a migrate-guard.toml that lists your migration directories:

cargo install migrate-guard

cargo migrate-guard check                 # CI gate: non-zero exit on collision
cargo migrate-guard renumber              # dry run: show the plan
cargo migrate-guard renumber --apply      # renumber this branch + rewrite include_str! refs
cargo migrate-guard max                   # print the max version per role

# migrate-guard.toml
base_ref = "main"
reference_globs = ["src/**/*.rs"]

[[dir]]
role = "platform"
path = "migrations"

As a library

The pure collision + renumber logic is exposed and needs no git or filesystem. Parse a filename:

use migrate_guard::parse_filename;

assert_eq!(parse_filename("0286_add_index.sql"), Some((286, 4, "add_index")));
assert_eq!(parse_filename("not-a-migration.sql"), None);

Detect a collision (same version, two different files):

use migrate_guard::MigrationFile;
use migrate_guard::model::{detect_collisions, Observation, Source};
let observations = vec![
    Observation { role: "platform".into(), version: 2,
        source: Source::Branch("feat-a".into()), file: file(2, "0002_a.sql") },
    Observation { role: "platform".into(), version: 2,
        source: Source::WorkingTree, file: file(2, "0002_b.sql") },
];
let collisions = detect_collisions(&observations);
assert_eq!(collisions.len(), 1);
assert_eq!(collisions[0].version, 2);

Modules

apply

Floor computation, reference rewriting, and renumber application.

config

migrate-guard.toml parsing.

error

git

Shells to the git binary. No git library.

model

Pure collision + renumber logic. No I/O.

Structs

MigrationDir

An independent numbering namespace (platform vs tenant, etc.).

MigrationFile

One parsed migration file within a numbering namespace.

Functions

parse_filename

Parse a migration filename: a leading run of ASCII digits, then ‘_’, then a description, then “.sql”. Returns (version, digit_width, desc).

scan_dir

Scan a directory for migration files (missing dir → empty), sorted by version.