croc100 · croc100 · Jun 13, 2026 · Jun 11, 2026 · Jun 13, 2026 · Jun 13, 2026
diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
@@ -81,13 +81,10 @@ jobs:
           allow-prereleases: true
 
       - name: Install
-        run: pip install -e ".[dev]" coverage
+        run: pip install -e ".[dev]"
 
       - name: Run tests
-        run: coverage run -m pytest tests/ -v --ignore=tests/test_postgres.py --ignore=tests/test_mysql.py --ignore=tests/test_oracle.py --ignore=tests/test_mssql.py
-
-      - name: Generate coverage report
-        run: coverage xml
+        run: pytest tests/ -v --ignore=tests/test_postgres.py --ignore=tests/test_mysql.py --ignore=tests/test_oracle.py --ignore=tests/test_mssql.py --cov=pytest_mrt --cov-report=xml
 
       - name: Upload coverage
         uses: codecov/codecov-action@v7

diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -7,6 +7,18 @@ Versioning: [Semantic Versioning](https://semver.org/spec/v2.0.0.html)
 
 ---
 
+## [1.5.0] — 2026-06-11
+
+### Removed
+- **`mrt fix` command and the entire auto-fix subsystem** (`core/fixer.py`, `adapters/django_fixer.py`, `commands/fix.py`). Migration code generation is a *transform*, not a *verify*, operation and was out of scope for a rollback-testing tool. **Breaking change.** Projects that need automatic `downgrade()` generation should pin `pytest-mrt<1.5.0`.
+- **`mrt clean-backups` command** — it only cleaned the `_mrt_backups` table created by `mrt fix`-generated migrations, which no longer exist. **Breaking change.** If you have `_mrt_backups` tables from a previous `mrt fix` run, drop them manually or run `pytest-mrt<1.5.0` one last time.
+- **`fixable` field in `mrt check --format json` output** — it advertised the now-removed auto-fix capability. **Breaking change** for downstream tooling that read this field.
+
+### Fixed
+- **`RollbackVerifier` false positive on failed custom seeds** — a custom seed row whose `INSERT` failed (caught and warned) was still tracked, so `verify()` reported it as "lost after rollback" and blamed the migration for data the seed never inserted. Rows are now tracked only after a successful insert.
+
+---
+
 ## [1.4.1] — 2026-06-11
 
 ### Added

diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
@@ -118,7 +118,6 @@ pytest_mrt/
 ├── core/
 │   ├── ast_analyzer.py     # MigrationAST — Alembic AST parsing
 │   ├── detector.py         # Built-in Alembic risk checks
-│   ├── fixer.py            # mrt fix — auto-generate downgrade()
 │   ├── graph.py            # Migration dependency graph
 │   ├── html_report.py      # mrt report — HTML output
 │   ├── runner.py           # MigrationRunner — wraps alembic commands
@@ -135,7 +134,6 @@ tests/
 ├── test_cli.py
 ├── test_detector.py
 ├── test_django_detector.py
-├── test_fixer.py
 ├── test_graph.py
 ├── test_html_report.py
 ├── test_integration.py     # SQLite end-to-end tests
@@ -167,7 +165,6 @@ Check [open issues](https://github.com/croc100/pytest-mrt/issues) and the [ROADM
 - Add an example to `examples/` for a common use case
 - Add a new CI integration guide to `examples/ci-integration/`
 - Improve HTML report output
-- Add a new `mrt fix` heuristic
 
 ### Higher effort (discuss in an issue first)
 

diff --git a/README.md b/README.md
@@ -160,27 +160,6 @@ pip install pytest-mrt[oracle]   # python-oracledb
 pip install pytest-mrt[mssql]    # pymssql
 ```
 
-## Auto-fix missing reverse operations
-
-`mrt fix` generates missing reverse operations for both Alembic and Django migrations.
-
-**Alembic** — generates a missing or stub `downgrade()`:
-```bash
-mrt fix migrations/versions/0042_drop_phone.py --apply
-```
-
-**Django** — adds `reverse_sql`, `reverse_code`, and full backup/restore scaffolding for data-loss operations (`RemoveField`, `DeleteModel`):
-```bash
-mrt fix myapp/migrations/0042_remove_user_phone.py --apply
-```
-
-For `RemoveField` and `DeleteModel`, the generated code backs up data to a `_mrt_backups` table before the migration runs, and restores it on rollback. After deployment is confirmed stable, clean up the backup rows:
-
-```bash
-mrt clean-backups --db $DATABASE_URL
-mrt clean-backups --db $DATABASE_URL --label 0042_remove_user_phone --yes
-```
-
 ## pre-commit integration
 
 Add to `.pre-commit-config.yaml` to run `mrt check` automatically before every push:
@@ -279,7 +258,6 @@ Legacy syntax `# mrt: ignore` is still supported for backward compatibility.
 | Dynamic rollback testing | ✅ | ✅ | ❌ | ✅ |
 | **Data survival check** (seeds rows, verifies after rollback) | ✅ | ❌ schema only | ❌ | ❌ |
 | Django support | ✅ | ❌ | ❌ | ✅ |
-| Auto-fix (`mrt fix`) | ✅ | ❌ | ❌ | ❌ |
 | Pre-commit hook | ✅ | ❌ | ❌ | ❌ |
 | Inline suppression (`# noqa: MRTxxx`) | ✅ | ❌ | ❌ | ❌ |
 
@@ -290,7 +268,6 @@ The key difference from pytest-alembic: pytest-mrt seeds actual rows before each
 - **`mrt check --format json/html`** — structured JSON output for CI tooling; self-contained HTML safety report
 - **`mrt check --watch`** — re-runs automatically whenever a migration file changes
 - **`mrt check --min-revision`** — skip revisions older than a configured floor (mirrors `MRTConfig.minimum_downgrade_revision`)
-- **`mrt fix --apply` batch mode** — fix all auto-fixable migrations at once; `--dry-run` previews without writing
 - **Django squashmigrations detection** — MRT601/MRT602 catch unsafe `RunPython` in squashed migrations
 - **`minimum_downgrade_revision` in dynamic tests** — floor now respected by the `mrt` fixture `check_all()`, not just static analysis
 

diff --git a/ROADMAP.md b/ROADMAP.md
@@ -96,13 +96,13 @@ These are not committed to a specific version yet:
 - **Sentry integration** — report migration failures as Sentry events
 - **GitHub App** — automated PR comments with migration risk summary
 - **VS Code extension** — inline warnings in migration files
-- **`mrt fix --apply` batch mode** — fix all migration files in a directory at once
 
 ---
 
 ## What won't be in scope
 
 - Executing migrations in production (this is a *testing* tool only)
+- **Migration code generation / auto-fix** — pytest-mrt verifies migrations; it does not rewrite them. The former `mrt fix` / `mrt clean-backups` commands were removed in v1.5.0 (out of scope: "transform", not "verify")
 - Schema diff tools (use `alembic check` or `django-migration-linter`)
 - ORM-agnostic support (focused on Alembic and Django)
 

diff --git a/docs/api.md b/docs/api.md
@@ -298,21 +298,6 @@ mrt check alembic/versions/ --format json
 
 ---
 
-### `mrt fix <migration_file>`
-
-Suggest or apply a missing/broken `downgrade()` function.
-
-```
-mrt fix alembic/versions/001_create_users.py
-mrt fix alembic/versions/001_create_users.py --apply
-```
-
-| Option | Default | Description |
-|--------|---------|-------------|
-| `--apply` | `False` | Write the suggested fix to the file |
-
----
-
 ### `mrt report <versions_dir>`
 
 Generate an HTML safety report for all migrations.

diff --git a/docs/best-practices.md b/docs/best-practices.md
@@ -20,8 +20,6 @@ def downgrade():
     op.drop_table("users")
 ```
 
-Use `mrt fix` to auto-generate a `downgrade()` when you're unsure what it should do.
-
 ### 2. Test rollback locally before code review
 
 ```bash

diff --git a/docs/cli.md b/docs/cli.md
@@ -17,9 +17,6 @@ For GitHub Actions integration, see [croc100/pytest-mrt-action](https://github.c
 | `mrt check <dir> --format json` | Structured JSON output for CI / downstream tools | No |
 | `mrt check <dir> --format html` | Self-contained HTML safety report | No |
 | `mrt check <dir> --watch` | Re-run on file change (dev mode) | No |
-| `mrt fix <file>` | Auto-generate reverse operations for a single file | No |
-| `mrt fix --apply` | Batch-fix all auto-fixable migrations in a directory | No |
-| `mrt clean-backups` | Remove `_mrt_backups` rows after stable deployment | Yes |
 | `mrt drift` | Compare live DB schema against ORM models | Yes |
 | `mrt report <dir>` | HTML safety report of entire migration history | No |
 | `mrt explain <file>` | AI explanation in plain English | No (needs API key) |
@@ -158,8 +155,7 @@ Output schema:
       "rule": "MRT103",
       "severity": "error",
       "pattern": "DROP COLUMN in upgrade",
-      "message": "Column dropped — data permanently lost on rollback",
-      "fixable": false
+      "message": "Column dropped — data permanently lost on rollback"
     }
   ]
 }
@@ -232,87 +228,6 @@ When there are no problems:
 
 ---
 
-## CLI: `mrt fix`
-
-Auto-generates missing reverse operations. Works for both Alembic and Django migrations.
-
-```bash
-# Single-file mode
-mrt fix <migration-file>           # preview suggested fix
-mrt fix <migration-file> --apply   # write fix to file
-
-# Batch mode (v1.4.0)
-mrt fix --apply                    # fix all auto-fixable migrations in the detected directory
-mrt fix --apply --dry-run          # preview without writing
-mrt fix --apply --dir <path>       # specify the directory explicitly
-```
-
-### Batch mode options
-
-| Option | Description |
-|---|---|
-| `--apply` | Required to write fixes. Without a file argument, scans the whole directory. |
-| `--dry-run` | Preview what would change without writing. Use with `--apply`. |
-| `--dir <path>` | Directory to scan. Auto-detected from cwd if omitted (`migrations/`, `alembic/versions/`, `versions/`). |
-
-### Alembic
-
-Generates a missing or stub `downgrade()` function with the inverse operations inferred from `upgrade()`.
-
-### Django (v1.3.0)
-
-Detects and fixes four operation types:
-
-| Operation | Fix | Confidence |
-|---|---|---|
-| `RunSQL` without `reverse_sql` | Adds `reverse_sql=migrations.RunSQL.noop` | High |
-| `RunPython` without `reverse_code` | Adds `reverse_code=migrations.RunPython.noop` | Medium |
-| `RemoveField` | Injects `RunPython(backup, restore)` before the op | Medium |
-| `DeleteModel` | Injects `RunPython(backup, restore)` before the op | Medium |
-
-For `RemoveField` and `DeleteModel`, the generated code:
-
-1. **Backs up** the column/row data into a `_mrt_backups` table using keyset pagination (safe for large tables, no server-side cursors required)
-2. **Restores** the data when the migration is reversed, with constraint checking disabled for FK safety
-3. **Inlines a type codec** (`__mrt_enc`/`__mrt_dec`) directly into the migration file — no runtime dependency on pytest-mrt in your production migrations
-
-After you've confirmed the deployment is stable and rollback is no longer needed:
-
-```bash
-mrt clean-backups --db $DATABASE_URL
-mrt clean-backups --db $DATABASE_URL --label 0042_remove_user_phone --yes
-```
-
-#### Known limitations (documented in generated code)
-
-- Type fidelity depends on the codec: complex custom types may not round-trip perfectly
-- Very large tables (millions of rows) increase migration time proportionally
-- The backup table (`_mrt_backups`) persists until explicitly cleaned
-
----
-
-## CLI: `mrt clean-backups` (v1.3.0)
-
-Removes rows from the `_mrt_backups` table created by Django `mrt fix` backup/restore operations.
-
-```bash
-mrt clean-backups --db <database-url>
-mrt clean-backups --db $DATABASE_URL --list        # preview without deleting
-mrt clean-backups --db $DATABASE_URL --label 0042  # delete one migration's backup
-mrt clean-backups --db $DATABASE_URL --yes         # skip confirmation prompt
-```
-
-### Options
-
-| Option | Description |
-|---|---|
-| `--db` | SQLAlchemy database URL. Also reads from `DATABASE_URL` env var. |
-| `--label` | Delete only rows for this migration label. Omit to delete all backup data. |
-| `--list`, `-l` | List backup labels and row counts without deleting. |
-| `--yes`, `-y` | Skip the confirmation prompt. |
-
----
-
 ## CLI: `mrt version`
 
 ```bash

diff --git a/docs/faq.md b/docs/faq.md
@@ -32,15 +32,13 @@ pytest-mrt auto-detects which framework you're using based on whether the migrat
 |---|---|---|
 | **Static analysis** | Yes | Yes |
 | **Dynamic rollback** | Yes | Yes (`DjangoMigrationRunner`) |
-| **`mrt fix`** | Yes | Yes (v1.3.0) |
 
 ### Django migrations don't have `downgrade()` — how does pytest-mrt help?
 
-For Django, pytest-mrt provides **static analysis**, **dynamic rollback verification**, and (since v1.3.0) **auto-fix**:
+For Django, pytest-mrt provides **static analysis** and **dynamic rollback verification**:
 
 - **Static**: detects `RemoveField`, `DeleteModel`, `RunPython` without `reverse_code`, `RunSQL` without `reverse_sql`, unsafe `AddField` patterns, and more (10 Django-specific patterns).
 - **Dynamic**: `DjangoMigrationRunner` runs the full `migrate` / `migrate --backwards` cycle and verifies data integrity, just like Alembic mode.
-- **Fix** (`mrt fix --apply`): adds `reverse_sql`/`reverse_code` where missing and generates transactional backup/restore scaffolding for `RemoveField` and `DeleteModel`. The generated code is self-contained — no runtime dependency on pytest-mrt in your production migrations.
 
 ---
 

diff --git a/pyproject.toml b/pyproject.toml
@@ -4,7 +4,7 @@ build-backend = "hatchling.build"
 
 [project]
 name = "pytest-mrt"
-version = "1.4.1"
+version = "1.5.0"
 description = "Catch database migration rollback failures before they reach production"
 readme = "README.md"
 license = { text = "MIT" }
@@ -47,6 +47,7 @@ Changelog = "https://github.com/croc100/pytest-mrt/releases"
 [project.optional-dependencies]
 dev = [
     "pytest",
+    "pytest-cov",
     "psycopg2-binary",
     "hatch",
     "ruff",
-Original file line number
+Diff line change
@@ Expand Up / @@ -20,8 +20,6 @@ def downgrade(): @@
         op.drop_table("users")
     ```
-    Use `mrt fix` to auto-generate a `downgrade()` when you're unsure what it should do.
     ### 2. Test rollback locally before code review
     ```bash
@@ Expand Down @@