> ## Documentation Index
> Fetch the complete documentation index at: https://docs.sifr.sh/llms.txt
> Use this file to discover all available pages before exploring further.

# SIFR-FMT-0001: Source formatting drift detected by sifr fmt --check.

> Source formatting drift detected by sifr fmt --check.

`SIFR-FMT-0001` belongs to the **Formatting** diagnostic family. It means: source formatting drift detected by sifr fmt --check.

## Why It Happens

The source file differs from canonical Sifr formatter output.

<Info>
  Use `sifr --explain SIFR-FMT-0001` locally to see the renderer's exact message template and any machine-applicable suggestions for the compiler version you are running.
</Info>

## Erroneous Code

```python theme={null}
def main()->int:
 return 1
```

## How To Fix It

Run `sifr fmt` to rewrite the file, or make the source match the formatter output before using `sifr fmt --check`.

## Fixed Code

```python theme={null}
def main() -> int:
    return 1
```

## Details

| Field                  | Value                                                           |
| ---------------------- | --------------------------------------------------------------- |
| Code                   | `SIFR-FMT-0001`                                                 |
| Family                 | `FMT`                                                           |
| Severity               | Error                                                           |
| Stability              | stable                                                          |
| Owner                  | `sifr_format`                                                   |
| Representative fixture | `crates/sifr_format/src/lib.rs::check_reports_formatting_drift` |

See the [Error Codes index](/diagnostics/error-codes) for the complete catalog.