Bug: NaN and Infinity float values silently drop the column from results

[pinodeca]

Summary

In src/activities/execute_sql.rs, when the f64 decode arm is taken, serde_json::Number::from_f64(val) returns None for NaN and ±Infinity (since JSON has no representation for these values). The current code simply skips the insert — the column disappears from the row object entirely rather than being stored as null.

} else if let Ok(val) = row.try_get::<f64, _>(col_name) {
    if let Some(n) = serde_json::Number::from_f64(val) {
        row_obj.insert(col_name.to_string(), serde_json::Value::Number(n));
    }
    // <- no else: column is silently dropped
}

Severity

Low — edge case, but causes confusing downstream failures: $result.nan_col is left unsubstituted because the column does not exist in the JSON.

Repro

SELECT df.start(
    $$SELECT 'NaN'::float8 AS nan_col, 'Infinity'::float8 AS inf_col, 1 AS normal$$ |=> 'x'
    ~> 'SELECT $x.nan_col AS got_nan, $x.inf_col AS got_inf, $x.normal AS got_normal',
    'bug12-nan-inf'
);
-- nan_col and inf_col are MISSING from the JSON; $x.nan_col is left as-is

Fix

Add an else branch to insert serde_json::Value::Null when from_f64 returns None:

} else if let Ok(val) = row.try_get::<f64, _>(col_name) {
    if let Some(n) = serde_json::Number::from_f64(val) {
        row_obj.insert(col_name.to_string(), serde_json::Value::Number(n));
    } else {
        row_obj.insert(col_name.to_string(), serde_json::Value::Null);
    }
}