iOfficeAI/OfficeCLI · error · ArgumentException

Invalid logBase '{value}': must be in the OOXML range [2, 10

Error message

Invalid logBase '{value}': must be in the OOXML range [2, 1000] (ST_LogBase).

What it means

The logBase setter parses the value as a double and enforces the OOXML ST_LogBase constraint: logVal must be in [2.0, 1000.0]. Values outside this range produce a schema-invalid file that Excel may silently rewrite back to linear. The guard prevents this ghost-rewrite. Note: '0' and false are handled upstream as falsy synonyms for removing the log scale (setting linear), so they do not reach this check.

Source

Thrown at src/officecli/Core/Chart/ChartHelper.Axis.cs:493

                            }
                            else if (value.Equals("none", StringComparison.OrdinalIgnoreCase) ||
                                     value.Equals("linear", StringComparison.OrdinalIgnoreCase) ||
                                     value.Equals("false", StringComparison.OrdinalIgnoreCase) ||
                                     value.Equals("no", StringComparison.OrdinalIgnoreCase))
                            {
                                newLogBase = null; // remove log scale (linear)
                            }
                            else
                            // "0" dropped as a falsy synonym for the same
                            // reason as the Setter.cs site — falls into the
                            // range check below and throws.
                            {
                                var logVal = ParseHelpers.SafeParseDouble(value, "logBase");
                                // ST_LogBase: minInclusive=2.0, maxInclusive=1000.0 — reject
                                // out-of-band values so Excel doesn't silently
                                // ghost-rewrite the chart back to linear.
                                if (logVal < 2.0 || logVal > 1000.0)
                                    throw new ArgumentException($"Invalid logBase '{value}': must be in the OOXML range [2, 1000] (ST_LogBase).");
                                newLogBase = logVal;
                            }
                            // A log scale requires axis min > 0 (Excel refuses
                            // the file, 0x800A03EC).
                            if (newLogBase != null
                                && scaling.GetFirstChild<C.MinAxisValue>()?.Val?.Value is { } curMin && curMin <= 0)
                                throw new ArgumentException(
                                    $"logBase cannot be enabled while the axis minimum ({curMin}) is <= 0: a logarithmic axis minimum must be greater than 0.");
                            scaling.RemoveAllChildren<C.LogBase>();
                            if (newLogBase != null)
                                scaling.PrependChild(new C.LogBase { Val = newLogBase.Value });
                        }
                    }
                    directlyHandled.Add(key);
                    break;
                }

                case "format":

View on GitHub (pinned to 1ced45e900)

Solutions

Use a base in [2, 1000]: logbase=10 or logbase=2.
To disable log scaling, use logbase=0, logbase=false, or logbase=none (intercepted before the range check).
Common valid bases: 2 (binary), 10 (decimal), 100, 1000.

Example fix

// before
logbase=1
// after
logbase=10
// to disable
logbase=false

Defensive patterns

Strategy: validation

Validate before calling

static bool IsLogBaseInRange(string value)
{
    if (!double.TryParse(value, System.Globalization.NumberStyles.Float,
        System.Globalization.CultureInfo.InvariantCulture, out var logVal))
        return false;
    return logVal >= 2.0 && logVal <= 1000.0;
}

Try / catch

try { axisSetter.Apply("logbase", value); }
catch (ArgumentException ex) when (ex.Message.StartsWith("Invalid logBase"))
{
    Console.Error.WriteLine($"{ex.Message}\nValid range: [2, 1000]. Use logbase=false to disable.");
}

Prevention

Keep logBase in the range 2–1000 (common: 2, 10, 100).
Use logbase=false or logbase=0 to disable log scaling.
Validate the numeric range before applying.

When it happens

Trigger: Setting logbase to a value < 2 or > 1000: logbase=1, logbase=0.5, logbase=5000. The value is parsed via SafeParseDouble before the range check.

Common situations: Using logbase=1 (log base 1 is mathematically undefined). Using logbase=10 and expecting it means 'scale by 10x' (it means logarithmic base 10, which is valid). Typing a percentage or multiplier instead of a base. Using logbase=0 expecting it to disable log scale (use 'false' or '0' which is intercepted upstream as falsy).

Related errors

AI-assisted analysis of iOfficeAI/OfficeCLI@1ced45e900 (2026-08-13). Data as JSON: /api/errors/2fb121b0f0a1e396. Report an issue: GitHub.