Synthetic example · not customer work

Sample diagnostic: cTrader indicator stops plotting after an update

This fictional incident demonstrates the structure of the 49 EUR diagnostic. It does not represent a client, a real proprietary indicator or a trading-performance result.

Finding

The indicator builds and loads; its index guard prevents every output assignment.

Smallest repair

Correct and document the warm-up boundary, then retest the same frozen cases.

Scope boundary

One failure is diagnosed; source repair is a separate fixed milestone.

1. Frozen evidence

Platform: cTrader Desktop 5.9 / Windows / synthetic environment
Artifact: One fictional authorized-source C# custom indicator
Last known working: cTrader Desktop 5.8 / clean instance
Current symptom: Build succeeds; indicator loads but plots no values
Build result: 0 errors, 0 warnings
Dependency boundary: No custom indicator, file, network or NuGet dependency
First divergence: Calculate executes, but every output remains NaN

2. Failure-stage matrix

Stage	Observed evidence	Conclusion
Build	Assembly compiles with 0 errors and 0 warnings	Not a compiler failure
Load	Indicator attaches in a clean instance without an exception	Not a loading failure
Calculate	Calculate is called, but source validation rejects every index	First reproducible divergence
Plot	Output series receives only NaN values	Downstream symptom, not root cause

3. Repair acceptance cases

First valid historical index writes a finite value.
Warm-up indices remain explicitly NaN without throwing.
The latest closed bar matches the frozen 5.8 reference value within the agreed tolerance.
A clean 5.9 instance builds, loads, calculates and plots with no hidden dependency.

Software-engineering example only. All versions, observations and values on this page are synthetic and are not trading advice.