Line graph parser broken: API returns series objects, parser expects [date, value] pairs

[AlexGodard]

Summary

The InsightParser cannot parse line graph insights from the current PostHog API. The parser expects time-series data as [[date, value], ...] pairs, but the API returns a single series object containing separate data and days arrays. This causes all line graph insights to silently fail detection and display as zero/error.

Root Cause

In InsightParser::private_hasLineGraphStructure() (InsightParser.cpp L187-219), the very first check fails:

JsonArrayConst timeseriesData = firstResult[JSON_KEY_RESULT];
if (timeseriesData.isNull() || timeseriesData.size() <= 1) return false;
// "Needs at least 2 points for a line graph"

results[0].result has 1 element (the series object), so size() <= 1 is true and detection bails immediately.

What the parser expects

{
  "results": [{
    "result": [
      ["2026-01-13", 8],
      ["2026-01-14", 2],
      ["2026-01-15", 13]
    ]
  }]
}

The data extraction methods (getSeriesYValues, getSeriesXLabel, getSeriesRange) all read result[i][0] as a date string and result[i][1] as a numeric value.

What the PostHog API actually returns

{
  "results": [{
    "result": [{
      "data": [8, 2, 13, 19, 5, 5, 7, ...],
      "days": ["2026-01-13", "2026-01-14", "2026-01-15", ...],
      "labels": ["13-Jan-2026", "14-Jan-2026", "15-Jan-2026", ...],
      "count": 155,
      "label": "$pageview"
    }]
  }]
}

This format is returned regardless of whether the insight is created with the legacy filters parameter or the new query parameter.

Additionally: query.display is not populated for new-format insights

For insights created with the new InsightVizNode / TrendsQuery format:

• filters is {} (empty)
• query.display does not exist (display is at query.source.trendsFilter.display)

This breaks the fallback display-type check on L204-207. Insights created with the legacy filters param have query: null, so this check also fails.

Suggested Fix

Update private_hasLineGraphStructure() and the data extraction methods to handle the current format:

bool InsightParser::private_hasLineGraphStructure() const {
    if (!valid) return false;

    JsonArrayConst results = m_insightDataRoot[JSON_KEY_RESULTS];
    if (results.isNull() || results.size() == 0) return false;

    JsonObjectConst firstResult = results[0];
    if (firstResult.isNull()) return false;

    JsonArrayConst resultArray = firstResult[JSON_KEY_RESULT];
    if (resultArray.isNull() || resultArray.size() == 0) return false;

    JsonVariantConst firstElement = resultArray[0];

    // New format: result[0] is an object with "data" and "days" arrays
    if (firstElement.is<JsonObjectConst>()) {
        JsonObjectConst series = firstElement.as<JsonObjectConst>();
        JsonArrayConst data = series["data"];
        JsonArrayConst days = series["days"];
        return !data.isNull() && !days.isNull() && data.size() >= 2;
    }

    // Legacy format: result is [[date, value], [date, value], ...]
    if (resultArray.size() <= 1) return false;
    JsonArrayConst firstPoint = resultArray[0];
    if (firstPoint.isNull() || firstPoint.size() != 2) return false;
    const char* dateStr = firstPoint[0];
    if (!dateStr || strlen(dateStr) < 10) return false;
    return firstPoint[1].is<double>();
}

Similarly, getSeriesPointCount, getSeriesYValues, getSeriesXLabel, and getSeriesRange would need to read from result[0].data and result[0].days instead of result[i][0] / result[i][1].

Impact

• BoldNumber insights work (the aggregated_value field is present in the current API format)
• Line graphs are completely broken for all users
• Funnel insights may also be affected depending on their API format

Environment

• Firmware: 0.1.5
• PostHog region: US
• Parser source: current main branch has the same issue