[BUG] Contribution heatmap month labels misalign when year starts mid-column

[Priyanshu-byte-coder]

Summary

ContributionHeatmap renders month labels above each column group. When a new month starts in the middle of a week column, the label is offset and overlaps with the previous month's label.

Steps to Reproduce

1. View ContributionHeatmap — observe January label position
2. If Jan 1 falls mid-week, the 'Jan' label appears in the wrong column

Expected Behaviour

Month label appears above the first column that contains any day of that month.

Implementation Notes

• Find the first week index where a date in the month appears
• Place the label at that column index
• Add overflow-hidden or min-width to prevent label overlap

GSSoC Info

• Difficulty: Intermediate — 35 pts
• Area: Bug Fix / UI

[srinidhi-2006-bit]

Hi @Priyanshu-byte-coder

I’m contributing under GSSoC’26 and I would like to work on this issue.

I understand that the bug involves incorrect month label positioning in the ContributionHeatmap when months begin mid-week, causing alignment and overlap issues. I’ll ensure the label placement logic correctly identifies the first relevant week column for each month and updates the UI to maintain proper spacing and readability.

I’ll also carefully handle edge cases related to week boundaries and responsive layout behavior while keeping the heatmap rendering efficient and visually consistent.

Looking forward to contributing to DevTrack.

[Visaka123]

Hi @Priyanshu-byte-coder , I’d love to fix this GSSoC'26 intermediate bug (35 pts). As an Amazon SDE Intern, I will correct the ContributionHeatmap column index logic and add overflow handling to prevent overlapping month labels.

Could you please assign this issue to me.

[anuragbraveboy-sudo]

Hi @Priyanshu-byte-coder 👋

I'd like to work on this bug under GSSoC'26!

I dug into the issue, and I believe the problem lies in how the month
label index is currently being calculated — it's likely using the
month's calendar start date rather than scanning week columns to find
The first column actually contains a day of that month.

Here's my exact fix plan:

Root Cause & Fix:

• Instead of deriving label position from the date directly, I'll scan
  the weeks array and find the first week index where
  week.some(day => day.month === targetMonth) returns true
• This ensures the label always sits above the correct column,
  even when Jan 1 falls on Wednesday or Thursday mid-week
• Will wrap labels in a container with overflow: hidden and
  set a min-width so December and January labels never bleed into each other

Edge Cases I'll Handle:

• Month starting on the last day of a week column
• December → January transition across the year boundary
• Leap year edge cases (Feb 29)
• Responsive behaviour on smaller screens

I would love to fix the ContributionHeatmap component
And I'm ready to start as soon as I'm assigned.
Please assign this issue to me! 🙏

[smirk-dev]

I'd like to work on this under GSSoC'26. The fix is to find the first week column index where a given month appears using date.getMonth() comparisons, then anchor the label to that column rather than the column where the month started outside the visible window. I have built GitHub-style contribution heatmaps before and understand the column math involved. Please assign this to me.

[mallya-m]

Hi @Priyanshu-byte-coder!
I'd like to work on this under GSSoC '26.

I've already contributed to this repo (PRs #303, #305, #306) so I'm
familiar with the codebase. I looked at ContributionHeatmap.tsx —
the label offset is calculated from a fixed index assumption rather
than deriving the actual week position from the data array.

I'll fix it by mapping month boundaries directly from the weeks data so labels
always align to the correct column regardless of what day the year starts.

Could you please assign this to me?
GitHub: github.com/mallya-m

[Visaka123]

@Priyanshu-byte-coder

Thank you for assigning this task!
I’ll work on fixing the month label alignment issue in the ContributionHeatmap by correctly identifying the first week index containing dates for each month and improving the label positioning to avoid overlaps. Looking forward to contributing this UI bug fix!