[ShortArrow]

Why

The rows read the history one commit at a time and the chart of lines over time reads it as sums, but neither shows at a glance which days the work happened on, how heavy each day was, or whether it added or removed code, and neither leads to a day's commits. A calendar strip under the rows does both. The decisions are in ADR 0050.

The calendar

A "Calendar" button in the pane's header shows the strip under whatever the pane's body shows, so the rows stay in view. Each column is a Monday-first week by the local calendar (calendarWeeks). A day is filled more strongly the more lines its commits changed, on the thickness's logarithmic scale, and runs from green when they added to red when they deleted (dayShade). Buttons above the weeks switch to the lines added alone or deleted alone. Every loaded commit counts except merges, whose lines against the first parent repeat the merged commits', stash entries and the uncommitted row (counts).

Clicking a day selects its newest commit in the rows and closes the chart if it is open; clicking it again walks to each older commit of the day and back round to the newest (nextInDay). The selected commit's day is outlined.

Reaching back

The calendar counts the loaded commits, and the rows load a page at a time. Scrolling the calendar to its oldest end, or pressing "Older" there, reads the next page, and the weeks already in view stay where they were. A page is asked for at most every half second, and one asked for sooner waits instead of being dropped, so resting at the oldest end keeps reading (Calendar.tsx).

The calendar lays out at most 530 weeks, about ten years back from its newest day (MAX_WEEKS). A commit's date is whatever its author wrote, and without the limit one dated centuries away stretched the calendar into hundreds of thousands of cells and froze the page.

Chart fixes

Two layout faults of the chart of lines over time show once a list or the calendar narrows it, and their fixes have commits of their own. The legend and the timeframe ran past the chart's right edge, and the timeframe's buttons drew on top of the list of commits beside it; the head now ends at the chart's margin and wraps, and the timeframe's buttons wrap among themselves when even a line of their own is too narrow (styles.css). The tip sat at the top right, over the wrapped legend; it now sits beside the cursor's line at the pointer's height, turned toward the room the chart has (tipPlace).

Tests

• Unit tests: a day's commits, newest first, without merges, stashes or the uncommitted row; the weeks and where months are named; the 530-week limit against a commit dated in the year 3000; each shading; walking a day's commits; the tip's place.
• E2E: the strip leaves the rows in view, its tip, walking a day's commits from the rows and from the chart, each shading, reading a four-year history page by page with the weekday names staying put, the chart's head inside the room the list leaves at 820 pixels wide, and the tip beside the cursor. Each failed before its change.