# PR#80: The Merge Chart Shows the Changed Lines per Period and per Pull Request

> **WARNING:** This document describes only the change applied in this PR.
> It may already be outdated once the next PR is merged.
> Historic PR documentation is not maintained along with new PRs; treat it as a snapshot.

## Related Links

- [werkregie PR#78](https://git.javagil.de/mi/werkregie/pulls/78): the merges per day, week and month of the configured authors.

## Problem

The merge chart counts the pull requests, but not their size.
The human wants to see how many lines a pull request changes on average,
e.g. 265 lines for `claude-code` in the 7 days up to 2026-10-14, with a median of 152.

Gitea has the data: the pull request that `MergeHistory` asks once for its base branch
names its `additions` and `deletions` as well.

## Non-Goals

- No split by file type, e.g. tests, documentation or lock files; the lines are those of the whole diff.
- No size classes, e.g. XS to XL.
- No JavaScript tests; werkregie has no framework for them yet, see Follow-up PRs.

## Specification

### Feature: the merge chart shows the changed lines

#### Scenario#80.01: the bars show the changed lines

… so that the human sees how much changes, not only how often.

- **Given** the merge chart of a Gitea with `mergeAuthors: [mi, claude-code]`,
  and on one day a merge of `mi` with 30 added and 10 deleted lines and one of `claude-code` with 200 changed lines
- **When** the human selects "Zeilen"
- **Then** the bar of that day stacks 40 lines for `mi` on 200 for `claude-code`

##### Verified by

- [MergeHistoryTest "the merges of each configured author, oldest first, in seconds since the epoch, with their changed lines"](../../dashboard/src/test/kotlin/de/hoennig/werkregie/dashboard/sources/MergeHistoryTest.kt)
- [MergeHistoryTest "the changed lines are the added and the deleted ones, none where Gitea names none"](../../dashboard/src/test/kotlin/de/hoennig/werkregie/dashboard/sources/MergeHistoryTest.kt)
- [GiteaSourceFetchTest "without mergeAuthors the merges of the token's user count, with an empty list none"](../../dashboard/src/test/kotlin/de/hoennig/werkregie/dashboard/sources/GiteaSourceFetchTest.kt)
- manual check in the browser, see "Solution"

#### Scenario#80.02: the legend names the mean and the median per pull request

… so that a few large pull requests do not hide the usual size.

- **Given** the merge chart with 3 merges of `claude-code` in the shown periods, of 100, 150 and 1000 changed lines
- **When** the human opens the dashboard
- **Then** the legend shows for `claude-code` 3 merges, a mean of 417 and a median of 150 lines

##### Verified by

- manual check in the browser, see "Solution"

#### Scenario#80.03: the choice stays

… so that the human does not select it on each visit.

- **Given** the merge chart, showing the changed lines
- **When** the human opens the dashboard again
- **Then** the chart shows the changed lines

##### Verified by

- manual check in the browser, see "Solution"

#### Scenario#80.04: the lines do not load Gitea more

… so that the chart asks Gitea no more than before.

- **Given** the merge chart, which counts a merged pull request
- **When** the chart is updated 10 minutes later
- **Then** it shows the same lines for that pull request, without asking Gitea for it again

##### Verified by

- [MergeHistoryTest "each merged pull request is asked once for its base and its lines, a failed answer again"](../../dashboard/src/test/kotlin/de/hoennig/werkregie/dashboard/sources/MergeHistoryTest.kt)

## Solution

- `MergeHistory` keeps for each merged pull request its base check and its changed lines, `additions` plus `deletions`,
  from the one answer it asks; `Merges.lines` holds them per author in the order of `mergedAt`.
  A server older than 0.50.0 sends no `lines`; the page then counts 0 lines.
- The merge tile gets a second switch, "PRs | Zeilen"; with "Zeilen" each bar stacks the changed lines of its period.
  The page keeps the choice, as it keeps the period.
- The legend names for each author the merges in the shown periods, and the mean and the median of their lines.
- Version 0.50.0.

### Manual Check

On 2026-10-14, a local dashboard with the configuration of the manual check of werkregie PR#78 showed for 30 days:

| Gitea                | Author               | Merges | Mean | Median |
|----------------------|----------------------|--------|------|--------|
| git.javagil.de       | `mi`                 | 127    | 395  | 269    |
| git.javagil.de       | `claude-code`        | 249    | 301  | 174    |
| dev.hostsharing.net  | `hsh-michaelhoennig` | 53     | 984  | 568    |

"Zeilen" stacked the lines per day, the tooltip of a bar named them per author, and the choice stayed after a reload.

## Open Questions

None.

## Follow-up PRs

- A test framework for the JavaScript of `index.html`, e.g. for `mergeSeries`; a new technology, it needs the consent of the human.