Commit d43c7784 authored by Douwe Maan's avatar Douwe Maan

Merge branch 'indicate-mr-diverged-from-target' into 'master'

Indicate when an MR diverged from the target branch

This adds an indicator to the "Merge MR" box, to tell if and how much an MR diverged from its target branch.

For instance, consider an MR to merge the branch `feature` into `master`. Some other commits were added to `master` since `feature` was created, and the two branches diverged.

```text
o master
|
o    o feature
|    |
o    o
|  /
o
```

In this case, there will be a label in the MR Merge box stating:

> This MR is by 3 commits behind the target branch `master`.

## Screenshots

### The branch diverged from the target (UI Proposal)

![UI_suggestion_1](/uploads/cd5bee3959e68026ec7d5097259d53f4/UI_suggestion_1.png)

### The branch diverged from the target (alternative UI Proposal)

![UI_suggestion_2](/uploads/f36977101b59a610850e129837dfbc83/UI_suggestion_2.png)

## How is this useful?

- In a _rebase-workflow_ (MR are preferably rebased before being merged), the reviewer wants to know if an MR is rebased on the target branch before merging it. 
    
    _With this indicator, the reviewer knows immediately if the branch is rebased, or if she needs to ask the committer to rebase its branch._

<br>

- To keep the git history readable, a team prefers to avoid merging branches that really lag a lot behind the target branch. Merging an MR that is 10 commits behind is fine, but 200 is too much.

    _With this indicator, the reviewer can see on the MR page if the branch is really far behind the target – or only a few commits behind._

## Open questions

We've been using this at @captaintrain for a few months now, and found it quite useful.

I guess the open-questions are mostly: what UI would be the more adequate? Any thoughts on this, on the general usefulness and/or on the code?

See merge request !2217
parents be1ae2d6 543845f7
......@@ -6,6 +6,7 @@ v 8.6.0 (unreleased)
- Fix issue when pushing to projects ending in .wiki
- Fix avatar stretching by providing a cropping feature (Johann Pardanaud)
- Don't load all of GitLab in mail_room
- Indicate how much an MR diverged from the target branch (Pierre de La Morinerie)
- Strip leading and trailing spaces in URL validator (evuez)
- Return empty array instead of 404 when commit has no statuses in commit status API
- Update documentation to reflect Guest role not being enforced on internal projects
......
......@@ -537,6 +537,29 @@ class MergeRequest < ActiveRecord::Base
end
end
def diverged_commits_count
cache = Rails.cache.read(:"merge_request_#{id}_diverged_commits")
if cache.blank? || cache[:source_sha] != source_sha || cache[:target_sha] != target_sha
cache = {
source_sha: source_sha,
target_sha: target_sha,
diverged_commits_count: compute_diverged_commits_count
}
Rails.cache.write(:"merge_request_#{id}_diverged_commits", cache)
end
cache[:diverged_commits_count]
end
def compute_diverged_commits_count
Gitlab::Git::Commit.between(target_project.repository.raw_repository, source_sha, target_sha).size
end
def diverged_from_target_branch?
diverged_commits_count > 0
end
def ci_commit
@ci_commit ||= source_project.ci_commit(last_commit.id) if last_commit && source_project
end
......
......@@ -34,6 +34,8 @@
%span into
= link_to namespace_project_commits_path(@project.namespace, @project, @merge_request.target_branch), class: "label-branch" do
= @merge_request.target_branch
- if @merge_request.open? && @merge_request.diverged_from_target_branch?
%span (#{pluralize(@merge_request.diverged_commits_count, 'commit')} behind)
= render "projects/merge_requests/show/how_to_merge"
= render "projects/merge_requests/widget/show.html.haml"
......
......@@ -26,6 +26,16 @@ Feature: Project Merge Requests
When I visit project "Shop" merge requests page
Then I should see "other_branch" branch
Scenario: I should not see the numbers of diverged commits if the branch is rebased on the target
Given project "Shop" have "Bug NS-07" open merge request with rebased branch
When I visit merge request page "Bug NS-07"
Then I should not see the diverged commits count
Scenario: I should see the numbers of diverged commits if the branch diverged from the target
Given project "Shop" have "Bug NS-08" open merge request with diverged branch
When I visit merge request page "Bug NS-08"
Then I should see the diverged commits count
Scenario: I should see rejected merge requests
Given I click link "Closed"
Then I should see "Feature NS-03" in merge requests
......
......@@ -60,7 +60,6 @@ class Spinach::Features::ProjectMergeRequests < Spinach::FeatureSteps
expect(page).not_to have_content "Feature NS-03"
end
step 'I should not see "Bug NS-04" in merge requests' do
expect(page).not_to have_content "Bug NS-04"
end
......@@ -121,6 +120,22 @@ class Spinach::Features::ProjectMergeRequests < Spinach::FeatureSteps
author: project.users.first)
end
step 'project "Shop" have "Bug NS-07" open merge request with rebased branch' do
create(:merge_request, :rebased,
title: "Bug NS-07",
source_project: project,
target_project: project,
author: project.users.first)
end
step 'project "Shop" have "Bug NS-08" open merge request with diverged branch' do
create(:merge_request, :diverged,
title: "Bug NS-08",
source_project: project,
target_project: project,
author: project.users.first)
end
step 'project "Shop" have "Feature NS-03" closed merge request' do
create(:closed_merge_request,
title: "Feature NS-03",
......@@ -490,6 +505,18 @@ class Spinach::Features::ProjectMergeRequests < Spinach::FeatureSteps
end
end
step 'I should see the diverged commits count' do
page.within ".mr-source-target" do
expect(page).to have_content /([0-9]+ commits behind)/
end
end
step 'I should not see the diverged commits count' do
page.within ".mr-source-target" do
expect(page).not_to have_content /([0-9]+ commit[s]? behind)/
end
end
step 'I should see "Bug NS-05" at the top' do
expect(page.find('ul.content-list.mr-list li.merge-request:first-child')).to have_content("Bug NS-05")
end
......
......@@ -388,13 +388,19 @@ module SharedPaths
end
step 'I visit merge request page "Bug NS-04"' do
mr = MergeRequest.find_by(title: "Bug NS-04")
visit namespace_project_merge_request_path(mr.target_project.namespace, mr.target_project, mr)
visit merge_request_path("Bug NS-04")
end
step 'I visit merge request page "Bug NS-05"' do
mr = MergeRequest.find_by(title: "Bug NS-05")
visit namespace_project_merge_request_path(mr.target_project.namespace, mr.target_project, mr)
visit merge_request_path("Bug NS-05")
end
step 'I visit merge request page "Bug NS-07"' do
visit merge_request_path("Bug NS-07")
end
step 'I visit merge request page "Bug NS-08"' do
visit merge_request_path("Bug NS-08")
end
step 'I visit merge request page "Bug CO-01"' do
......@@ -503,6 +509,11 @@ module SharedPaths
Project.find_by!(name: 'Shop')
end
def merge_request_path(title)
mr = MergeRequest.find_by(title: title)
namespace_project_merge_request_path(mr.target_project.namespace, mr.target_project, mr)
end
# ----------------------------------------
# Errors
# ----------------------------------------
......
......@@ -69,6 +69,16 @@ FactoryGirl.define do
target_branch "master"
end
trait :rebased do
source_branch "markdown"
target_branch "improve/awesome"
end
trait :diverged do
source_branch "feature"
target_branch "master"
end
trait :merge_when_build_succeeds do
merge_when_build_succeeds true
merge_user author
......
......@@ -274,6 +274,70 @@ describe MergeRequest, models: true do
end
end
describe '#diverged_commits_count' do
let(:project) { create(:project) }
let(:fork_project) { create(:project, forked_from_project: project) }
context 'diverged on same repository' do
subject(:merge_request_with_divergence) { create(:merge_request, :diverged, source_project: project, target_project: project) }
it 'counts commits that are on target branch but not on source branch' do
expect(subject.diverged_commits_count).to eq(5)
end
end
context 'diverged on fork' do
subject(:merge_request_fork_with_divergence) { create(:merge_request, :diverged, source_project: fork_project, target_project: project) }
it 'counts commits that are on target branch but not on source branch' do
expect(subject.diverged_commits_count).to eq(5)
end
end
context 'rebased on fork' do
subject(:merge_request_rebased) { create(:merge_request, :rebased, source_project: fork_project, target_project: project) }
it 'counts commits that are on target branch but not on source branch' do
expect(subject.diverged_commits_count).to eq(0)
end
end
describe 'caching' do
before(:example) do
allow(Rails).to receive(:cache).and_return(ActiveSupport::Cache::MemoryStore.new)
end
it 'caches the output' do
expect(subject).to receive(:compute_diverged_commits_count).
once.
and_return(2)
subject.diverged_commits_count
subject.diverged_commits_count
end
it 'invalidates the cache when the source sha changes' do
expect(subject).to receive(:compute_diverged_commits_count).
twice.
and_return(2)
subject.diverged_commits_count
allow(subject).to receive(:source_sha).and_return('123abc')
subject.diverged_commits_count
end
it 'invalidates the cache when the target sha changes' do
expect(subject).to receive(:compute_diverged_commits_count).
twice.
and_return(2)
subject.diverged_commits_count
allow(subject).to receive(:target_sha).and_return('123abc')
subject.diverged_commits_count
end
end
end
it_behaves_like 'an editable mentionable' do
subject { create(:merge_request) }
......
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