Commit 7466df87 authored by Bob Van Landuyt's avatar Bob Van Landuyt

Get the `merge-base` of 2 refs trough the API

This adds an endpoint to get the common ancestor of 2 refs from the API.
parent 456a4dde
---
title: Get the merge base of two refs through the API
merge_request: 20929
author:
type: added
...@@ -204,3 +204,39 @@ Response: ...@@ -204,3 +204,39 @@ Response:
"deletions": 244 "deletions": 244
}] }]
``` ```
## Merge Base
Get the common ancestor for 2 refs (commit SHAs, branch names or tags).
```
GET /projects/:id/repository/merge_base
```
| Attribute | Type | Required | Description |
| --------- | ---- | -------- | ----------- |
| `id` | integer/string | yes | The ID or [URL-encoded path of the project](README.md#namespaced-path-encoding) |
| `refs` | array | yes | The refs to find the common ancestor of, for now only 2 refs are supported |
```bash
curl --header "PRIVATE-TOKEN: 9koXpg98eAheJpvBs5tK" "https://gitlab.example.com/api/v4/projects/5/repository/merge_base?refs[]=304d257dcb821665ab5110318fc58a007bd104ed&refs[]=0031876facac3f2b2702a0e53a26e89939a42209"
```
Example response:
```json
{
"id": "1a0b36b3cdad1d2ee32457c102a8c0b7056fa863",
"short_id": "1a0b36b3",
"title": "Initial commit",
"created_at": "2014-02-27T08:03:18.000Z",
"parent_ids": [],
"message": "Initial commit\n",
"author_name": "Dmitriy Zaporozhets",
"author_email": "dmitriy.zaporozhets@gmail.com",
"authored_date": "2014-02-27T08:03:18.000Z",
"committer_name": "Dmitriy Zaporozhets",
"committer_email": "dmitriy.zaporozhets@gmail.com",
"committed_date": "2014-02-27T08:03:18.000Z"
}
```
...@@ -123,6 +123,39 @@ module API ...@@ -123,6 +123,39 @@ module API
not_found! not_found!
end end
end end
desc 'Get the common ancestor between commits' do
success Entities::Commit
end
params do
# For now we just support 2 refs passed, but `merge-base` supports
# multiple defining this as an Array instead of 2 separate params will
# make sure we don't need to deprecate this API in favor of one
# supporting multiple commits when this functionality gets added to
# Gitaly
requires :refs, type: Array[String]
end
get ':id/repository/merge_base' do
refs = params[:refs]
unless refs.size == 2
render_api_error!('Provide exactly 2 refs', 400)
end
merge_base = Gitlab::Git::MergeBase.new(user_project.repository, refs)
if merge_base.unknown_refs.any?
ref_noun = 'ref'.pluralize(merge_base.unknown_refs.size)
message = "Could not find #{ref_noun}: #{merge_base.unknown_refs.join(', ')}"
render_api_error!(message, 400)
end
if merge_base.commit
present merge_base.commit, with: Entities::Commit
else
not_found!("Merge Base")
end
end
end end
end end
end end
...@@ -10,9 +10,11 @@ module Gitlab ...@@ -10,9 +10,11 @@ module Gitlab
TAG_REF_PREFIX = "refs/tags/".freeze TAG_REF_PREFIX = "refs/tags/".freeze
BRANCH_REF_PREFIX = "refs/heads/".freeze BRANCH_REF_PREFIX = "refs/heads/".freeze
CommandError = Class.new(StandardError) BaseError = Class.new(StandardError)
CommitError = Class.new(StandardError) CommandError = Class.new(BaseError)
OSError = Class.new(StandardError) CommitError = Class.new(BaseError)
OSError = Class.new(BaseError)
UnknownRef = Class.new(BaseError)
class << self class << self
include Gitlab::EncodingHelper include Gitlab::EncodingHelper
......
# frozen_string_literal: true
module Gitlab
module Git
class MergeBase
include Gitlab::Utils::StrongMemoize
def initialize(repository, refs)
@repository, @refs = repository, refs
end
# Returns the SHA of the first common ancestor
def sha
if unknown_refs.any?
raise UnknownRef, "Can't find merge base for unknown refs: #{unknown_refs.inspect}"
end
strong_memoize(:sha) do
@repository.merge_base(*commits_for_refs)
end
end
# Returns the merge base as a Gitlab::Git::Commit
def commit
return unless sha
@commit ||= @repository.commit_by(oid: sha)
end
# Returns the refs passed on initialization that aren't found in
# the repository, and thus cannot be used to find a merge base.
def unknown_refs
@unknown_refs ||= Hash[@refs.zip(commits_for_refs)]
.select { |ref, commit| commit.nil? }.keys
end
private
def commits_for_refs
@commits_for_refs ||= @repository.commits_by(oids: @refs)
end
end
end
end
# frozen_string_literal: true
require 'spec_helper'
describe Gitlab::Git::MergeBase do
set(:project) { create(:project, :repository) }
let(:repository) { project.repository }
subject(:merge_base) { described_class.new(repository, refs) }
shared_context 'existing refs with a merge base', :existing_refs do
let(:refs) do
%w(304d257dcb821665ab5110318fc58a007bd104ed 0031876facac3f2b2702a0e53a26e89939a42209)
end
end
shared_context 'when passing a missing ref', :missing_ref do
let(:refs) do
%w(304d257dcb821665ab5110318fc58a007bd104ed aaaa)
end
end
shared_context 'when passing refs that do not have a common ancestor', :no_common_ancestor do
let(:refs) { ['304d257dcb821665ab5110318fc58a007bd104ed', TestEnv::BRANCH_SHA['orphaned-branch']] }
end
describe '#sha' do
context 'when the refs exist', :existing_refs do
it 'returns the SHA of the merge base' do
expect(merge_base.sha).not_to be_nil
end
it 'memoizes the result' do
expect(repository).to receive(:merge_base).once.and_call_original
2.times { merge_base.sha }
end
end
context 'when passing a missing ref', :missing_ref do
it 'does not call merge_base on the repository but raises an error' do
expect(repository).not_to receive(:merge_base)
expect { merge_base.sha }.to raise_error(Gitlab::Git::UnknownRef)
end
end
it 'returns `nil` when the refs do not have a common ancestor', :no_common_ancestor do
expect(merge_base.sha).to be_nil
end
it 'returns a merge base when passing 2 branch names' do
merge_base = described_class.new(repository, %w(master feature))
expect(merge_base.sha).to be_present
end
it 'returns a merge base when passing a tag name' do
merge_base = described_class.new(repository, %w(master v1.0.0))
expect(merge_base.sha).to be_present
end
end
describe '#commit' do
context 'for existing refs with a merge base', :existing_refs do
it 'finds the commit for the merge base' do
expect(merge_base.commit).to be_a(Commit)
end
it 'only looks up the commit once' do
expect(repository).to receive(:commit_by).once.and_call_original
2.times { merge_base.commit }
end
end
it 'does not try to find the commit when there is no sha', :no_common_ancestor do
expect(repository).not_to receive(:commit_by)
merge_base.commit
end
end
describe '#unknown_refs', :missing_ref do
it 'returns the the refs passed that are not part of the repository' do
expect(merge_base.unknown_refs).to contain_exactly('aaaa')
end
it 'only looks up the commits once' do
expect(merge_base).to receive(:commits_for_refs).once.and_call_original
2.times { merge_base.unknown_refs }
end
end
end
...@@ -465,4 +465,77 @@ describe API::Repositories do ...@@ -465,4 +465,77 @@ describe API::Repositories do
end end
end end
end end
describe 'GET :id/repository/merge_base' do
let(:refs) do
%w(304d257dcb821665ab5110318fc58a007bd104ed 0031876facac3f2b2702a0e53a26e89939a42209)
end
subject(:request) do
get(api("/projects/#{project.id}/repository/merge_base", current_user), refs: refs)
end
shared_examples 'merge base' do
it 'returns the common ancestor' do
request
expect(response).to have_gitlab_http_status(:success)
expect(json_response['id']).to be_present
end
end
context 'when unauthenticated', 'and project is public' do
it_behaves_like 'merge base' do
let(:project) { create(:project, :public, :repository) }
let(:current_user) { nil }
end
end
context 'when unauthenticated', 'and project is private' do
it_behaves_like '404 response' do
let(:current_user) { nil }
let(:message) { '404 Project Not Found' }
end
end
context 'when authenticated', 'as a developer' do
it_behaves_like 'merge base' do
let(:current_user) { user }
end
end
context 'when authenticated', 'as a guest' do
it_behaves_like '403 response' do
let(:current_user) { guest }
end
end
context 'when passing refs that do not exist' do
it_behaves_like '400 response' do
let(:refs) { %w(304d257dcb821665ab5110318fc58a007bd104ed missing) }
let(:current_user) { user }
let(:message) { 'Could not find ref: missing' }
end
end
context 'when passing refs that do not have a merge base' do
it_behaves_like '404 response' do
let(:refs) { ['304d257dcb821665ab5110318fc58a007bd104ed', TestEnv::BRANCH_SHA['orphaned-branch']] }
let(:current_user) { user }
let(:message) { '404 Merge Base Not Found' }
end
end
context 'when not enough refs are passed' do
let(:refs) { %w(only-one) }
let(:current_user) { user }
it 'renders a bad request error' do
request
expect(response).to have_gitlab_http_status(:bad_request)
expect(json_response['message']).to eq('Provide exactly 2 refs')
end
end
end
end end
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