Make ee_compat_check work on other remotes and branchessh-fix-issue-56760

Right now ee_compat_check can only use GitLab.com CE and EE repositories
and only checks against a target branch of `master`.

The EE repository can now be overriden via the `EE_REPOSITORY_URL` variable.

In addition, the EE target branch will be derived from the CI variable
CI_MERGE_REQUEST_TARGET_BRANCH_NAME. If the variable is blank or
`master`, then the EE target branch will be `master`. Otherwise, if the
merge request targets some other branch, it will append `-ee` as the
target branch. For example, if a merge request targets `11-7-stable`,
then ee_compat_check will check `11-7-stable-ee`.

Closes https://gitlab.com/gitlab-org/gitlab-ce/issues/56760

1 files changed, 45 insertions, 32 deletions

diff --git a/lib/gitlab/ee_compat_check.rb b/lib/gitlab/ee_compat_check.rb
index 01fd261404b..b565b5d7b48 100644
--- a/lib/gitlab/ee_compat_check.rb
+++ b/lib/gitlab/ee_compat_check.rb
@@ -33,16 +33,17 @@ module Gitlab
       @patches_dir = CHECK_DIR.join('patches')
       @ce_branch = branch
       @ce_project_url = ce_project_url
-      @ee_repo_url = ce_public_repo_url.sub('gitlab-ce', 'gitlab-ee')
+      @ee_repo_url = ENV.fetch(
+        'EE_REPOSITORY_URL', ce_public_repo_url.sub('gitlab-ce', 'gitlab-ee'))
       @job_id = job_id
     end
 
     def check
       ensure_patches_dir
       # We're generating the patch against the canonical-ce remote since forks'
-      # master branch are not necessarily up-to-date.
+      # target EE branch (e.g. master) may not be up-to-date.
       add_remote('canonical-ce', "#{CANONICAL_CE_PROJECT_URL}.git")
-      generate_patch(branch: ce_branch, patch_path: ce_patch_full_path, branch_remote: 'origin', master_remote: 'canonical-ce')
+      generate_patch(branch: ce_branch, patch_path: ce_patch_full_path, branch_remote: 'origin', target_remote: 'canonical-ce')
 
       ensure_ee_repo
       Dir.chdir(ee_repo_dir) do
@@ -51,7 +52,7 @@ module Gitlab
         ee_remotes.each do |key, url|
           add_remote(key, url)
         end
-        fetch(branch: 'master', depth: 20, remote: 'canonical-ee')
+        fetch(branch: target_ee_branch, depth: 20, remote: 'canonical-ee')
 
         status = catch(:halt_check) do
           ce_branch_compat_check!
@@ -59,7 +60,7 @@ module Gitlab
           ee_branch_presence_check!
 
           step("Checking out #{ee_remote_with_branch}/#{ee_branch_found}", %W[git checkout -b #{ee_branch_found} #{ee_remote_with_branch}/#{ee_branch_found}])
-          generate_patch(branch: ee_branch_found, patch_path: ee_patch_full_path, branch_remote: ee_remote_with_branch, master_remote: 'canonical-ee')
+          generate_patch(branch: ee_branch_found, patch_path: ee_patch_full_path, branch_remote: ee_remote_with_branch, target_remote: 'canonical-ee')
           ee_branch_compat_check!
         end
 
@@ -96,16 +97,16 @@ module Gitlab
     end
 
     def ensure_ee_repo
-      unless clone_repo(ee_repo_url, ee_repo_dir)
+      unless clone_repo(ee_repo_url, target_ee_branch, ee_repo_dir)
         # Fallback to using the canonical EE if there is no forked EE
-        clone_repo(CANONICAL_EE_REPO_URL, ee_repo_dir)
+        clone_repo(CANONICAL_EE_REPO_URL, target_ee_branch, ee_repo_dir)
       end
     end
 
-    def clone_repo(url, dir)
+    def clone_repo(url, branch, dir)
       _, status = step(
         "Cloning #{url} into #{dir}",
-        %W[git clone --branch master --single-branch --depth=200 #{url} #{dir}]
+        %W[git clone --branch #{branch} --single-branch --depth=200 #{url} #{dir}]
       )
       status.zero?
     end
@@ -114,14 +115,14 @@ module Gitlab
       FileUtils.mkdir_p(patches_dir)
     end
 
-    def generate_patch(branch:, patch_path:, branch_remote:, master_remote:)
+    def generate_patch(branch:, patch_path:, branch_remote:, target_remote:)
       FileUtils.rm(patch_path, force: true)
 
-      find_merge_base_with_master(branch: branch, branch_remote: branch_remote, master_remote: master_remote)
+      find_merge_base_with_target_branch(branch: branch, branch_remote: branch_remote, target_remote: target_remote, target_branch: target_ee_branch)
 
       step(
-        "Generating the patch against #{master_remote}/master in #{patch_path}",
-        %W[git diff --binary #{master_remote}/master...#{branch_remote}/#{branch}]
+        "Generating the patch against #{target_remote}/#{target_ee_branch} in #{patch_path}",
+        %W[git diff --binary #{target_remote}/#{target_ee_branch}...#{branch_remote}/#{branch}]
       ) do |output, status|
         throw(:halt_check, :ko) unless status.zero?
 
@@ -178,10 +179,10 @@ module Gitlab
     end
 
     def check_patch(patch_path)
-      step("Checking out master", %w[git checkout master])
-      step("Resetting to latest master", %w[git reset --hard canonical-ee/master])
+      step("Checking out #{target_ee_branch}", %W[git checkout #{target_ee_branch}])
+      step("Resetting to latest #{target_ee_branch}", %W[git reset --hard canonical-ee/#{target_ee_branch}])
       step(
-        "Checking if #{patch_path} applies cleanly to EE/master",
+        "Checking if #{patch_path} applies cleanly to EE/#{target_ee_branch}",
         # Don't use --check here because it can result in a 0-exit status even
         # though the patch doesn't apply cleanly, e.g.:
         #   > git apply --check --3way foo.patch
@@ -213,15 +214,15 @@ module Gitlab
     end
 
     def delete_ee_branches_locally!
-      command(%w[git checkout master])
+      command(%W[git checkout #{target_ee_branch}])
       command(%W[git branch --delete --force #{ee_branch_prefix}])
       command(%W[git branch --delete --force #{ee_branch_suffix}])
     end
 
-    def merge_base_found?(branch:, branch_remote:, master_remote:)
+    def merge_base_found?(branch:, branch_remote:, target_remote:, target_branch:)
       step(
-        "Finding merge base with #{master_remote}/master",
-        %W[git merge-base #{master_remote}/master #{branch_remote}/#{branch}]
+        "Finding merge base with #{target_remote}/#{target_branch}",
+        %W[git merge-base #{target_remote}/#{target_branch} #{branch_remote}/#{branch}]
       ) do |output, status|
         if status.zero?
           puts "Merge base was found: #{output}"
@@ -230,7 +231,7 @@ module Gitlab
       end
     end
 
-    def find_merge_base_with_master(branch:, branch_remote:, master_remote:)
+    def find_merge_base_with_target_branch(branch:, branch_remote:, target_remote:, target_branch:)
       # Start with (Math.exp(3).to_i = 20) until (Math.exp(6).to_i = 403)
       # In total we go (20 + 54 + 148 + 403 = 625) commits deeper
       depth = 20
@@ -240,12 +241,12 @@ module Gitlab
           # Repository is initially cloned with a depth of 20 so we need to fetch
           # deeper in the case the branch has more than 20 commits on top of master
           fetch(branch: branch, depth: depth, remote: branch_remote)
-          fetch(branch: 'master', depth: depth, remote: master_remote)
+          fetch(branch: target_branch, depth: depth, remote: target_remote)
 
-          merge_base_found?(branch: branch, branch_remote: branch_remote, master_remote: master_remote)
+          merge_base_found?(branch: branch, branch_remote: branch_remote, target_remote: target_remote, target_branch: target_branch)
         end
 
-      raise "\n#{branch} is too far behind #{master_remote}/master, please rebase it!\n" unless success
+      raise "\n#{branch} is too far behind #{target_remote}/#{target_branch}, please rebase it!\n" unless success
     end
 
     def fetch(branch:, depth:, remote: 'origin')
@@ -293,6 +294,18 @@ module Gitlab
       "#{ce_project_url}/-/jobs/#{job_id}/artifacts/raw/ee_compat_check/patches/#{ce_patch_name}"
     end
 
+    def target_ee_branch
+      @target_ee_branch ||= begin
+        target = ENV['CI_MERGE_REQUEST_TARGET_BRANCH_NAME']
+
+        if target.blank? || target == 'master'
+          'master'
+        else
+          ENV['CI_MERGE_REQUEST_TARGET_BRANCH_NAME'] + '-ee'
+        end
+      end
+    end
+
     def step(desc, cmd = nil)
       puts "\n=> #{desc}\n"
 
@@ -327,7 +340,7 @@ module Gitlab
         #{PLEASE_READ_THIS_BANNER}
         🎉 Congratulations!! 🎉
 
-        The `#{branch}` branch applies cleanly to EE/master!
+        The `#{branch}` branch applies cleanly to EE/#{target_ee_branch}!
 
         Much ❤️! For more information, see
         https://docs.gitlab.com/ce/development/automatic_ce_ee_merge.html
@@ -343,7 +356,7 @@ module Gitlab
         💥 Oh no! 💥
 
         The `#{ce_branch}` branch does not apply cleanly to the current
-        EE/master, and no `#{ee_branch_prefix}` or `#{ee_branch_suffix}` branch
+        EE/#{target_ee_branch}, and no `#{ee_branch_prefix}` or `#{ee_branch_suffix}` branch
         was found in #{ee_repos.join(' nor in ')}.
 
         If you're a community contributor, don't worry, someone from
@@ -355,16 +368,16 @@ module Gitlab
 
         We advise you to create a `#{ee_branch_prefix}` or `#{ee_branch_suffix}`
         branch that includes changes from `#{ce_branch}` but also specific changes
-        than can be applied cleanly to EE/master. In some cases, the conflicts
+        than can be applied cleanly to EE/#{target_ee_branch}. In some cases, the conflicts
         are trivial and you can ignore the warning from this job. As always,
         use your best judgement!
 
         There are different ways to create such branch:
 
-        1. Create a new branch from master and cherry-pick your CE commits
+        1. Create a new branch from #{target_ee_branch} and cherry-pick your CE commits
 
           # In the EE repo
-          $ git fetch #{CANONICAL_EE_REPO_URL} master
+          $ git fetch #{CANONICAL_EE_REPO_URL} #{target_ee_branch}
           $ git checkout -b #{ee_branch_prefix} FETCH_HEAD
           $ git fetch #{ce_public_repo_url} #{ce_branch}
           $ git cherry-pick SHA # Repeat for all the commits you want to pick
@@ -374,7 +387,7 @@ module Gitlab
         2. Apply your branch's patch to EE
 
           # In the EE repo
-          $ git fetch #{CANONICAL_EE_REPO_URL} master
+          $ git fetch #{CANONICAL_EE_REPO_URL} #{target_ee_branch}
           $ git checkout -b #{ee_branch_prefix} FETCH_HEAD
           $ wget #{patch_url} && git apply --3way #{ce_patch_name}
 
@@ -418,10 +431,10 @@ module Gitlab
         #{PLEASE_READ_THIS_BANNER}
         💥 Oh no! 💥
 
-        The `#{ce_branch}` does not apply cleanly to the current EE/master, and
+        The `#{ce_branch}` does not apply cleanly to the current EE/#{target_ee_branch}, and
         even though a `#{ee_branch_found}` branch
         exists in #{ee_repo_url}, it does not apply cleanly either to
-        EE/master!
+        EE/#{target_ee_branch}!
 
         #{conflicting_files_msg}