gitlab-org--gitlab-foss/app/models/merge_request_diff.rb
Sean McGivern 991bf24ec8 Use latest_merge_request_diff association
Compared to the merge_request_diff association:

1. It's simpler to query. The query uses a foreign key to the
   merge_request_diffs table, so no ordering is necessary.
2. It's faster for preloading. The merge_request_diff association has to load
   every diff for the MRs in the set, then discard all but the most recent for
   each. This association means that Rails can just query for N diffs from N
   MRs.
3. It's more complicated to update. This is a bidirectional foreign key, so we
   need to update two tables when adding a diff record. This also means we need
   to handle this as a special case when importing a GitLab project.

There is some juggling with this association in the merge request model:

* `MergeRequest#latest_merge_request_diff` is _always_ the latest diff.
* `MergeRequest#merge_request_diff` reuses
  `MergeRequest#latest_merge_request_diff` unless:
    * Arguments are passed. These are typically to force-reload the association.
    * It doesn't exist. That means we might be trying to implicitly create a
      diff. This only seems to happen in specs.
    * The association is already loaded. This is important for the reasons
      explained in the comment, which I'll reiterate here: if we a) load a
      non-latest diff, then b) get its `merge_request`, then c) get that MR's
      `merge_request_diff`, we should get the diff we loaded in c), even though
      that's not the latest diff.

Basically, `MergeRequest#merge_request_diff` is the latest diff in most cases,
but not quite all.
2017-11-23 12:14:56 +00:00

345 lines
9.2 KiB
Ruby

class MergeRequestDiff < ActiveRecord::Base
include Sortable
include Importable
include Gitlab::EncodingHelper
include ManualInverseAssociation
# Prevent store of diff if commits amount more then 500
COMMITS_SAFE_SIZE = 100
# Valid types of serialized diffs allowed by Gitlab::Git::Diff
VALID_CLASSES = [Hash, Rugged::Patch, Rugged::Diff::Delta].freeze
belongs_to :merge_request
manual_inverse_association :merge_request, :merge_request_diff
has_many :merge_request_diff_files, -> { order(:merge_request_diff_id, :relative_order) }
has_many :merge_request_diff_commits, -> { order(:merge_request_diff_id, :relative_order) }
serialize :st_commits # rubocop:disable Cop/ActiveRecordSerialize
serialize :st_diffs # rubocop:disable Cop/ActiveRecordSerialize
state_machine :state, initial: :empty do
state :collected
state :overflow
# Deprecated states: these are no longer used but these values may still occur
# in the database.
state :timeout
state :overflow_commits_safe_size
state :overflow_diff_files_limit
state :overflow_diff_lines_limit
end
scope :viewable, -> { without_state(:empty) }
# All diff information is collected from repository after object is created.
# It allows you to override variables like head_commit_sha before getting diff.
after_create :save_git_content, unless: :importing?
def self.find_by_diff_refs(diff_refs)
find_by(start_commit_sha: diff_refs.start_sha, head_commit_sha: diff_refs.head_sha, base_commit_sha: diff_refs.base_sha)
end
def self.select_without_diff
select(column_names - ['st_diffs'])
end
def st_commits
super || []
end
# Collect information about commits and diff from repository
# and save it to the database as serialized data
def save_git_content
MergeRequest
.where('id = ? AND COALESCE(latest_merge_request_diff_id, 0) < ?', self.merge_request_id, self.id)
.update_all(latest_merge_request_diff_id: self.id)
ensure_commit_shas
save_commits
save_diffs
keep_around_commits
end
def ensure_commit_shas
self.start_commit_sha ||= merge_request.target_branch_sha
self.head_commit_sha ||= merge_request.source_branch_sha
self.base_commit_sha ||= find_base_sha
save
end
# Override head_commit_sha to keep compatibility with merge request diff
# created before version 8.4 that does not store head_commit_sha in separate db field.
def head_commit_sha
if persisted? && super.nil?
last_commit_sha
else
super
end
end
# This method will rely on repository branch sha
# in case start_commit_sha is nil. Its necesarry for old merge request diff
# created before version 8.4 to work
def safe_start_commit_sha
start_commit_sha || merge_request.target_branch_sha
end
def size
real_size.presence || raw_diffs.size
end
def raw_diffs(options = {})
if options[:ignore_whitespace_change]
@diffs_no_whitespace ||= compare.diffs(options)
else
@raw_diffs ||= {}
@raw_diffs[options] ||= load_diffs(options)
end
end
def commits
@commits ||= load_commits
end
def last_commit_sha
commit_shas.first
end
def first_commit
commits.last
end
def base_commit
return unless base_commit_sha
project.commit(base_commit_sha)
end
def start_commit
return unless start_commit_sha
project.commit(start_commit_sha)
end
def head_commit
return unless head_commit_sha
project.commit(head_commit_sha)
end
def commit_shas
if st_commits.present?
st_commits.map { |commit| commit[:id] }
else
merge_request_diff_commits.map(&:sha)
end
end
def diff_refs=(new_diff_refs)
self.base_commit_sha = new_diff_refs&.base_sha
self.start_commit_sha = new_diff_refs&.start_sha
self.head_commit_sha = new_diff_refs&.head_sha
end
def diff_refs
return unless start_commit_sha || base_commit_sha
Gitlab::Diff::DiffRefs.new(
base_sha: base_commit_sha,
start_sha: start_commit_sha,
head_sha: head_commit_sha
)
end
# MRs created before 8.4 don't store their true diff refs (start and base),
# but we need to get a commit SHA for the "View file @ ..." link by a file,
# so we use an approximation of the diff refs if we can't get the actual one.
#
# These will not be the actual diff refs if the target branch was merged into
# the source branch after the merge request was created, but it is good enough
# for the specific purpose of linking to a commit.
#
# It is not good enough for highlighting diffs, so we can't simply pass
# these as `diff_refs.`
def fallback_diff_refs
real_refs = diff_refs
return real_refs if real_refs
likely_base_commit_sha = (first_commit&.parent || first_commit)&.sha
Gitlab::Diff::DiffRefs.new(
base_sha: likely_base_commit_sha,
start_sha: safe_start_commit_sha,
head_sha: head_commit_sha
)
end
def diff_refs_by_sha?
base_commit_sha? && head_commit_sha? && start_commit_sha?
end
def diffs(diff_options = nil)
Gitlab::Diff::FileCollection::MergeRequestDiff.new(self, diff_options: diff_options)
end
def project
merge_request.target_project
end
def compare
@compare ||=
Gitlab::Git::Compare.new(
repository.raw_repository,
safe_start_commit_sha,
head_commit_sha
)
end
def latest?
self.id == merge_request.latest_merge_request_diff_id
end
def compare_with(sha)
# When compare merge request versions we want diff A..B instead of A...B
# so we handle cases when user does squash and rebase of the commits between versions.
# For this reason we set straight to true by default.
CompareService.new(project, head_commit_sha).execute(project, sha, straight: true)
end
def commits_count
if st_commits.present?
st_commits.size
else
merge_request_diff_commits.size
end
end
def utf8_st_diffs
return [] if st_diffs.blank?
st_diffs.map do |diff|
diff.each do |k, v|
diff[k] = encode_utf8(v) if v.respond_to?(:encoding)
end
end
end
private
# Old GitLab implementations may have generated diffs as ["--broken-diff"].
# Avoid an error 500 by ignoring bad elements. See:
# https://gitlab.com/gitlab-org/gitlab-ce/issues/20776
def valid_raw_diff?(raw)
return false unless raw.respond_to?(:each)
raw.any? { |element| VALID_CLASSES.include?(element.class) }
end
def create_merge_request_diff_files(diffs)
rows = diffs.map.with_index do |diff, index|
diff_hash = diff.to_hash.merge(
binary: false,
merge_request_diff_id: self.id,
relative_order: index
)
# Compatibility with old diffs created with Psych.
diff_hash.tap do |hash|
diff_text = hash[:diff]
if diff_text.encoding == Encoding::BINARY && !diff_text.ascii_only?
hash[:binary] = true
hash[:diff] = [diff_text].pack('m0')
end
end
end
Gitlab::Database.bulk_insert('merge_request_diff_files', rows)
end
def load_diffs(options)
return Gitlab::Git::DiffCollection.new([]) unless diffs_from_database
raw = diffs_from_database
if paths = options[:paths]
raw = raw.select do |diff|
paths.include?(diff[:old_path]) || paths.include?(diff[:new_path])
end
end
Gitlab::Git::DiffCollection.new(raw, options)
end
def diffs_from_database
return @diffs_from_database if defined?(@diffs_from_database)
@diffs_from_database =
if st_diffs.present?
if valid_raw_diff?(st_diffs)
st_diffs
end
elsif merge_request_diff_files.present?
merge_request_diff_files.map(&:to_hash)
end
end
def load_commits
commits = st_commits.presence || merge_request_diff_commits
commits = commits.map { |commit| Commit.from_hash(commit.to_hash, project) }
CommitCollection
.new(merge_request.source_project, commits, merge_request.source_branch)
end
def save_diffs
new_attributes = {}
if compare.commits.size.zero?
new_attributes[:state] = :empty
else
diff_collection = compare.diffs(Commit.max_diff_options)
new_attributes[:real_size] = diff_collection.real_size
if diff_collection.any?
new_attributes[:state] = :collected
create_merge_request_diff_files(diff_collection)
end
# Set our state to 'overflow' to make the #empty? and #collected?
# methods (generated by StateMachine) return false.
#
# This attribution has to come at the end of the method so 'overflow'
# state does not get overridden by 'collected'.
new_attributes[:state] = :overflow if diff_collection.overflow?
end
update(new_attributes)
end
def save_commits
MergeRequestDiffCommit.create_bulk(self.id, compare.commits.reverse)
merge_request_diff_commits.reload
end
def repository
project.repository
end
def find_base_sha
return unless head_commit_sha && start_commit_sha
project.merge_base_commit(head_commit_sha, start_commit_sha).try(:sha)
end
def keep_around_commits
[repository, merge_request.source_project.repository].each do |repo|
repo.keep_around(start_commit_sha)
repo.keep_around(head_commit_sha)
repo.keep_around(base_commit_sha)
end
end
end