233 lines
9.7 KiB
Ruby
233 lines
9.7 KiB
Ruby
# frozen_string_literal: true
|
|
|
|
# Finds the diff position in the new diff that corresponds to the same location
|
|
# specified by the provided position in the old diff.
|
|
module Gitlab
|
|
module Diff
|
|
class PositionTracer
|
|
attr_accessor :project
|
|
attr_accessor :old_diff_refs
|
|
attr_accessor :new_diff_refs
|
|
attr_accessor :paths
|
|
|
|
def initialize(project:, old_diff_refs:, new_diff_refs:, paths: nil)
|
|
@project = project
|
|
@old_diff_refs = old_diff_refs
|
|
@new_diff_refs = new_diff_refs
|
|
@paths = paths
|
|
end
|
|
|
|
def trace(ab_position)
|
|
return unless old_diff_refs&.complete? && new_diff_refs&.complete?
|
|
return unless ab_position.diff_refs == old_diff_refs
|
|
|
|
# Suppose we have an MR with source branch `feature` and target branch `master`.
|
|
# When the MR was created, the head of `master` was commit A, and the
|
|
# head of `feature` was commit B, resulting in the original diff A->B.
|
|
# Since creation, `master` was updated to C.
|
|
# Now `feature` is being updated to D, and the newly generated MR diff is C->D.
|
|
# It is possible that C and D are direct descendants of A and B respectively,
|
|
# but this isn't necessarily the case as rebases and merges come into play.
|
|
#
|
|
# Suppose we have a diff note on the original diff A->B. Now that the MR
|
|
# is updated, we need to find out what line in C->D corresponds to the
|
|
# line the note was originally created on, so that we can update the diff note's
|
|
# records and continue to display it in the right place in the diffs.
|
|
# If we cannot find this line in the new diff, this means the diff note is now
|
|
# outdated, and we will display that fact to the user.
|
|
#
|
|
# In the new diff, the file the diff note was originally created on may
|
|
# have been renamed, deleted or even created, if the file existed in A and B,
|
|
# but was removed in C, and restored in D.
|
|
#
|
|
# Every diff note stores a Position object that defines a specific location,
|
|
# identified by paths and line numbers, within a specific diff, identified
|
|
# by start, head and base commit ids.
|
|
#
|
|
# For diff notes for diff A->B, the position looks like this:
|
|
# Position
|
|
# start_sha - ID of commit A
|
|
# head_sha - ID of commit B
|
|
# base_sha - ID of base commit of A and B
|
|
# old_path - path as of A (nil if file was newly created)
|
|
# new_path - path as of B (nil if file was deleted)
|
|
# old_line - line number as of A (nil if file was newly created)
|
|
# new_line - line number as of B (nil if file was deleted)
|
|
#
|
|
# We can easily update `start_sha` and `head_sha` to hold the IDs of
|
|
# commits C and D, and can trivially determine `base_sha` based on those,
|
|
# but need to find the paths and line numbers as of C and D.
|
|
#
|
|
# If the file was unchanged or newly created in A->B, the path as of D can be found
|
|
# by generating diff B->D ("head to head"), finding the diff file with
|
|
# `diff_file.old_path == position.new_path`, and taking `diff_file.new_path`.
|
|
# The path as of C can be found by taking diff C->D, finding the diff file
|
|
# with that same `new_path` and taking `diff_file.old_path`.
|
|
# The line number as of D can be found by using the LineMapper on diff B->D
|
|
# and providing the line number as of B.
|
|
# The line number as of C can be found by using the LineMapper on diff C->D
|
|
# and providing the line number as of D.
|
|
#
|
|
# If the file was deleted in A->B, the path as of C can be found
|
|
# by generating diff A->C ("base to base"), finding the diff file with
|
|
# `diff_file.old_path == position.old_path`, and taking `diff_file.new_path`.
|
|
# The path as of D can be found by taking diff C->D, finding the diff file
|
|
# with `old_path` set to that `diff_file.new_path` and taking `diff_file.new_path`.
|
|
# The line number as of C can be found by using the LineMapper on diff A->C
|
|
# and providing the line number as of A.
|
|
# The line number as of D can be found by using the LineMapper on diff C->D
|
|
# and providing the line number as of C.
|
|
|
|
if ab_position.added?
|
|
trace_added_line(ab_position)
|
|
elsif ab_position.removed?
|
|
trace_removed_line(ab_position)
|
|
else # unchanged
|
|
trace_unchanged_line(ab_position)
|
|
end
|
|
end
|
|
|
|
private
|
|
|
|
def trace_added_line(ab_position)
|
|
b_path = ab_position.new_path
|
|
b_line = ab_position.new_line
|
|
|
|
bd_diff = bd_diffs.diff_file_with_old_path(b_path)
|
|
|
|
d_path = bd_diff&.new_path || b_path
|
|
d_line = LineMapper.new(bd_diff).old_to_new(b_line)
|
|
|
|
if d_line
|
|
cd_diff = cd_diffs.diff_file_with_new_path(d_path)
|
|
|
|
c_path = cd_diff&.old_path || d_path
|
|
c_line = LineMapper.new(cd_diff).new_to_old(d_line)
|
|
|
|
if c_line
|
|
# If the line is still in D but also in C, it has turned from an
|
|
# added line into an unchanged one.
|
|
new_position = position(cd_diff, c_line, d_line)
|
|
if valid_position?(new_position)
|
|
# If the line is still in the MR, we don't treat this as outdated.
|
|
{ position: new_position, outdated: false }
|
|
else
|
|
# If the line is no longer in the MR, we unfortunately cannot show
|
|
# the current state on the CD diff, so we treat it as outdated.
|
|
ac_diff = ac_diffs.diff_file_with_new_path(c_path)
|
|
|
|
{ position: position(ac_diff, nil, c_line), outdated: true }
|
|
end
|
|
else
|
|
# If the line is still in D and not in C, it is still added.
|
|
{ position: position(cd_diff, nil, d_line), outdated: false }
|
|
end
|
|
else
|
|
# If the line is no longer in D, it has been removed from the MR.
|
|
{ position: position(bd_diff, b_line, nil), outdated: true }
|
|
end
|
|
end
|
|
|
|
def trace_removed_line(ab_position)
|
|
a_path = ab_position.old_path
|
|
a_line = ab_position.old_line
|
|
|
|
ac_diff = ac_diffs.diff_file_with_old_path(a_path)
|
|
|
|
c_path = ac_diff&.new_path || a_path
|
|
c_line = LineMapper.new(ac_diff).old_to_new(a_line)
|
|
|
|
if c_line
|
|
cd_diff = cd_diffs.diff_file_with_old_path(c_path)
|
|
|
|
d_path = cd_diff&.new_path || c_path
|
|
d_line = LineMapper.new(cd_diff).old_to_new(c_line)
|
|
|
|
if d_line
|
|
# If the line is still in C but also in D, it has turned from a
|
|
# removed line into an unchanged one.
|
|
bd_diff = bd_diffs.diff_file_with_new_path(d_path)
|
|
|
|
{ position: position(bd_diff, nil, d_line), outdated: true }
|
|
else
|
|
# If the line is still in C and not in D, it is still removed.
|
|
{ position: position(cd_diff, c_line, nil), outdated: false }
|
|
end
|
|
else
|
|
# If the line is no longer in C, it has been removed outside of the MR.
|
|
{ position: position(ac_diff, a_line, nil), outdated: true }
|
|
end
|
|
end
|
|
|
|
def trace_unchanged_line(ab_position)
|
|
a_path = ab_position.old_path
|
|
a_line = ab_position.old_line
|
|
b_path = ab_position.new_path
|
|
b_line = ab_position.new_line
|
|
|
|
ac_diff = ac_diffs.diff_file_with_old_path(a_path)
|
|
|
|
c_path = ac_diff&.new_path || a_path
|
|
c_line = LineMapper.new(ac_diff).old_to_new(a_line)
|
|
|
|
bd_diff = bd_diffs.diff_file_with_old_path(b_path)
|
|
|
|
d_line = LineMapper.new(bd_diff).old_to_new(b_line)
|
|
|
|
cd_diff = cd_diffs.diff_file_with_old_path(c_path)
|
|
|
|
if c_line && d_line
|
|
# If the line is still in C and D, it is still unchanged.
|
|
new_position = position(cd_diff, c_line, d_line)
|
|
if valid_position?(new_position)
|
|
# If the line is still in the MR, we don't treat this as outdated.
|
|
{ position: new_position, outdated: false }
|
|
else
|
|
# If the line is no longer in the MR, we unfortunately cannot show
|
|
# the current state on the CD diff or any change on the BD diff,
|
|
# so we treat it as outdated.
|
|
{ position: nil, outdated: true }
|
|
end
|
|
elsif d_line # && !c_line
|
|
# If the line is still in D but no longer in C, it has turned from
|
|
# an unchanged line into an added one.
|
|
# We don't treat this as outdated since the line is still in the MR.
|
|
{ position: position(cd_diff, nil, d_line), outdated: false }
|
|
else # !d_line && (c_line || !c_line)
|
|
# If the line is no longer in D, it has turned from an unchanged line
|
|
# into a removed one.
|
|
{ position: position(bd_diff, b_line, nil), outdated: true }
|
|
end
|
|
end
|
|
|
|
def ac_diffs
|
|
@ac_diffs ||= compare(
|
|
old_diff_refs.base_sha || old_diff_refs.start_sha,
|
|
new_diff_refs.base_sha || new_diff_refs.start_sha,
|
|
straight: true
|
|
)
|
|
end
|
|
|
|
def bd_diffs
|
|
@bd_diffs ||= compare(old_diff_refs.head_sha, new_diff_refs.head_sha, straight: true)
|
|
end
|
|
|
|
def cd_diffs
|
|
@cd_diffs ||= compare(new_diff_refs.start_sha, new_diff_refs.head_sha)
|
|
end
|
|
|
|
def compare(start_sha, head_sha, straight: false)
|
|
compare = CompareService.new(project, head_sha).execute(project, start_sha, straight: straight)
|
|
compare.diffs(paths: paths, expanded: true)
|
|
end
|
|
|
|
def position(diff_file, old_line, new_line)
|
|
Position.new(diff_file: diff_file, old_line: old_line, new_line: new_line)
|
|
end
|
|
|
|
def valid_position?(position)
|
|
!!position.diff_line(project.repository)
|
|
end
|
|
end
|
|
end
|
|
end
|