Resolve schema migration merge conflicts

resolve.rb

#!/usr/bin/env ruby
# frozen_string_literal: true

#
# This script automatically resolves merge conflicts in the schema migrations
# part of structure.sql. It sorts, deduplicates and reformats all migration
# entries in the file.
#
# Example:
#
# ('20211222080000'),
# ('20211222120729'),
# ('20211223150854'),
# <<<<<<< HEAD
# ('20220104100925'),
# =======
# ('20211223181009'),
# >>>>>>> e16b8ffc8 (Add started_at column to session)
# ('20220106134342');
#
# Will result in:
#
# ('20211222120729'),
# ('20211223150854'),
# ('20211223181009'),
# ('20220104100925'),
# ('20220106134342');
#

# Read structure.sql
structure = File.readlines("db/structure.sql")

# Find schema_migrations line
index = structure.index { |l| l.start_with?("INSERT INTO \"schema_migrations\"") }

abort("Merge conflict found before schema migrations. Please resolve the conflicts and rerun this script.") if structure[..index].any? { |l| l.start_with?("<<<<<<<", "=======", ">>>>>>>") }

migrations = structure[(index + 1)..]

# Drop trailing empty lines
migrations.reject!(&:empty?)

# Drop git conflict delimiters
migrations.reject! { |l| l.start_with?("<<<<<<<", "=======", ">>>>>>>") }

# Replace semicolons with commas
migrations.map! { |l| l.tr(";", ",") }

# Sort and deduplicate
migrations.sort!
migrations.uniq!

# Add semicolon to last statement
migrations[-1].tr!(",", ";")

# Write structure.sql
File.write("db/structure.sql", (structure[..index] + migrations).join)

puts "Resolved merge conflicts in db/structure.sql"