ASCII 8-bit encoded strings fail comparison even if all ASCII characters

[forthrin]

#!/usr/bin/env ruby

require 'sqlite3'

db = SQLite3::Database.open("#{Dir.home}/db")
db.execute('create table if not exists foo (bar, unique (bar))')
db.execute('replace into foo values (?)', u = 'a')
a = u.encode('ascii-8bit')
pp a == u
[u, a].each do
  pp db.execute('select * from foo where bar = ?', [it])
end

true
[["a"]]
[]

System Version: macOS 26.5.2 (25F84)
Model Identifier: MacBookAir10,1
ruby 4.0.6 (2026-07-14 revision 03b6d3f889) +PRISM [arm64-darwin25]
sqlite3 (2.9.6)

[flavorjones]

This behavior is intentional. Documented in #736.

[forthrin]

This is a tricky one. It happened when Sinatra request body data using as an argument. Consider:

• HTML request data will variably be ASCII, ASCII 8-bit, UTF-8 or even other things.
• A notice/warning will just be annoying with lots of false positives.
• Implying BLOB for ASCII 8-bit is rational.
• It's a likely pitfall and head-scratcher that evades equality tests

So documentation really appears to be the proper solution. But suggest to put that fact front and center somewhere, or sneak it into a basic introductory example so people catch it incidentally.