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Thread::Backtrace::Location#absolute_path returns relative path for files loaded via load with bare relative path #9245

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Thread::Backtrace::Location#absolute_path returns relative path for files loaded via load with bare relative path#9245
@myronmarston

Description

@myronmarston
myronmarston
opened on Feb 17, 2026

Environment

  • JRuby 10.0.2.0 (Ruby 3.4.2 compat)
  • macOS / aarch64

Summary

Thread::Backtrace::Location#absolute_path returns a relative path (identical to #path) when the source file was loaded via Kernel#load with a bare relative path that is resolved via cwd (e.g. load "file.rb"). On MRI, absolute_path correctly resolves to the full absolute path.

The bug is specific to the case where load resolves the file via the current working directory. It does not occur when:

  • load is given a ./ prefix (e.g. load "./file.rb")
  • load is given an absolute path
  • load resolves the file via $LOAD_PATH
  • require is used (always resolves via $LOAD_PATH)
  • require_relative is used

Reproduction Script

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

# Reproduction: Thread::Backtrace::Location#absolute_path returns a relative path
# when the source file was loaded via `load` with a bare relative path.
#
# Expected: absolute_path always returns an absolute path (or nil).
# Actual on JRuby: absolute_path returns the same relative string as #path.

require "tmpdir"

class Capturer
  attr_reader :location

  def capture
    @location = caller_locations(1, 1).to_a.first
  end
end

capturer = Capturer.new
dir = Dir.mktmpdir
begin
  Dir.chdir(dir) do
    File.write("test_file.rb", <<~'RUBY')
      $capturer.capture
    RUBY
    $capturer = capturer

    puts "RUBY_ENGINE: #{RUBY_ENGINE}"
    puts "RUBY_VERSION: #{RUBY_VERSION}"
    puts "JRUBY_VERSION: #{defined?(JRUBY_VERSION) ? JRUBY_VERSION : 'N/A'}"
    puts

    # Helper to check result
    check = ->(loc) do
      abs = loc.absolute_path
      if abs && !abs.start_with?("/")
        puts "  BUG: absolute_path is not absolute!"
      else
        puts "  OK: absolute_path is absolute"
      end
    end

    # --- load ---

    # Case 1: load with bare relative path (BUG on JRuby)
    load "test_file.rb"
    loc = capturer.location
    puts '=== load "test_file.rb" (bare relative, cwd resolution) ==='
    puts "  path:          #{loc.path.inspect}"
    puts "  absolute_path: #{loc.absolute_path.inspect}"
    check.call(loc)
    puts

    # Case 2: load with bare relative path, dir in $LOAD_PATH (OK)
    $LOAD_PATH.unshift(dir)
    load "test_file.rb"
    loc = capturer.location
    puts '=== load "test_file.rb" (bare relative, $LOAD_PATH resolution) ==='
    puts "  path:          #{loc.path.inspect}"
    puts "  absolute_path: #{loc.absolute_path.inspect}"
    check.call(loc)
    $LOAD_PATH.delete(dir)
    puts

    # Case 3: load with ./ relative path (OK)
    load "./test_file.rb"
    loc = capturer.location
    puts '=== load "./test_file.rb" (./ relative path) ==='
    puts "  path:          #{loc.path.inspect}"
    puts "  absolute_path: #{loc.absolute_path.inspect}"
    check.call(loc)
    puts

    # Case 4: load with absolute path (OK)
    load File.join(dir, "test_file.rb")
    loc = capturer.location
    puts '=== load "/absolute/path/test_file.rb" ==='
    puts "  path:          #{loc.path.inspect}"
    puts "  absolute_path: #{loc.absolute_path.inspect}"
    check.call(loc)
    puts

    # --- require ---

    # Case 5: require via $LOAD_PATH (OK)
    $LOAD_PATH.unshift(dir)
    $LOADED_FEATURES.delete_if { |f| f.include?("test_file") }
    require "test_file"
    loc = capturer.location
    puts '=== require "test_file" (via $LOAD_PATH) ==='
    puts "  path:          #{loc.path.inspect}"
    puts "  absolute_path: #{loc.absolute_path.inspect}"
    check.call(loc)
    $LOAD_PATH.delete(dir)
    puts

    # Case 6: require with ./ relative path (OK)
    $LOADED_FEATURES.delete_if { |f| f.include?("test_file") }
    require "./test_file"
    loc = capturer.location
    puts '=== require "./test_file" (./ relative path) ==='
    puts "  path:          #{loc.path.inspect}"
    puts "  absolute_path: #{loc.absolute_path.inspect}"
    check.call(loc)
    puts

    # Case 7: require_relative (OK)
    File.write("wrapper.rb", "require_relative 'test_file'\n")
    $LOADED_FEATURES.delete_if { |f| f.include?("test_file") }
    load "wrapper.rb"
    loc = capturer.location
    puts '=== require_relative "test_file" (via wrapper) ==='
    puts "  path:          #{loc.path.inspect}"
    puts "  absolute_path: #{loc.absolute_path.inspect}"
    check.call(loc)
  end
ensure
  FileUtils.rm_rf(dir)
end

Expected Behavior

Here's what that script produces on MRI 3.4.5:

RUBY_ENGINE: ruby
RUBY_VERSION: 3.4.5
JRUBY_VERSION: N/A

=== load "test_file.rb" (bare relative, cwd resolution) ===
  path:          "test_file.rb"
  absolute_path: "/private/var/folders/t0/0v26g3fs33gc0vk7hydx3wzw0000gp/T/d20260216-34796-kjeupa/test_file.rb"
  OK: absolute_path is absolute

=== load "test_file.rb" (bare relative, $LOAD_PATH resolution) ===
  path:          "/private/var/folders/t0/0v26g3fs33gc0vk7hydx3wzw0000gp/T/d20260216-34796-kjeupa/test_file.rb"
  absolute_path: "/private/var/folders/t0/0v26g3fs33gc0vk7hydx3wzw0000gp/T/d20260216-34796-kjeupa/test_file.rb"
  OK: absolute_path is absolute

=== load "./test_file.rb" (./ relative path) ===
  path:          "/private/var/folders/t0/0v26g3fs33gc0vk7hydx3wzw0000gp/T/d20260216-34796-kjeupa/test_file.rb"
  absolute_path: "/private/var/folders/t0/0v26g3fs33gc0vk7hydx3wzw0000gp/T/d20260216-34796-kjeupa/test_file.rb"
  OK: absolute_path is absolute

=== load "/absolute/path/test_file.rb" ===
  path:          "/var/folders/t0/0v26g3fs33gc0vk7hydx3wzw0000gp/T/d20260216-34796-kjeupa/test_file.rb"
  absolute_path: "/private/var/folders/t0/0v26g3fs33gc0vk7hydx3wzw0000gp/T/d20260216-34796-kjeupa/test_file.rb"
  OK: absolute_path is absolute

=== require "test_file" (via $LOAD_PATH) ===
  path:          "/private/var/folders/t0/0v26g3fs33gc0vk7hydx3wzw0000gp/T/d20260216-34796-kjeupa/test_file.rb"
  absolute_path: "/private/var/folders/t0/0v26g3fs33gc0vk7hydx3wzw0000gp/T/d20260216-34796-kjeupa/test_file.rb"
  OK: absolute_path is absolute

=== require "./test_file" (./ relative path) ===
  path:          "/private/var/folders/t0/0v26g3fs33gc0vk7hydx3wzw0000gp/T/d20260216-34796-kjeupa/test_file.rb"
  absolute_path: "/private/var/folders/t0/0v26g3fs33gc0vk7hydx3wzw0000gp/T/d20260216-34796-kjeupa/test_file.rb"
  OK: absolute_path is absolute

=== require_relative "test_file" (via wrapper) ===
  path:          "/private/var/folders/t0/0v26g3fs33gc0vk7hydx3wzw0000gp/T/d20260216-34796-kjeupa/test_file.rb"
  absolute_path: "/private/var/folders/t0/0v26g3fs33gc0vk7hydx3wzw0000gp/T/d20260216-34796-kjeupa/test_file.rb"
  OK: absolute_path is absolute

Actual Behavior

Here's the result on JRuby:

RUBY_ENGINE: jruby
RUBY_VERSION: 3.4.2
JRUBY_VERSION: 10.0.2.0

=== load "test_file.rb" (bare relative, cwd resolution) ===
  path:          "test_file.rb"
  absolute_path: "test_file.rb"
  BUG: absolute_path is not absolute!

=== load "test_file.rb" (bare relative, $LOAD_PATH resolution) ===
  path:          "/private/var/folders/t0/0v26g3fs33gc0vk7hydx3wzw0000gp/T/d20260216-33652-d19nm7/test_file.rb"
  absolute_path: "/private/var/folders/t0/0v26g3fs33gc0vk7hydx3wzw0000gp/T/d20260216-33652-d19nm7/test_file.rb"
  OK: absolute_path is absolute

=== load "./test_file.rb" (./ relative path) ===
  path:          "/private/var/folders/t0/0v26g3fs33gc0vk7hydx3wzw0000gp/T/d20260216-33652-d19nm7/test_file.rb"
  absolute_path: "/private/var/folders/t0/0v26g3fs33gc0vk7hydx3wzw0000gp/T/d20260216-33652-d19nm7/test_file.rb"
  OK: absolute_path is absolute

=== load "/absolute/path/test_file.rb" ===
  path:          "/private/var/folders/t0/0v26g3fs33gc0vk7hydx3wzw0000gp/T/d20260216-33652-d19nm7/test_file.rb"
  absolute_path: "/private/var/folders/t0/0v26g3fs33gc0vk7hydx3wzw0000gp/T/d20260216-33652-d19nm7/test_file.rb"
  OK: absolute_path is absolute

=== require "test_file" (via $LOAD_PATH) ===
  path:          "/private/var/folders/t0/0v26g3fs33gc0vk7hydx3wzw0000gp/T/d20260216-33652-d19nm7/test_file.rb"
  absolute_path: "/private/var/folders/t0/0v26g3fs33gc0vk7hydx3wzw0000gp/T/d20260216-33652-d19nm7/test_file.rb"
  OK: absolute_path is absolute

=== require "./test_file" (./ relative path) ===
  path:          "/private/var/folders/t0/0v26g3fs33gc0vk7hydx3wzw0000gp/T/d20260216-33652-d19nm7/test_file.rb"
  absolute_path: "/private/var/folders/t0/0v26g3fs33gc0vk7hydx3wzw0000gp/T/d20260216-33652-d19nm7/test_file.rb"
  OK: absolute_path is absolute

=== require_relative "test_file" (via wrapper) ===
  path:          "/private/var/folders/t0/0v26g3fs33gc0vk7hydx3wzw0000gp/T/d20260216-33652-d19nm7/test_file.rb"
  absolute_path: "/private/var/folders/t0/0v26g3fs33gc0vk7hydx3wzw0000gp/T/d20260216-33652-d19nm7/test_file.rb"
  OK: absolute_path is absolute

Scope of the bug

Method Affected?
load "file.rb" (cwd resolution) YES
load "file.rb" ($LOAD_PATH resolution) no
load "./file.rb" no
load "/absolute/path/file.rb" no
require "file" (via $LOAD_PATH) no
require "./file" no
require_relative "file" no

Impact

Code that relies on absolute_path being absolute (e.g. Pathname#relative_path_from) fails with ArgumentError: different prefix.

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