Set Up a Development Environment

$ git clone git@github.com:ruby/debug.git
$ bundle install
$ rake - this will
- Compile the C extension locally (which can also be done solely with rake compile).
- Run tests.
- Re-generate README.md.

If you spot any problem, please open an issue.

Run Tests

Run all tests

$ rake test_all

Run all console tests

$ rake test_console

Run all protocol (DAP & CDP) tests

$ rake test_protocol

Run specific test(s)

$ ruby test/console/break_test.rb # run all tests in the specified file
$ ruby test/console/break_test.rb -h # to see all the test options

Generate Tests

There is a test generator in debug.rb project to make it easier to write tests.

Quickstart

This section shows you how to create test file by test generator. For more advanced information on creating tests, please take a look at gentest options. (You can also check by $bin/gentest -h)

1. Create a target file for debuggee.

Let's say, we created target.rb which is located in top level directory of debugger.

module Foo
  class Bar
    def self.a
      "hello"
    end
  end
  Bar.a
  bar = Bar.new
end

2. Run `gentest` as shown in the example below.

$ bin/gentest target.rb

3. Debugger will be executed. You can type any debug commands.

$ bin/gentest target.rb
DEBUGGER: Session start (pid: 11139)
[1, 9] in ~/workspace/debug/target.rb
=>   1| module Foo
     2|   class Bar
     3|     def self.a
     4|       "hello"
     5|     end
     6|   end
     7|   Bar.a
     8|   bar = Bar.new
     9| end
=>#0	<main> at ~/workspace/debug/target.rb:1
INTERNAL_INFO: {"location":"~/workspace/debug/target.rb:1","line":1}
(rdbg)s
 s
[1, 9] in ~/workspace/debug/target.rb
     1| module Foo
=>   2|   class Bar
     3|     def self.a
     4|       "hello"
     5|     end
     6|   end
     7|   Bar.a
     8|   bar = Bar.new
     9| end
=>#0	<module:Foo> at ~/workspace/debug/target.rb:2
  #1	<main> at ~/workspace/debug/target.rb:1
INTERNAL_INFO: {"location":"~/workspace/debug/target.rb:2","line":2}
(rdbg)n
 n
[1, 9] in ~/workspace/debug/target.rb
     1| module Foo
     2|   class Bar
=>   3|     def self.a
     4|       "hello"
     5|     end
     6|   end
     7|   Bar.a
     8|   bar = Bar.new
     9| end
=>#0	<class:Bar> at ~/workspace/debug/target.rb:3
  #1	<module:Foo> at ~/workspace/debug/target.rb:2
  # and 1 frames (use `bt' command for all frames)
INTERNAL_INFO: {"location":"~/workspace/debug/target.rb:3","line":3}
(rdbg)b 7
 b 7
#0  BP - Line  /Users/naotto/workspace/debug/target.rb:7 (line)
INTERNAL_INFO: {"location":"~/workspace/debug/target.rb:3","line":3}
(rdbg)c
 c
[2, 9] in ~/workspace/debug/target.rb
     2|   class Bar
     3|     def self.a
     4|       "hello"
     5|     end
     6|   end
=>   7|   Bar.a
     8|   bar = Bar.new
     9| end
=>#0	<module:Foo> at ~/workspace/debug/target.rb:7
  #1	<main> at ~/workspace/debug/target.rb:1

Stop by #0  BP - Line  /Users/naotto/workspace/debug/target.rb:7 (line)
INTERNAL_INFO: {"location":"~/workspace/debug/target.rb:7","line":7}
(rdbg)q!
 q!
created: /Users/naotto/workspace/debug/test/tool/../debug/foo_test.rb
    class: FooTest
    method: test_1629720194

4. The test file will be created as `test/debug/foo_test.rb`.

If the file already exists, only method will be added to it.

# frozen_string_literal: true

require_relative '../support/console_test_case'

module DEBUGGER__
  class FooTest < ConsoleTestCase
    def program
      <<~RUBY
        1| module Foo
        2|   class Bar
        3|     def self.a
        4|       "hello"
        5|     end
        6|   end
        7|   Bar.a
        8|   bar = Bar.new
        9| end
      RUBY
    end

    def test_1629720194
      debug_code(program) do
        type 's'
        assert_line_num 2
        assert_line_text([
          /\[1, 9\] in .*/,
          /     1\| module Foo/,
          /=>   2\|   class Bar/,
          /     3\|     def self\.a/,
          /     4\|       "hello"/,
          /     5\|     end/,
          /     6\|   end/,
          /     7\|   Bar\.a/,
          /     8\|   bar = Bar\.new/,
          /     9\| end/,
          /=>\#0\t<module:Foo> at .*/,
          /  \#1\t<main> at .*/
        ])
        type 'n'
        assert_line_num 3
        assert_line_text([
          /\[1, 9\] in .*/,
          /     1\| module Foo/,
          /     2\|   class Bar/,
          /=>   3\|     def self\.a/,
          /     4\|       "hello"/,
          /     5\|     end/,
          /     6\|   end/,
          /     7\|   Bar\.a/,
          /     8\|   bar = Bar\.new/,
          /     9\| end/,
          /=>\#0\t<class:Bar> at .*/,
          /  \#1\t<module:Foo> at .*/,
          /  \# and 1 frames \(use `bt' command for all frames\)/
        ])
        type 'b 7'
        assert_line_text(/\#0  BP \- Line  .*/)
        type 'c'
        assert_line_num 7
        assert_line_text([
          /\[2, 9\] in .*/,
          /     2\|   class Bar/,
          /     3\|     def self\.a/,
          /     4\|       "hello"/,
          /     5\|     end/,
          /     6\|   end/,
          /=>   7\|   Bar\.a/,
          /     8\|   bar = Bar\.new/,
          /     9\| end/,
          /=>\#0\t<module:Foo> at .*/,
          /  \#1\t<main> at .*/,
          //,
          /Stop by \#0  BP \- Line  .*/
        ])
        type 'q!'
      end
    end
  end
end

gentest options

You can get more information about gentest here.

The default method name is test_#{some integer numbers}, the class name is FooTest#{some integer numbers}, and the file name will be foo_test.rb. The following table shows examples of the gentest options.

Command	Description	File	Class	Method
`$ bin/gentest target.rb`	Run without any options	`foo_test.rb`	`FooTest...`	`test_...`
`$ bin/gentest target.rb --open=vscode`	Run the debugger with VScode	`foo_test.rb`	`FooTest...`	`test_...`
`$ bin/gentest target.rb -c step`	Specify the class name	`step_test.rb`	`StepTest...`	`test_...`
`$ bin/gentest target.rb -m test_step`	Specify the method name	`foo_test.rb`	`FooTest...`	`test_step`
`$ bin/gentest target.rb -c step -m test_step`	Specify the class name and the method name	`step_test.rb`	`StepTest...`	`test_step`

Assertions

assert_line_num(expected)

Passes if expected is equal to the location where debugger stops.

assert_line_text(text)

Passes if text is included in the last debugger log.

assert_no_line_text(text)

Passes if text is not included in the last debugger log.

assert_debuggee_line_text(text)

Passes if text is included in the debuggee log.

Tests for DAP and CDP

Currently, there are 2 kinds of test frameworks for DAP and CDP.

Protocol-based tests

If you want to write protocol-based tests, you should use the test generator. To run the test generator, you can enter $ bin/gentest target.rb --open=vscode in the terminal, VSCode will be executed. Also, if you enter $ bin/gentest target.rb --open=chrome there, Chrome will be executed. If you need to modify existing tests, it is basically a good idea to regenerate them by the test generator instead of rewriting them directly. Please refer to the Microsoft "Debug Adapter Protocol" article to learn more about DAP formats. Please refer to the "Chrome DevTools Protocol" official documentation to learn more about CDP formats.

High-level tests

High-level tests are designed to test both DAP and CDP for a single method. You can write tests as follows: NOTE: Use req_terminate_debuggee to finish debugging. You can't use any methods such as req_continue, req_next and so on.

require_relative '../support/test_case'
module DEBUGGER__
  class BreakTest < TestCase
    # PROGRAM is the target script.
    PROGRAM = <<~RUBY
      1| module Foo
      2|   class Bar
      3|     def self.a
      4|       "hello"
      5|     end
      6|   end
      7|   Bar.a
      8|   bar = Bar.new
      9| end
    RUBY

    def test_break1
      run_protocol_scenario PROGRAM do # Start debugging with DAP and CDP
        req_add_breakpoint 5 # Set a breakpoint on line 5.
        req_add_breakpoint 8 # Set a breakpoint on line 8.
        req_continue # Resume the program.
        assert_line_num 5 # Check if debugger stops at line 5.
        req_continue # Resume the program.
        assert_line_num 8 # Check if debugger stops at line 8.
        req_terminate_debuggee # Terminate debugging.
      end
    end
  end
end

API

run_protocol_scenario program, dap: true, cdp: true, &scenario

Execute debugging program with &scenario. If you want to test it only for DAP, you can write as follows:

run_protocol_scenario program, cdp: false ...

attach_to_dap_server(terminate_debuggee:)

Attach to the running DAP server through UNIX Domain Socket.

attach_to_cdp_server

Attach to the running CDP server through TCP/IP.

req_dap_disconnect

Disconnect from the currently connected DAP server.

req_cdp_disconnect

Disconnect from the currently connected CDP server.

req_add_breakpoint(lineno, path: temp_file_path, cond: nil)

Sends request to rdbg to add a breakpoint.

req_delete_breakpoint bpnum

Sends request to rdbg to delete a breakpoint.

req_set_exception_breakpoints(breakpoints)

Sends request to rdbg to set exception breakpoints. e.g.

req_set_exception_breakpoints([{ name: "RuntimeError", condition: "a == 1" }])

Please note that setExceptionBreakpoints resets all exception breakpoints in every request.

So the following code will only set breakpoint for Exception.

req_set_exception_breakpoints([{ name: "RuntimeError" }])
req_set_exception_breakpoints([{ name: "Exception" }])

This means you can also use

req_set_exception_breakpoints([])

to clear all exception breakpoints.

req_continue

Sends request to rdbg to resume the program.

req_step

Sends request to rdbg to step into next method.

req_next

Sends request to rdbg to step over next method.

req_finish

Sends request to rdbg to step out of current method.

req_step_back

Sends request to rdbg to step back from current method.

req_terminate_debuggee

Sends request to rdbg to terminate the debuggee.

assert_hover_result(expected, expression)

Passes if result of expression matches expected.

expected need to be a Hash object as follows:

assert_hover_result({value: '2', type: 'Integer'}, 'a')

NOTE: value and type need to be strings.

assert_repl_result(expected, expression)

Passes if result of expression matches expected.

expected need to be a Hash object as follows:

assert_repl_result({value: '2', type: 'Integer'}, 'a')

NOTE: value and type need to be strings.

assert_watch_result(expected, expression)

Passes if result of expression matches expected.

expected need to be a Hash object as follows:

assert_watch_result({value: '2', type: 'Integer'}, 'a')

NOTE: value and type need to be strings.

assert_line_num(expected)

Passes if expected is equal to the location where debugger stops.

assert_locals_result(expected)

Passes if all of expected local variable entries match the ones returned by debugger.

An variable entry looks like this: { name: "bar", value: "nil", type: "NilClass" }.

Please note that both value and type need to be strings.

assert_threads_result(expected)

Passes if both conditions are true:

The number of expected patterns matches the number of threads.
Every pattern matches a thread name. Notice that the order of threads info is not guaranteed.

Example:

assert_threads_result(
  [
    /\.rb:\d:in `<main>'/,
    /\.rb:\d:in `block in foo'/
  ]
)

To Update README

This project generates README.md from the template misc/README.md.erb

So do not directly update README.md. Instead, you should update the template's source and run

$ rake

to reflect the changes on README.md.

When to re-generate `README.md`

After updating misc/README.md.erb.
After updating rdbg executable's options.
After updating comments of debugger's commands.

Manually Test Your Changes

You can manually test your changes with a simple Ruby script + a line of command. The following example will help you check:

Breakpoint insertion.
Resume from the breakpoint.
Backtrace display.
Information (local variables, ivars..etc.) display.
Debugger exit.

Script

# target.rb
class Foo
  def first_call
    second_call(20)
  end

  def second_call(num)
    third_call_with_block do |ten|
      forth_call(num, ten)
    end
  end

  def third_call_with_block(&block)
    @ivar1 = 10; @ivar2 = 20

    yield(10)
  end

  def forth_call(num1, num2)
    num1 + num2
  end
end

Foo.new.first_call

Command

$ exe/rdbg -e 'b 20;; c ;; bt ;; info ;; q!' -e c target.rb

Expect Result

❯ exe/rdbg -e 'b 20;; c ;; bt ;; info ;; q!' -e c target.rb
DEBUGGER: Session start (pid: 9815)
[1, 10] in target.rb
=>    1| class Foo
      2|   def first_call
      3|     second_call(20)
      4|   end
      5|
      6|   def second_call(num)
      7|     third_call_with_block do |ten|
      8|       forth_call(num, ten)
      9|     end
     10|   end
=>#0    <main> at target.rb:1
(rdbg:commands) b 20
#0  BP - Line  /PATH_TO_PROJECT/target.rb:20 (return)
(rdbg:commands) c
[15, 24] in target.rb
     15|     yield(10)
     16|   end
     17|
     18|   def forth_call(num1, num2)
     19|     num1 + num2
=>   20|   end
     21| end
     22|
     23| Foo.new.first_call
     24|
=>#0    Foo#forth_call(num1=20, num2=10) at target.rb:20 #=> 30
  #1    block {|ten=10|} in second_call at target.rb:8
  # and 4 frames (use `bt' command for all frames)

Stop by #0  BP - Line  /PATH_TO_PROJECT/target.rb:20 (return)
(rdbg:commands) bt
=>#0    Foo#forth_call(num1=20, num2=10) at target.rb:20 #=> 30
  #1    block {|ten=10|} in second_call at target.rb:8
  #2    Foo#third_call_with_block(block=#<Proc:0x00007f9283101568 target.rb:7>) at target.rb:15
  #3    Foo#second_call(num=20) at target.rb:7
  #4    Foo#first_call at target.rb:3
  #5    <main> at target.rb:23
(rdbg:commands) info
=>#0    Foo#forth_call(num1=20, num2=10) at target.rb:20 #=> 30
%self => #<Foo:0x00007f92831016d0 @ivar1=10, @ivar2=20>
%return => 30
num1 => 20
num2 => 10
@ivar1 => 10
@ivar2 => 20
(rdbg:commands) q!

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