Use dap mode layer for python debugging

- I had to remove the "db" keybinding manually before setting the dap bindings.
  An alternative approach is to use a different binding for it.

CHANGELOG.develop

@@ -1881,6 +1881,7 @@ Other:
 - Fixed conflict between pipenv directory .venv and pyvenv file .venv (thanks to
   rgb-24bit)
 - Added diminish for importmagic (thanks to Loys Ollivier)
+- Added debugger integration via =dap= layer
 **** Racket
 - Restore smart closing paren behavior in racket-mode (thanks to Don March)
 **** Ranger

layers/+lang/python/README.org

@@ -18,6 +18,7 @@
   - [[#automatic-save-of-buffer-when-testing][Automatic save of buffer when testing]]
   - [[#autoflake][autoflake]]
   - [[#pylookup][pylookup]]
+  - [[#dap-mode-debuggeronly-for-lsp-backend][dap-mode debugger(only for lsp backend)]]
 - [[#configuration][Configuration]]
   - [[#fill-column][Fill column]]
   - [[#sort-imports][Sort imports]]
@@ -33,6 +34,7 @@
   - [[#pip-package-management][Pip package management]]
   - [[#live-coding][Live coding]]
   - [[#other-python-commands][Other Python commands]]
+  - [[#debugger][Debugger]]
 
 * Description
 This layer adds support for the Python language.
@@ -191,6 +193,11 @@ To be able to suppress unused imports easily, install [[https://github.com/myint
 To use =pylookup= on ~SPC m h H~, make sure you update the database first, using
 ~SPC SPC pylookup-update~.
 
+** dap-mode debugger(only for lsp backend)
+To use =dap-mode= for debugging do:
+#+BEGIN_SRC bash
+  pip install "ptvsd>=4.2"
+#+END_SRC
 * Configuration
 ** Fill column
 If you want to customize the fill column value, use something like this inside
@@ -377,3 +384,49 @@ Live coding is provided by the [[https://github.com/donkirkby/live-py-plugin][li
 | ~SPC m v p o~ | open pipenv module in buffer                                                      |
 | ~SPC m v p s~ | launch pipenv shell in current project                                            |
 | ~SPC m v p u~ | uninstall module from pipenv environment                                          |
+** Debugger
+
+| Key binding   | Description                     |
+|---------------+---------------------------------|
+| ~SPC m d d d~ | start debugging                 |
+| ~SPC m d d l~ | debug last configuration        |
+| ~SPC m d d r~ | debug recent configuration      |
+|---------------+---------------------------------|
+| ~SPC m d c~   | continue                        |
+| ~SPC m d i~   | step in                         |
+| ~SPC m d o~   | step out                        |
+| ~SPC m d s~   | next step                       |
+| ~SPC m d v~   | inspect value at point          |
+| ~SPC m d r~   | restart frame                   |
+|---------------+---------------------------------|
+| ~SPC m d .~   | debug transient state           |
+|---------------+---------------------------------|
+| ~SPC m d a~   | abandon current session         |
+| ~SPC m d A~   | abandon all process             |
+|---------------+---------------------------------|
+| ~SPC m d e e~ | eval                            |
+| ~SPC m d e r~ | eval region                     |
+| ~SPC m d e t~ | eval value at point             |
+|---------------+---------------------------------|
+| ~SPC m d S s~ | switch session                  |
+| ~SPC m d S t~ | switch thread                   |
+| ~SPC m d S f~ | switch frame                    |
+|---------------+---------------------------------|
+| ~SPC m d I i~ | inspect                         |
+| ~SPC m d I r~ | inspect region                  |
+| ~SPC m d I t~ | inspect value at point          |
+|---------------+---------------------------------|
+| ~SPC m d b b~ | toggle a breakpoint             |
+| ~SPC m d b c~ | change breakpoint condition     |
+| ~SPC m d b l~ | change breakpoint log condition |
+| ~SPC m d b h~ | change breakpoint hit count     |
+| ~SPC m d b a~ | add a breakpoint                |
+| ~SPC m d b d~ | delete a breakpoint             |
+| ~SPC m d b D~ | clear all breakpoints           |
+|---------------+---------------------------------|
+| ~SPC m d '_~  | Run debug REPL                  |
+|---------------+---------------------------------|
+| ~SPC m d w l~ | list local variables            |
+| ~SPC m d w o~ | goto output buffer if present   |
+| ~SPC m d w s~ | list sessions                   |
+| ~SPC m d w b~ | list breakpoints                |

layers/+lang/python/funcs.el

@@ -69,7 +69,13 @@ when this mode is enabled since the minibuffer is cleared all the time."
   "Setup lsp backend."
   (if (configuration-layer/layer-used-p 'lsp)
       (lsp)
-    (message "`lsp' layer is not installed, please add `lsp' layer to your dotfile.")))
+    (message "`lsp' layer is not installed, please add `lsp' layer to your dotfile."))
+  (if (configuration-layer/layer-used-p 'dap)
+    (progn
+      (require 'dap-python)
+      (spacemacs/set-leader-keys-for-major-mode 'python-mode "db" nil)
+      (spacemacs/dap-bind-keys-for-mode 'python-mode))
+    (message "`dap' layer is not installed, please add `dap' layer to your dotfile.")))
 
 (defun spacemacs//python-setup-lsp-company ()
   "Setup lsp auto-completion."