Make pry opt-in on dbg with --dbg pry

Author: josevalim

bin/elixir

@@ -114,7 +114,7 @@ while [ $I -le $LENGTH ]; do
         C=1
         MODE="elixirc"
         ;;
-    -v|--no-halt|--no-pry)
+    -v|--no-halt|--dbg)
         C=1
         ;;
     -e|-r|-pr|-pa|-pz|--app|--eval|--remsh|--dot-iex)

bin/elixir.bat

@@ -143,7 +143,7 @@ if ""==!par:--app=!       (set "parsElixir=!parsElixir! --app %~1" && shift && g
 if ""==!par:--no-halt=!   (set "parsElixir=!parsElixir! --no-halt" && goto startloop)
 if ""==!par:--remsh=!     (set "parsElixir=!parsElixir! --remsh %~1" && shift && goto startloop)
 if ""==!par:--dot-iex=!   (set "parsElixir=!parsElixir! --dot-iex %~1" && shift && goto startloop)
-if ""==!par:--no-pry=!    (set "parsElixir=!parsElixir! --no-pry" && goto startloop)
+if ""==!par:--dbg=!       (set "parsElixir=!parsElixir! --dbg %~1" && shift && goto startloop)
 rem ******* ERLANG PARAMETERS **********************
 if ""==!par:--boot=!                (set "parsErlang=!parsErlang! -boot %~1" && shift && goto startloop)
 if ""==!par:--boot-var=!            (set "parsErlang=!parsErlang! -boot_var %~1 %~2" && shift && shift && goto startloop)

bin/iex

@@ -7,11 +7,11 @@ Usage: $(basename "$0") [options] [.exs file] [data]
 
 The following options are exclusive to IEx:
 
+  --dbg pry           Sets the backend for Kernel.dbg/2 to IEx.pry/0
   --dot-iex "FILE"    Evaluates FILE, line by line, to set up IEx' environment.
                       Defaults to evaluating .iex.exs or ~/.iex.exs, if any exists.
                       If FILE is empty, then no file will be loaded.
   --remsh NAME        Connects to a node using a remote shell.
-  --no-pry            Doesn't start pry sessions when dbg/2 is called.
 
 It accepts all other options listed by "elixir --help".
 USAGE

bin/iex.bat

@@ -11,12 +11,12 @@ echo Usage: %~nx0 [options] [.exs file] [data]
 echo.
 echo The following options are exclusive to IEx:
 echo.
+echo   --dbg pry           Sets the backend for Kernel.dbg/2 to IEx.pry/0
 echo   --dot-iex "FILE"    Evaluates FILE, line by line, to set up IEx' environment.
 echo                       Defaults to evaluating .iex.exs or ~/.iex.exs, if any exists.
 echo                       If FILE is empty, then no file will be loaded.
 echo   --remsh NAME        Connects to a node using a remote shell
 echo   --werl              Uses Erlang's Windows shell GUI (Windows only)
-echo   --no-pry            Doesn't start pry sessions when dbg/2 is called.
 echo.
 echo Set the IEX_WITH_WERL environment variable to always use werl.
 echo It accepts all other options listed by "elixir --help".

lib/elixir/lib/kernel.ex

@@ -5870,17 +5870,16 @@ defmodule Kernel do
 
   ## `dbg` inside IEx
 
-  IEx integrates with `dbg` to provide additional features:
+  You can enable IEx to replace `dbg` with its `IEx.pry/0` backend by calling:
 
-    * If you have IEx running and you call `dbg`, it will start a `pry`
-      session where you can interact with the imports, aliases, and
-      variables of the current environment at the location of the `dbg` call
+      $ iex --dbg pry
 
-    * If you call `dbg` at the end of a pipeline (using `|>`) within IEx,
-      you are able to go through each step of the pipeline one by one by
-      entering "next" (or "n")
+  In such cases, `dbg` will start a `pry` session where you can interact with
+  the imports, aliases, and variables of the current environment at the location
+  of the `dbg` call.
 
-    * You can disable this behaviour by calling `iex --no-pry`
+  If you call `dbg` at the end of a pipeline (using `|>`) within IEx, you are able
+  to go through each step of the pipeline one by one by entering "next" (or "n").
 
   Note `dbg` only supports stepping for pipelines (in other words, it can only
   step through the code it sees). For general stepping, you can set breakpoints

lib/elixir/lib/kernel/cli.ex

@@ -326,7 +326,7 @@ defmodule Kernel.CLI do
   end
 
   defp parse_argv(["+iex" | t], config) do
-    parse_iex(t, %{config | pry: true})
+    parse_iex(t, config)
   end
 
   defp parse_argv(["-S", h | t], config) do
@@ -416,11 +416,17 @@ defmodule Kernel.CLI do
   end
 
   # These clauses are here so that Kernel.CLI does not error out with "unknown option"
+  defp parse_iex(["--dbg", backend | t], config) do
+    case backend do
+      "pry" -> parse_iex(t, %{config | pry: true})
+      "kernel" -> parse_iex(t, %{config | pry: false})
+      _ -> {:error, "--dbg : Unknown dbg backend #{inspect(backend)}"}
+    end
+  end
+
   defp parse_iex(["--dot-iex", _ | t], config), do: parse_iex(t, config)
   defp parse_iex(["--remsh", _ | t], config), do: parse_iex(t, config)
 
-  defp parse_iex(["--no-pry" | t], config), do: parse_iex(t, %{config | pry: false})
-
   defp parse_iex([h | t] = list, config) do
     case h do
       "-" <> _ -> shared_option?(list, config, &parse_iex(&1, &2))

lib/iex/lib/iex.ex

@@ -173,16 +173,20 @@ defmodule IEx do
   ## `dbg` and breakpoints
 
   IEx integrates with `Kernel.dbg/2` and introduces a backend that
-  can pause code execution:
+  can pause code execution. To enable it, you must pass `--dbg pry`:
+
+      $ iex --dbg pry
+
+  For example, take the following function:
 
       def my_fun(arg1, arg2) do
         dbg(arg1 + arg2)
         ... implementation ...
       end
 
   When the code is executed with `iex` (most often by calling
-  `iex -S mix`), it will ask you permission to use "pry". If you
-  agree, it will start an IEx shell in the context of the function
+  `iex --dbg pry -S mix`), it will ask you permission to use "pry".
+  If you agree, it will start an IEx shell in the context of the function
   above, with access to its variables, imports, and aliases. However,
   you can only access existing values, it is not possible to access
   private functions nor change the execution itself (hence the name
@@ -194,7 +198,6 @@ defmodule IEx do
   of the steps but stay within the pried process. Type `respawn` when
   you want to leave the pried process and start a new shell.
 
-  You can disable "pry" as the `dbg/2` backend by calling `iex --no-pry`.
   Alternatively, you can start a pry session directly, without `dbg/2`
   by calling `IEx.pry/0`.