From 896b20f49004831fa2378c5e344f1804cdf35fa6 Mon Sep 17 00:00:00 2001
From: Ben Jackson <puremourning@gmail.com>
Date: Sun, 2 Feb 2020 17:31:05 +0000
Subject: [PATCH 1/2] Hackaround for missing 'env' in termopen and jobstart in
 neovim

---
 autoload/vimspector/internal/neojob.vim  | 30 ++++++++++++-------
 autoload/vimspector/internal/neoterm.vim | 38 ++++++++++++++++++++++--
 2 files changed, 56 insertions(+), 12 deletions(-)

diff --git a/autoload/vimspector/internal/neojob.vim b/autoload/vimspector/internal/neojob.vim
index f885337..2a87c4c 100644
--- a/autoload/vimspector/internal/neojob.vim
+++ b/autoload/vimspector/internal/neojob.vim
@@ -44,17 +44,27 @@ function! vimspector#internal#neojob#StartDebugSession( config ) abort
     return v:false
   endif
 
-  let s:job = jobstart( a:config[ 'command' ],
-        \                {
-        \                    'on_stdout': funcref( 's:_OnEvent' ),
-        \                    'on_stderr': funcref( 's:_OnEvent' ),
-        \                    'on_exit': funcref( 's:_OnEvent' ),
-        \                    'cwd': a:config[ 'cwd' ],
-        \                    'env': a:config[ 'env' ],
-        \                }
-        \              )
 
-  " FIXME: env might not work: Missing in neovim 0.4. But in master:
+  " HACK: Workaround for 'env' not being supported.
+
+  let old_env={}
+  try
+    let old_env = vimspector#internal#neoterm#PrepareEnvironment(
+          \ a:config[ 'env' ] )
+    let s:job = jobstart( a:config[ 'command' ],
+          \                {
+          \                    'on_stdout': funcref( 's:_OnEvent' ),
+          \                    'on_stderr': funcref( 's:_OnEvent' ),
+          \                    'on_exit': funcref( 's:_OnEvent' ),
+          \                    'cwd': a:config[ 'cwd' ],
+          \                    'env': a:config[ 'env' ],
+          \                }
+          \              )
+  finally
+    call vimspector#internal#neoterm#ResetEnvironment( a:config[ 'env' ],
+                                                     \ old_env )
+  endtry
+
   return v:true
 endfunction
 
diff --git a/autoload/vimspector/internal/neoterm.vim b/autoload/vimspector/internal/neoterm.vim
index ab71b2f..627f570 100644
--- a/autoload/vimspector/internal/neoterm.vim
+++ b/autoload/vimspector/internal/neoterm.vim
@@ -25,6 +25,27 @@ set cpoptions&vim
 " FIXME: Tidy this map when buffers are closed ?
 let s:buffer_to_id = {}
 
+function! vimspector#internal#neoterm#PrepareEnvironment( env ) abort
+  let old_env = {}
+
+  let new_env = copy( environ() )
+  for key in keys( a:env )
+    if has_key( new_env, key )
+      let old_env[ key ] = new_env[ key ]
+    endif
+    call setenv( key, a:env[ key ] )
+  endfor
+
+  return old_env
+endfunction
+
+function! vimspector#internal#neoterm#ResetEnvironment( env, old_env ) abort
+  for key in keys( a:env )
+    let value = get( a:old_env, key, v:null )
+    call setenv( key, value )
+  endfor
+endfunction
+
 function! vimspector#internal#neoterm#Start( cmd, opts ) abort
   if ! get( a:opts, 'curwin', 0 )
     if get( a:opts, 'vertical', 0 )
@@ -34,8 +55,21 @@ function! vimspector#internal#neoterm#Start( cmd, opts ) abort
     endif
   endif
 
-  " FIXME: 'env' doesn't work
-  let id = termopen( a:cmd, { 'cwd': a:opts[ 'cwd' ] } )
+  " HACK: Neovim's termopen doesn't support env
+
+  let old_env={}
+  try
+    let old_env = vimspector#internal#neoterm#PrepareEnvironment(
+          \ a:opts[ 'env' ] )
+    let id = termopen( a:cmd, {
+          \ 'cwd': a:opts[ 'cwd' ],
+          \ 'env': a:opts[ 'env' ],
+          \ } )
+  finally
+    call vimspector#internal#neoterm#ResetEnvironment( a:opts[ 'env' ],
+                                                     \ old_env )
+  endtry
+
   let bufnr = bufnr()
   let s:buffer_to_id[ bufnr ] = id
   return bufnr

From 6878c80cfbfe993fe3a2213c98d5762f588a373e Mon Sep 17 00:00:00 2001
From: Ben Jackson <puremourning@gmail.com>
Date: Sun, 2 Feb 2020 17:33:33 +0000
Subject: [PATCH 2/2] Update readme for environment hackaround

---
 README.md | 8 --------
 1 file changed, 8 deletions(-)

diff --git a/README.md b/README.md
index 76df4a7..1811a04 100644
--- a/README.md
+++ b/README.md
@@ -174,7 +174,6 @@ neovim doesn't implement some features Vimspector relies on:
   the output window's current output.
 * Prompt Buffers - used to send commands in the Console and add Watches
 * Balloons - used to display the values of variables when debugging.
-* Environment variables when laucnhing debugee in embedded terminal.
 
 Workarounds are in place as follows:
 
@@ -187,9 +186,6 @@ Workarounds are in place as follows:
 There is no workaroud for the lack of balloons; you'll just have to use
 `:VimspectorEval` or `:VimspectorWatch`, or switch to Vim.
 
-The only workaround for the missing environment variables feature is to use
-neovim master (it doesn't work in neovim 0.4).
-
 ## Language dependencies
 
 The debug adapters themselves have certain runtime dependencies:
@@ -732,10 +728,6 @@ session.
 
 ### Alternative: Use debugpy directly
 
-*** NOTE: This solution does not work in NeoVim 0.4 due to missing environment
-variables support when launching a terminal. Do not raise issues about this if
-you are using NeoVim 0.4. ***
-
 If you can't get a node 10 environment set up for whatver reason, then you can
 avoid that issue by using `debugpy` (formerly `ptvsd`) directly.