resolve several issues in nu_conda and nu_msvs (#872)

1. fix: update `(sys).host` to `sys host` to work for 0.94.x
2. fix: handle incorrect behaviors when re-importing nu_conda or nu_msvs
3. doc: update minimum requirements of nushell in README.md

modules/virtual_environments/nu_conda/README.md

@@ -3,7 +3,7 @@ A simple module for activating and deactivating Conda environments.
 
 
 ## Prerequisites
-- [nushell](https://github.com/nushell/nushell) >= 0.83.0
+- [nushell](https://github.com/nushell/nushell) >= 0.94.0
 
 
 ## Installation

modules/virtual_environments/nu_conda/nu_conda.nu

@@ -1,5 +1,6 @@
 export-env {
-  $env.CONDA_BASE_PATH = (if ((sys).host.name == "Windows") {$env.Path} else {$env.PATH})
+  if not ("CONDA_CURR" in $env) {
+    $env.CONDA_BASE_PATH = (if ((sys host).name == "Windows") {$env.Path} else {$env.PATH})
 
     let info = (
         if not (which mamba | is-empty) {
@@ -20,11 +21,12 @@ export-env {
         }})
 
     $env.CONDA_CURR = null
+  }
 }
 
 export def --env activate [name: string] {
   if ($env.CONDA_ROOT | is-empty) {
-    print "Neither Conda nor Mamba is valid."
+    print "Neither Conda nor Mamba is available."
     return
   }
 
@@ -35,7 +37,7 @@ export def --env activate [name: string] {
   }
 
   let new_path = (
-    if ((sys).host.name == "Windows") {
+    if ((sys host).name == "Windows") {
       update-path-windows ($env.CONDA_ENVS | get $name)
     } else {
       update-path-linux ($env.CONDA_ENVS | get $name)
@@ -46,7 +48,7 @@ export def --env activate [name: string] {
 
 export def --env deactivate [] {
   if ($env.CONDA_ROOT | is-empty) {
-    print "Neither Conda nor Mamba is valid."
+    print "Neither Conda nor Mamba is available."
     return
   }
 

modules/virtual_environments/nu_msvs/README.md

@@ -3,7 +3,7 @@ A module for Using Microsoft Visual Studio (MSVS) command line tools from Nushel
 
 
 ## Prerequisites
-- [nushell](https://github.com/nushell/nushell) >= 0.91.0
+- [nushell](https://github.com/nushell/nushell) >= 0.94.0
 - [vswhere](https://github.com/microsoft/vswhere) standalone or comes with VS
 
 

modules/virtual_environments/nu_msvs/nu_msvs.nu

@@ -1,4 +1,5 @@
 export-env {
+  if not ("MSVS_ACTIVATED" in $env) {
     $env.MSVS_BASE_PATH = $env.Path
 
     let info = (
@@ -33,6 +34,9 @@ export-env {
       $"($env.MSVS_MSDK_ROOT)Include/($env.MSVS_MSDK_VER)/um",
       $"($env.MSVS_MSDK_ROOT)Include/($env.MSVS_MSDK_VER)/winrt"
     ] | str join ";")
+
+    $env.MSVS_ACTIVATED = false
+  }
 }
 
 export def --env activate [
@@ -41,7 +45,7 @@ export def --env activate [
     --sdk    (-s): string = "latest"  # Version of Windows SDK, must be "latest" or a valid version string
   ] {
   if (($env.MSVS_ROOT | is-empty) or ($env.MSVS_MSVC_ROOT | is-empty)) {
-    print "Either Microsoft Visual Studio or MSVC is valid."
+    print "Neither Microsoft Visual Studio nor MSVC is available."
     return
   }
 
@@ -125,17 +129,12 @@ export def --env activate [
     LIB: $lib_path
   }
 
-  hide-env MSVS_BASE_PATH
-  hide-env MSVS_ROOT
-  hide-env MSVS_MSVC_ROOT
-  hide-env MSVS_MSDK_ROOT
-  hide-env MSVS_MSDK_VER
-  hide-env MSVS_INCLUDE_PATH
+  $env.MSVS_ACTIVATED = true
 }
 
 export def --env deactivate [] {
-  if (($env.MSVS_ROOT | is-empty) or ($env.MSVS_MSVC_ROOT | is-empty)) {
-    print "Either Microsoft Visual Studio or MSVC is valid."
+  if (($env.MSVS_ROOT? | is-empty) or ($env.MSVS_MSVC_ROOT? | is-empty)) {
+    print "Neither Microsoft Visual Studio nor MSVC is available."
     return
   }
 
@@ -144,6 +143,5 @@ export def --env deactivate [] {
     PATH: $env.MSVS_BASE_PATH
   }
 
-  hide-env INCLUDE
-  hide-env LIB
+  $env.MSVS_ACTIVATED = false
 }