FIX: Restore original path when DO of a script fails

fixes: metaeducation/rebol-issues#2374

src/mezz/sys-base.r

@@ -84,7 +84,7 @@ do*: func [
  "Date:" select hdr 'date
  ]
 
- also
+ set/any 'value try [
  ; Eval the block or make the module, returned
  either mod? [ ; Import the module and set the var
  spec: reduce [hdr data do-needs/no-user hdr]
@@ -95,8 +95,10 @@ do*: func [
  intern data ; Bind the user script
  catch/quit either var [[do/next data var]] [data]
  ]
- ; Restore system/script and the dir
- all [system/script: :scr dir change-dir dir]
+ ]
+ ; Restore system/script and the dir
+ all [system/script: :scr dir change-dir dir]
+ value
  ]
 ]
 

src/tests/units/evaluation-test.r3

@@ -54,6 +54,14 @@ Rebol [
 
 ===end-group===
 
+===start-group=== "do script"
+ --test-- "script with error"
+ ;@@ https://github.com/rebol/rebol-issues/issues/2374
+ dir: what-dir
+ --assert error? do %units/files/error.r3
+ --assert dir = what-dir
+===end-group===
+
 ===start-group=== "do function"
 
  --test-- "do-func-1"