Make variables.* back off if already set

Author: dra27

src/state/opamEnv.ml

@@ -1030,6 +1030,14 @@ let env_hook_script shell =
       ^ script)
     (env_hook_script_base shell)
 
+let abort_if_set var shell =
+  match shell with
+  | SH_zsh | SH_bash | SH_sh -> Printf.sprintf "test -z \"$%s\" || return\n" var
+  | SH_csh -> Printf.sprintf "if ( ${?%s} ) then\n  if ( \"$%s\" != \"\") exit\nendif\n" var var
+  | SH_pwsh _ -> Printf.sprintf "if ($env:%s) { return }\n" var
+  | SH_fish -> Printf.sprintf "test -n \"$%s\"; and return\n" var
+  | SH_cmd -> Printf.sprintf "if defined %s goto :EOF\n" var
+
 let source root shell f =
   let fname = OpamFilename.to_string (OpamPath.init root // f) in
   let unix_transform ?using_backslashes () =
@@ -1223,7 +1231,7 @@ let write_dynamic_init_scripts st =
     List.iter
       (fun shell ->
          write_script (OpamPath.init st.switch_global.root)
-           (variables_file shell, string_of_update st shell updates))
+           (variables_file shell, abort_if_set "OPAM_SWITCH_PREFIX" shell ^ string_of_update st shell updates))
       [SH_sh; SH_csh; SH_fish; SH_pwsh Powershell; SH_cmd]
   with OpamSystem.Locked ->
     OpamConsole.warning

tests/reftests/init-scripts.unix.test

@@ -18,7 +18,7 @@ User configuration:
 ### # we need the switch for variables file
 ### opam switch create fake --empty --root root
 ### sh locally-in-sh.sh sh -lc "sh -lc env" | grep MANPATH
-MANPATH=:${BASEDIR}/root/fake/man:${BASEDIR}/root/fake/man
+MANPATH=:${BASEDIR}/root/fake/man
 ### ls root/opam-init | unordered
 complete.sh
 complete.zsh
@@ -73,29 +73,36 @@ if exist "${BASEDIR}/root/opam-init/variables.cmd" call "${BASEDIR}/root/opam-in
 if Test-Path "${BASEDIR}/root/opam-init/variables.ps1" { . "${BASEDIR}/root/opam-init/variables.ps1" *> $null }
 ### : Variables scripts :
 ### cat root/opam-init/variables.sh | grep -v man | grep -v MANPATH
+test -z "$OPAM_SWITCH_PREFIX" || return
 # Prefix of the current opam switch
 OPAM_SWITCH_PREFIX='${BASEDIR}/root/fake'; export OPAM_SWITCH_PREFIX;
 # Binary dir for opam switch fake
 PATH='${BASEDIR}/root/fake/bin':"$PATH"; export PATH;
 ### test -f root/opam-init/variables.zsh
 # Return code 1 #
 ### cat root/opam-init/variables.fish | grep -v man | grep -v MANPATH
+test -n "$OPAM_SWITCH_PREFIX"; and return
 # Prefix of the current opam switch
 set -gx OPAM_SWITCH_PREFIX '${BASEDIR}/root/fake';
 # Binary dir for opam switch fake
 set -gx PATH '${BASEDIR}/root/fake/bin' $PATH;
 ### cat root/opam-init/variables.csh | grep -v man | grep -v MANPATH
+if ( ${?OPAM_SWITCH_PREFIX} ) then
+  if ( "$OPAM_SWITCH_PREFIX" != "") exit
+endif
 # Prefix of the current opam switch
 setenv OPAM_SWITCH_PREFIX '${BASEDIR}/root/fake'
 # Binary dir for opam switch fake
 if ( ! ${?PATH} ) setenv PATH ""
 setenv PATH '${BASEDIR}/root/fake/bin':"$PATH"
 ### cat root/opam-init/variables.cmd | grep -v man | grep -v MANPATH
+if defined OPAM_SWITCH_PREFIX goto :EOF
 :: Prefix of the current opam switch
 set "OPAM_SWITCH_PREFIX=${BASEDIR}/root/fake"
 :: Binary dir for opam switch fake
 set "PATH=${BASEDIR}/root/fake/bin:%PATH%"
 ### cat root/opam-init/variables.ps1 | grep -v man | grep -v MANPATH
+if ($env:OPAM_SWITCH_PREFIX) { return }
 # Prefix of the current opam switch
 $env:OPAM_SWITCH_PREFIX='${BASEDIR}/root/fake'
 # Binary dir for opam switch fake

tests/reftests/init-scripts.win32.test

@@ -60,6 +60,7 @@ if exist "${BASEDIR}/root/opam-init/variables.cmd" call "${BASEDIR}/root/opam-in
 if Test-Path "${BASEDIR}/root/opam-init/variables.ps1" { . "${BASEDIR}/root/opam-init/variables.ps1" *> $null }
 ### : Variables scripts :
 ### cat root/opam-init/variables.sh | grep -v man | grep -v MANPATH
+test -z "$OPAM_SWITCH_PREFIX" || return
 # Prefix of the current opam switch
 OPAM_SWITCH_PREFIX='${BASEDIR}/root/fake'; export OPAM_SWITCH_PREFIX;
 # Binary dir for opam switch fake
@@ -69,17 +70,22 @@ PATH='${BASEDIR}/root/fake/bin':"$PATH"; export PATH;
 ### # ERROR, broken, see opam#5854 testing only its existence
 ### test -f root/opam-init/variables.fish
 ### cat root/opam-init/variables.csh | grep -v man | grep -v MANPATH
+if ( ${?OPAM_SWITCH_PREFIX} ) then
+  if ( "$OPAM_SWITCH_PREFIX" != "") exit
+endif
 # Prefix of the current opam switch
 setenv OPAM_SWITCH_PREFIX '${BASEDIR}/root/fake'
 # Binary dir for opam switch fake
 if ( ! ${?PATH} ) setenv PATH ""
 setenv PATH '${BASEDIR}/root/fake/bin':"$PATH"
 ### cat root/opam-init/variables.cmd | grep -v man | grep -v MANPATH
+if defined OPAM_SWITCH_PREFIX goto :EOF
 :: Prefix of the current opam switch
 set "OPAM_SWITCH_PREFIX=${BASEDIR}/root/fake"
 :: Binary dir for opam switch fake
 set "PATH=${BASEDIR}/root/fake/bin;%PATH%"
 ### cat root/opam-init/variables.ps1 | grep -v man | grep -v MANPATH
+if ($env:OPAM_SWITCH_PREFIX) { return }
 # Prefix of the current opam switch
 $env:OPAM_SWITCH_PREFIX='${BASEDIR}/root/fake'
 # Binary dir for opam switch fake