From a64855dfd6d34446a41d27db2a34fc73b9ca8fdb Mon Sep 17 00:00:00 2001
From: Benjamin Voisin <benjamin.voisin@ens-rennes.fr>
Date: Tue, 10 Dec 2024 13:28:01 +0100
Subject: [PATCH 1/7] client: add support for nushell in the `opam env` command

---
 src/client/opamArg.ml            |  1 +
 src/client/opamClient.ml         |  2 +-
 src/client/opamCommands.ml       |  8 ++++----
 src/client/opamConfigCommand.ml  | 19 ++++++++++++++++---
 src/client/opamConfigCommand.mli |  4 ++--
 src/core/opamStd.ml              |  6 +++++-
 src/core/opamStd.mli             |  2 +-
 src/format/opamTypes.mli         |  2 +-
 src/format/opamTypesBase.ml      |  1 +
 src/state/opamEnv.ml             | 22 +++++++++++++++++-----
 10 files changed, 49 insertions(+), 18 deletions(-)

diff --git a/src/client/opamArg.ml b/src/client/opamArg.ml
index a2783006409..e8905644fb9 100644
--- a/src/client/opamArg.ml
+++ b/src/client/opamArg.ml
@@ -1155,6 +1155,7 @@ let shell_opt ?section cli validity =
     None,"csh",SH_csh;
     None,"zsh",SH_zsh;
     None,"fish",SH_fish;
+    None,"nu",SH_nu;
     Some cli2_2,"pwsh",SH_pwsh Powershell_pwsh;
     Some cli2_2,"cmd",SH_cmd;
     Some cli2_2,"powershell",SH_pwsh Powershell
diff --git a/src/client/opamClient.ml b/src/client/opamClient.ml
index 16d9368a35f..db9ba3b1355 100644
--- a/src/client/opamClient.ml
+++ b/src/client/opamClient.ml
@@ -1137,7 +1137,7 @@ let rec cygwin_menu ~bypass_checks ~interactive header =
             options, internal_option, Some warning
           | None ->
             match OpamStd.Sys.guess_shell_compat () with
-            | SH_sh | SH_bash | SH_zsh | SH_csh | SH_fish ->
+            | SH_sh | SH_bash | SH_zsh | SH_csh | SH_fish | SH_nu ->
               let default, warning =
                 if kind = `Msys2 && OpamSystem.resolve_command pacman = None then
                   internal_option, Printf.sprintf
diff --git a/src/client/opamCommands.ml b/src/client/opamCommands.ml
index cac6ffbeb8d..0ef13e2a324 100644
--- a/src/client/opamCommands.ml
+++ b/src/client/opamCommands.ml
@@ -1448,7 +1448,7 @@ let config cli =
          `Ok (OpamConfigCommand.env gt sw
                 ~set_opamroot ~set_opamswitch
                 ~csh:(shell=SH_csh) ~sexp ~fish:(shell=SH_fish)
-                ~pwsh ~cmd:(shell=SH_cmd)
+                ~pwsh ~cmd:(shell=SH_cmd) ~nu:(shell=SH_nu)
                 ~inplace_path))
     | Some `revert_env, [] ->
       OpamGlobalState.with_ `Lock_none @@ fun gt ->
@@ -1458,7 +1458,7 @@ let config cli =
          `Ok (OpamConfigCommand.ensure_env gt sw;
               OpamConfigCommand.print_eval_env
                 ~csh:(shell=SH_csh) ~sexp ~fish:(shell=SH_fish)
-                ~pwsh ~cmd:(shell=SH_cmd)
+                ~pwsh ~cmd:(shell=SH_cmd) ~nu:(shell=SH_nu)
                 (OpamEnv.add [] [])))
     | Some `list, [] ->
       OpamGlobalState.with_ `Lock_none @@ fun gt ->
@@ -1763,12 +1763,12 @@ let env cli =
          OpamConfigCommand.env gt sw
            ~set_opamroot ~set_opamswitch
            ~csh:(shell=SH_csh) ~sexp ~fish:(shell=SH_fish)
-           ~pwsh ~cmd:(shell=SH_cmd)
+           ~pwsh ~cmd:(shell=SH_cmd) ~nu:(shell=SH_nu)
            ~inplace_path);
     | true ->
       OpamConfigCommand.print_eval_env
         ~csh:(shell=SH_csh) ~sexp ~fish:(shell=SH_fish)
-        ~pwsh ~cmd:(shell=SH_cmd)
+        ~pwsh ~cmd:(shell=SH_cmd) ~nu:(shell=SH_nu)
         (OpamEnv.add [] [])
   in
   let open Common_config_flags in
diff --git a/src/client/opamConfigCommand.ml b/src/client/opamConfigCommand.ml
index 1fd67fef36c..9db2fd0b813 100644
--- a/src/client/opamConfigCommand.ml
+++ b/src/client/opamConfigCommand.ml
@@ -131,6 +131,14 @@ let print_sexp_env output env =
   aux env;
   output ")\n"
 
+let rec print_nu_env output env =
+  match env with
+    | [] -> ()
+    | (k,v,_)::r -> begin
+      Printf.ksprintf output "\t\"%s\" : \"%s\",\n" k v;
+      print_nu_env output r
+    end
+
 let rec print_fish_env output env =
   let set_arr_cmd ?(modf=fun x -> x) k v =
     let v = modf @@ OpamStd.String.split v ':' in
@@ -183,7 +191,7 @@ let print_without_cr s =
     output_string stdout s;
     flush stdout
 
-let print_eval_env ~csh ~sexp ~fish ~pwsh ~cmd env =
+let print_eval_env ~csh ~sexp ~fish ~pwsh ~cmd ~nu env =
   let env = (env : OpamTypes.env :> (string * string * string option) list) in
   let output_normally = OpamConsole.msg "%s" in
   let never_with_cr =
@@ -202,6 +210,11 @@ let print_eval_env ~csh ~sexp ~fish ~pwsh ~cmd env =
     print_pwsh_env output_normally env
   else if cmd then
     print_cmd_env output_normally env
+  else if nu then begin
+    Printf.ksprintf never_with_cr "{\n";
+    print_nu_env never_with_cr env;
+    Printf.ksprintf never_with_cr "}"
+  end
   else
     print_env never_with_cr env
 
@@ -331,7 +344,7 @@ let ensure_env gt switch =
   ignore (ensure_env_aux gt switch)
 
 let env gt switch ?(set_opamroot=false) ?(set_opamswitch=false)
-    ~csh ~sexp ~fish ~pwsh ~cmd ~inplace_path =
+    ~csh ~sexp ~fish ~pwsh ~cmd ~nu ~inplace_path =
   log "config-env";
   let opamroot_not_current =
     let current = gt.root in
@@ -371,7 +384,7 @@ let env gt switch ?(set_opamroot=false) ?(set_opamswitch=false)
   let env =
     ensure_env_aux ~set_opamroot ~set_opamswitch ~force_path gt switch
   in
-  print_eval_env ~csh ~sexp ~fish ~pwsh ~cmd env
+  print_eval_env ~csh ~sexp ~fish ~pwsh ~cmd ~nu env
 [@@ocaml.warning "-16"]
 
 let subst gt fs =
diff --git a/src/client/opamConfigCommand.mli b/src/client/opamConfigCommand.mli
index a205bd376a5..d38f1a4b222 100644
--- a/src/client/opamConfigCommand.mli
+++ b/src/client/opamConfigCommand.mli
@@ -23,7 +23,7 @@ open OpamStateTypes
 val env:
   'a global_state -> switch ->
   ?set_opamroot:bool -> ?set_opamswitch:bool ->
-  csh:bool -> sexp:bool -> fish:bool -> pwsh:bool -> cmd:bool ->
+  csh:bool -> sexp:bool -> fish:bool -> pwsh:bool -> cmd:bool -> nu:bool ->
   inplace_path:bool -> unit
 
 (** Ensures that the environment file exists in the given switch, regenerating
@@ -32,7 +32,7 @@ val ensure_env: 'a global_state -> switch -> unit
 
 (** Like [env] but allows one to specify the precise env to print rather than
     compute it from a switch state *)
-val print_eval_env: csh:bool -> sexp:bool -> fish:bool -> pwsh:bool -> cmd:bool -> env -> unit
+val print_eval_env: csh:bool -> sexp:bool -> fish:bool -> pwsh:bool -> cmd:bool -> nu:bool -> env -> unit
 
 (** Display the content of all available packages variables *)
 val list: 'a switch_state -> name list -> unit
diff --git a/src/core/opamStd.ml b/src/core/opamStd.ml
index 253abf7fc7f..bf2886cee23 100644
--- a/src/core/opamStd.ml
+++ b/src/core/opamStd.ml
@@ -936,7 +936,7 @@ module OpamSys = struct
     fun () -> Lazy.force os
 
   type powershell_host = Powershell_pwsh | Powershell
-  type shell = SH_sh | SH_bash | SH_zsh | SH_csh | SH_fish
+  type shell = SH_sh | SH_bash | SH_zsh | SH_csh | SH_fish | SH_nu
     | SH_pwsh of powershell_host | SH_cmd
 
   let all_shells =
@@ -944,6 +944,7 @@ module OpamSys = struct
      SH_zsh;
      SH_csh;
      SH_fish;
+     SH_nu;
      SH_pwsh Powershell_pwsh;
      SH_pwsh Powershell;
      SH_cmd]
@@ -958,6 +959,7 @@ module OpamSys = struct
     | "zsh"  -> Some SH_zsh
     | "bash" -> Some SH_bash
     | "fish" -> Some SH_fish
+    | "nu"   -> Some SH_nu
     | "pwsh" -> Some (SH_pwsh Powershell_pwsh)
     | "dash"
     | "sh"   -> Some SH_sh
@@ -1078,6 +1080,8 @@ module OpamSys = struct
     match shell with
     | SH_fish ->
       Some (List.fold_left Filename.concat (home ".config") ["fish"; "config.fish"])
+    | SH_nu ->
+      Some (List.fold_left Filename.concat (home ".config") ["nushell"; "env.nu"])
     | SH_zsh  ->
       let zsh_home f =
         try Filename.concat (Env.get "ZDOTDIR") f
diff --git a/src/core/opamStd.mli b/src/core/opamStd.mli
index d219de17640..971b2b637ad 100644
--- a/src/core/opamStd.mli
+++ b/src/core/opamStd.mli
@@ -503,7 +503,7 @@ module Sys : sig
 
   (** The different families of shells we know about *)
   type powershell_host = Powershell_pwsh | Powershell
-  type shell = SH_sh | SH_bash | SH_zsh | SH_csh | SH_fish
+  type shell = SH_sh | SH_bash | SH_zsh | SH_csh | SH_fish | SH_nu
     | SH_pwsh of powershell_host | SH_cmd
 
   (** List of all supported shells *)
diff --git a/src/format/opamTypes.mli b/src/format/opamTypes.mli
index e7bf8036128..0b8f174f7f8 100644
--- a/src/format/opamTypes.mli
+++ b/src/format/opamTypes.mli
@@ -321,7 +321,7 @@ type pin_kind = [ `version | OpamUrl.backend ]
 (** Shell compatibility modes *)
 type powershell_host = OpamStd.Sys.powershell_host = Powershell_pwsh | Powershell
 type shell = OpamStd.Sys.shell =
-  | SH_sh | SH_bash | SH_zsh | SH_csh | SH_fish | SH_pwsh of powershell_host
+  | SH_sh | SH_bash | SH_zsh | SH_csh | SH_fish | SH_nu | SH_pwsh of powershell_host
   | SH_cmd
 
 (** {2 Generic command-line definitions with filters} *)
diff --git a/src/format/opamTypesBase.ml b/src/format/opamTypesBase.ml
index 9e3d09a47a8..6a5126f90c1 100644
--- a/src/format/opamTypesBase.ml
+++ b/src/format/opamTypesBase.ml
@@ -42,6 +42,7 @@ let all_std_paths =
 
 let string_of_shell = function
   | SH_fish -> "fish"
+  | SH_nu   -> "nu"
   | SH_csh  -> "csh"
   | SH_zsh  -> "zsh"
   | SH_sh   -> "sh"
diff --git a/src/state/opamEnv.ml b/src/state/opamEnv.ml
index 7a671c30666..6c939b05fbc 100644
--- a/src/state/opamEnv.ml
+++ b/src/state/opamEnv.ml
@@ -879,6 +879,8 @@ let opam_env_invocation ?root ?switch ?(set_opamswitch=false) shell =
       Printf.sprintf " \"--%s=%s\"" argname
     | SH_sh | SH_bash | SH_zsh | SH_csh | SH_fish ->
       Printf.sprintf " '--%s=%s'" argname
+    | SH_nu ->
+      Printf.sprintf " '--%s=%s'" argname
     in
     if filepath_needs_quote pathval then
       quoted pathval
@@ -928,24 +930,25 @@ let eval_string gt ?(set_opamswitch=false) switch =
 
 (** The shells for which we generate init scripts (bash and sh are the same
     entry) *)
-let shells_list = [ SH_sh; SH_zsh; SH_csh; SH_fish; SH_pwsh Powershell; SH_cmd ]
+let shells_list = [ SH_sh; SH_zsh; SH_csh; SH_fish; SH_pwsh Powershell; SH_cmd ; SH_nu]
 
 let complete_file = function
   | SH_sh | SH_bash -> Some "complete.sh"
   | SH_zsh -> Some "complete.zsh"
-  | SH_csh | SH_fish | SH_pwsh _ | SH_cmd -> None
+  | SH_csh | SH_fish | SH_pwsh _ | SH_cmd | SH_nu-> None
 
 let env_hook_file = function
   | SH_sh | SH_bash -> Some "env_hook.sh"
   | SH_zsh -> Some "env_hook.zsh"
   | SH_csh -> Some "env_hook.csh"
   | SH_fish -> Some "env_hook.fish"
-  | SH_pwsh _ | SH_cmd -> None
+  | SH_pwsh _ | SH_cmd | SH_nu -> None
 
 let variables_file = function
   | SH_sh | SH_bash | SH_zsh -> "variables.sh"
   | SH_csh -> "variables.csh"
   | SH_fish -> "variables.fish"
+  | SH_nu -> "variables.nu"
   | SH_pwsh _ -> "variables.ps1"
   | SH_cmd -> "variables.cmd"
 
@@ -954,13 +957,14 @@ let init_file = function
   | SH_zsh -> "init.zsh"
   | SH_csh -> "init.csh"
   | SH_fish -> "init.fish"
+  | SH_nu -> "init.nu"
   | SH_pwsh _ -> "init.ps1"
   | SH_cmd -> "init.cmd"
 
 let complete_script = function
   | SH_sh | SH_bash -> Some OpamScript.complete
   | SH_zsh -> Some OpamScript.complete_zsh
-  | SH_csh | SH_fish -> None
+  | SH_csh | SH_fish | SH_nu -> None
   | SH_pwsh _ | SH_cmd -> None
 
 let env_hook_script_base = function
@@ -968,7 +972,7 @@ let env_hook_script_base = function
   | SH_zsh -> Some OpamScript.env_hook_zsh
   | SH_csh -> Some OpamScript.env_hook_csh
   | SH_fish -> Some OpamScript.env_hook_fish
-  | SH_pwsh _ | SH_cmd -> None
+  | SH_pwsh _ | SH_cmd | SH_nu -> None
 
 let export_in_shell ~unconditional shell =
   let make_comment comment_opt =
@@ -1008,6 +1012,9 @@ let export_in_shell ~unconditional shell =
       Printf.sprintf "%sset -gx %s %s;\n"
         (make_comment comment) k v
   in
+  let nu (k,v,comment) =
+      Printf.sprintf "load-env (opam env %s  %s %s)\n" (make_comment comment) k v
+  in
   let pwsh (k,v,comment) =
     Printf.sprintf "%s$env:%s=%s\n"
       (make_comment comment) k v in
@@ -1020,6 +1027,7 @@ let export_in_shell ~unconditional shell =
   match shell with
   | SH_zsh | SH_bash | SH_sh -> sh
   | SH_fish -> fish
+  | SH_nu   -> nu
   | SH_csh -> csh
   | SH_pwsh _ -> pwsh
   | SH_cmd -> cmd
@@ -1062,6 +1070,8 @@ let source root shell f =
   | SH_fish ->
     let fname = unix_transform ~using_backslashes:true () in
     Printf.sprintf "test -r '%s' && source '%s' > /dev/null 2> /dev/null; or true\n" fname fname
+  | SH_nu ->
+    Printf.sprintf "%s:TODO" fname 
   | SH_sh | SH_bash ->
     let fname = unix_transform () in
     Printf.sprintf "test -r '%s' && . '%s' > /dev/null 2> /dev/null || true\n"
@@ -1097,6 +1107,8 @@ let if_interactive_script shell t e =
     Printf.sprintf "if ( $?prompt ) then\n  %s%sendif\n" t @@ ielse e
   | SH_fish ->
     Printf.sprintf "if status is-interactive\n  %s%send\n" t @@ ielse e
+  | SH_nu ->
+    Printf.sprintf "%sTODO%s" t @@ ielse e
   | SH_cmd ->
     Printf.sprintf "echo %%cmdcmdline%% | find /i \"%%~0\" >nul\nif errorlevel 1 (\n%s%s)\n" t @@ ielse_cmd e
   | SH_pwsh _ ->

From d1490d38c02e75d5d30e10c9edba48939813b21d Mon Sep 17 00:00:00 2001
From: Benjamin Voisin <benjamin.voisin@ens-rennes.fr>
Date: Tue, 10 Dec 2024 14:17:47 +0100
Subject: [PATCH 2/7] add changes to master_changes.md file

---
 master_changes.md | 1 +
 1 file changed, 1 insertion(+)

diff --git a/master_changes.md b/master_changes.md
index a39d475e315..7589177e6c0 100644
--- a/master_changes.md
+++ b/master_changes.md
@@ -69,6 +69,7 @@ users)
 ## Clean
 
 ## Env
+  * [NEW] Add support for nushell in the opam env command
 
 ## Opamfile
   * The `url` file now only supports the legacy opam 1.2 fields [#6827 @kit-ty-kate]

From 5ec5f349f52e0f5b133452033e53b2412b3534af Mon Sep 17 00:00:00 2001
From: Joe Neeman <joe@neeman.me>
Date: Thu, 26 Mar 2026 22:18:18 -0500
Subject: [PATCH 3/7] Make initial shell environment work on nushell

Auto-reloading is not yet implemented
---
 src/core/opamStd.ml  |  6 +++++-
 src/state/opamEnv.ml | 16 +++++++++++-----
 2 files changed, 16 insertions(+), 6 deletions(-)

diff --git a/src/core/opamStd.ml b/src/core/opamStd.ml
index bf2886cee23..1e902f1138b 100644
--- a/src/core/opamStd.ml
+++ b/src/core/opamStd.ml
@@ -1081,7 +1081,11 @@ module OpamSys = struct
     | SH_fish ->
       Some (List.fold_left Filename.concat (home ".config") ["fish"; "config.fish"])
     | SH_nu ->
-      Some (List.fold_left Filename.concat (home ".config") ["nushell"; "env.nu"])
+      let config_home =
+        try Env.get "XDG_CONFIG_HOME"
+        with Not_found -> home ".config"
+      in
+      Some (List.fold_left Filename.concat config_home ["nushell"; "autoload"; "opam.nu"])
     | SH_zsh  ->
       let zsh_home f =
         try Filename.concat (Env.get "ZDOTDIR") f
diff --git a/src/state/opamEnv.ml b/src/state/opamEnv.ml
index 6c939b05fbc..ec8ee215b40 100644
--- a/src/state/opamEnv.ml
+++ b/src/state/opamEnv.ml
@@ -830,6 +830,8 @@ let shell_eval_invocation shell cmd =
     Printf.sprintf "(& %s) -split '\\r?\\n' | ForEach-Object { Invoke-Expression $_ }" cmd
   | SH_fish ->
     Printf.sprintf "eval (%s)" cmd
+  | SH_nu ->
+    Printf.sprintf "load-env (%s | from-json)" cmd
   | SH_csh ->
     Printf.sprintf "eval `%s`" cmd
   | SH_cmd ->
@@ -1013,7 +1015,7 @@ let export_in_shell ~unconditional shell =
         (make_comment comment) k v
   in
   let nu (k,v,comment) =
-      Printf.sprintf "load-env (opam env %s  %s %s)\n" (make_comment comment) k v
+      Printf.sprintf "$env.%s = %s %s\n" k v (make_comment comment)
   in
   let pwsh (k,v,comment) =
     Printf.sprintf "%s$env:%s=%s\n"
@@ -1040,7 +1042,7 @@ let env_hook_script shell =
 
 let abort_if_set var shell =
   (* Each of these incantations aborts the currently running script if [var] is
-     unset or empty ("null") *)
+     set to something non-empty *)
   match shell with
   | SH_zsh | SH_bash | SH_sh ->
     Printf.sprintf "test -z \"${%s:+x}\" || return\n" var
@@ -1052,6 +1054,8 @@ let abort_if_set var shell =
       var var
   | SH_fish ->
     Printf.sprintf "test -z \"$%s\"; or return\n" var
+  | SH_nu ->
+    Printf.sprintf "if ($env.%s? | default \"\") != \"\" { return }\n" var
   | SH_cmd ->
     Printf.sprintf "if defined %s if \"%%%s%%\" neq \"\" goto :EOF\n" var var
 
@@ -1071,7 +1075,7 @@ let source root shell f =
     let fname = unix_transform ~using_backslashes:true () in
     Printf.sprintf "test -r '%s' && source '%s' > /dev/null 2> /dev/null; or true\n" fname fname
   | SH_nu ->
-    Printf.sprintf "%s:TODO" fname 
+    Printf.sprintf "const source_path = if ('%s' | path exists) { '%s' } else { null }\nsource $source_path\n" fname fname
   | SH_sh | SH_bash ->
     let fname = unix_transform () in
     Printf.sprintf "test -r '%s' && . '%s' > /dev/null 2> /dev/null || true\n"
@@ -1108,7 +1112,7 @@ let if_interactive_script shell t e =
   | SH_fish ->
     Printf.sprintf "if status is-interactive\n  %s%send\n" t @@ ielse e
   | SH_nu ->
-    Printf.sprintf "%sTODO%s" t @@ ielse e
+    Printf.sprintf "if $nu.is_interactive {\n  %s%s}\n" t @@ ielse_pwsh e
   | SH_cmd ->
     Printf.sprintf "echo %%cmdcmdline%% | find /i \"%%~0\" >nul\nif errorlevel 1 (\n%s%s)\n" t @@ ielse_cmd e
   | SH_pwsh _ ->
@@ -1155,11 +1159,13 @@ let string_of_update st shell updates =
            Printf.sprintf "'%s%c' + \"$env:%s\""
              (OpamStd.Env.escape_powershell string) sep envu_var
          | SH_cmd -> Printf.sprintf "%s%c%%%s%%" string sep envu_var
+         | SH_nu -> Printf.sprintf "$env.%s? | default [] | prepend '%s'" envu_var string
          | _ -> Printf.sprintf "'%s':\"$%s\"" string envu_var)
       | EqColon | EqPlus ->
         (match shell with
          | SH_pwsh _ -> Printf.sprintf "\"$env:%s\" + '%c%s'" envu_var sep string
          | SH_cmd -> Printf.sprintf "%%%s%%%c%s" envu_var sep string
+         | SH_nu -> Printf.sprintf "$env.%s? | default [] | append '%s'" envu_var string
          | _ -> Printf.sprintf "\"$%s\":'%s'" envu_var string)
     in
     export_in_shell shell ~unconditional:(envu_op = Eq) (key, value, envu_comment) in
@@ -1255,7 +1261,7 @@ let write_dynamic_init_scripts st =
            (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]
+      [SH_sh; SH_csh; SH_fish; SH_nu; SH_pwsh Powershell; SH_cmd]
   with OpamSystem.Locked ->
     OpamConsole.warning
       "Global shell init scripts not installed (could not acquire lock)"

From 11a157ab2da05e234ffa6bb90d377c601d02a3c2 Mon Sep 17 00:00:00 2001
From: Joe Neeman <joe@neeman.me>
Date: Sun, 29 Mar 2026 22:32:18 -0500
Subject: [PATCH 4/7] Use json output for the env, and the appropriate system
 fallback for nushell config

---
 src/client/opamConfigCommand.ml | 12 +++---------
 src/core/opamStd.ml             | 10 +++++++---
 src/state/opamEnv.ml            |  4 +---
 3 files changed, 11 insertions(+), 15 deletions(-)

diff --git a/src/client/opamConfigCommand.ml b/src/client/opamConfigCommand.ml
index 9db2fd0b813..13cd86e3811 100644
--- a/src/client/opamConfigCommand.ml
+++ b/src/client/opamConfigCommand.ml
@@ -131,13 +131,9 @@ let print_sexp_env output env =
   aux env;
   output ")\n"
 
-let rec print_nu_env output env =
-  match env with
-    | [] -> ()
-    | (k,v,_)::r -> begin
-      Printf.ksprintf output "\t\"%s\" : \"%s\",\n" k v;
-      print_nu_env output r
-    end
+let print_nu_env output env =
+  let json = `O (List.map (fun (k,v,_) -> (k, `String v)) env) in
+  output @@ OpamJson.to_string json
 
 let rec print_fish_env output env =
   let set_arr_cmd ?(modf=fun x -> x) k v =
@@ -211,9 +207,7 @@ let print_eval_env ~csh ~sexp ~fish ~pwsh ~cmd ~nu env =
   else if cmd then
     print_cmd_env output_normally env
   else if nu then begin
-    Printf.ksprintf never_with_cr "{\n";
     print_nu_env never_with_cr env;
-    Printf.ksprintf never_with_cr "}"
   end
   else
     print_env never_with_cr env
diff --git a/src/core/opamStd.ml b/src/core/opamStd.ml
index 1e902f1138b..9649f7933d3 100644
--- a/src/core/opamStd.ml
+++ b/src/core/opamStd.ml
@@ -1081,9 +1081,13 @@ module OpamSys = struct
     | SH_fish ->
       Some (List.fold_left Filename.concat (home ".config") ["fish"; "config.fish"])
     | SH_nu ->
-      let config_home =
-        try Env.get "XDG_CONFIG_HOME"
-        with Not_found -> home ".config"
+      (* nu checks XDG_CONFIG_HOME on all operating systems,
+         and then falls back to the system-dependent "dirs" crate *)
+      let config_home = try Env.get "XDG_CONFIG_HOME"
+        with Not_found -> match os () with
+        | Darwin -> home "Library/Application Support"
+        | Win32 -> (try Env.get "APPDATA" with Not_found -> home ".config")
+        | _ -> home ".config"
       in
       Some (List.fold_left Filename.concat config_home ["nushell"; "autoload"; "opam.nu"])
     | SH_zsh  ->
diff --git a/src/state/opamEnv.ml b/src/state/opamEnv.ml
index ec8ee215b40..9f5f24d9637 100644
--- a/src/state/opamEnv.ml
+++ b/src/state/opamEnv.ml
@@ -879,9 +879,7 @@ let opam_env_invocation ?root ?switch ?(set_opamswitch=false) shell =
     let quoted = match shell with
     | SH_cmd | SH_pwsh _ ->
       Printf.sprintf " \"--%s=%s\"" argname
-    | SH_sh | SH_bash | SH_zsh | SH_csh | SH_fish ->
-      Printf.sprintf " '--%s=%s'" argname
-    | SH_nu ->
+    | SH_sh | SH_bash | SH_zsh | SH_csh | SH_fish | SH_nu ->
       Printf.sprintf " '--%s=%s'" argname
     in
     if filepath_needs_quote pathval then

From dd885defd2626d4a0ddc612539b1ebcf87086362 Mon Sep 17 00:00:00 2001
From: Joe Neeman <joe@neeman.me>
Date: Sun, 29 Mar 2026 22:33:25 -0500
Subject: [PATCH 5/7] Remove redundant else null

---
 src/state/opamEnv.ml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/state/opamEnv.ml b/src/state/opamEnv.ml
index 9f5f24d9637..d1a45ff9786 100644
--- a/src/state/opamEnv.ml
+++ b/src/state/opamEnv.ml
@@ -1073,7 +1073,7 @@ let source root shell f =
     let fname = unix_transform ~using_backslashes:true () in
     Printf.sprintf "test -r '%s' && source '%s' > /dev/null 2> /dev/null; or true\n" fname fname
   | SH_nu ->
-    Printf.sprintf "const source_path = if ('%s' | path exists) { '%s' } else { null }\nsource $source_path\n" fname fname
+    Printf.sprintf "const source_path = if ('%s' | path exists) { '%s' } \nsource $source_path\n" fname fname
   | SH_sh | SH_bash ->
     let fname = unix_transform () in
     Printf.sprintf "test -r '%s' && . '%s' > /dev/null 2> /dev/null || true\n"

From 5ba20c80a63be2364c882c042e05762d70d2d185 Mon Sep 17 00:00:00 2001
From: Joe Neeman <joe@neeman.me>
Date: Sun, 29 Mar 2026 22:35:19 -0500
Subject: [PATCH 6/7] Fix is-interactive variable

---
 src/state/opamEnv.ml | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/state/opamEnv.ml b/src/state/opamEnv.ml
index d1a45ff9786..1f7dceb6393 100644
--- a/src/state/opamEnv.ml
+++ b/src/state/opamEnv.ml
@@ -1100,6 +1100,7 @@ let if_interactive_script shell t e =
     |  None -> ""
     | Some e -> Printf.sprintf "} else {\n  %s" e
   in
+  let ielse_nu = ielse_pwsh in
   match shell with
   | SH_sh| SH_bash ->
     Printf.sprintf "if [ -t 0 ]; then\n  %s%sfi\n" t @@ ielse e
@@ -1110,7 +1111,7 @@ let if_interactive_script shell t e =
   | SH_fish ->
     Printf.sprintf "if status is-interactive\n  %s%send\n" t @@ ielse e
   | SH_nu ->
-    Printf.sprintf "if $nu.is_interactive {\n  %s%s}\n" t @@ ielse_pwsh e
+    Printf.sprintf "if $nu.is-interactive {\n  %s%s}\n" t @@ ielse_nu e
   | SH_cmd ->
     Printf.sprintf "echo %%cmdcmdline%% | find /i \"%%~0\" >nul\nif errorlevel 1 (\n%s%s)\n" t @@ ielse_cmd e
   | SH_pwsh _ ->

From 070aea565d8b5f92b9167a39219c0c6be5acc457 Mon Sep 17 00:00:00 2001
From: Joe Neeman <joe@neeman.me>
Date: Mon, 30 Mar 2026 20:00:31 -0500
Subject: [PATCH 7/7] Support autoload in nushell

---
 src/state/dune                     |  2 +-
 src/state/opamEnv.ml               | 12 +++++++++---
 src/state/opamScript.mli           |  1 +
 src/state/shellscripts/env_hook.nu |  5 +++++
 4 files changed, 16 insertions(+), 4 deletions(-)
 create mode 100644 src/state/shellscripts/env_hook.nu

diff --git a/src/state/dune b/src/state/dune
index 3f4338b003b..2dd14a30fe6 100644
--- a/src/state/dune
+++ b/src/state/dune
@@ -13,7 +13,7 @@
 
 (rule
   (targets opamScript.ml)
-  (deps    ../../shell/crunch.ml (glob_files shellscripts/*.*sh))
+  (deps    ../../shell/crunch.ml (glob_files shellscripts/*.*sh) (glob_files shellscripts/*.nu))
   (action  (with-stdout-to %{targets} (run ocaml %{deps}))))
 
 ; Embedded Cygwin mechanism (done in the configure script on Windows if requested)
diff --git a/src/state/opamEnv.ml b/src/state/opamEnv.ml
index 1f7dceb6393..b5427602035 100644
--- a/src/state/opamEnv.ml
+++ b/src/state/opamEnv.ml
@@ -942,7 +942,8 @@ let env_hook_file = function
   | SH_zsh -> Some "env_hook.zsh"
   | SH_csh -> Some "env_hook.csh"
   | SH_fish -> Some "env_hook.fish"
-  | SH_pwsh _ | SH_cmd | SH_nu -> None
+  | SH_nu -> Some "env_hook.nu"
+  | SH_pwsh _ | SH_cmd -> None
 
 let variables_file = function
   | SH_sh | SH_bash | SH_zsh -> "variables.sh"
@@ -972,7 +973,8 @@ let env_hook_script_base = function
   | SH_zsh -> Some OpamScript.env_hook_zsh
   | SH_csh -> Some OpamScript.env_hook_csh
   | SH_fish -> Some OpamScript.env_hook_fish
-  | SH_pwsh _ | SH_cmd | SH_nu -> None
+  | SH_nu -> Some OpamScript.env_hook_nu
+  | SH_pwsh _ | SH_cmd -> None
 
 let export_in_shell ~unconditional shell =
   let make_comment comment_opt =
@@ -1034,7 +1036,11 @@ let export_in_shell ~unconditional shell =
 
 let env_hook_script shell =
   Option.map (fun script ->
-      export_in_shell shell ~unconditional:true ("OPAMNOENVNOTICE", "true", None)
+      let var = match shell with
+      | SH_nu -> "'true'"
+      | _ -> "true"
+      in
+      export_in_shell shell ~unconditional:true ("OPAMNOENVNOTICE", var, None)
       ^ script)
     (env_hook_script_base shell)
 
diff --git a/src/state/opamScript.mli b/src/state/opamScript.mli
index 8bfe74d0e3e..78f99c5eb5e 100644
--- a/src/state/opamScript.mli
+++ b/src/state/opamScript.mli
@@ -20,3 +20,4 @@ val env_hook : string
 val env_hook_zsh : string
 val env_hook_csh : string
 val env_hook_fish : string
+val env_hook_nu: string
diff --git a/src/state/shellscripts/env_hook.nu b/src/state/shellscripts/env_hook.nu
new file mode 100644
index 00000000000..413a2b1db7b
--- /dev/null
+++ b/src/state/shellscripts/env_hook.nu
@@ -0,0 +1,5 @@
+$env.config = ($env.config | upsert hooks.pre_prompt {
+    default [] | append {
+        load-env (opam env --shell=nu | from json)
+    }
+})