Redirect opam on Windows if path contains a space.

It is needed for Cygwin installation, that doesn't handle paths with
space.
At init, detection and redirection are done, afterwards opam always load
redirected opam root.
Original root directory is stored in
`OpamStateConfig.!r.original_root_dir`.

Co-authored-by: David Allsopp <david.allsopp@metastack.com>

master_changes.md

@@ -29,6 +29,7 @@ users)
   * Enhance the Git menu by warning if the user appears to need to restart the shell to pick up PATH changes [#5963 @dra27]
   * Include Git for Windows installations in the list of possibilities where the user instructed Git-for-Windows setup not to update PATH [#5963 @dra27]
   * [BUG] Fail if `--git-location` points to a directory not containing git [#6000 @dra27]
+  * Redirect the opam root to `C:\opamroot-xxx` when the opam root contains spaces on Windows [#5457 @rjbou @dra27]
 
 ## Config report
 

src/client/opamClient.ml

@@ -1645,6 +1645,114 @@ let reinit ?(init_config=OpamInitDefaults.init_config()) ~interactive
   in
   OpamRepositoryState.drop rt
 
+let has_space s = OpamStd.String.contains_char s ' '
+
+let default_redirect_root = OpamFilename.Dir.of_string "C:\\opamroot"
+
+let setup_redirection target =
+  let {contents = {OpamStateConfig.original_root_dir = root; _}} =
+    OpamStateConfig.r
+  in
+  let target =
+    match target with
+    | Some target -> target
+    | None ->
+      OpamFilename.mkdir default_redirect_root;
+      let readme = OpamFilename.Op.(default_redirect_root // "ReadMe.txt") in
+      if not (OpamFilename.exists readme) then
+        OpamFilename.write readme
+          "This directory is used to contain redirected opam roots.\n\n\
+           The contents may be shared with other users on this system.";
+      OpamSystem.mk_unique_dir ~dir:(OpamFilename.Dir.to_string default_redirect_root) ()
+  in
+  let root_dir = OpamFilename.Dir.of_string target in
+  OpamFilename.write (OpamPath.redirected root) target;
+  OpamStateConfig.update ~root_dir ();
+  root_dir
+
+let get_redirected_root () =
+  let {contents = {OpamStateConfig.original_root_dir = root; root_from; _}} =
+    OpamStateConfig.r
+  in
+  let r = OpamConsole.colorise `bold (OpamFilename.Dir.to_string root) in
+  let collision =
+    let collision = OpamConsole.utf8_symbol OpamConsole.Symbols.collision "" in
+    if collision = "" then
+      ""
+    else
+      " " ^ collision
+  in
+  let options = [
+    `Redirect, Printf.sprintf
+      "Redirect files to a directory in %s"
+      (OpamConsole.colorise `bold (OpamFilename.Dir.to_string default_redirect_root));
+    `Ask, "Redirect files to an alternate directory";
+    `Endure, Printf.sprintf
+      "Do not redirect anything and stick with %s%s" r collision;
+    `Quit, "Abort initialisation"
+  ] in
+  let default, explanation =
+    match root_from with
+    | `Command_line ->
+      (* The user has been explicit with --root; nemo salvet modo... *)
+      `Endure,
+      "You have specified a root directory for opam containing a space."
+    | `Env ->
+      (* The user has perhaps carelessly set an environment variable *)
+      `Redirect,
+      "Your OPAMROOT environment variable contains a space."
+    | `Default ->
+      (* The user has fallen victim to the defaults of Windows Setup and has a
+         space in their user name *)
+      `Redirect,
+      Printf.sprintf
+        "By default, opam would store its data in:\n\
+           %s\n\
+         however, this directory contains a space." r
+  in
+  let rec ask () =
+    let check r =
+      if Filename.is_relative r then begin
+        OpamConsole.msg
+          "That path is relative!\n\
+           Please enter an absolute path without spaces.\n";
+        ask ()
+      end else if has_space r then begin
+        OpamConsole.msg
+          "That path contains contains a space!\n\
+           Please enter an absolute path without spaces.\n";
+        ask ()
+      end else
+        Some (Some r)
+    in
+    OpamStd.Option.replace check (OpamConsole.read "Root directory for opam: ")
+  in
+  let rec menu () =
+    match OpamConsole.menu "Where should opam store files?" ~default ~options
+            ~no:default with
+    | `Redirect ->
+      Some None
+    | `Endure ->
+      None
+    | `Ask ->
+      let r = ask () in
+      if r = None then
+        menu ()
+      else
+        r
+    | `Quit ->
+      OpamStd.Sys.exit_because `Aborted
+  in
+  OpamConsole.header_msg "opam root file store";
+  OpamConsole.msg
+    "\n\
+     %s\n\
+     \n\
+     Many parts of the OCaml ecosystem do not presently work correctly\n\
+     when installed to directories containing spaces. You have been warned!%s\n\
+     \n" explanation collision;
+  Option.map setup_redirection (menu ())
+
 let init
     ~init_config ~interactive
     ?repo ?(bypass_checks=false)
@@ -1654,10 +1762,34 @@ let init
     shell =
   log "INIT %a"
     (slog @@ OpamStd.Option.to_string OpamRepositoryBackend.to_string) repo;
+  let original_root = OpamStateConfig.(!r.original_root_dir) in
+  let root_empty =
+    not (OpamFilename.exists_dir original_root)
+    || OpamFilename.dir_is_empty original_root in
   let root = OpamStateConfig.(!r.root_dir) in
+  let root, remove_root =
+    let ignore_non_fatal f x =
+      try f x
+      with e -> OpamStd.Exn.fatal e
+    in
+    let new_root =
+      if root_empty &&
+         Sys.win32 &&
+         has_space (OpamFilename.Dir.to_string root) then
+        get_redirected_root ()
+      else
+        None
+    in
+    match new_root with
+    | None ->
+      root, (fun () -> ignore_non_fatal OpamFilename.rmdir root)
+    | Some root ->
+      root, (fun () ->
+        ignore_non_fatal OpamFilename.rmdir root;
+        ignore_non_fatal OpamFilename.rmdir original_root
+      )
+  in
   let config_f = OpamPath.config root in
-  let root_empty =
-    not (OpamFilename.exists_dir root) || OpamFilename.dir_is_empty root in
 
   let gt, rt, default_compiler =
     if OpamFile.exists config_f then (
@@ -1671,7 +1803,7 @@ let init
     ) else (
       if not root_empty then (
         OpamConsole.warning "%s exists and is not empty"
-          (OpamFilename.Dir.to_string root);
+          (OpamFilename.Dir.to_string original_root);
         if not (OpamConsole.confirm "Proceed?") then
           OpamStd.Sys.exit_because `Aborted);
       try
@@ -1743,7 +1875,7 @@ let init
         in
         if failed <> [] then
           (if root_empty then
-             (try OpamFilename.rmdir root with _ -> ());
+             remove_root ();
            OpamConsole.error_and_exit `Sync_error
              "Initial download of repository failed.");
         let default_compiler =
@@ -1778,7 +1910,7 @@ let init
         OpamStd.Exn.finalise e @@ fun () ->
         if not (OpamConsole.debug ()) && root_empty then begin
           OpamSystem.release_all_locks ();
-          OpamFilename.rmdir root
+          remove_root ()
         end)
   in
   OpamEnv.setup root ~interactive

src/state/opamStateConfig.ml

@@ -71,6 +71,12 @@ type t = {
   no_depexts: bool;
 }
 
+let win_space_redirection root =
+  let redirected = OpamPath.redirected root in
+  if OpamFilename.exists redirected then
+    OpamFilename.Dir.of_string (OpamFilename.read redirected)
+  else root
+
 let default_root =
   (* On Windows, if a .opam directory is found in %HOME% or %USERPROFILE% then
      then we'll use it. Otherwise, we use %LOCALAPPDATA%. *)
@@ -88,7 +94,7 @@ let default_root =
   concat_and_resolve local_appdata "opam"
 
 let default = {
-  root_dir = default_root;
+  root_dir = win_space_redirection default_root;
   original_root_dir = default_root;
   root_from = `Default;
   current_switch = None;
@@ -185,7 +191,7 @@ let initk k =
     | None -> None, None, None
     | Some root ->
       let root = OpamFilename.Dir.of_string root in
-      Some root, Some root, Some `Env
+      Some (win_space_redirection root), Some root, Some `Env
   in
   let current_switch, switch_from =
     match E.switch () with
@@ -219,11 +225,11 @@ let init ?noop:_ = initk (fun () -> ())
 
 let opamroot ?root_dir () =
   match root_dir with
-  | Some root -> `Command_line, root
+  | Some root -> `Command_line, win_space_redirection root
   | None ->
     match OpamStd.Env.getopt "OPAMROOT" with
     | Some root ->
-      `Env, OpamFilename.Dir.of_string root
+      `Env, win_space_redirection (OpamFilename.Dir.of_string root)
     | None ->
       `Default, default.root_dir
 

tests/reftests/env.test

@@ -439,60 +439,6 @@ The following actions will be performed:
 Done.
 ### opam exec -- sh -c "eval $(opam env | tr -d '\\r'); opam remove foo; opam env; eval $(opam env | tr -d '\\r'); opam env" | grep "FOO"
 FOO=''; export FOO;
-### : root and switch with spaces :
-### RT="$BASEDIR/root 2"
-### SW="switch w spaces"
-### OPAMNOENVNOTICE=0
-### opam init -na --bare --bypass-check --disable-sandbox --root "$RT" defaut ./REPO | grep -v Cygwin
-No configuration file found, using built-in defaults.
-
-<><> Fetching repository information ><><><><><><><><><><><><><><><><><><><><><>
-[defaut] Initialised
-### opam switch create "./$SW" nv --root "$RT"
-
-<><> Installing new switch packages <><><><><><><><><><><><><><><><><><><><><><>
-Switch invariant: ["nv"]
-
-<><> Processing actions <><><><><><><><><><><><><><><><><><><><><><><><><><><><>
--> installed nv.1
-Done.
-# Run eval $(opam env '--root=${BASEDIR}/root 2' '--switch=${BASEDIR}/switch w spaces') to update the current shell environment
-### opam env --root "$RT" --switch "./$SW" | grep "NV_VARS" | ';' -> ':'
-NV_VARS3='foo:/yet/another/different/path': export NV_VARS3:
-NV_VARS4='': export NV_VARS4:
-NV_VARS_5925_1='foo': export NV_VARS_5925_1:
-NV_VARS_5925_2='foo': export NV_VARS_5925_2:
-NV_VARS_5925_3='foo': export NV_VARS_5925_3:
-NV_VARS_5925_4='foo': export NV_VARS_5925_4:
-NV_VARS_5925_5='foo:': export NV_VARS_5925_5:
-NV_VARS_5925_6='foo:': export NV_VARS_5925_6:
-NV_VARS_5925_7=':foo': export NV_VARS_5925_7:
-NV_VARS_5925_8=':foo': export NV_VARS_5925_8:
-NV_VARS_5926_L_1='b::a': export NV_VARS_5926_L_1:
-NV_VARS_5926_L_2='b::a': export NV_VARS_5926_L_2:
-NV_VARS_5926_L_3=':a:b': export NV_VARS_5926_L_3:
-NV_VARS_5926_L_4=':a:b': export NV_VARS_5926_L_4:
-NV_VARS_5926_L_5='b::a': export NV_VARS_5926_L_5:
-NV_VARS_5926_L_6='b::a': export NV_VARS_5926_L_6:
-NV_VARS_5926_L_7=':a:b': export NV_VARS_5926_L_7:
-NV_VARS_5926_L_8=':a:b': export NV_VARS_5926_L_8:
-NV_VARS_5926_M_1='b:a1::a2': export NV_VARS_5926_M_1:
-NV_VARS_5926_M_2='a1::a2:b': export NV_VARS_5926_M_2:
-NV_VARS_5926_M_3='b:a1::a2': export NV_VARS_5926_M_3:
-NV_VARS_5926_M_4='a1::a2:b': export NV_VARS_5926_M_4:
-NV_VARS_5926_S_1='a:': export NV_VARS_5926_S_1:
-NV_VARS_5926_S_2=':a': export NV_VARS_5926_S_2:
-NV_VARS_5926_S_3='a:': export NV_VARS_5926_S_3:
-NV_VARS_5926_S_4=':a': export NV_VARS_5926_S_4:
-NV_VARS_5926_T_1='b:a:': export NV_VARS_5926_T_1:
-NV_VARS_5926_T_2='b:a:': export NV_VARS_5926_T_2:
-NV_VARS_5926_T_3='a::b': export NV_VARS_5926_T_3:
-NV_VARS_5926_T_4='a::b': export NV_VARS_5926_T_4:
-NV_VARS_5926_T_5='b:a:': export NV_VARS_5926_T_5:
-NV_VARS_5926_T_6='b:a:': export NV_VARS_5926_T_6:
-NV_VARS_5926_T_7='a::b': export NV_VARS_5926_T_7:
-NV_VARS_5926_T_8='a::b': export NV_VARS_5926_T_8:
-### OPAMNOENVNOTICE=1
 ### : Env hooks :
 ### <pkg:av.1>
 opam-version: "2.0"

tests/reftests/env.unix.test

@@ -1,4 +1,30 @@
 N0REP0
+### : root and switches with spaces :
+### <pkg:nv.1>
+opam-version: "2.0"
+flags: compiler
+### RT="$BASEDIR/root 2"
+### SW="switch w spaces"
+### OPAMNOENVNOTICE=0
+### opam init -na --bare --bypass-check --disable-sandbox --root "$RT" defaut ./REPO
+No configuration file found, using built-in defaults.
+
+<><> Fetching repository information ><><><><><><><><><><><><><><><><><><><><><>
+[defaut] Initialised
+### opam switch create "./$SW" nv --root "$RT"
+
+<><> Installing new switch packages <><><><><><><><><><><><><><><><><><><><><><>
+Switch invariant: ["nv"]
+
+<><> Processing actions <><><><><><><><><><><><><><><><><><><><><><><><><><><><>
+-> installed nv.1
+Done.
+# Run eval $(opam env '--root=${BASEDIR}/root 2' '--switch=${BASEDIR}/switch w spaces') to update the current shell environment
+### opam env --root "$RT" --switch "./$SW" | grep "PREFIX" | ';' -> ':'
+OPAM_SWITCH_PREFIX='${BASEDIR}/switch w spaces/_opam': export OPAM_SWITCH_PREFIX:
+### opam var root --root "$RT"
+${BASEDIR}/root 2
+### OPAMNOENVNOTICE=1
 ### : setenv & build env rewriting :
 ### opam switch create rewriting --empty
 ### ::::::::::::::::::