Infer shells automatically, and `use` versions based on the current working directory (optional) (#68)

* `use` on every `cd`, infer shell type

* Add the ability to `use` on every pwd change (bash, zsh)
* infers shell type automatically. Fixes #20

.ci/install.sh

@@ -97,12 +97,12 @@ setup_shell() {
     echo ""
     echo '  # fnm'
     echo '  export PATH=$HOME/.fnm:$PATH'
-    echo '  eval `fnm env --multi`'
+    echo '  eval "`fnm env --multi`"'
 
     echo '' >> $CONF_FILE
     echo '# fnm' >> $CONF_FILE
     echo 'export PATH=$HOME/.fnm:$PATH' >> $CONF_FILE
-    echo 'eval `fnm env --multi`' >> $CONF_FILE
+    echo 'eval "`fnm env --multi`"' >> $CONF_FILE
 
   elif [ "$CURRENT_SHELL" == "fish" ]; then
     CONF_FILE=$HOME/.config/fish/config.fish
@@ -110,12 +110,12 @@ setup_shell() {
     echo ""
     echo '  # fnm'
     echo '  set PATH $HOME/.fnm $PATH'
-    echo '  eval (fnm env --multi --fish)'
+    echo '  fnm env --multi | source'
 
     echo '' >> $CONF_FILE
     echo '# fnm' >> $CONF_FILE
     echo 'set PATH $HOME/.fnm $PATH' >> $CONF_FILE
-    echo 'eval (fnm env --multi --fish)' >> $CONF_FILE
+    echo 'fnm env --multi | source"' >> $CONF_FILE
 
   elif [ "$CURRENT_SHELL" == "bash" ]; then
     if [ "$OS" == "Darwin" ]; then
@@ -127,12 +127,12 @@ setup_shell() {
     echo ""
     echo '  # fnm'
     echo '  export PATH=$HOME/.fnm:$PATH'
-    echo '  eval `fnm env --multi`'
+    echo '  eval "`fnm env --multi`"'
 
     echo '' >> $CONF_FILE
     echo '# fnm' >> $CONF_FILE
     echo 'export PATH=$HOME/.fnm:$PATH' >> $CONF_FILE
-    echo 'eval `fnm env --multi`' >> $CONF_FILE
+    echo 'eval "`fnm env --multi`"' >> $CONF_FILE
 
   else
     echo "Could not infer shell type. Please set up manually."

README.md

@@ -51,13 +51,13 @@ curl https://raw.githubusercontent.com/Schniz/fnm/master/.ci/install.sh | bash -
 - Add the following line to your `.bashrc`/`.zshrc` file:
 
   ```bash
-  eval `fnm env --multi`
+  eval "`fnm env --multi`"
   ```
 
   If you are using [fish shell](https://fishshell.com/), add this line to your `config.fish` file:
 
   ```fish
-  eval (fnm env --multi --fish)
+  fnm env --multi | source
   ```
 
 ## Usage
@@ -80,13 +80,14 @@ Lists the installed Node versions.
 
 Lists the Node versions available to download remotely.
 
-### `fnm env [--multi] [--fish] [--node-dist-mirror=URI] [--base-dir=DIR]`
+### `fnm env [--multi] [--shell=fish|bash|zsh] [--node-dist-mirror=URI] [--use-on-cd] [--base-dir=DIR]`
 
 Prints the required shell commands in order to configure your shell, Bash compliant by default.
 
 - Providing `--multi` will output the multishell support, allowing a different current Node version per shell
-- Providing `--fish` will output the Fish-compliant version.
+- Providing `--shell=fish` will output the Fish-compliant version. Omitting it and `fnm` will try to infer the current shell based on the process tree
 - Providing `--node-dist-mirror="https://npm.taobao.org/dist"` will use the Chinese mirror of Node.js
+- Providing `--use-on-cd` will also output a script that will automatically change the node version if a `.nvmrc`/`.node-version` file is found
 - Providing `--base-dir="/tmp/fnm"` will install and use versions in `/tmp/fnm` directory
 
 ## Future Plans

executable/Env.re

@@ -1,10 +1,9 @@
 open Fnm;
 
-let symlinkExists = path => {
+let symlinkExists = path =>
   try%lwt (Lwt_unix.lstat(path) |> Lwt.map(_ => true)) {
   | _ => Lwt.return(false)
   };
-};
 
 let rec makeTemporarySymlink = () => {
   let suggestedName =
@@ -25,8 +24,66 @@ let rec makeTemporarySymlink = () => {
   };
 };
 
-let run = (~shell, ~multishell, ~nodeDistMirror, ~fnmDir) => {
+let rec printUseOnCd = (~shell) =>
+  switch (shell) {
+  | System.Shell.Bash => {|
+    __fnmcd () {
+      cd $@
+
+      if [[ -f .node-version && .node-version ]]; then
+        echo "fnm: Found .node-version"
+        fnm use
+      elif [[ -f .nvmrc && .nvmrc ]]; then
+        echo "fnm: Found .nvmrc"
+        fnm use
+      fi
+    }
+
+    alias cd=__fnmcd
+  |}
+  | Fish => {|
+      function _fnm_autoload_hook --on-variable PWD --description 'Change Node version on directory change'
+        status --is-command-substitution; and return
+        if test -f .node-version
+          echo "fnm: Found .node-version"
+          fnm use
+        else if test -f .nvmrc
+          echo "fnm: Found .nvmrc"
+          fnm use
+        end
+      end
+    |}
+  | Zsh => {|
+      autoload -U add-zsh-hook
+      _fnm_autoload_hook () {
+        if [[ -f .node-version && -r .node-version ]]; then
+          echo "fnm: Found .node-version"
+          fnm use
+          elsif
+        elif [[ -f .nvmrc && -r .nvmrc ]]; then
+          echo "fnm: Found .nvmrc"
+          fnm use
+        fi
+      }
+
+      add-zsh-hook chpwd _fnm_autoload_hook \
+        && _fnm_autoload_hook
+    |}
+  };
+
+let run = (~forceShell, ~multishell, ~nodeDistMirror, ~fnmDir, ~useOnCd) => {
   open Lwt;
+  open System.Shell;
+
+  let%lwt shell =
+    switch (forceShell) {
+    | None =>
+      switch%lwt (System.Shell.infer()) {
+      | None => Lwt.return(Bash)
+      | Some(shell) => Lwt.return(shell)
+      }
+    | Some(shell) => Lwt.return(shell)
+    };
 
   Random.self_init();
 
@@ -35,7 +92,8 @@ let run = (~shell, ~multishell, ~nodeDistMirror, ~fnmDir) => {
       ? makeTemporarySymlink() : Lwt.return(Directories.globalCurrentVersion);
 
   switch (shell) {
-  | System.Shell.Bash =>
+  | Bash
+  | Zsh =>
     Printf.sprintf("export PATH=%s/bin:$PATH", path) |> Console.log;
     Printf.sprintf("export %s=%s", Config.FNM_MULTISHELL_PATH.name, path)
     |> Console.log;
@@ -46,7 +104,7 @@ let run = (~shell, ~multishell, ~nodeDistMirror, ~fnmDir) => {
       nodeDistMirror,
     )
     |> Console.log;
-  | System.Shell.Fish =>
+  | Fish =>
     Printf.sprintf("set PATH %s/bin $PATH;", path) |> Console.log;
     Printf.sprintf("set %s %s;", Config.FNM_MULTISHELL_PATH.name, path)
     |> Console.log;
@@ -59,5 +117,9 @@ let run = (~shell, ~multishell, ~nodeDistMirror, ~fnmDir) => {
     |> Console.log;
   };
 
+  if (useOnCd) {
+    printUseOnCd(~shell) |> Console.log;
+  };
+
   Lwt.return();
 };

executable/FnmApp.re

@@ -6,13 +6,15 @@ module Commands = {
   let listRemote = () => Lwt_main.run(ListRemote.run());
   let listLocal = () => Lwt_main.run(ListLocal.run());
   let install = version => Lwt_main.run(Install.run(~version));
-  let env = (isFishShell, isMultishell, nodeDistMirror, fnmDir) =>
+  let env =
+      (isFishShell, isMultishell, nodeDistMirror, fnmDir, shell, useOnCd) =>
     Lwt_main.run(
       Env.run(
-        ~shell=Fnm.System.Shell.(isFishShell ? Fish : Bash),
+        ~forceShell=Fnm.System.Shell.(isFishShell ? Some(Fish) : shell),
         ~multishell=isMultishell,
         ~nodeDistMirror,
         ~fnmDir,
+        ~useOnCd,
       ),
     );
 };
@@ -149,6 +151,14 @@ let env = {
     Arg.(value & flag & info(["fish"], ~doc));
   };
 
+  let shell = {
+    open Fnm.System.Shell;
+    let doc = "Specifies a specific shell type. If omitted, it will be inferred based on the process tree. $(docv)";
+    let shellChoices =
+      Arg.enum([("fish", Fish), ("bash", Bash), ("zsh", Zsh)]);
+    Arg.(value & opt(some(shellChoices), None) & info(["shell"], ~doc));
+  };
+
   let nodeDistMirror = {
     let doc = "https://nodejs.org/dist mirror";
     Arg.(
@@ -172,6 +182,11 @@ let env = {
     Arg.(value & flag & info(["multi"], ~doc));
   };
 
+  let useOnCd = {
+    let doc = "Hook into the shell `cd` and automatically use the specified version for the project";
+    Arg.(value & flag & info(["use-on-cd"], ~doc));
+  };
+
   (
     Term.(
       const(Commands.env)
@@ -179,6 +194,8 @@ let env = {
       $ isMultishell
       $ nodeDistMirror
       $ fnmDir
+      $ shell
+      $ useOnCd
     ),
     Term.info("env", ~version, ~doc, ~exits=Term.default_exits, ~man, ~sdocs),
   );

feature_tests/fish/run.fish

@@ -1,6 +1,6 @@
 #!/usr/bin/env fish
 
-eval (fnm env --fish)
+fnm env --fish | source
 
 fnm install v8.11.3
 fnm use v8.11.3

feature_tests/use_on_cd/app/.nvmrc

@@ -0,0 +1 @@
+8.11.3

feature_tests/use_on_cd/run.sh

@@ -0,0 +1,82 @@
+#!/bin/bash
+
+set -e
+
+DIRECTORY=`dirname $0`
+
+eval "`fnm env --multi`"
+fnm install 6.11.3
+fnm install 8.11.3
+fnm use 6.11.3
+
+if hash zsh 2>/dev/null; then
+  echo ' > Running test on Zsh'
+
+  zsh -c '
+    set -e
+
+    eval "`fnm env --multi --use-on-cd`"
+
+    fnm use 6.11.3
+
+    NODE_VERSION=$(node -v)
+    if [ "$NODE_VERSION" != "v6.11.3" ]; then
+      echo "Failed: Node version ($NODE_VERSION) is not v6.11.3"
+      exit 1
+    fi
+
+    cd app
+
+    NODE_VERSION=$(node -v)
+    if [ "$NODE_VERSION" != "v8.11.3" ]; then
+      echo "Failed: Node version ($NODE_VERSION) is not v8.11.3"
+      exit 1
+    fi
+  '
+else
+  echo "Skipping zsh test: \`zsh\` is not installed"
+fi
+
+if hash fish 2>/dev/null; then
+  echo ' > Running test on Fish'
+
+  fish -c '
+    fnm env --multi --use-on-cd | source
+
+    fnm use 6.11.3
+
+    set NODE_VERSION (node -v)
+    if test "$NODE_VERSION" != "v6.11.3"
+      echo "Failed: Node version ($NODE_VERSION) is not v6.11.3"
+      exit 1
+    end
+
+    cd app
+
+    set NODE_VERSION (node -v)
+    if test "$NODE_VERSION" != "v8.11.3"
+      echo "Failed: Node version ($NODE_VERSION) is not v8.11.3"
+      exit 1
+    end
+  '
+else
+  echo "Skipping fish test: \`zsh\` is not installed"
+fi
+
+echo " > Running test on Bash..."
+bash -c '
+  shopt -s expand_aliases
+  eval "`fnm env --multi --use-on-cd`"
+  fnm use 6.11.3
+  NODE_VERSION=$(node -v)
+  if [ "$NODE_VERSION" != "v6.11.3" ]; then
+    echo "Failed: Node version ($NODE_VERSION) is not v6.11.3"
+    exit 1
+  fi
+  cd app
+  NODE_VERSION=$(node -v)
+  if [ "$NODE_VERSION" != "v8.11.3" ]; then
+    echo "Failed: Node version ($NODE_VERSION) is not v8.11.3"
+    exit 1
+  fi
+'

library/System.re

@@ -11,7 +11,40 @@ let mkdirp = destination =>
 module Shell = {
   type t =
     | Bash
+    | Zsh
     | Fish;
+
+  let infer = () => {
+    let processInfo = pid => {
+      switch%lwt (unix_exec("ps", ~args=[|"-o", "ppid,comm", pid|])) {
+      | [] => Lwt.return_none
+      | [_headers, line, ..._otherLines] =>
+        let psResult = String.split_on_char(' ', line |> String.trim);
+        let parentPid = List.nth(psResult, 0);
+        let executable = List.nth(psResult, 1) |> Filename.basename;
+        Lwt.return_some((parentPid, executable));
+      | [_, ...xs] => Lwt.return_none
+      };
+    };
+
+    let rec getShell = (~level=0, pid) => {
+      switch%lwt (processInfo(pid)) {
+      | Some((_, "sh"))
+      | Some((_, "-sh"))
+      | Some((_, "-bash"))
+      | Some((_, "bash")) => Lwt.return_some(Bash)
+      | Some((_, "-zsh"))
+      | Some((_, "zsh")) => Lwt.return_some(Zsh)
+      | Some((_, "fish"))
+      | Some((_, "-fish")) => Lwt.return_some(Fish)
+      | Some((ppid, _)) when level < 10 => getShell(~level=level + 1, ppid)
+      | Some(_)
+      | None => Lwt.return_none
+      };
+    };
+
+    getShell(Unix.getpid() |> string_of_int);
+  };
 };
 
 module NodeArch = {