From 19e2b9588a3824e007a7689f9a918336768e120f Mon Sep 17 00:00:00 2001
From: Zach Riggle <riggle@google.com>
Date: Mon, 13 Nov 2017 15:12:13 -0600
Subject: [PATCH] Fix $PWD changes when executing Python

Specifically, this does not play well with PWD=/proc/self/cwd
---
 libexec/pyenv                         | 15 +++++++++------
 libexec/pyenv-hooks                   |  6 +++---
 libexec/pyenv-versions                |  5 +++--
 plugins/python-build/bin/python-build |  5 +++--
 4 files changed, 18 insertions(+), 13 deletions(-)

diff --git a/libexec/pyenv b/libexec/pyenv
index 79a20149..a1266c1f 100755
--- a/libexec/pyenv
+++ b/libexec/pyenv
@@ -36,9 +36,10 @@ else
   }
 
   abs_dirname() {
-    local cwd="$PWD"
     local path="$1"
 
+    # Use a subshell to avoid changing the current path
+    (
     while [ -n "$path" ]; do
       cd "${path%/*}"
       local name="${path##*/}"
@@ -46,7 +47,7 @@ else
     done
 
     pwd
-    cd "$cwd"
+    )
   }
 fi
 
@@ -72,11 +73,13 @@ fi
 
 if [ -z "${PYENV_DIR}" ]; then
   PYENV_DIR="$PWD"
-else
-  cd "$PYENV_DIR" 2>/dev/null || abort "cannot change working directory to \`$PYENV_DIR'"
-  PYENV_DIR="$PWD"
-  cd "$OLDPWD"
 fi
+
+if [ ! -d "$PYENV_DIR" ] || [ ! -e "$PYENV_DIR" ]; then
+  abort "cannot change working directory to \`$PYENV_DIR'"
+fi
+
+PYENV_DIR=$(cd "$PYENV_DIR" && echo "$PWD")
 export PYENV_DIR
 
 
diff --git a/libexec/pyenv-hooks b/libexec/pyenv-hooks
index a861c9f1..2c1620f3 100755
--- a/libexec/pyenv-hooks
+++ b/libexec/pyenv-hooks
@@ -37,10 +37,10 @@ resolve_link() {
 }
 
 realpath() {
-  local cwd="$PWD"
   local path="$1"
   local name
-
+  # Use a subshell to avoid changing the current path
+  (
   while [ -n "$path" ]; do
     name="${path##*/}"
     [ "$name" = "$path" ] || cd "${path%/*}"
@@ -48,7 +48,7 @@ realpath() {
   done
 
   echo "${PWD}/$name"
-  cd "$cwd"
+  )
 }
 fi
 
diff --git a/libexec/pyenv-versions b/libexec/pyenv-versions
index 87363c7b..019c0e90 100755
--- a/libexec/pyenv-versions
+++ b/libexec/pyenv-versions
@@ -44,10 +44,11 @@ if ! enable -f "${BASH_SOURCE%/*}"/pyenv-realpath.dylib realpath 2>/dev/null; th
   }
 
   realpath() {
-    local cwd="$PWD"
     local path="$1"
     local name
 
+    # Use a subshell to avoid changing the current path
+    (
     while [ -n "$path" ]; do
       name="${path##*/}"
       [ "$name" = "$path" ] || cd "${path%/*}"
@@ -55,7 +56,7 @@ if ! enable -f "${BASH_SOURCE%/*}"/pyenv-realpath.dylib realpath 2>/dev/null; th
     done
 
     echo "${PWD}/$name"
-    cd "$cwd"
+    )
   }
 fi
 
diff --git a/plugins/python-build/bin/python-build b/plugins/python-build/bin/python-build
index 3dfb9385..be180d66 100755
--- a/plugins/python-build/bin/python-build
+++ b/plugins/python-build/bin/python-build
@@ -60,9 +60,10 @@ resolve_link() {
 }
 
 abs_dirname() {
-  local cwd="$(pwd)"
   local path="$1"
 
+  # Use a subshell to avoid modifying the current path
+  (
   while [ -n "$path" ]; do
     cd "${path%/*}"
     local name="${path##*/}"
@@ -70,7 +71,7 @@ abs_dirname() {
   done
 
   pwd
-  cd "$cwd"
+  )
 }
 
 capitalize() {