From 0704e65781cea29c0e6abe5f175eaf4d21e6ebd2 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Mislav=20Marohni=C4=87?= <git@mislav.net>
Date: Wed, 15 Feb 2023 17:09:20 +0100
Subject: [PATCH] Fix resolving `rbenv` symlink to its final location (#1482)

1. On systems with `readlink -f`, use that to canonicalize the path to libexec directory;
2. Otherwise, resolve symlinks recursively rather than just once.
---
 libexec/rbenv   | 45 ++++++++++++++++++++++++++-------------------
 test/rbenv.bats |  6 +++---
 2 files changed, 29 insertions(+), 22 deletions(-)

diff --git a/libexec/rbenv b/libexec/rbenv
index e5ce0a9a..1241ab6c 100755
--- a/libexec/rbenv
+++ b/libexec/rbenv
@@ -39,30 +39,37 @@ export RBENV_DIR
 
 [ -n "$RBENV_ORIG_PATH" ] || export RBENV_ORIG_PATH="$PATH"
 
+canonicalize() {
+  local readlink resolved_path
+  if readlink="$(type -P greadlink)" || readlink="$(type -P readlink)"; then
+    # happy path: GNU & BSD readlink, macOS 12.3+
+    if resolved_path="$("$readlink" -f "$1" 2>/dev/null)"; then
+      printf "%s\n" "$resolved_path"
+      return 0
+    fi
+    # likely macOS < 12.3 with old readlink
+    local path="$1"
+    while [ -L "$path" ]; do
+      resolved_path="$("$readlink" "$path" 2>/dev/null)"
+      [[ $resolved_path == /* ]] || resolved_path="$(cd "${path%/*}/${resolved_path%/*}" && pwd)/${resolved_path##*/}"
+      path="$resolved_path"
+    done
+    printf "%s\n" "$path"
+    return 0
+  fi
+  # fail if the argument is a symlink and was not canonicalized
+  [ ! -L "$1" ] || return 1
+}
+
 shopt -s nullglob
 
+# all this trouble just to find out where rbenv's executables live
 rbenv_bin="${BASH_SOURCE:-$0}"
-if [ -L "$rbenv_bin" ]; then
-  # resolve rbenv symlink to find out where the actual libexec directory is
-  if readlink="$(type -P greadlink)" || readlink="$(type -P readlink)"; then
-    resolved="$("$readlink" "$rbenv_bin" 2>/dev/null)"
-    if [[ $resolved == /* ]]; then
-      libexec_dir="${resolved%/*}"
-    else
-      libexec_dir="$(cd "${rbenv_bin%/*}/${resolved%/*}" && pwd)"
-    fi
-  else
-    # no readlink available; assume rbenv project layout
-    libexec_dir="${rbenv_bin%/*}"
-    if [[ $libexec_dir == */* ]]; then
-      libexec_dir="${libexec_dir%/*}/libexec"
-    else
-      libexec_dir="${PWD}/libexec"
-    fi
-  fi
+if libexec_dir="$(canonicalize "$rbenv_bin")"; then
+  libexec_dir="${libexec_dir%/*}"
 else
   libexec_dir="${rbenv_bin%/*}"
-  [[ $libexec_dir != "." ]] || libexec_dir="$PWD"
+  [ "$libexec_dir" != "." ] || libexec_dir="$PWD"
 fi
 
 for plugin_bin in "${RBENV_ROOT}/plugins/"*/bin; do
diff --git a/test/rbenv.bats b/test/rbenv.bats
index bde18d7c..0f305bca 100644
--- a/test/rbenv.bats
+++ b/test/rbenv.bats
@@ -48,7 +48,7 @@ load test_helper
 
 @test "adds its own libexec to PATH" {
   run rbenv echo "PATH"
-  assert_success "${BATS_TEST_DIRNAME}/../libexec:$PATH"
+  assert_success "${BATS_TEST_DIRNAME%/*}/libexec:$PATH"
 }
 
 @test "adds plugin bin dirs to PATH" {
@@ -56,7 +56,7 @@ load test_helper
   mkdir -p "$RBENV_ROOT"/plugins/rbenv-each/bin
   run rbenv echo -F: "PATH"
   assert_success
-  assert_line 0 "${BATS_TEST_DIRNAME}/../libexec"
+  assert_line 0 "${BATS_TEST_DIRNAME%/*}/libexec"
   assert_line 1 "${RBENV_ROOT}/plugins/ruby-build/bin"
   assert_line 2 "${RBENV_ROOT}/plugins/rbenv-each/bin"
 }
@@ -72,5 +72,5 @@ load test_helper
 @test "RBENV_HOOK_PATH includes rbenv built-in plugins" {
   unset RBENV_HOOK_PATH
   run rbenv echo "RBENV_HOOK_PATH"
-  assert_success "${RBENV_ROOT}/rbenv.d:${BATS_TEST_DIRNAME}/../rbenv.d:/usr/local/etc/rbenv.d:/etc/rbenv.d:/usr/lib/rbenv/hooks"
+  assert_success "${RBENV_ROOT}/rbenv.d:${BATS_TEST_DIRNAME%/*}/rbenv.d:/usr/local/etc/rbenv.d:/etc/rbenv.d:/usr/lib/rbenv/hooks"
 }