bin/bats,install.sh: Fix symlink bugs

Closes sstephenson#90. Closes sstephenson#83. Closes sstephenson#56. Closes sstephenson#55. Closes sstephenson#53. Resolves
outstanding issues from sstephenson#32.

Per all these earlier issues and PRs:

- The original bin/bats symlink was causing problems on Windows.
- The attempted fix from sstephenson#32 created problems for install.sh.
- Per sstephenson#90, changing bin/bats to a one-line script in sstephenson#88 broke some Bats
  installations that rely on symlink schemes (such as when installed via
  https://github.com/basherpm/basher).

For an idea of why I wanted to keep bin/bats as a script due to how
symlinks complicate things on Windows, see the following results I
discovered during a search for "git symlink windows":

- https://github.com/git-for-windows/git/wiki/Symbolic-Links
- https://blogs.windows.com/buildingapps/2016/12/02/symlinks-windows-10/
- libgit2/libgit2#4107
- https://stackoverflow.com/q/5917249

In the course of applying these changes, I realized libexec/bats
computed some extraneous variables, so I removed them, eliminating a few
external processes and subshells. I also cleaned up other small bits of
logic.

On top of making install.sh, bin/bats, and libexec/bats more resilient
and compact, the existing test suite (before adding the new
test/installer.bats file) sped up significantly, running 0.6s-0.7s
faster on my MacBook Pro (2.9 GHz Intel Core i5, 8GB RAM):

  Bash 3.2.57(1)-release before:
  58 tests, 0 failures

  real    0m4.924s
  user    0m3.045s
  sys     0m1.798s

  Bash 3.2.57(1)-release after:
  58 tests, 0 failures

  real    0m4.341s
  user    0m2.808s
  sys     0m1.540s

  Bash 4.4.23(1)-release before:
  58 tests, 0 failures

  real    0m5.228s
  user    0m3.046s
  sys     0m1.952s

  Bash 4.4.23(1)-release after:
  58 tests, 0 failures

  real    0m4.582s
  user    0m2.791s
  sys     0m1.643s

Also tweaks the Dockerfile to update the symlink to point to bin/bats,
not libexec/bats.

Dockerfile

@@ -1,7 +1,7 @@
 FROM alpine:3.6
 
 RUN apk --no-cache add bash \
-    && ln -s /opt/bats/libexec/bats /usr/sbin/bats
+    && ln -s /opt/bats/bin/bats /usr/sbin/bats
 
 COPY . /opt/bats/
 

bin/bats

@@ -1,3 +1,35 @@
 #! /usr/bin/env bash
 
-exec "${0%/*}/../libexec/bats" "$@"
+set -e
+
+export BATS_READLINK='true'
+if command -v 'greadlink' >/dev/null; then
+  BATS_READLINK='greadlink'
+elif command -v 'readlink' >/dev/null; then
+  BATS_READLINK='readlink'
+fi
+
+bats_resolve_link() {
+  if ! "$BATS_READLINK" "$1"; then
+    return 0
+  fi
+}
+
+bats_absolute_path() {
+  local cwd="$PWD"
+  local path="$1"
+
+  while [[ -n "$path" ]]; do
+    cd "${path%/*}"
+    local name="${path##*/}"
+    path="$(bats_resolve_link "$name")"
+  done
+
+  printf -v "$2" -- '%s' "$PWD"
+  cd "$cwd"
+}
+
+export BATS_ROOT
+bats_absolute_path "$0" 'BATS_ROOT'
+BATS_ROOT="${BATS_ROOT%/*}"
+exec "$BATS_ROOT/libexec/bats" "$@"

install.sh

@@ -1,41 +1,57 @@
 #!/usr/bin/env bash
+
 set -e
 
-resolve_link() {
-  $(type -p greadlink readlink | head -n1) "$1"
+PREFIX="$1"
+if [ -z "$1" ]; then
+  { echo "usage: $0 <prefix>"
+    echo "  e.g. $0 /usr/local"
+  } >&2
+  exit 1
+fi
+
+export BATS_READLINK='true'
+if command -v 'greadlink' >/dev/null; then
+  BATS_READLINK='greadlink'
+elif command -v 'readlink' >/dev/null; then
+  BATS_READLINK='readlink'
+fi
+
+bats_resolve_link() {
+  if ! "$BATS_READLINK" "$1"; then
+    return 0
+  fi
 }
 
-abs_dirname() {
-  local cwd="$(pwd)"
+bats_absolute_path() {
+  local cwd="$PWD"
   local path="$1"
 
-  while [ -n "$path" ]; do
+  while [[ -n "$path" ]]; do
     cd "${path%/*}"
     local name="${path##*/}"
-    path="$(resolve_link "$name" || true)"
+    path="$(bats_resolve_link "$name")"
   done
 
-  pwd
+  printf -v "$2" -- '%s' "$PWD"
   cd "$cwd"
 }
 
-PREFIX="$1"
-if [ -z "$1" ]; then
-  { echo "usage: $0 <prefix>"
-    echo "  e.g. $0 /usr/local"
-  } >&2
-  exit 1
-fi
+bats_install_scripts() {
+  local scripts_dir
+  local scripts=()
+
+  for scripts_dir in "$@"; do
+    scripts=("$BATS_ROOT/$scripts_dir"/*)
+    cp "${scripts[@]}" "$PREFIX/$scripts_dir"
+    chmod a+x "${scripts[@]/#$BATS_ROOT[/]/$PREFIX/}"
+  done
+}
 
-BATS_ROOT="$(abs_dirname "$0")"
 mkdir -p "$PREFIX"/{bin,libexec,share/man/man{1,7}}
-cp -R "$BATS_ROOT"/bin/* "$PREFIX"/bin
-cp -R "$BATS_ROOT"/libexec/* "$PREFIX"/libexec
-cp "$BATS_ROOT"/man/bats.1 "$PREFIX"/share/man/man1
-cp "$BATS_ROOT"/man/bats.7 "$PREFIX"/share/man/man7
-
-# fix file permission
-chmod a+x "$PREFIX"/bin/*
-chmod a+x "$PREFIX"/libexec/*
+bats_absolute_path "$0" 'BATS_ROOT'
+bats_install_scripts 'bin' 'libexec'
+cp "$BATS_ROOT/man/bats.1" "$PREFIX/share/man/man1"
+cp "$BATS_ROOT/man/bats.7" "$PREFIX/share/man/man7"
 
 echo "Installed Bats to $PREFIX/bin/bats"

libexec/bats

@@ -26,57 +26,23 @@ help() {
   echo
 }
 
-export BATS_READLINK='true'
-if command -v 'greadlink' >/dev/null; then
-  BATS_READLINK='greadlink'
-elif command -v 'readlink' >/dev/null; then
-  BATS_READLINK='readlink'
-fi
-
-resolve_link() {
-  if ! "$BATS_READLINK" "$1"; then
-    return 0
-  fi
-}
-
-abs_dirname() {
-  local cwd="$PWD"
-  local path="$1"
-
-  while [[ -n "$path" ]]; do
-    cd "${path%/*}"
-    local name="${path##*/}"
-    path="$(resolve_link "$name")"
-  done
-
-  printf -v "$2" -- '%s' "$PWD"
-  cd "$cwd"
-}
-
 expand_path() {
   local path="${1%/}"
   local dirname="${path%/*}"
 
   if [[ "$dirname" == "$path" ]]; then
     dirname="$PWD"
-  elif cd "$dirname" 2>/dev/null; then
+  else
+    cd "$dirname"
     dirname="$PWD"
     cd "$OLDPWD"
-  else
-    printf '%s' "$path"
-    return
   fi
   printf -v "$2" '%s/%s' "$dirname" "${path##*/}"
 }
 
-abs_dirname "$0" 'BATS_LIBEXEC'
-abs_dirname "$BATS_LIBEXEC" 'BATS_PREFIX'
-abs_dirname '.' 'BATS_CWD'
-
-export BATS_PREFIX
-export BATS_CWD
+export BATS_CWD="${PWD%/*}"
 export BATS_TEST_PATTERN="^[[:blank:]]*@test[[:blank:]]+(.*[^[:blank:]])[[:blank:]]+\{(.*)\$"
-export PATH="$BATS_LIBEXEC:$PATH"
+export PATH="$BATS_ROOT/libexec:$PATH"
 
 options=()
 arguments=()

libexec/bats-exec-test

@@ -211,11 +211,7 @@ bats_strip_string() {
 }
 
 bats_trim_filename() {
-  if [[ "$1" =~ ^${BATS_CWD}/ ]]; then
-    printf -v "$2" '%s' "${1#$BATS_CWD/}"
-  else
-    printf -v "$2" '%s' "$1"
-  fi
+  printf -v "$2" '%s' "${1#$BATS_CWD/}"
 }
 
 bats_debug_trap() {

test/install.bats

@@ -0,0 +1,65 @@
+#!/usr/bin/env bats
+
+load test_helper
+
+INSTALL_DIR=
+
+setup() {
+  make_bats_test_suite_tmpdir
+  INSTALL_DIR="$BATS_TEST_SUITE_TMPDIR/bats-core"
+}
+
+@test "install.sh creates a valid installation" {
+  run "$BATS_ROOT/install.sh" "$INSTALL_DIR"
+  [ "$status" -eq 0 ]
+  [ "$output" == "Installed Bats to $INSTALL_DIR/bin/bats" ]
+  [ -x "$INSTALL_DIR/bin/bats" ]
+  [ -x "$INSTALL_DIR/libexec/bats" ]
+  [ -x "$INSTALL_DIR/libexec/bats-exec-suite" ]
+  [ -x "$INSTALL_DIR/libexec/bats-exec-test" ]
+  [ -x "$INSTALL_DIR/libexec/bats-format-tap-stream" ]
+  [ -x "$INSTALL_DIR/libexec/bats-preprocess" ]
+  [ -f "$INSTALL_DIR/share/man/man1/bats.1" ]
+  [ -f "$INSTALL_DIR/share/man/man7/bats.7" ]
+
+  run "$INSTALL_DIR/bin/bats" -v
+  [ "$status" -eq 0 ]
+  [ "${output%% *}" == 'Bats' ]
+}
+
+@test "install.sh only updates permissions for Bats files" {
+  mkdir -p "$INSTALL_DIR"/{bin,libexec}
+
+  local dummy_bin="$INSTALL_DIR/bin/dummy"
+  printf 'dummy' >"$dummy_bin"
+
+  local dummy_libexec="$INSTALL_DIR/libexec/dummy"
+  printf 'dummy' >"$dummy_libexec"
+
+  run "$BATS_ROOT/install.sh" "$INSTALL_DIR"
+  [ "$status" -eq 0 ]
+  [ -f "$dummy_bin" ]
+  [ ! -x "$dummy_bin" ]
+  [ -f "$dummy_libexec" ]
+  [ ! -x "$dummy_libexec" ]
+}
+
+@test "bin/bats is resilient to symbolic links" {
+  run "$BATS_ROOT/install.sh" "$INSTALL_DIR"
+  [ "$status" -eq 0 ]
+
+  # Simulate a symlink to bin/bats (without using a symlink, for Windows sake)
+  # by creating a wrapper script that executes bin/bats via a relative path.
+  #
+  # The real test is in the .travis.yml script using the Dockerfile, which uses
+  # a real symbolic link.
+  local bats_symlink="$INSTALL_DIR/bin/bats-link"
+  printf '%s\n' '#! /usr/bin/env bash' \
+    "cd '$INSTALL_DIR/bin'" \
+    './bats "$@"' >"$bats_symlink"
+  chmod 700 "$bats_symlink"
+
+  run "$bats_symlink" -v
+  [ "$status" -eq 0 ]
+  [ "${output%% *}" == 'Bats' ]
+}