scripts/vim-patch.sh: Misc. improvements #2108

- Check for mercurial before using it
- Make 'Merging patches...' wiki page easier to copy
- Use `basename` instead of assuming the user is running vim-patch.sh
  via the repo root
- Appease shellcheck by quoting path variables
- Remove unneeded variable quoting inside [[ ]] blocks
- Don't unconditionally 'exit 1'
  '-h' and '--help' are both recognized options, so current behavior is
  misleading.

1 files changed, 52 insertions, 42 deletions

diff --git a/scripts/vim-patch.sh b/scripts/vim-patch.sh
index c4bc2d156a..4935ca5994 100755
--- a/scripts/vim-patch.sh
+++ b/scripts/vim-patch.sh
@@ -3,37 +3,38 @@
 set -e
 set -o pipefail
 
-NEOVIM_SOURCE_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")/.." && pwd)"
-VIM_SOURCE_DIR_DEFAULT=${NEOVIM_SOURCE_DIR}/.vim-src
-VIM_SOURCE_DIR="${VIM_SOURCE_DIR:-${VIM_SOURCE_DIR_DEFAULT}}"
+readonly NEOVIM_SOURCE_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")/.." && pwd)"
+readonly VIM_SOURCE_DIR_DEFAULT=${NEOVIM_SOURCE_DIR}/.vim-src
+readonly VIM_SOURCE_DIR="${VIM_SOURCE_DIR:-${VIM_SOURCE_DIR_DEFAULT}}"
+readonly BASENAME="$(basename "${0}")"
 
 usage() {
-  >&2 echo "Helper script for porting Vim patches. For more information,"
-  >&2 echo "see https://github.com/neovim/neovim/wiki/Merging-patches-from-upstream-vim."
-  >&2 echo
-  >&2 echo "Usage:  ${0} [option]"
-  >&2 echo "        ${0} vim-revision"
-  >&2 echo
-  >&2 echo "Options:"
-  >&2 echo "    -h, --help    Show this message."
-  >&2 echo "    -l, --list    Show list of Vim patches missing from Neovim."
-  >&2 echo
-  >&2 echo "vim-revision can be a version number in format '7.4.xxx'"
-  >&2 echo "or a Mercurial commit hash."
-  >&2 echo
-  >&2 echo "Set VIM_SOURCE_DIR to change where Vim's sources are stored."
-  >&2 echo "The default is '${VIM_SOURCE_DIR_DEFAULT}'."
+  echo "Helper script for porting Vim patches. For more information, see"
+  echo "https://github.com/neovim/neovim/wiki/Merging-patches-from-upstream-vim"
+  echo
+  echo "Usage:  ${BASENAME} [option]"
+  echo "        ${BASENAME} vim-revision"
+  echo
+  echo "Options:"
+  echo "    -h, --help    Show this message."
+  echo "    -l, --list    Show list of Vim patches missing from Neovim."
+  echo
+  echo "vim-revision can be a version number of the format '7.4.xxx'"
+  echo "or a Mercurial commit hash."
+  echo
+  echo "Set VIM_SOURCE_DIR to change where Vim's sources are stored."
+  echo "The default is '${VIM_SOURCE_DIR_DEFAULT}'."
 }
 
 get_vim_sources() {
   echo "Retrieving Vim sources."
   if [[ ! -d ${VIM_SOURCE_DIR} ]]; then
     echo "Cloning Vim sources into '${VIM_SOURCE_DIR}'."
-    hg clone https://code.google.com/p/vim ${VIM_SOURCE_DIR}
-    cd ${VIM_SOURCE_DIR}
+    hg clone https://code.google.com/p/vim "${VIM_SOURCE_DIR}"
+    cd "${VIM_SOURCE_DIR}"
   else
     echo "Updating Vim sources in '${VIM_SOURCE_DIR}'."
-    cd ${VIM_SOURCE_DIR}
+    cd "${VIM_SOURCE_DIR}"
     hg pull --update &&
       echo "✔ Updated Vim sources." ||
       echo "✘ Could not update Vim sources; ignoring error."
@@ -41,7 +42,7 @@ get_vim_sources() {
 }
 
 get_vim_patch() {
-  if [[ "${1}" =~ [0-9]\.[0-9]\.[0-9]{3,4} ]]; then
+  if [[ ${1} =~ [0-9]\.[0-9]\.[0-9]{3,4} ]]; then
     # Interpret parameter as version number.
     vim_version="${1}"
     vim_commit="v${1//./-}"
@@ -53,7 +54,7 @@ get_vim_patch() {
     strip_commit_line=false
   fi
 
-  hg log --rev ${vim_commit} >/dev/null 2>&1 || {
+  hg log --rev "${vim_commit}" >/dev/null 2>&1 || {
     >&2 echo "✘ Couldn't find Vim revision '${vim_commit}'."
     exit 3
   }
@@ -61,13 +62,13 @@ get_vim_patch() {
   echo "✔ Found Vim revision '${vim_commit}'."
 
   # Collect patch details and store into variables.
-  vim_full="$(hg log --patch --git --verbose --rev ${vim_commit})"
-  vim_message="$(hg log --template "{desc}" --rev ${vim_commit})"
-  if [[ "${strip_commit_line}" == "true" ]]; then
+  vim_full="$(hg log --patch --git --verbose --rev "${vim_commit}")"
+  vim_message="$(hg log --template "{desc}" --rev "${vim_commit}")"
+  if [[ ${strip_commit_line} == "true" ]]; then
     # Remove first line of commit message.
     vim_message="$(echo "${vim_message}" | sed -e '1d')"
   fi
-  vim_diff="$(hg diff --show-function --git --change ${vim_commit} \
+  vim_diff="$(hg diff --show-function --git --change "${vim_commit}" \
     | sed -e 's/\( [ab]\/src\)/\1\/nvim/g')" # Change directory to src/nvim.
   neovim_message="
   vim-patch:${vim_version}
@@ -91,7 +92,7 @@ get_vim_patch() {
 
   echo
   echo "Creating Git branch."
-  cd ${NEOVIM_SOURCE_DIR}
+  cd "${NEOVIM_SOURCE_DIR}"
   output="$(git checkout -b "${neovim_branch}" 2>&1)" &&
     echo "✔ ${output}" ||
     (echo "✘ ${output}"; false)
@@ -104,11 +105,11 @@ get_vim_patch() {
 
   echo
   echo "Creating files."
-  echo "${vim_diff}" > ${NEOVIM_SOURCE_DIR}/${neovim_branch}.diff
+  echo "${vim_diff}" > "${NEOVIM_SOURCE_DIR}/${neovim_branch}.diff"
   echo "✔ Saved patch to '${NEOVIM_SOURCE_DIR}/${neovim_branch}.diff'."
-  echo "${vim_full}" > ${NEOVIM_SOURCE_DIR}/${neovim_branch}.patch
+  echo "${vim_full}" > "${NEOVIM_SOURCE_DIR}/${neovim_branch}.patch"
   echo "✔ Saved full commit details to '${NEOVIM_SOURCE_DIR}/${neovim_branch}.patch'."
-  echo "${neovim_pr}" > ${NEOVIM_SOURCE_DIR}/${neovim_branch}.pr
+  echo "${neovim_pr}" > "${NEOVIM_SOURCE_DIR}/${neovim_branch}.pr"
   echo "✔ Saved suggested PR description to '${NEOVIM_SOURCE_DIR}/${neovim_branch}.pr'."
   echo "You can use 'git clean' to remove these files when you're done."
 
@@ -136,7 +137,7 @@ list_vim_patches() {
   # Start from 7.4.442. The runtime was re-integrated from 7.4.384, but
   # runtime patches before between 384 and 442 have already been ported
   # to Neovim as of the creation of this script.
-  local vim_commits=$(cd ${VIM_SOURCE_DIR} && \
+  local vim_commits=$(cd "${VIM_SOURCE_DIR}" && \
     hg log --removed --template='{if(startswith("Added tag", firstline(desc)),
       "{latesttag}\n",
       "{if(startswith(\"updated for version\", firstline(desc)),
@@ -144,7 +145,7 @@ list_vim_patches() {
         \"{node}\n\")}")}' -r tip:v7-4-442)
   # Append remaining vim patches.
   # Start from 7.4.160, where Neovim was forked.
-  local vim_old_commits=$(cd ${VIM_SOURCE_DIR} && \
+  local vim_old_commits=$(cd "${VIM_SOURCE_DIR}" && \
     hg log --removed --template='{if(startswith("Added tag",
       firstline(desc)),
       "{latesttag}\n")}' -r v7-4-442:v7-4-161)
@@ -152,21 +153,21 @@ list_vim_patches() {
   local vim_commit
   for vim_commit in ${vim_commits} ${vim_old_commits}; do
     local is_missing
-    if [[ "${vim_commit}" =~ v([0-9]-[0-9]-([0-9]{3,4})) ]]; then
+    if [[ ${vim_commit} =~ v([0-9]-[0-9]-([0-9]{3,4})) ]]; then
       local patch_number="${BASH_REMATCH[2]}"
       # "Proper" Vim patch
       # Check version.c:
-      is_missing="$(sed -n '/static int included_patches/,/}/p' ${NEOVIM_SOURCE_DIR}/src/nvim/version.c |
+      is_missing="$(sed -n '/static int included_patches/,/}/p' "${NEOVIM_SOURCE_DIR}/src/nvim/version.c" |
         grep -x -e "[[:space:]]*//${patch_number} NA" -e "[[:space:]]*${patch_number}," >/dev/null && echo "false" || echo "true")"
       vim_commit="${BASH_REMATCH[1]//-/.}"
     else
       # Untagged Vim patch, e.g. runtime updates.
       # Check Neovim log:
-      is_missing="$(cd ${NEOVIM_SOURCE_DIR} &&
+      is_missing="$(cd "${NEOVIM_SOURCE_DIR}" &&
         git log -1 --no-merges --grep="vim\-patch:${vim_commit:0:7}" --pretty=format:"false")"
     fi
 
-    if [[ "${is_missing}" != "false" ]]; then
+    if [[ ${is_missing} != "false" ]]; then
       echo "  • ${vim_commit}"
     fi
   done
@@ -177,19 +178,28 @@ list_vim_patches() {
   echo "  To port one of the above patches to Neovim, execute"
   echo "  this script with the patch revision as argument."
   echo
-  echo "  Examples: './scripts/vim-patch.sh 7.4.487'"
-  echo "            './scripts/vim-patch.sh 1e8ebf870720e7b671f98f22d653009826304c4f'"
+  echo "  Examples: '${BASENAME} 7.4.487'"
+  echo "            '${BASENAME} 1e8ebf870720e7b671f98f22d653009826304c4f'"
 }
 
-if [[ ${#} != 1 || "${1}" == "--help" || "${1}" == "-h" ]]; then
+if [[ ${1} == "--help" || ${1} == "-h" ]]; then
   usage
+  exit 0
+elif [[ ${#} != 1 ]]; then
+  usage
+  exit 1
+fi
+
+# Checks if mercurial is in the user's PATH, and is executable.
+if [[ ! -x $(command -v hg) ]]; then
+  >&2 echo "${BASENAME}: 'hg' (mercurial) not found in PATH or not executable"
   exit 1
 fi
 
 get_vim_sources
 
-if [[ "${1}" == "--list" || "${1}" == "-l" ]]; then
+if [[ ${1} == "--list" || ${1} == "-l" ]]; then
   list_vim_patches
 else
-  get_vim_patch ${1}
+  get_vim_patch "${1}"
 fi