treesitter: enhance script and add README

The script now updates a `treesitter_commit_sha.txt` file to keep track
of which commit/branch/tag we're at.

scripts/update-ts-runtime.sh

@@ -3,14 +3,16 @@
 # This script will update the treesitter runtime to the provided commit.
 # Usage :
 #   $0 <tree-sitter commit sha>
+set -e
 
 ts_source_dir="/tmp/tree-sitter"
 ts_url="https://github.com/tree-sitter/tree-sitter.git"
 
 base_dir="$(cd "$(dirname $(dirname $0))" && pwd)"
 ts_dest_dir="$base_dir/src/tree_sitter/"
+ts_current_commit="$ts_dest_dir/treesitter_commit_hash.txt"
 
-echo "$ts_dest_dir"
+echo "Updating treesitter runtime from $(cat "$ts_current_commit") to $1..."
 
 if [ ! -d "$ts_source_dir" ]; then
   echo "Cloning treesitter..."
@@ -20,16 +22,17 @@ else
 fi
 
 echo "Checking out $1..."
-cd "$ts_source_dir"
 git -C "$ts_source_dir" checkout $1
 
 echo "Removing old files..."
-find "$ts_dest_dir" -not -name "LICENSE" -not -type d -delete
+find "$ts_dest_dir" -not -name "LICENSE" -not -name "README.md" -not -type d -delete
 
 echo "Copying files..."
 cp -t "$ts_dest_dir" -r "$ts_source_dir/lib/src"/*
 cp -t "$ts_dest_dir" "$ts_source_dir/lib/include/tree_sitter"/*
 
-cd "$base_dir"
+echo "$1" > "$ts_current_commit"
+
 make
 TEST_FILE="$base_dir/test/functional/lua/treesitter_spec.lua" make test
+

src/tree_sitter/README.md

@@ -0,0 +1,16 @@
+Tree-sitter vendor runtime
+==========================
+
+This is the vendor runtime code for treesitter.
+
+The original code can be found [here](https://github.com/tree-sitter/tree-sitter).
+
+As this code is not ours, if you find any bugs, feel free to open an issue, so that we can
+investigate and determine if this should go upstream.
+
+# Updating
+
+To update the treesitter runtime, use the `update-ts-runtime.sh` script in the `scripts` directory:
+```sh
+./scripts/update-ts-runtime.sh <commit you want to update to>
+```

src/tree_sitter/treesitter_commit_hash.txt

@@ -0,0 +1 @@
+9a82dcc666d06617cbab3061467075019fae0b0d