check-abi: Default to HEAD for new version

tools/check-abi.sh

@@ -3,7 +3,7 @@
 set -eu
 
 default_base_version="$(git describe --match "v*.*.*" --abbrev=0)"
-default_new_version="master"
+default_new_version="HEAD"
 
 display_help_and_exit() {
     echo "Usage: $0 <base_ver> <new_ver>"
@@ -33,7 +33,8 @@ else
 fi
 
 checkout_and_build() {
-    git worktree add -d "$1" "$2"
+    _orig_dir="$(pwd)"
+    git worktree add --detach "$1" "$2"
     cd "$1"
     mkdir build && cd build
     cmake -S .. --preset dev-mode \
@@ -45,20 +46,18 @@ checkout_and_build() {
         -DSECP256K1_BUILD_EXAMPLES=OFF
     cmake --build . -j "$(nproc)"
     abi-dumper src/libsecp256k1.so -o ABI.dump -lver "$2"
+    cd "$_orig_dir"
 }
 
 echo "Comparing $base_version (base version) to $new_version (new version)"
 echo
 
-original_dir="$(pwd)"
-
 base_source_dir=$(mktemp -d)
 checkout_and_build "$base_source_dir" "$base_version"
 
 new_source_dir=$(mktemp -d)
 checkout_and_build "$new_source_dir" "$new_version"
 
-cd "$original_dir"
 abi-compliance-checker -lib libsecp256k1 -old "${base_source_dir}/build/ABI.dump" -new "${new_source_dir}/build/ABI.dump"
 git worktree remove "$base_source_dir"
 git worktree remove "$new_source_dir"