Detect the base commit in extract-patches.sh

* Detect the base commit in extract-patches.sh

* Fix: hard-coded src/cli

* Fix: don't prevent nested submodule patch support

(cherry picked from commit 1bda26d)

Author: dagood

extract-patches.sh

@@ -2,6 +2,13 @@
 set -euo pipefail
 IFS=$'\n\t'
 
+getIndexedSubmoduleSha() {
+    (
+        cd ".."
+        git ls-tree HEAD "$REPO_NAME" | awk '{print $3}'
+    )
+}
+
 SOURCE="${BASH_SOURCE[0]}"
 while [ -h "$SOURCE" ]; do # resolve $SOURCE until the file is no longer a symlink
   DIR="$( cd -P "$( dirname "$SOURCE" )" && pwd )"
@@ -10,9 +17,9 @@ while [ -h "$SOURCE" ]; do # resolve $SOURCE until the file is no longer a symli
 done
 DIR="$( cd -P "$( dirname "$SOURCE" )" && pwd )"
 
-BASE_SHA=$1
 REPO_NAME=$(basename $(pwd))
 PATCHES_DIR=$DIR/patches/$REPO_NAME
+BASE_SHA=${1:-$(getIndexedSubmoduleSha)}
 
 if [ ! -d $PATCHES_DIR ]; then
     mkdir -p $PATCHES_DIR