fix: get ISO filename from build output

.github/build_and_split.sh

@@ -7,8 +7,6 @@ GITHUB_WORKSPACE=${GITHUB_WORKSPACE:-$(pwd)}
 
 REPO_DIR=${REPO_DIR:-${GITHUB_WORKSPACE}/repo}
 NIX_BUILD_RESULT_ISO_DIR="${REPO_DIR}/result/iso"
-NIX_BUILD_RESULT_ISO_NAME="JohnOS-${GITHUB_SHA}.iso"
-NIX_BUILD_RESULT_ISO="${NIX_BUILD_RESULT_ISO_DIR}/${NIX_BUILD_RESULT_ISO_NAME}"
 
 SPLIT_DIR=${1:-${GITHUB_WORKSPACE}/split}
 
@@ -27,24 +25,32 @@ echo "checking dirty working tree"
 git --no-pager diff # see why it's dirty
 git --no-pager status # see why it's dirty
 
-tree -l -L 8 ${GITHUB_WORKSPACE}
-
 echo "building the ISO"
 nix build .#flash-drive-iso
 
-tree -l -L 8 ${GITHUB_WORKSPACE}
-
 echo "splitting the ISO into pieces"
+cd "${NIX_BUILD_RESULT_ISO_DIR}"
+NIX_BUILD_RESULT_ISO_NAME="" # default empty
+for iso in $(ls -1 *.iso); do
+  if [[ NIX_BUILD_RESULT_ISO_NAME != "" ]]; then
+    tree -l L 8 "${GITHUB_WORKSPACE}"
+    echo "we have more than one built ISO. we shouldn't..."
+  fi
+  NIX_BUILD_RESULT_ISO_NAME="${iso}"
+done
+
+NIX_BUILD_RESULT_ISO="${NIX_BUILD_RESULT_ISO_DIR}/${NIX_BUILD_RESULT_ISO_NAME}"
 split -d -b 128MiB \
-	"${NIX_BUILD_RESULT_ISO}" \
-	"${SPLIT_DIR}/JohnOS-${GITHUB_REF_NAME}-${SHORT_SHA}.iso."
+  "${NIX_BUILD_RESULT_ISO}" \
+  "${SPLIT_DIR}/JohnOS-*.iso."
 
 echo "generating checksum file"
-# generate SHA256 checksums of all relevant files
+# generate SHA256 checksums of all pieces
 cd "${SPLIT_DIR}"
-for i in $(ls *.iso.*); do sha256sum $i >> "${CHECKSUM_FILE}"; done
+for i in $(ls -1 JohnOS-*.iso.*); do sha256sum $i >> "${CHECKSUM_FILE}"; done
 
-cd "${NIX_BUILD_RESULT_ISO_DIR}"
+# generate SHA256 checksums of original file
+cd "${NIX_BUILD_RESULT_ISO_DIR}" # keep only basename in checksum file
 sha256sum "${NIX_BUILD_RESULT_ISO_NAME}"  >> "${CHECKSUM_FILE}"
 
 tree -l -L 8 ${GITHUB_WORKSPACE}