Check if an installed file exists and report error if not.

So far there is only one case happened in b/277039235 that an installed file in that product is moved to another directory in LOCAL_POST_INSTALL_CMD. The team agreed to convert to Android.bp, but better to add a check and report the error.

Resend this to check symlinks using os.path.islink(), which doesn't follow the link. os.path.isfile() follows symlinks and returns false since the symlinks are for devices and could not be resolved on host file systems.

Bug: 277039235
Test: m sbom
Test: build/soong/tests/sbom_test.sh
Change-Id: Ia9f1cd24dc974a3e41487bc17c9c76a26d419395
diff --git a/tools/generate-sbom.py b/tools/generate-sbom.py
index eae7945..9583395 100755
--- a/tools/generate-sbom.py
+++ b/tools/generate-sbom.py
@@ -87,6 +87,7 @@
 ISSUE_NO_METADATA_FILE = 'No METADATA file found for installed file:'
 ISSUE_METADATA_FILE_INCOMPLETE = 'METADATA file incomplete:'
 ISSUE_UNKNOWN_SECURITY_TAG_TYPE = 'Unknown security tag type:'
+ISSUE_INSTALLED_FILE_NOT_EXIST = 'Non-exist installed files:'
 INFO_METADATA_FOUND_FOR_PACKAGE = 'METADATA file found for packages:'
 
 
@@ -597,11 +598,12 @@
 
   # Report on some issues and information
   report = {
-      ISSUE_NO_METADATA: [],
-      ISSUE_NO_METADATA_FILE: [],
-      ISSUE_METADATA_FILE_INCOMPLETE: [],
-      ISSUE_UNKNOWN_SECURITY_TAG_TYPE: [],
-      INFO_METADATA_FOUND_FOR_PACKAGE: []
+    ISSUE_NO_METADATA: [],
+    ISSUE_NO_METADATA_FILE: [],
+    ISSUE_METADATA_FILE_INCOMPLETE: [],
+    ISSUE_UNKNOWN_SECURITY_TAG_TYPE: [],
+    ISSUE_INSTALLED_FILE_NOT_EXIST: [],
+    INFO_METADATA_FOUND_FOR_PACKAGE: [],
   }
 
   # Scan the metadata in CSV file and create the corresponding package and file records in SPDX
@@ -619,6 +621,10 @@
 
       if not installed_file_has_metadata(installed_file_metadata, report):
         continue
+      file_path = args.product_out_dir + '/' + installed_file
+      if not (os.path.islink(file_path) or os.path.isfile(file_path)):
+        report[ISSUE_INSTALLED_FILE_NOT_EXIST].append(installed_file)
+        continue
 
       file_id = new_file_id(installed_file)
       product_files.append(new_file_record(file_id, installed_file, checksum(installed_file)))