delta: Do not create delta if all files are different

pisi/operations/delta.py

@@ -21,6 +21,10 @@ import pisi.util as util
 import pisi.archive as archive
 
 
+class AllFilesChangedException(Exception):
+    pass
+
+
 # FIXME Reduce code duplication
 def create_delta_packages_from_obj(old_packages, new_package_obj, specdir):
     new_pkg_info = new_package_obj.metadata.package
@@ -54,6 +58,14 @@ def create_delta_packages_from_obj(old_packages, new_package_obj, specdir):
 
         old_pkg_files = old_pkg.get_files()
 
+        try:
+            files_delta = find_delta(old_pkg_files, new_pkg_files)
+        except AllFilesChangedException:
+            ctx.ui.warning(_("All files in the package '%s' are different "
+                             "from the files in the new package. Skipping "
+                             "it...") % old_package)
+            continue
+
         delta_pkg = pisi.package.Package(delta_name, "w", format=target_format)
 
         # add comar files to package
@@ -68,8 +80,6 @@ def create_delta_packages_from_obj(old_packages, new_package_obj, specdir):
         delta_pkg.add_metadata_xml(ctx.const.metadata_xml)
         delta_pkg.add_files_xml(ctx.const.files_xml)
 
-        files_delta = find_delta(old_pkg_files, new_pkg_files)
-
         # only metadata information may change in a package,
         # so no install archive added to delta package
         if files_delta:
@@ -152,6 +162,14 @@ def create_delta_packages(old_packages, new_package):
 
         old_pkg_files = old_pkg.get_files()
 
+        try:
+            files_delta = find_delta(old_pkg_files, new_pkg_files)
+        except AllFilesChangedException:
+            ctx.ui.warning(_("All files in the package '%s' are different "
+                             "from the files in the new package. Skipping "
+                             "it...") % old_package)
+            continue
+
         delta_pkg = pisi.package.Package(delta_name, "w", format=target_format)
 
         os.chdir(new_pkg_path)
@@ -165,8 +183,6 @@ def create_delta_packages(old_packages, new_package):
         delta_pkg.add_metadata_xml(ctx.const.metadata_xml)
         delta_pkg.add_files_xml(ctx.const.files_xml)
 
-        files_delta = find_delta(old_pkg_files, new_pkg_files)
-
         # only metadata information may change in a package,
         # so no install archive added to delta package
         if files_delta:
@@ -210,6 +226,9 @@ def find_delta(old_files, new_files):
     old_hashes = set([f.hash for f in old_files.list])
     hashes_delta = new_hashes - old_hashes
 
+    if hashes_delta == new_hashes:
+        raise AllFilesChangedException
+
     deltas = []
     for h in hashes_delta:
         deltas.extend(hashto_files[h])