tree: address latest pylint issues

Looks like a new pylint release brought some new warnings. Fix or
explicitly ignore those.

Author: jlebon

src/cmd-buildextend-live

@@ -229,6 +229,8 @@ def generate_iso():
         raise Exception("Live image generation requires `metal` image")
     img_metal = os.path.join(builddir, img_metal_obj['path'])
     img_metal_checksum = img_metal_obj['sha256']
+    img_metal4k = None
+    img_metal4k_checksum = None
     img_metal4k_obj = buildmeta.get_artifact_meta("metal4k", unmerged=True)["images"].get("metal4k")
     if not img_metal4k_obj:
         if not args.fast:
@@ -319,6 +321,8 @@ def generate_iso():
             '--description', pretty_name, '--checksum', img_metal_checksum,
             '--output', '/var/tmp/coreos-installer-output'] + fast_arg)
     if img_metal4k_obj:
+        assert img_metal4k
+        assert img_metal4k_checksum
         tmp_osmet4k = os.path.join(tmpinitrd_rootfs, img_metal4k_obj['path'] + '.osmet')
         print('Generating osmet file for 4k metal image')
         runcmd(['/usr/lib/coreos-assembler/runvm-coreos-installer',
@@ -695,7 +699,7 @@ boot
     # Write out the igninfo.json file. This is used by coreos-installer to know
     # how to embed the Ignition config.
     with open(os.path.join(tmpisocoreos, igninfo_file), 'w') as fh:
-        json.dump(igninfo_json, fh, indent=2, sort_keys=True)
+        json.dump(igninfo_json, fh, indent=2, sort_keys=True)  # pylint: disable=E0601
         fh.write('\n')
 
     # Define inputs and outputs

src/cmd-compress

@@ -121,7 +121,7 @@ def compress_one_builddir(builddir):
                 elif args.compressor == 'zstd':
                     runcmd(['zstd', '-10', '-c', f'-T{t}', filepath], stdout=f)
                 else:
-                    runcmd(['gzip', f'-{gzip_level}', '-c', filepath], stdout=f)
+                    runcmd(['gzip', f'-{gzip_level}', '-c', filepath], stdout=f)  # pylint: disable=E0606
             file_with_ext = file + ext
             filepath_with_ext = filepath + ext
             compressed_size = os.path.getsize(tmpfile)

src/cmd-koji-upload

@@ -169,10 +169,9 @@ class Build(_Build):
             ftype = (os.path.splitext(base)[1]).replace(".", "")
             ctype = f"{ftype}.{x}"
             if ctype not in KOJI_CG_TYPES and ftype in KOJI_CG_TYPES:
-                if x == "gz":
-                    compressor = gzip
-                elif x == "xz":
+                if x != "gz":
                     raise Exception("not supported yet")
+                compressor = gzip
 
                 new_path = os.path.join(self._tmpdir, base)
                 try: