Merge lp:~laney/ubuntu-archive-tools/retry-autopkgtest-regressions-lzma-cache into lp:ubuntu-archive-tools

[Iain Lane]

Handle LZMA files in the cache by moving lzma.open down to a more common location.

=== modified file 'retry-autopkgtest-regressions'
--- retry-autopkgtest-regressions	2020-07-01 16:28:26 +0000
+++ retry-autopkgtest-regressions	2020-07-10 20:54:52 +0000
@@ -110,12 +110,14 @@
         new_timestamp = datetime.now(tz=tzutc()).timestamp()
 
     try:
-        f = lzma.open(urllib.request.urlopen(excuses_url))
+        f = urllib.request.urlopen(excuses_url)
+        is_xz = True
     except urllib.error.HTTPError as e:
         if e.code == 404:
             # some versions of britney output this file uncompressed, try that
             # location too
             f = urllib.request.urlopen(excuses_url.rstrip('.xz'))
+            is_xz = False
         else:
             raise
     if cache_file:
@@ -129,7 +131,12 @@
         f.close()
         f = open(cache_file, 'rb')
 
-    excuses = yaml.load(f, Loader=yaml.CSafeLoader)
+    if is_xz:
+        lzma_f = lzma.open(f)
+        excuses = yaml.load(lzma_f, Loader=yaml.CSafeLoader)
+        lzma_f.close()
+    else:
+        excuses = yaml.load(f, Loader=yaml.CSafeLoader)
     f.close()
     regressions = {}
     for excuse in excuses['sources']: