patchtest-send-results: improve subject line

Pull the actual email's subject line from the .mbox file and use that in
patchtest's test results response, so that it's clearer which patch it
is replying to.

Signed-off-by: Trevor Gamblin <tgamblin@baylibre.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

diff --git a/scripts/patchtest-send-results b/scripts/patchtest-send-results
index 15ee5b077fc73a2c38ded724b798ae2c094086f9..bb4604aeaf1eae9a9e5331ee08d4d93cfac2def4 100755 (executable)
--- a/scripts/patchtest-send-results
+++ b/scripts/patchtest-send-results
@@ -53,7 +53,12 @@ with open(result_file, "r") as f:
     testresult = f.read()
 
 reply_contents = greeting + testresult + suggestions
-subject_line = f"Patchtest results for {result_basename}"
+
+# we know these patch files will only contain a single patch, so only
+# worry about the first element for getting the subject
+mbox = mailbox.mbox(args.patch)
+mbox_subject = mbox[0]['subject']
+subject_line = f"Patchtest results for {mbox_subject}"
 
 if "FAIL" in testresult:
     ses_client = boto3.client('ses', region_name='us-west-2')