[LNT] Python 3 support: Do not encode report for stdout

Summary:
Daily report and run comparison are both output to stdout and sent by
email as attachment. Under Python 3's strict separation between text and
binary data the former needs to be done as a string while the latter
needs to be an encoded text, i.e. as binary data. This commit implements
that separation.

Reviewers: cmatthews, hubert.reinterpretcast, kristof.beyls, leandron, PrzemekWirkus

Reviewed By: PrzemekWirkus

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D68797

Author: Thomas Preud'homme

lnt/lnttool/main.py

@@ -270,7 +270,8 @@ def action_send_daily_report(instance_path, address, database, testsuite, host,
             % (config.zorgURL, database, testsuite)
         subject = "Daily Report: %04d-%02d-%02d" % (
             report.year, report.month, report.day)
-        html_report = report.render(ts_url, only_html_body=False).encode('utf-8')
+        html_report = report.render(ts_url, only_html_body=False)
+        utf8_html_report = html_report.encode('utf-8')
 
         if subject_prefix is not None:
             subject = "%s %s" % (subject_prefix, subject)
@@ -280,7 +281,7 @@ def action_send_daily_report(instance_path, address, database, testsuite, host,
         msg['Subject'] = subject
         msg['From'] = from_address
         msg['To'] = address
-        msg.attach(email.mime.text.MIMEText(html_report, 'html', 'utf-8'))
+        msg.attach(email.mime.text.MIMEText(utf8_html_report, 'html', 'utf-8'))
 
         # Send the report.
         if not dry_run:
@@ -355,9 +356,11 @@ def action_send_run_comparison(instance_path, run_a_id, run_b_id, database,
 
         env = lnt.server.ui.app.create_jinja_environment()
         text_template = env.get_template('reporting/run_report.txt')
-        text_report = text_template.render(data).encode('utf-8')
+        text_report = text_template.render(data)
+        utf8_text_report = text_report.encode('utf-8')
         html_template = env.get_template('reporting/run_report.html')
-        html_report = html_template.render(data).encode('utf-8')
+        html_report = html_template.render(data)
+        utf8_html_report = html_report.encode('utf-8')
 
         subject = data['subject']
         if subject_prefix is not None:
@@ -368,8 +371,8 @@ def action_send_run_comparison(instance_path, run_a_id, run_b_id, database,
         msg['Subject'] = subject
         msg['From'] = from_address
         msg['To'] = to_address
-        msg.attach(email.mime.text.MIMEText(text_report, 'plain', 'utf-8'))
-        msg.attach(email.mime.text.MIMEText(html_report, 'html', 'utf-8'))
+        msg.attach(email.mime.text.MIMEText(utf8_text_report, 'plain', 'utf-8'))
+        msg.attach(email.mime.text.MIMEText(utf8_html_report, 'html', 'utf-8'))
 
         # Send the report.
         if not dry_run: