[glibc] Further build-many-glibcs.py fixes for utcnow() deprecation

[Joseph Myers <jsm28@sourceware.org>]

https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=b86cb494f9a27a106c96c025c6d834334d85b80a

commit b86cb494f9a27a106c96c025c6d834334d85b80a
Author: Joseph Myers <josmyers@redhat.com>
Date:   Fri Jan 19 13:30:34 2024 +0000

    Further build-many-glibcs.py fixes for utcnow() deprecation
    
    It turns out that the replacement of datetime.datetime.utcnow(), for a
    warning produced early in running build-many-glibcs.py with Python
    3.12, (a) wasn't complete (there were other uses elsewhere in the
    script also needing updating) and (b) broke reading of build-time from
    build-state.json, because an aware datetime was written out including
    +00:00 for the timezone, which was not expected by the strptime call.
    
    Fix the first by making the change to
    datetime.datetime.now(datetime.timezone.utc) for all the remaining
    utcnow() calls.  Fix the second by using strftime with an explicit
    format instead of just str() when formatting build times for
    build-state.json and and email subjects, and then setting the timezone
    explicitly when reading from build-state.json.  (Other uses, in
    particular messages output by the bot, continue to use str() as the
    precise format should not matter in those cases; it shouldn't actually
    matter for email subjects either but it seems a good idea to keep
    those short.)
    
    Tested with a bot-cycle run and checking the format of times in
    build-state.json afterwards.

Diff:
---
 scripts/build-many-glibcs.py | 23 ++++++++++++++---------
 1 file changed, 14 insertions(+), 9 deletions(-)

diff --git a/scripts/build-many-glibcs.py b/scripts/build-many-glibcs.py
index 9cdf3e682f..d08afc4074 100755
--- a/scripts/build-many-glibcs.py
+++ b/scripts/build-many-glibcs.py
@@ -1057,7 +1057,8 @@ class Context(object):
     def update_build_state(self, action, build_time, build_versions):
         """Update the build state after a build."""
         build_time = build_time.replace(microsecond=0)
-        self.build_state[action]['build-time'] = str(build_time)
+        self.build_state[action]['build-time'] = build_time.strftime(
+            '%Y-%m-%d %H:%M:%S')
         self.build_state[action]['build-versions'] = build_versions
         build_results = {}
         for log in self.status_log_list:
@@ -1103,15 +1104,17 @@ class Context(object):
         old_time_str = self.build_state[action]['build-time']
         if not old_time_str:
             return True
-        old_time = datetime.datetime.strptime(old_time_str,
-                                              '%Y-%m-%d %H:%M:%S')
-        new_time = datetime.datetime.utcnow()
+        old_time = datetime.datetime.strptime(
+            old_time_str, '%Y-%m-%d %H:%M:%S').replace(
+                tzinfo=datetime.timezone.utc)
+        new_time = datetime.datetime.now(datetime.timezone.utc)
         delta = new_time - old_time
         return delta.total_seconds() >= delay
 
     def bot_cycle(self):
         """Run a single round of checkout and builds."""
-        print('Bot cycle starting %s.' % str(datetime.datetime.utcnow()))
+        print('Bot cycle starting %s.'
+              % str(datetime.datetime.now(datetime.timezone.utc)))
         self.load_bot_config_json()
         actions = ('host-libraries', 'compilers', 'glibcs')
         self.bot_run_self(['--replace-sources'], 'checkout')
@@ -1163,12 +1166,13 @@ class Context(object):
             shutil.copytree(self.logsdir, self.logsdir_old)
         for a in actions:
             if must_build[a]:
-                build_time = datetime.datetime.utcnow()
+                build_time = datetime.datetime.now(datetime.timezone.utc)
                 print('Rebuilding %s at %s.' % (a, str(build_time)))
                 self.bot_run_self([], a)
                 self.load_build_state_json()
                 self.bot_build_mail(a, build_time)
-        print('Bot cycle done at %s.' % str(datetime.datetime.utcnow()))
+        print('Bot cycle done at %s.'
+              % str(datetime.datetime.now(datetime.timezone.utc)))
 
     def bot_build_mail(self, action, build_time):
         """Send email with the results of a build."""
@@ -1184,7 +1188,7 @@ class Context(object):
         build_time = build_time.replace(microsecond=0)
         subject = (self.bot_config['email-subject'] %
                    {'action': action,
-                    'build-time': str(build_time)})
+                    'build-time': build_time.strftime('%Y-%m-%d %H:%M:%S')})
         results = self.build_state[action]['build-results']
         changes = self.build_state[action]['result-changes']
         ever_passed = set(self.build_state[action]['ever-passed'])
@@ -1233,7 +1237,8 @@ class Context(object):
         msg['From'] = self.bot_config['email-from']
         msg['To'] = self.bot_config['email-to']
         msg['Message-ID'] = email.utils.make_msgid()
-        msg['Date'] = email.utils.format_datetime(datetime.datetime.utcnow())
+        msg['Date'] = email.utils.format_datetime(
+            datetime.datetime.now(datetime.timezone.utc))
         with smtplib.SMTP(self.bot_config['email-server']) as s:
             s.send_message(msg)