[FIX] profiling: fix speedscope with empty ctx

Since de077243 the iter(False) will occur when trying to render a
speedscope output with `use_context=False` since the context given in
parameter of `stack_to_ids` won't be an iterable.

This simple fix avoid this by always giving an empty iterable
in this case.

closes odoo/odoo#75851

Signed-off-by: Xavier Dollé (xdo) <xdo@odoo.com>

odoo/addons/base/tests/test_profiler.py

@@ -332,6 +332,44 @@ class TestSpeedscope(BaseCase):
             ('C', 'level4'),
         ])
 
+    def test_converts_no_context(self):
+        stack = [
+            ['file.py', 10, 'level4', 'level4'],
+            ['file.py', 11, 'level5', 'level5'],
+        ]
+        profile = {
+            'init_stack_trace': [
+                ['file.py', 1, 'level0', 'level0'],
+                ['file.py', 1, 'level1', 'level1'],
+                ['file.py', 1, 'level2', 'level2'],
+                ['file.py', 1, 'level3', 'level3'],
+            ],
+            'result': [{  # init frame
+                'start': 2.0,
+                'exec_context': ((2, {'a': '1'}), (6, {'b': '1'})),
+                'stack': list(stack),
+            }, {  # final frame
+                'start': 10.35,
+                'exec_context': (),
+                'stack': None,
+            }],
+        }
+        sp = Speedscope(init_stack_trace=profile['init_stack_trace'])
+        sp.add('profile', profile['result'])
+        sp.add_output(['profile'], complete=False, use_context=False)
+        res = sp.make()
+        events = [
+            (e['type'], res['shared']['frames'][e['frame']]['name'])
+            for e in res['profiles'][0]['events']
+        ]
+        self.assertEqual(events, [
+            # pylint: disable=bad-continuation
+            ('O', 'level4'),
+                ('O', 'level5'),
+                ('C', 'level5'),
+            ('C', 'level4'),
+        ])
+
 
 @tagged('post_install', '-at_install', 'profiling')
 class TestProfiling(TransactionCase):

odoo/tools/speedscope.py

@@ -131,7 +131,7 @@ class Speedscope:
             level.
         """
         stack_ids = []
-        context_iterator = iter(context)
+        context_iterator = iter(context or ())
         context_level, context_value = next(context_iterator, (None, None))
         # consume iterator until we are over stack_offset
         while context_level is not None and context_level < stack_offset:
@@ -178,7 +178,7 @@ class Speedscope:
             entry_end = None if entry_time is None else entry_start + entry_time
             entry_stack_ids = self.stack_to_ids(
                 entry['stack'] or [],
-                use_context and entry.get('exec_context', {}),
+                use_context and entry.get('exec_context'),
                 self.init_stack_trace_level
             )
             level = 0