Merge #32619

src/sage/doctest/forker.py

@@ -2496,6 +2496,11 @@ def _run(self, runner, options, results):
         from importlib import import_module
         sage_all = import_module(options.environment)
         dict_all = sage_all.__dict__
+        # When using global environments other than sage.all,
+        # make sure startup is finished so we don't get "Resolving lazy import"
+        # warnings.
+        from sage.misc.lazy_import import ensure_startup_finished
+        ensure_startup_finished()
         # Remove '__package__' item from the globals since it is not
         # always in the globals in an actual Sage session.
         dict_all.pop('__package__', None)

src/sage/misc/lazy_import.pyx

@@ -31,7 +31,8 @@ it is actually resolved after the startup, so that the developer knows
 that (s)he can remove the flag::
 
     sage: ZZ
-    Option ``at_startup=True`` for lazy import ZZ not needed anymore
+    doctest:warning...
+    UserWarning: Option ``at_startup=True`` for lazy import ZZ not needed anymore
     Integer Ring
 
 .. SEEALSO:: :func:`lazy_import`, :class:`LazyImport`
@@ -63,6 +64,7 @@ cdef extern from *:
 
 import os
 import pickle
+from warnings import warn
 import inspect
 from . import sageinspect
 
@@ -79,11 +81,15 @@ cdef inline obj(x):
 # boolean to determine whether Sage is still starting up
 cdef bint startup_guard = True
 
+cdef bint finish_startup_called = False
+
 
 cpdef finish_startup():
     """
+    Finish the startup phase.
+
     This function must be called exactly once at the end of the Sage
-    import process
+    import process (:mod:`~sage.all`).
 
     TESTS::
 
@@ -93,9 +99,27 @@ cpdef finish_startup():
         ...
         AssertionError: finish_startup() must be called exactly once
     """
-    global startup_guard
+    global startup_guard, finish_startup_called
     assert startup_guard, 'finish_startup() must be called exactly once'
     startup_guard = False
+    finish_startup_called = True
+
+
+cpdef ensure_startup_finished():
+    """
+    Make sure that the startup phase is finished.
+
+    In contrast to :func:`finish_startup`, this function can
+    be called repeatedly.
+
+    TESTS::
+
+        sage: from sage.misc.lazy_import import ensure_startup_finished
+        sage: ensure_startup_finished()
+    """
+    global startup_guard
+    startup_guard = False
+
 
 cpdef bint is_during_startup():
     """
@@ -114,6 +138,7 @@ cpdef bint is_during_startup():
     global startup_guard
     return startup_guard
 
+
 cpdef test_fake_startup():
     """
     For testing purposes only.
@@ -125,12 +150,14 @@ cpdef test_fake_startup():
         sage: sage.misc.lazy_import.test_fake_startup()
         sage: lazy_import('sage.rings.all', 'ZZ', 'my_ZZ')
         sage: my_ZZ(123)
-        Resolving lazy import ZZ during startup
+        doctest:warning...
+        UserWarning: Resolving lazy import ZZ during startup
         123
         sage: sage.misc.lazy_import.finish_startup()
     """
-    global startup_guard
+    global startup_guard, finish_startup_called
     startup_guard = True
+    finish_startup_called = False
 
 
 @cython.final
@@ -207,18 +234,20 @@ cdef class LazyImport(object):
             Integer Ring
             sage: my_integer_ring._object is None
             False
-            sage: my_integer_ring = LazyImport('sage.rings.all', 'ZZ', at_startup=True)
-            sage: my_integer_ring
-            Option ``at_startup=True`` for lazy import ZZ not needed anymore
-            Integer Ring
+            sage: my_rats = LazyImport('sage.rings.rational_field', 'QQ', at_startup=True)
+            sage: my_rats
+            doctest:warning...
+            UserWarning: Option ``at_startup=True`` for lazy import QQ not needed anymore
+            Rational Field
         """
         if self._object is not None:
             return self._object
 
         if startup_guard and not self._at_startup:
-            print(f"Resolving lazy import {self._name} during startup")
+            warn(f"Resolving lazy import {self._name} during startup")
         elif self._at_startup and not startup_guard:
-            print(f"Option ``at_startup=True`` for lazy import {self._name} not needed anymore")
+            if finish_startup_called:
+                warn(f"Option ``at_startup=True`` for lazy import {self._name} not needed anymore")
 
         try:
             self._object = getattr(__import__(self._module, {}, {}, [self._name]), self._name)