Release: pip-installable packaging metadata (#6337, @rodboev) (#6344)

* build(#2695): add packaging metadata for the current runtime layout

* docs(changelog): stamp #6337 pip-installable packaging metadata

---------

Co-authored-by: Rod Boev <rod.boev@gmail.com>
Co-authored-by: nesquena-hermes <agent@nesquena-hermes>

tests/test_issue3407_sigpipe_ignore.py

@@ -5,7 +5,7 @@ connection mid-response cannot kill the whole WebUI process (salvaged from
 Python's default SIGPIPE action is ``Term``: a single broken-pipe ``send()``
 in any ThreadingHTTPServer worker thread would terminate the entire server
 silently — no exception, no log, no ``/health`` response. server.py sets
-``SIGPIPE`` to ``SIG_IGN`` at import time so the kernel surfaces EPIPE as a
+``SIGPIPE`` to ``SIG_IGN`` during startup so the kernel surfaces EPIPE as a
 catchable ``BrokenPipeError`` and the server keeps serving.
 
 The handler is guarded with ``getattr(signal, "SIGPIPE", None)`` because
@@ -16,34 +16,82 @@ SIGPIPE is POSIX-only and does not exist on Windows (native-Windows support,
 from __future__ import annotations
 
 import signal
+import sys
 from pathlib import Path
 
 REPO_ROOT = Path(__file__).parent.parent
 
 
-def test_sigpipe_set_to_ignore_after_import():
-    """After importing server, SIGPIPE's handler must be SIG_IGN on POSIX."""
+def test_sigpipe_set_to_ignore_by_startup_helper():
+    """The startup helper installs SIG_IGN on POSIX."""
     if not hasattr(signal, "SIGPIPE"):
         # Windows / no-SIGPIPE platform: nothing to assert, importing server
         # must simply not raise (covered by test_import_does_not_raise below).
         return
-    import server  # noqa: F401  (import installs the handler at module load)
-
-    current = signal.getsignal(signal.SIGPIPE)
-    assert current == signal.SIG_IGN, (
-        "server.py must set SIGPIPE to SIG_IGN so a dropped client mid-response "
-        f"cannot Term the whole process; got handler {current!r}"
-    )
+    import server
+    previous = signal.getsignal(signal.SIGPIPE)
+    try:
+        server._ignore_sigpipe()
+        current = signal.getsignal(signal.SIGPIPE)
+        assert current == signal.SIG_IGN, (
+            "server.py must set SIGPIPE to SIG_IGN so a dropped client mid-response "
+            f"cannot Term the whole process; got handler {current!r}"
+        )
+    finally:
+        signal.signal(signal.SIGPIPE, previous)
 
 
 def test_import_does_not_raise():
     """Importing server must not raise — proves the getattr guard works on
     any platform (including a hypothetical no-SIGPIPE one)."""
-    import server  # noqa: F401
+    import server
 
     assert server is not None
 
 
+def test_import_does_not_change_sigpipe_handler():
+    """Plain import must leave process-global SIGPIPE handling unchanged."""
+    if not hasattr(signal, "SIGPIPE"):
+        return
+    previous = signal.getsignal(signal.SIGPIPE)
+    sys.modules.pop("server", None)
+    try:
+        signal.signal(signal.SIGPIPE, signal.SIG_DFL)
+        import server
+        assert signal.getsignal(signal.SIGPIPE) == signal.SIG_DFL
+        assert server is not None
+    finally:
+        signal.signal(signal.SIGPIPE, previous)
+
+
+def test_main_installs_sigpipe_ignore_before_startup():
+    """The real startup path must invoke the SIGPIPE helper before serving."""
+    if not hasattr(signal, "SIGPIPE"):
+        return
+    import server
+
+    class _StopStartup(Exception):
+        pass
+
+    previous = signal.getsignal(signal.SIGPIPE)
+    original = server.install_crash_visibility
+    try:
+        signal.signal(signal.SIGPIPE, signal.SIG_DFL)
+
+        def _stop_startup():
+            raise _StopStartup()
+
+        server.install_crash_visibility = _stop_startup
+        try:
+            server.main()
+        except _StopStartup:
+            pass
+        assert signal.getsignal(signal.SIGPIPE) == signal.SIG_IGN
+    finally:
+        server.install_crash_visibility = original
+        signal.signal(signal.SIGPIPE, previous)
+
+
 def test_sigpipe_handler_is_getattr_guarded_in_source():
     """The handler must be guarded with getattr(signal, 'SIGPIPE', None) so the
     POSIX-only signal can't AttributeError on Windows (native-Windows support,
@@ -54,3 +102,4 @@ def test_sigpipe_handler_is_getattr_guarded_in_source():
         "bare signal.SIGPIPE reference would AttributeError on native Windows."
     )
     assert "SIG_IGN" in src, "server.py must set the SIGPIPE handler to SIG_IGN"
+    assert "def main() -> None:" in src and "_ignore_sigpipe()" in src