Add back 3.7 support (#848)

* Restore 3.7 support

* Match documented behavior in stdlib

* Pass tests on Python 3.7

---------

Co-authored-by: Itamar Turner-Trauring <itamar@pythonspeed.com>

.github/workflows/test.yaml

@@ -29,6 +29,7 @@ jobs:
       fail-fast: false
       matrix:
         include:
+          - { py: 3.7, toxenv: py37-epolls, ignore-error: false, os: ubuntu-latest }
           - { py: 3.8, toxenv: py38-epolls, ignore-error: false, os: ubuntu-latest }
           - { py: 3.8, toxenv: py38-openssl, ignore-error: false, os: ubuntu-latest }
           - { py: 3.8, toxenv: py38-poll, ignore-error: false, os: ubuntu-latest }

README.rst

@@ -65,7 +65,7 @@ Apologies for any inconvenience.
 Supported Python versions
 =========================
 
-Python 3.8-3.12 are currently supported.
+Python 3.7-3.12 are currently supported.
 
 Flair
 =====

eventlet/green/ssl.py

@@ -24,6 +24,7 @@
 _original_sslsocket = __ssl.SSLSocket
 _original_sslcontext = __ssl.SSLContext
 _is_under_py_3_7 = sys.version_info < (3, 7)
+_is_py_3_7 = sys.version_info[:2] == (3, 7)
 _original_wrap_socket = __ssl.SSLContext.wrap_socket
 
 
@@ -191,6 +192,11 @@ def _call_trampolining(self, func, *a, **kw):
                                    write=True,
                                    timeout=self.gettimeout(),
                                    timeout_exc=timeout_exc('timed out'))
+                    elif _is_py_3_7 and "unexpected eof" in exc.args[1]:
+                        # For reasons I don't understand on 3.7 we get [ssl:
+                        # KRB5_S_TKT_NYV] unexpected eof while reading]
+                        # errors...
+                        raise IOClosed
                     else:
                         raise
 
@@ -200,14 +206,17 @@ def write(self, data):
         return self._call_trampolining(
             super(GreenSSLSocket, self).write, data)
 
-    def read(self, *args, **kwargs):
+    def read(self, len=1024, buffer=None):
         """Read up to LEN bytes and return them.
         Return zero-length string on EOF."""
         try:
             return self._call_trampolining(
-                super(GreenSSLSocket, self).read, *args, **kwargs)
+                super(GreenSSLSocket, self).read, len, buffer)
         except IOClosed:
-            return b''
+            if buffer is None:
+                return b''
+            else:
+                return 0
 
     def send(self, data, flags=0):
         if self._sslobj:

pyproject.toml

@@ -17,7 +17,7 @@ authors = [
 ]
 description = "Highly concurrent networking library"
 readme = "README.rst"
-requires-python = ">=3.8"
+requires-python = ">=3.7"
 license = {text = "MIT"}
 classifiers = [
     "Development Status :: 4 - Beta",

tests/wsgi_test.py

@@ -568,6 +568,12 @@ def server(sock, site, log):
             except (ssl.SSLZeroReturnError, ssl.SSLEOFError):
                 # Can't write a response to a closed TLS session
                 return True
+            except OSError:
+                if sys.version_info[:2] == (3, 7):
+                    return True
+                else:
+                    traceback.print_exc()
+                    return False
             except Exception:
                 traceback.print_exc()
                 return False

tox.ini

@@ -30,7 +30,7 @@ setenv =
     {[testenv]setenv}
     eventlet_test_ipv6 = 1
 deps =
-    coverage==7.3.3
+    coverage
     pytest
     pytest-cov
 usedevelop = True
@@ -60,7 +60,7 @@ setenv =
     epolls: EVENTLET_HUB = epolls
     tox_cover_args = --cov=eventlet
 deps =
-    coverage==7.3.3
+    coverage
     pytest
     pytest-cov
     py38-openssl: pyopenssl==22.1.0