gh-106669: Revert "gh-102988: Detect email address parsing errors ... (#105127)" (#106733)

This reverts commit 18dfbd035775c15533d13a98e56b1d2bf5c65f00.
Adds a regression test from the issue.

See https://github.com/python/cpython/issues/106669.

1 files changed, 6 insertions, 57 deletions

diff --git a/Lib/email/utils.py b/Lib/email/utils.py
index 11ad75e..81da539 100644
--- a/Lib/email/utils.py
+++ b/Lib/email/utils.py
@@ -106,54 +106,12 @@ def formataddr(pair, charset='utf-8'):
     return address
 
 
-def _pre_parse_validation(email_header_fields):
-    accepted_values = []
-    for v in email_header_fields:
-        s = v.replace('\\(', '').replace('\\)', '')
-        if s.count('(') != s.count(')'):
-            v = "('', '')"
-        accepted_values.append(v)
-
-    return accepted_values
-
-
-def _post_parse_validation(parsed_email_header_tuples):
-    accepted_values = []
-    # The parser would have parsed a correctly formatted domain-literal
-    # The existence of an [ after parsing indicates a parsing failure
-    for v in parsed_email_header_tuples:
-        if '[' in v[1]:
-            v = ('', '')
-        accepted_values.append(v)
-
-    return accepted_values
-
 
 def getaddresses(fieldvalues):
-    """Return a list of (REALNAME, EMAIL) or ('','') for each fieldvalue.
-
-    When parsing fails for a fieldvalue, a 2-tuple of ('', '') is returned in
-    its place.
-
-    If the resulting list of parsed address is not the same as the number of
-    fieldvalues in the input list a parsing error has occurred.  A list
-    containing a single empty 2-tuple [('', '')] is returned in its place.
-    This is done to avoid invalid output.
-    """
-    fieldvalues = [str(v) for v in fieldvalues]
-    fieldvalues = _pre_parse_validation(fieldvalues)
-    all = COMMASPACE.join(v for v in fieldvalues)
+    """Return a list of (REALNAME, EMAIL) for each fieldvalue."""
+    all = COMMASPACE.join(str(v) for v in fieldvalues)
     a = _AddressList(all)
-    result = _post_parse_validation(a.addresslist)
-
-    n = 0
-    for v in fieldvalues:
-        n += v.count(',') + 1
-
-    if len(result) != n:
-        return [('', '')]
-
-    return result
+    return a.addresslist
 
 
 def _format_timetuple_and_zone(timetuple, zone):
@@ -254,18 +212,9 @@ def parseaddr(addr):
     Return a tuple of realname and email address, unless the parse fails, in
     which case return a 2-tuple of ('', '').
     """
-    if isinstance(addr, list):
-        addr = addr[0]
-
-    if not isinstance(addr, str):
-        return ('', '')
-
-    addr = _pre_parse_validation([addr])[0]
-    addrs = _post_parse_validation(_AddressList(addr).addresslist)
-
-    if not addrs or len(addrs) > 1:
-        return ('', '')
-
+    addrs = _AddressList(addr).addresslist
+    if not addrs:
+        return '', ''
     return addrs[0]