From 66edb6295f956af9c559ef037c5016c9f6b64261 Mon Sep 17 00:00:00 2001
From: Neil Schemenauer <nascheme@enme.ucalgary.ca>
Date: Mon, 19 Jul 2004 15:38:11 +0000
Subject: [PATCH] Don't return spurious empty fields if 'keep_empty_values' is
 True. Fixes SF bug #990307.

---
 Lib/cgi.py               |  2 ++
 Lib/test/output/test_cgi | 11 +++++++++++
 Lib/test/test_cgi.py     | 23 +++++++++++++++++++++--
 Misc/NEWS                |  4 ++++
 4 files changed, 38 insertions(+), 2 deletions(-)

diff --git a/Lib/cgi.py b/Lib/cgi.py
index 487b01e3f2e..7c3d6579434 100755
--- a/Lib/cgi.py
+++ b/Lib/cgi.py
@@ -209,6 +209,8 @@ def parse_qsl(qs, keep_blank_values=0, strict_parsing=0):
     pairs = [s2 for s1 in qs.split('&') for s2 in s1.split(';')]
     r = []
     for name_value in pairs:
+        if not name_value and not strict_parsing:
+            continue
         nv = name_value.split('=', 1)
         if len(nv) != 2:
             if strict_parsing:
diff --git a/Lib/test/output/test_cgi b/Lib/test/output/test_cgi
index 3741c22d015..d5d6f75c376 100644
--- a/Lib/test/output/test_cgi
+++ b/Lib/test/output/test_cgi
@@ -1,4 +1,15 @@
 test_cgi
+'' => []
+'&' => []
+'&&' => []
+'=' => [('', '')]
+'=a' => [('', 'a')]
+'a' => [('a', '')]
+'a=' => [('a', '')]
+'a=' => [('a', '')]
+'&a=b' => [('a', 'b')]
+'a=a+b&b=b+c' => [('a', 'a b'), ('b', 'b c')]
+'a=1&a=2' => [('a', '1'), ('a', '2')]
 ''
 '&'
 '&&'
diff --git a/Lib/test/test_cgi.py b/Lib/test/test_cgi.py
index 980e3b64864..5ecaf7f120c 100644
--- a/Lib/test/test_cgi.py
+++ b/Lib/test/test_cgi.py
@@ -55,7 +55,21 @@ def do_test(buf, method):
 # A list of test cases.  Each test case is a a two-tuple that contains
 # a string with the query and a dictionary with the expected result.
 
-parse_test_cases = [
+parse_qsl_test_cases = [
+    ("", []),
+    ("&", []),
+    ("&&", []),
+    ("=", [('', '')]),
+    ("=a", [('', 'a')]),
+    ("a", [('a', '')]),
+    ("a=", [('a', '')]),
+    ("a=", [('a', '')]),
+    ("&a=b", [('a', 'b')]),
+    ("a=a+b&b=b+c", [('a', 'a b'), ('b', 'b c')]),
+    ("a=1&a=2", [('a', '1'), ('a', '2')]),
+]
+
+parse_strict_test_cases = [
     ("", ValueError("bad query field: ''")),
     ("&", ValueError("bad query field: ''")),
     ("&&", ValueError("bad query field: ''")),
@@ -114,7 +128,12 @@ def first_second_elts(list):
     return map(lambda p:(p[0], p[1][0]), list)
 
 def main():
-    for orig, expect in parse_test_cases:
+    for orig, expect in parse_qsl_test_cases:
+        result = cgi.parse_qsl(orig, keep_blank_values=True)
+        print repr(orig), '=>', result
+        verify(result == expect, "Error parsing %s" % repr(orig))
+
+    for orig, expect in parse_strict_test_cases:
         # Test basic parsing
         print repr(orig)
         d = do_test(orig, "GET")
diff --git a/Misc/NEWS b/Misc/NEWS
index cd34d13a8bc..29adb457b90 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -94,6 +94,10 @@ Library
 - The threading module has a new class, local, for creating objects
   that provide thread-local data.
 
+- Bug #990307: when keep_empty_values is True, cgi.parse_qsl()
+  no longer returns spurious empty fields.
+
+
 Tools/Demos
 -----------