From e14675c2dcbf0804bd025ed04a5bd0da9a104633 Mon Sep 17 00:00:00 2001
From: rocky <rb@dustyfeet.com>
Date: Fri, 12 Jun 2020 13:18:33 -0400
Subject: [PATCH] Handle 3.7+ "else" branch removal...

As seen in _cmp() of python3.8/distutils/version.py with optimization -O2
---
 test/add-test.py                            |   3 ++-
 test/bytecode_3.7/03_else_removal.pyc       | Bin 0 -> 254 bytes
 test/bytecode_3.8/03_else_removal.pyc       | Bin 0 -> 262 bytes
 test/simple_source/bug37/03_else_removal.py |  12 ++++++++++++
 uncompyle6/parsers/parse37.py               |   9 +++++++++
 5 files changed, 23 insertions(+), 1 deletion(-)
 create mode 100644 test/bytecode_3.7/03_else_removal.pyc
 create mode 100644 test/bytecode_3.8/03_else_removal.pyc
 create mode 100644 test/simple_source/bug37/03_else_removal.py

diff --git a/test/add-test.py b/test/add-test.py
index 758fe934..160c6d82 100755
--- a/test/add-test.py
+++ b/test/add-test.py
@@ -19,6 +19,7 @@ for path in py_source:
     else:
         cfile = "bytecode_%s%s/%s" % (version, suffix, short) + "c"
     print("byte-compiling %s to %s" % (path, cfile))
-    py_compile.compile(path, cfile)
+    optimize = 2
+    py_compile.compile(path, cfile, optimize=optimize)
     if isinstance(version, str) or version >= (2, 6, 0):
         os.system("../bin/uncompyle6 -a -T %s" % cfile)
diff --git a/test/bytecode_3.7/03_else_removal.pyc b/test/bytecode_3.7/03_else_removal.pyc
new file mode 100644
index 0000000000000000000000000000000000000000..f010c82baa7e3a47f515484a5bbfbcfd5530a88e
GIT binary patch
literal 254
zcmZ?b<>g`kf`{85$9Xd{FgylvV1Nn8Z~)?B9w3pzkiyu)5XF$f6wIK>oD7l!0T2z;
z$KVXa#bQ9BhM`EPhOvkzg)tbcHV>#1q{HteP?F&#NbO1nO{QCnNw*l2i<p62F!4*R
zI5W2(CpEq}zqBYhRX?dT-Pl~;z&JiNr#LmfC^a{~EHOu~pz;<=d~$99D^Oc8*x`&U
oAjrhVRKyMx^V4Jm(+G1REH<FrEe@O9{FKt1R6CIF&p^xo0JJ$Su>b%7

literal 0
HcmV?d00001

diff --git a/test/bytecode_3.8/03_else_removal.pyc b/test/bytecode_3.8/03_else_removal.pyc
new file mode 100644
index 0000000000000000000000000000000000000000..06e16fb8979e53ccfdcb1cfafdbc2358bb8c8121
GIT binary patch
literal 262
zcmWIL<>g`kf`{85$9Xd{FgylvkO32r;{e3PJU}9aA%(GpA&Mb|DVRZ%IT<7e10Xg~
zKZ7$67mERj8ipdF8pa}?6vkk%`aGa+kS@QMKuLy|AhjzQG?{KOCf#C8E@B39!Nf1M
z;>_HFoYeT@{L-T2RQ;sVbYpXU1LOGAoZ{5@qSV~{vcw#{g34Pg@yWRbtUztWU=J{|
ofFKhaQxQ8*%ukaMOe4&Nu-Jfdw>WHa^HWN5Qtd#xKLarX0Qu`K!~g&Q

literal 0
HcmV?d00001

diff --git a/test/simple_source/bug37/03_else_removal.py b/test/simple_source/bug37/03_else_removal.py
new file mode 100644
index 00000000..fe51da52
--- /dev/null
+++ b/test/simple_source/bug37/03_else_removal.py
@@ -0,0 +1,12 @@
+# From python3.8/distutils/version.py with optimization -O2
+# The bug was that the other "else" constant propagated removed.
+
+# NOTE: this program needs to be compile with optimization
+def _cmp (b, c):
+    if b:
+        if c:
+            return 0
+        else:
+            return 1
+    else:
+        assert False, "never get here"
diff --git a/uncompyle6/parsers/parse37.py b/uncompyle6/parsers/parse37.py
index 11c1967a..a4d0bc29 100644
--- a/uncompyle6/parsers/parse37.py
+++ b/uncompyle6/parsers/parse37.py
@@ -94,6 +94,9 @@ class Python37Parser(Python37BaseParser):
         else_suitec ::= c_stmts
         else_suitec ::= returns
 
+        else_suite_opt ::= else_suite
+        else_suite_opt ::= pass
+
         stmt ::= classdef
         stmt ::= call_stmt
 
@@ -635,6 +638,12 @@ class Python37Parser(Python37BaseParser):
         if_exp37                   ::= expr expr jf_cfs expr COME_FROM
         jf_cfs                     ::= JUMP_FORWARD _come_froms
         ifelsestmt                 ::= testexpr c_stmts_opt jf_cfs else_suite opt_come_from_except
+
+        # This is probably more realistically an "ifstmt" (with a null else)
+        # see _cmp() of python3.8/distutils/__pycache__/version.cpython-38.opt-1.pyc
+        ifelsestmt                 ::= testexpr stmts jf_cfs else_suite_opt opt_come_from_except
+
+
         expr_pjit                  ::= expr POP_JUMP_IF_TRUE
         expr_jit                   ::= expr JUMP_IF_TRUE
         expr_jt                    ::= expr jmp_true