From a967605df5264cbeed90f469fc79b75f4c69a325 Mon Sep 17 00:00:00 2001
From: Andy Chu <andy@oilshell.org>
Date: Mon, 20 Aug 2018 15:41:09 -0700
Subject: [PATCH] Fix bug on syntax errors in the interactive loop.

';f' would first give a parse error, and then try to execute 'f'.  Now
it just gives the parse error, as expected.
---
 bin/oil.py        | 23 ++++++++++++-----------
 osh/cmd_parse.py  | 19 +++++++++++++++++++
 test/osh-usage.sh |  4 ++++
 3 files changed, 35 insertions(+), 11 deletions(-)

diff --git a/bin/oil.py b/bin/oil.py
index a241862c31..84edb34b68 100755
--- a/bin/oil.py
+++ b/bin/oil.py
@@ -95,7 +95,7 @@ def _tlog(msg):
 _tlog('after imports')
 
 
-def InteractiveLoop(opts, ex, c_parser, w_parser, line_reader, arena):
+def InteractiveLoop(opts, ex, c_parser, arena):
   if opts.show_ast:
     ast_f = fmt.DetectConsoleOutput(sys.stdout)
   else:
@@ -103,14 +103,18 @@ def InteractiveLoop(opts, ex, c_parser, w_parser, line_reader, arena):
 
   status = 0
   while True:
+    # Why is this the way to handle Control-C?
+    # Also, we shouldn't exit the shell!
     try:
       w = c_parser.Peek()
     except KeyboardInterrupt:
       print('Ctrl-C')
       break
 
+    # TODO: When does this happen?
     if w is None:
       raise RuntimeError('Failed parse: %s' % c_parser.Error())
+
     c_id = word.CommandId(w)
     if c_id == Id.Op_Newline:
       #print('nothing to execute')
@@ -120,6 +124,7 @@ def InteractiveLoop(opts, ex, c_parser, w_parser, line_reader, arena):
       break
     else:
       node = c_parser.ParseCommandLine()
+      #log('parsed node: %s', node)
 
       # Failed parse.
       # TODO: Need an error for an empty command, which we ignore?  GetLine
@@ -129,8 +134,9 @@ def InteractiveLoop(opts, ex, c_parser, w_parser, line_reader, arena):
         e = c_parser.Error()
         # NOTE: This is a bit verbose.
         ui.PrintErrorStack(e, arena, sys.stderr)
-        w_parser.Reset()
+
         c_parser.Reset()
+        c_parser.ResetInputObjects()
         continue
 
       if ast_f:
@@ -143,15 +149,10 @@ def InteractiveLoop(opts, ex, c_parser, w_parser, line_reader, arena):
       if opts.print_status:
         print('STATUS', repr(status))
 
-    # Reset prompt to PS1.
-    line_reader.Reset()
-
-    # Reset internal newline state.
-    # NOTE: It would actually be correct to reinitialize all objects (except
-    # Env) on every iteration.  But we know that the w_parser is the only thing
-    # that needs to be reset, for now.
-    w_parser.Reset()
+    # Reset internal newline state.  NOTE: It would actually be correct to
+    # reinitialize all objects (except Env) on every iteration.
     c_parser.Reset()
+    c_parser.ResetInputObjects()
 
   return status
 
@@ -311,7 +312,7 @@ def OshMain(argv0, argv, login_shell):
       completion.Init(pool, builtin.BUILTIN_DEF, mem, funcs, comp_lookup,
                       status_out, ev)
 
-    return InteractiveLoop(opts, ex, c_parser, w_parser, line_reader, arena)
+    return InteractiveLoop(opts, ex, c_parser, arena)
   else:
     # Parse the whole thing up front
     #print('Parsing file')
diff --git a/osh/cmd_parse.py b/osh/cmd_parse.py
index 531c1005dc..09e7f9050c 100644
--- a/osh/cmd_parse.py
+++ b/osh/cmd_parse.py
@@ -43,6 +43,10 @@ def __init__(self, w_parser, lexer, line_reader, arena):
     self.Reset()
 
   def Reset(self):
+    """Reset our own internal state.
+
+    Called by the interactive loop.
+    """
     self.error_stack = []
     self.completion_stack = []
 
@@ -54,6 +58,21 @@ def Reset(self):
 
     self.pending_here_docs = []
 
+  def ResetInputObjects(self):
+    """Reset the internal state of our inputs.
+
+    Called by the interactive loop.
+
+    TODO: Should we just make new objects on every iteration?
+    """
+    # All the stuff we read from
+    self.w_parser.Reset()
+    #self.lexer.Reset()
+    # TODO: This should be a method on Lexer.  But I'm not sure if we want to
+    # reuse objects at all.
+    self.lexer.line_lexer.Reset('', -1)
+    self.line_reader.Reset()
+
   def Error(self):
     return self.error_stack
 
diff --git a/test/osh-usage.sh b/test/osh-usage.sh
index e53d47818c..d68a7a4d7d 100755
--- a/test/osh-usage.sh
+++ b/test/osh-usage.sh
@@ -100,6 +100,10 @@ osh-interactive() {
 
   # Parse failure
   echo ';' | $OSH -i
+
+  # Bug fix: this shouldn't try execute 'echo OIL OIL'
+  # The line lexer wasn't getting reset on parse failures.
+  echo ';echo OIL OIL' | $OSH -i
 }
 
 help() {