Improve "list" error handling

Author: rocky

trepan/interfaces/user.py

@@ -18,6 +18,8 @@
 """Interface when communicating with the user in the same process as
     the debugged program."""
 import atexit
+import os.path as osp
+import pathlib
 
 from os import environ
 
@@ -28,6 +30,10 @@
 
 histfile = environ.get("TREPAN3KHISTFILE", default_configfile("history"))
 
+# Create HISTFILE if it doesn't exist already
+if not osp.isfile(histfile):
+    pathlib.Path(histfile).touch()
+
 # is_pypy = '__pypy__' in sys.builtin_module_names
 
 DEFAULT_USER_SETTINGS = {
@@ -45,7 +51,8 @@
         write_history_file,
     )
 except ImportError:
-        pass
+    def write_history_file(histfile: str):
+        return
 
 class UserInterface(TrepanInterface):
     """Interface when communicating with the user in the same
@@ -86,10 +93,7 @@ def __init__(self, inp=None, out=None, opts={}):
         return
 
     def user_write_history_file(self):
-        try:
-            write_history_file(self.histfile)
-        except Exception:
-            pass
+        write_history_file(self.histfile)
 
     def close(self):
         """Closes both input and output"""

trepan/processor/cmdlist.py

@@ -17,7 +17,7 @@
 from trepan.processor.location import resolve_location
 from trepan.processor.parse.parser import LocationError
 from trepan.processor.parse.scanner import ScannerError
-from trepan.processor.parse.semantics import Location, build_location, build_range
+from trepan.processor.parse.semantics import Location, RangeError, build_location, build_range
 
 INVALID_PARSE_LIST = (None, None, None)
 
@@ -63,6 +63,9 @@ def parse_list_cmd(proc, args, listsize=10):
             proc.errmsg(e.text)
             proc.errmsg(e.text_cursor)
             return INVALID_PARSE_LIST
+        except RangeError as e:
+            proc.errmsg(e.errmsg)
+            return INVALID_PARSE_LIST
 
         if list_range.first is None:
             # Last must have been given
@@ -100,6 +103,8 @@ def parse_list_cmd(proc, args, listsize=10):
                 last = first + int(last[1:])
             elif not last:
                 last = first + listsize
+            elif first is None:
+                return INVALID_PARSE_LIST
             elif last < first:
                 # Treat as a count rather than an absolute location
                 last = first + last

trepan/processor/cmdproc.py

@@ -197,11 +197,6 @@ def get_option_fn(key):
 
         self._populate_cmd_lists()
 
-        # Note: prompt_str's value set below isn't used. It is
-        # computed dynamically. The value is suggestive of what it
-        # looks like.
-        self.prompt_str = "(trepan3k) "
-
         # Stop only if line/file is different from last time
         self.different_line = None
 
@@ -234,6 +229,8 @@ def get_option_fn(key):
         initfile_list = get_option("initfile_list")
         for init_cmdfile in initfile_list:
             self.queue_startfile(init_cmdfile)
+
+        self.set_prompt()
         return
 
     def _saferepr(self, str, maxwidth=None):

trepan/processor/location.py

@@ -151,10 +151,11 @@ def resolve_location(proc, location) -> Optional[Location]:
             if lineinfo:
                 offset = lineinfo[0].offsets[0]
                 mod_func = lineinfo[0].name
-            else:
-                print(f"No offset found for {filename} {lineno}")
 
     elif location.line_number:
+        if curframe is None:
+            proc.errmsg("Current frame is not set")
+            return INVALID_LOCATION
         filename = frame2file(proc.core, curframe, canonic=False)
         lineno = location.line_number
         is_address = location.is_address

trepan/processor/parse/semantics.py

@@ -204,7 +204,8 @@ def n_range(self, range_node):
                     Location(None, last_node.value, False, None, offset=None), None
                 )
             else:
-                assert last_node == "DIRECTION"
+                if last_node != "DIRECTION":
+                    raise RangeError("Expecting a range direction at the end")
                 self.result = ListRange(None, last_node.value)
                 pass
             self.prune()