Update IPyBreak to have traceback, up & down commands

Author: briantoby

GSASII/GSASIIpath.py

@@ -1095,42 +1095,118 @@ def runScript(cmds=[], wait=False, G2frame=None):
         sys.exit()
 
 def IPyBreak_base(userMsg=None):
-    '''A routine that invokes an IPython session at the calling location
+    '''A routine that invokes an IPython session at the calling location.
+    Called by a call to :func:`IPyBreak` or command ``breakpoint()``.
     This routine is only used when debug=True is set in the configuration
-    settings
+    settings.
     '''
     savehook = sys.excepthook # save the exception hook
     try:
-        from IPython.terminal.embed import InteractiveShellEmbed
+        import IPython.core
+        # get the Ipython shell routine
+        if IPython.core.getipython.get_ipython() is None:
+            ipshell = IPython.terminal.embed.InteractiveShellEmbed.instance(banner1='')
+        else: # older IPython (still needed?)
+            ipshell = IPython.terminal.embed.InteractiveShellEmbed()
+        import inspect
     except ImportError:
-        try:
-            # try the IPython 0.12 approach
-            from IPython.frontend.terminal.embed import InteractiveShellEmbed
-        except ImportError:
-            print ('IPython InteractiveShellEmbed not found')
-            return
-    import inspect
-    #from IPython import __version__
-    #if __version__.startswith('8.12.'): # see https://github.com/ipython/ipython/issues/13966
-    from IPython.core import getipython
-    if getipython.get_ipython() is None:
-        ipshell = InteractiveShellEmbed.instance()
-    else:
-        ipshell = InteractiveShellEmbed()
+        return
+
+    stack = inspect.stack()     # Get the full stack
+    current_level = [1]  # mutable so inner function can modify it
+    
+    def up(levels=1):
+        '''Move the IPython shell environment up the call stack.
+        Initially coded by Claude Sonnet 4.5
+        '''
+        new_level = current_level[0] + levels
+        if new_level < len(stack):
+            current_level[0] = new_level
+            frame = stack[current_level[0]].frame
+            print(f"Moving to: {stack[current_level[0]].filename}:{stack[current_level[0]].lineno} in {stack[current_level[0]].function}")
+            # Replace the IPython namespace (not update), but preserve IPython internals
+            # Save IPython internal variables and built-in commands
+            ipython_preserve = {k: v for k, v in ipshell.user_ns.items() 
+                              if k.startswith('_') or k in ('exit', 'quit', 'get_ipython')}
+            ipshell.user_ns.clear()
+            ipshell.user_ns.update(ipython_preserve)  # Restore IPython internals
+            ipshell.user_ns.update(frame.f_globals)
+            ipshell.user_ns.update(frame.f_locals)
+            ipshell.user_ns['TB'] = TB
+            ipshell.user_ns['up'] = up
+            ipshell.user_ns['down'] = down
+            ipshell.user_ns['where'] = where
+        else:
+            print(f"Already at top of stack (level {current_level[0]} of {len(stack)-1})")
+    
+    def down(levels=1):
+        '''Move the IPython shell environment down the call stack.
+        Initially coded by Claude Sonnet 4.5
+        '''
+        new_level = current_level[0] - levels
+        if new_level >= 0:
+            current_level[0] = new_level
+            frame = stack[current_level[0]].frame
+            print(f"Moving to: {stack[current_level[0]].filename}:{stack[current_level[0]].lineno} in {stack[current_level[0]].function}")
+            # Replace the IPython namespace (not update), but preserve IPython internals
+            # Save IPython internal variables and built-in commands
+            ipython_preserve = {k: v for k, v in ipshell.user_ns.items() 
+                              if k.startswith('_') or k in ('exit', 'quit', 'get_ipython')}
+            ipshell.user_ns.clear()
+            ipshell.user_ns.update(ipython_preserve)  # Restore IPython internals
+            ipshell.user_ns.update(frame.f_globals)
+            ipshell.user_ns.update(frame.f_locals)
+            ipshell.user_ns['TB'] = TB
+            ipshell.user_ns['up'] = up
+            ipshell.user_ns['down'] = down
+            ipshell.user_ns['where'] = where
+        else:
+            print(f"Already at bottom of stack (level 0)")
+    
+    def where():
+        '''Show current position in stack related to up/down commands.
+        Initially coded by Claude Sonnet 4.5 & revised to reverse display order.
+        '''
+        i = len(stack)
+        for frame_info in reversed(stack):
+            i -= 1
+            marker = ">>>" if i == current_level[0] else "   "
+            print(f"{marker} [{i}] {frame_info.filename}:{frame_info.lineno} in {frame_info.function}")
+
+    def TB(depth=None):
+        '''Show a traceback (to the optional specified depth) to how we got to
+        the breakpoint. Omit the current level as the calling level to here 
+        and above is likely all that we would be interested in.
+        '''
+        if depth is not None: depth += 1
+        for frame_info in reversed(stack[1:depth]):
+            print(f'  File "{frame_info.filename}", line {frame_info.lineno}, in {frame_info.function}')
+            if frame_info.code_context:
+                print(f'    {frame_info.code_context[0].strip()}')
 
     frame = inspect.currentframe().f_back
     msg   = 'Entering IPython console inside {0.f_code.co_filename} at line {0.f_lineno}\n'.format(frame)
+    msg += '\n[up()/down()/where() to navigate stack; TB()/TB(n) for n level tracebacks]'
     if userMsg: msg += userMsg
+    
+    # Add commands to shell namespace
+    locals = frame.f_locals
+    locals['TB'] = TB
+    locals['up'] = up
+    locals['down'] = down
+    locals['where'] = where
+    
     # globals().update(locals()) # This might help with vars inside list comprehensions, etc.
-    ipshell(msg,stack_depth=2) # Go up one level, to see the calling routine
+    ipshell(msg,stack_depth=2,local_ns=locals,global_ns=frame.f_globals)
     sys.excepthook = savehook # reset IPython's change to the exception hook
 
 def exceptHook(*args):
     '''A routine to be called when an exception occurs. It prints the traceback
     with fancy formatting and then calls an IPython shell with the environment
     of the exception location.
 
-    This routine is only used when debug=True is set in the configuration settings
+    This routine is only used when debug=True is set in the configuration 
+    settings.
     '''
     import IPython.core
     savehook = sys.excepthook # save the exception hook
@@ -1139,7 +1215,6 @@ def exceptHook(*args):
         tb_formatter = IPython.core.ultratb.ListTB() # better for windows?
     else:
         tb_formatter = IPython.core.ultratb.FormattedTB()
-    print() # blank line
     print(tb_formatter.text(*args,-1),end='') # show only last routine
     # get the Ipython shell routine
     if IPython.core.getipython.get_ipython() is None: