gh-136057: Allow step and next to step over for loops #136160
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| if self.stop_here(frame) or self.break_here(frame): | ||
| # GH-136057 | ||
| # For line events, besides whether we should stop at the frame, we | ||
| # also need to check if it's the same line as we issue the command. |
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I don't think this is very clear: "it's the same line as we issue the command". I think you mean "the same frame and line at which the break command was issued by the user".
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It's not the break command, it's either next or step. But yes I'm open to all suggestions to make this clearer.
| @@ -548,6 +554,10 @@ def _set_stopinfo(self, stopframe, returnframe, stoplineno=0, opcode=False): | |||
| # stoplineno >= 0 means: stop at line >= the stoplineno | |||
| # stoplineno -1 means: don't stop at all | |||
| self.stoplineno = stoplineno | |||
| # startframe/startlineno is the frame/line number when the user does | |||
| # step or next. We don't want to stop at the same line for those commands. | |||
| self.startframe = startframe | |||
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Maybe we could pick a more informative name, something like "command frame", because it's ambiguous here what exactly started at that frame.
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Yeah we can change it, but there's actually a caveat here - it's not really the command frame. You can do up to an upper frame and do next/step - the behavior is different. next will next to the line at the upper frame, so the frame we need is the "command frame". step however, will stop at the innermost frame, no matter which frame you are inspecting - that's just how step works.
So it's more like a "do not stop here again if it's a line event" frame/lineno. Do you think there's better name to describe it?
Due to historical reasons,
sys.settraceissues a line event forforloops even if the jump target is on the same line:We don't want to touch this behavior, because it's been like this for like forever.
However, it's not desirable to
pdb. When the user doesnextorstepcommand, they want to step over this line and reach the next line.Our documentation also clearly states such behavior:
So I consider the current behavior as a bug, which we should fix.
A thought might be - why don't we check this in
stop_here? The reason is becausedispatch_exceptionalso usesstop_hereand we should triggeruser_exceptioneven if it's on the same line.An extra check in
dispatch_lineis the cleanest way I can think of to make this happen - only line events should be dealt with. We don't need to worry about the extra reference to a frame because the eventualcontinue(or anything other thanstepornext) will clear this reference.Let me know if anyone has a better idea of how to implement this.