Fix AttributeError in NBMasterBar.show() when self.out is not initialized #119
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…ized Problem In certain Jupyter environments (like VS Code and some local JupyterLab setups), calling `learn.fine_tune()` in fastai crashes with: ``` AttributeError: 'NBMasterBar' object has no attribute 'out' ``` This occurs because `show()` is called during the `before_fit` event (via `write()`), which happens before `on_iter_begin()` initializes `self.out`. This patch adds `hasattr(self, 'out')` check before calling `self.out.update()` in the `show()` method which is consistent with how `on_iter_end()` and `on_interrupt()` already handle this attribute. Current workarounds Users currently work around this by: - Using `with learn.no_bar(): learn.fine_tune(1)` - Or by completely disabling progress callbacks This fix eliminates the need for these workarounds. I tested this locally in Jupyter environment with fastai/fastbook Chapter 1 where it previously crashed. After applying this fix, the progress bars display correctly.
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Problem
In certain Jupyter environments (like VS Code and some local JupyterLab setups), calling
learn.fine_tune()in fastai crashes with:This occurs because
show()is called during thebefore_fitevent (viawrite()), which happens beforeon_iter_begin()initializesself.out.This patch adds
hasattr(self, 'out')check before callingself.out.update()in theshow()method which is consistent with howon_iter_end()andon_interrupt()already handle this attribute.Current workarounds
Users currently work around this by:
with learn.no_bar(): learn.fine_tune(1)This fix eliminates the need for these workarounds.
I tested this locally in Jupyter environment with fastai/fastbook Chapter 1 where it previously crashed. After applying this fix, the progress bars display correctly.