Progressbar do not advance with `.next()` call

Expected Behavior

with the following code:

import time
import click

lst = list(range(10))
with click.progressbar(lst) as bar:
    for i in lst:
        next(bar)
        time.sleep(0.2)

bar just don’t advance, related to https://github.com/pallets/click/issues/1125.

Actual Behavior

works fine with click-6.7.

Environment

• Python version: 3.8.2 on macOS
• Click version: 7.1.2

[obfusk]

I don’t think this is a bug in click. You’re calling next() on something that may not be an iterator.

I’m also not sure why you’re iterating over lst instead of bar. The following works fine:

import time
import click

lst = list(range(10))
with click.progressbar(lst) as bar:
    for i in bar:
        time.sleep(0.2)

If, for some reason, you really want to iterate over lst instead of bar, you can call next() on an iterator over bar (obtained using iter()):

import time
import click

lst = list(range(10))
with click.progressbar(lst) as bar:
    it = iter(bar)
    for i in lst:
        next(it)
        time.sleep(0.2)

[obfusk]

@obfusk besides, with your code, the progress bar will not reach 100%:

You got me there. It’s missing the final step. This does work:

import time
import click

lst = list(range(10))
with click.progressbar(lst) as bar:
    it = iter(bar)
    for i in lst:
        next(it)
        time.sleep(0.2)
    next(it, None)

But the first example I gave of just iterating over bar in the for loop – and not calling next() manually – works just fine and is the intended use case.