For the side question, you can always use rebase instead of merge. Let me know if you need further particulars? -- H On Fri, 19 Mar 2021 at 09:31, Faisal Mahmood wrote:

Hello,

Following my previous e-mail last month, thank you for responding. I almost immediately got two reviewers who posted helpful comments on my PR which I believe have all been resolved now.

Today, I got a notification to say my branch is stale again so wanted to understand what the next steps are.

Is there anything else I can do to get my PR merged? This is my first time submitting a PR to Cpython so not sure of the workflow, or if I have missed something so would appreciate your guidance.

SIDE QUESTION: Also, when I originally submitted this PR, I used a different Git config and user called "KillerKode" - however I was asked to change this, which is totally understandable so I changed everything to my name, however the commit history of that PR now contains some commits from my old Git config (as KillerKode) and some with my new Git config (as Faisal Mahmood). I am wondering, when this gets merged, how can I make sure that the commits are squashed and any history of my previous git config (i.e. KillerKode) do not show?

Kind regards,

Faisal.

On Mon, 15 Feb 2021 at 14:20, Faisal Mahmood wrote:

...

Hello,

I hope you are all well, I currently have an issue / merge request that has become stale and as per the guidelines I am sending this e-mail to request someone to review it for me please.

Issue Number: 42861 (https://bugs.python.org/issue42861) Pull Request: 24180 (https://github.com/python/cpython/pull/24180)

This is my first contribution to CPython and I am very keen to get this added as I think it is an almost essential enhancement missing from the ipaddress module. I would greatly appreciate if someone can take a look and give me feedback, I am more than happy to help explain things, as I appreciate this is not the most straightforward thing to do.

Effectively, this method allows you to get the next closest network of any prefix size, it works by effectively adding 1 to the host portion of the network. There is actually a very nice guide someone made on stackexchange explaining how to do this calculation manually, I simply followed this logic and have tested it as much as possible and it seems to work great. See here: https://networkengineering.stackexchange.com/questions/7106/how-do-you-calcu...

Please let me know if there is anything else I can do to help get this merged.

Kind regards,

Faisal.

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On Fri, Mar 19, 2021 at 9:29 AM Faisal Mahmood wrote:

Hello,

Following my previous e-mail last month, thank you for responding. I almost immediately got two reviewers who posted helpful comments on my PR which I believe have all been resolved now.

Today, I got a notification to say my branch is stale again so wanted to understand what the next steps are.

Is there anything else I can do to get my PR merged? This is my first time submitting a PR to Cpython so not sure of the workflow, or if I have missed something so would appreciate your guidance.

At this point it's up to a core dev to have the time and inclination to look at the PR and either give feedback or to merge it (unfortunately I personally lack the knowledge to help out with this PR). -Brett

SIDE QUESTION: Also, when I originally submitted this PR, I used a different Git config and user called "KillerKode" - however I was asked to change this, which is totally understandable so I changed everything to my name, however the commit history of that PR now contains some commits from my old Git config (as KillerKode) and some with my new Git config (as Faisal Mahmood). I am wondering, when this gets merged, how can I make sure that the commits are squashed and any history of my previous git config (i.e. KillerKode) do not show?

Kind regards,

Faisal.

On Mon, 15 Feb 2021 at 14:20, Faisal Mahmood wrote:

...

Hello,

I hope you are all well, I currently have an issue / merge request that has become stale and as per the guidelines I am sending this e-mail to request someone to review it for me please.

Issue Number: 42861 (https://bugs.python.org/issue42861) Pull Request: 24180 (https://github.com/python/cpython/pull/24180)

This is my first contribution to CPython and I am very keen to get this added as I think it is an almost essential enhancement missing from the ipaddress module. I would greatly appreciate if someone can take a look and give me feedback, I am more than happy to help explain things, as I appreciate this is not the most straightforward thing to do.

Effectively, this method allows you to get the next closest network of any prefix size, it works by effectively adding 1 to the host portion of the network. There is actually a very nice guide someone made on stackexchange explaining how to do this calculation manually, I simply followed this logic and have tested it as much as possible and it seems to work great. See here: https://networkengineering.stackexchange.com/questions/7106/how-do-you-calcu...

Please let me know if there is anything else I can do to help get this merged.

Kind regards,

Faisal.

_______________________________________________ Python-Dev mailing list -- python-dev@python.org To unsubscribe send an email to python-dev-leave@python.org https://mail.python.org/mailman3/lists/python-dev.python.org/ Message archived at https://mail.python.org/archives/list/python-dev@python.org/message/DUL55S2S... Code of Conduct: http://python.org/psf/codeofconduct/

Honestly this is an example of a module that would have been better off outside the stdlib. On Fri, Mar 19, 2021 at 14:43 Senthil Kumaran wrote:

On Mon, Feb 15, 2021 at 8:36 AM Faisal Mahmood wrote:

...

Hello,

I hope you are all well, I currently have an issue / merge request that

has become stale and as per the guidelines I am sending this e-mail to request someone to review it for me please.

...

Issue Number: 42861 (https://bugs.python.org/issue42861) Pull Request: 24180 (https://github.com/python/cpython/pull/24180)

Could you share some motivation references that could help explain why this next_network method will be helpful? Is this common enough to warrant a method in the stdlib IP-Address module? If there is prior-art in other external libraries or libraries of other languages, that will be helpful to know and review too.

I had looked at this a month ago when you pinged for review, but I could not immediately determine the benefit of having this method in stdlib, irrespective of implementation correctness or API Signature. I also lack extensive experience with ipv6.

Thanks, Senthil _______________________________________________ Python-Dev mailing list -- python-dev@python.org To unsubscribe send an email to python-dev-leave@python.org https://mail.python.org/mailman3/lists/python-dev.python.org/ Message archived at https://mail.python.org/archives/list/python-dev@python.org/message/OABKRDE2... Code of Conduct: http://python.org/psf/codeofconduct/

-- --Guido (mobile)

On 20 Mar 2021, at 04:39, Guido van Rossum wrote:

Honestly this is an example of a module that would have been better off outside the stdlib.

On Fri, Mar 19, 2021 at 14:43 Senthil Kumaran wrote: On Mon, Feb 15, 2021 at 8:36 AM Faisal Mahmood wrote:

...

Hello,

I hope you are all well, I currently have an issue / merge request that has become stale and as per the guidelines I am sending this e-mail to request someone to review it for me please.

Issue Number: 42861 (https://bugs.python.org/issue42861) Pull Request: 24180 (https://github.com/python/cpython/pull/24180)

Could you share some motivation references that could help explain why this next_network method will be helpful? Is this common enough to warrant a method in the stdlib IP-Address module? If there is prior-art in other external libraries or libraries of other languages, that will be helpful to know and review too.

I had looked at this a month ago when you pinged for review, but I could not immediately determine the benefit of having this method in stdlib, irrespective of implementation correctness or API Signature. I also lack extensive experience with ipv6.

Thanks, Senthil

I don’t know if this is gonna support Faisal’s cause (“It’s used in a third party library in the wild, that means stdlib could use it!”) or the exact opposite (“it’s provided by a third party library, so may as well use third party library and stdlib doesn’t necessarily need this”) but the quite popular netaddr library that I’m a maintainer of does have IPNetwork.next() and IPNetwork.previous() methods[1][2]. The main difference is that in netaddr: * next() and previous() can produce networks arbitrary number of steps away, not just the first closest network forwards or backwards * going from a network to its supernetwork or subnetwork is done through a separate set of supernet() and subnet() methods[3][4] I can’t say how many library users actually consume this particular section of the API, of course, but I expect this API to be used and it seems rather useful. Best, Jakub [1] https://netaddr.readthedocs.io/en/latest/api.html#netaddr.IPNetwork.next [2] https://netaddr.readthedocs.io/en/latest/api.html#netaddr.IPNetwork.previous [3] https://netaddr.readthedocs.io/en/latest/api.html#netaddr.IPNetwork.subnet [4] https://netaddr.readthedocs.io/en/latest/api.html#netaddr.IPNetwork.supernet

On 22 Mar 2021, at 13:07, Faisal Mahmood wrote:

Thanks Jakub, I wasn't aware of the netaddr library but just gave it a play and it does seem very similar and I think it's very useful and completely valid.

I think the subtle difference is also that my implementation allows you to specify the next prefix as well, so it won't just find the next prefix of the same size. This is a common use case when you are trying to find free address spaces, you will need to look for networks of different sizes depending on what you are doing.

Currently, you could say that you were given a network of 10.200.20.0/24 and asked to split this network into a bunch of /26 networks, you can do this easily using the subnets method:

...

...

...

list(IPv4Network("10.200.20.0/24").subnets(prefixlen_diff=2)) [IPv4Network('10.200.20.0/26'), IPv4Network('10.200.20.64/26'), IPv4Network('10.200.20.128/26'), IPv4Network('10.200.20.192/26')]

That is very simple and effective, but not a very realistic example of how you would split networks up. Given how limited the IPv4 address space is, normally you may have to use that /24 block for multiple things, so can't just simply split it up into /26's, you may need to instead get two /30's, one /27 and one /25. Currently, I don't think there is any straightforward way to do this without a 'next_network' method that I have implemented.

Example, given a network of 10.200.20.0/24, to get two /30's out of it, one /27 and one /25, I would do the following with my method:

...

...

...

first_network = IPv4Network("10.200.20.0/30") # first_network = IPv4Network("10.200.20.0/30")

Then get the next one (note not specifying prefix just gives me another /30 - i.e. same prefix size):

...

...

...

second_network = first_network.next_network() # second_network = IPv4Network("10.200.20.4/30")

Then I would need to get the /27, so do this:

...

...

...

third_network = second_network.next_network(new_prefixlen=27) # third_network = IPv4Network("10.200.20.32/27)

Finally the /25:

...

...

...

fourth_network = third_network.next_network(new_prefixlen=25) # fourth_network = IPv4Network("10.200.20.128/25)

When you are dealing with the same prefix size for each new network, I think it's just a simple case of adding 1 to the broadcast address each time, but when you have different prefix sizes it's a bit more complicated.

On Sat, 20 Mar 2021 at 22:04, Jakub Stasiak wrote:

I don’t know if this is gonna support Faisal’s cause (“It’s used in a third party library in the wild, that means stdlib could use it!”) or the exact opposite (“it’s provided by a third party library, so may as well use third party library and stdlib doesn’t necessarily need this”) but the quite popular netaddr library that I’m a maintainer of does have IPNetwork.next() and IPNetwork.previous() methods[1][2]. The main difference is that in netaddr:

* next() and previous() can produce networks arbitrary number of steps away, not just the first closest network forwards or backwards * going from a network to its supernetwork or subnetwork is done through a separate set of supernet() and subnet() methods[3][4]

I can’t say how many library users actually consume this particular section of the API, of course, but I expect this API to be used and it seems rather useful.

Best, Jakub

[1] https://netaddr.readthedocs.io/en/latest/api.html#netaddr.IPNetwork.next [2] https://netaddr.readthedocs.io/en/latest/api.html#netaddr.IPNetwork.previous [3] https://netaddr.readthedocs.io/en/latest/api.html#netaddr.IPNetwork.subnet [4] https://netaddr.readthedocs.io/en/latest/api.html#netaddr.IPNetwork.supernet

Thank you for the explanation – now I understand better how that prefix parameter is useful. It’s not *that* difficult to emulate this using netaddr, there’s an extra switch-to-supernet or switch-to-subnet step but that’s about it:

...

...

from netaddr import IPNetwork first_network = IPNetwork("10.200.20.0/30") second_network = first_network.next() second_network IPNetwork('10.200.20.4/30') third_network = second_network.supernet(27)[0].next() third_network IPNetwork('10.200.20.32/27') fourth_network = third_network.supernet(25)[0].next() fourth_network IPNetwork('10.200.20.128/25’)

That said, if merging this into the Python stdlib doesn’t work out I’m open to improving netaddr’s interface to better serve this use case. Best wishes, Jakub

On 3/22/2021 8:51 PM, Senthil Kumaran wrote:

Given this discussion, I am motivated to review this and merge this into stdlib. The conversation was helpful to me to understand for utility value of the method introduced by the patch. I had stated in the PR as well.

Thank you, both, Faisal and Jakub.

Yes, thank you. I've also needed the "next network of a given prefix size" feature. Eric

On Mon, Mar 22, 2021 at 5:40 PM Jakub Stasiak wrote:

...

...

On 22 Mar 2021, at 13:07, Faisal Mahmood wrote:

Thanks Jakub, I wasn't aware of the netaddr library but just gave it a play and it does seem very similar and I think it's very useful and completely valid.

I think the subtle difference is also that my implementation allows you to specify the next prefix as well, so it won't just find the next prefix of the same size. This is a common use case when you are trying to find free address spaces, you will need to look for networks of different sizes depending on what you are doing.

Currently, you could say that you were given a network of 10.200.20.0/24 and asked to split this network into a bunch of /26 networks, you can do this easily using the subnets method:

...

...

...

list(IPv4Network("10.200.20.0/24").subnets(prefixlen_diff=2)) [IPv4Network('10.200.20.0/26'), IPv4Network('10.200.20.64/26'), IPv4Network('10.200.20.128/26'), IPv4Network('10.200.20.192/26')]

That is very simple and effective, but not a very realistic example of how you would split networks up. Given how limited the IPv4 address space is, normally you may have to use that /24 block for multiple things, so can't just simply split it up into /26's, you may need to instead get two /30's, one /27 and one /25. Currently, I don't think there is any straightforward way to do this without a 'next_network' method that I have implemented.

Example, given a network of 10.200.20.0/24, to get two /30's out of it, one /27 and one /25, I would do the following with my method:

...

...

...

first_network = IPv4Network("10.200.20.0/30") # first_network = IPv4Network("10.200.20.0/30")

Then get the next one (note not specifying prefix just gives me another /30 - i.e. same prefix size):

...

...

...

second_network = first_network.next_network() # second_network = IPv4Network("10.200.20.4/30")

Then I would need to get the /27, so do this:

...

...

...

third_network = second_network.next_network(new_prefixlen=27) # third_network = IPv4Network("10.200.20.32/27)

Finally the /25:

...

...

...

fourth_network = third_network.next_network(new_prefixlen=25) # fourth_network = IPv4Network("10.200.20.128/25)

When you are dealing with the same prefix size for each new network, I think it's just a simple case of adding 1 to the broadcast address each time, but when you have different prefix sizes it's a bit more complicated.

On Sat, 20 Mar 2021 at 22:04, Jakub Stasiak wrote:

I don’t know if this is gonna support Faisal’s cause (“It’s used in a third party library in the wild, that means stdlib could use it!”) or the exact opposite (“it’s provided by a third party library, so may as well use third party library and stdlib doesn’t necessarily need this”) but the quite popular netaddr library that I’m a maintainer of does have IPNetwork.next() and IPNetwork.previous() methods[1][2]. The main difference is that in netaddr:

* next() and previous() can produce networks arbitrary number of steps away, not just the first closest network forwards or backwards * going from a network to its supernetwork or subnetwork is done through a separate set of supernet() and subnet() methods[3][4]

I can’t say how many library users actually consume this particular section of the API, of course, but I expect this API to be used and it seems rather useful.

Best, Jakub

[1] https://netaddr.readthedocs.io/en/latest/api.html#netaddr.IPNetwork.next [2] https://netaddr.readthedocs.io/en/latest/api.html#netaddr.IPNetwork.previous [3] https://netaddr.readthedocs.io/en/latest/api.html#netaddr.IPNetwork.subnet [4] https://netaddr.readthedocs.io/en/latest/api.html#netaddr.IPNetwork.supernet Thank you for the explanation – now I understand better how that prefix parameter is useful.

It’s not *that* difficult to emulate this using netaddr, there’s an extra switch-to-supernet or switch-to-subnet step but that’s about it:

...

...

...

from netaddr import IPNetwork first_network = IPNetwork("10.200.20.0/30") second_network = first_network.next() second_network IPNetwork('10.200.20.4/30') third_network = second_network.supernet(27)[0].next() third_network IPNetwork('10.200.20.32/27') fourth_network = third_network.supernet(25)[0].next() fourth_network IPNetwork('10.200.20.128/25’)

That said, if merging this into the Python stdlib doesn’t work out I’m open to improving netaddr’s interface to better serve this use case.

Best wishes, Jakub

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