python-xmltodict: add a new package

[BKPepe]

Maintainer: me (@BKPepe)
Compile tested: Turris MOX, cortexa53, OpenWrt master and Turris Omnia, mvebu, OpenWrt SNAPSHOT r9420-c17a68c
Run tested: Turris MOX, cortexa53, OpenWrt master and Turris Omnia, mvebu, OpenWrt SNAPSHOT r9420-c17a68c

Proof of run tested:

Description:

• add xmltodict

[BKPepe]

@commodo: Could you take a look if it is OK? :-)

[commodo]

rest looks good;

one question before merging;
should we resolve a consensus about naming ?

i.e. whether it's python3-xmltodict or python-xmltodict all the way [except for places where it cannot be avoided like python3-package.mk, Py3Package, VARIANT:=python3, etc] ?

related to this comment: #8741 (comment)

[BKPepe]

For now, I think the package should be named python3-xmltodict as it is only Python3 package which is the same as in Debian. But it's question if the folder should be named as well as python[3]-xmltodict or just xmltodict.

[jefferyto]

I'd like to mention some background info first:

• I remember adding the python- prefix for PKG_NAMEs after 7a79f2d.
• Directory names are used as part of make target names (e.g. make package/<dir-name>/compile).

I'm not sure if these dependencies (PKG_BUILD_DEPENDS uses PKG_NAME, make target names use directory names) can be changed, but let's assume we are keeping them as-is.

I think we can be reasonably sure a Python library name is unique only among Python libraries (more specifically, ones available in PyPI). For example, there is only one xmltodict Python library, but there could also be a xmltodict Node library or a xmltodict PHP library.

So wherever a Python library name is used globally, I think we should scope it with a python- prefix. (I don't think having a version number in there is necessary, except when there is a need to distinguish between Python 2 and 3 versions.)

By this reasoning, because PKG_NAMEs and directory names are used globally (in PKG_BUILD_DEPENDS and the make command line, respectively), these should have a python- prefix.

(Binary package names (define Package/<name>, opkg install <name>) are also global, and there is a need to distinguish between Python versions, so having python- and python3- make sense.)

I'd be interested to hear any other reasons for or against the prefix; I don't have any strong feelings either way. (Actually, I would prefer to lose the prefix for directory names, since all Python libraries are in the python directory, but I think the effort involved in changing the build system is greater than the strength of my annoyance 😆)

[commodo]

hmm; i thought I replied on this earlier;
oh well, need to rewrite

let's propose this:

• lang/python/<pkg> - no python[3]- prefix
• PKG_NAME:=python-<pkg> - has python- prefix to avoid collisions
• define Package/python3-<pkg> - same as before for Python3 / Python variants; evidently we don't allow python variants [unless really good reasons];

i'll check if it's make package/<dir-name>/compile or make package/<PKG_NAME>/compile;
if it is make package/<dir-name>/compile, then let's have ``lang/python/python-`

thoughts ?

strictly speaking for this PR, I'm fine for merging it as-is;
if there are issues, we can fix them later;

Thanks
Alex

[jefferyto]

@commodo I'm okay with that 👍 😂

[BKPepe]

The folder should be named exactly the same as it is in PKG_NAME to be more consistent with other packages in OpenWrt. However, it's a question for xmltodict.

If I set PKG_NAME as python-xmltodict, I will need to override PKG_BUILD_DIR to look for folder xmltodict instead of python-xmltodict.

[commodo]

If I set PKG_NAME as python-xmltodict, I will need to override PKG_BUILD_DIR to look for folder xmltodict instead of python-xmltodict.

Yep, I know. It is annoying.
I am working on a general change to impose PKG_BUILD_DIR.
See commodo/openwrt@81f43bb
This needs a change in OpenWrt core that is a bit bigger than I thought initially, and requires more testing, but I will try to do it.

Python has had too many PKG_BUILD_DIR & PKG_UNPACK rules because of this.

[commodo]

The folder should be named exactly the same as it is in PKG_NAME to be more consistent with other packages in OpenWrt. However, it's a question for xmltodict.

I am also fine to have the folder be named python-xmltodict; it is a bit redundant, since everything is under lang/python, then you get lang/python/python-<pkg>
In time, this could become a convention [for Python packages], that all Python packages have PKG_NAME:=python-<pkg> but the folder be lang/python/<pkg>

hmm; i still did not find time today to test this;

[jefferyto]

I have a core PR open that is semi-related to this: openwrt/openwrt#1920 (seems no one is interested in it though 😂)

I wanted to get rid of the PKG_BUILD_DIR / PKG_UNPACK rules for variants by standardizing what core packages (that have variants) were already doing on a per-package basis: adding an extra directory level, basically:

PKG_BUILD_DIR:=$(BUILD_DIR)/$(PKG_NAME)-$(BUILD_VARIANT)/$(PKG_NAME)-$(PKG_VERSION)

so the default PKG_UNPACK rule still works (the base directory name is still $(PKG_NAME)-$(PKG_VERSION))

I know this doesn't immediately help in this case (PKG_NAME is "python-x" but the extracted directory is "x"), but perhaps the two ideas can be combined somehow.

[commodo]

so, it seems that it is make package/<pkg_dir>/compile and not make package/<PKG_NAME>/compile
i was never sure about this [ i know it sounds stupid ]

regarding this PR, it is fine as is; so, it can be merged ; sorry for the delay

maybe at a later point we could change the build-system [in a graceful manner] to do make package/<PKG_NAME>/compile
until then, I'll try to not make much fuss about PKG_NAME and/or to have a python- prefix [or not have it]

thanks :)
Alex

[commodo]

sorry for prolonging this longer than needed;

LGTM

thanks
Alex

[BKPepe]

No need to worry about it. I'm just waiting to buildpr to finish its job (of course with pass) as I don't want to merge anything while it is in progress.