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nick_0189
n00b
Joined: 28 Jul 2022
Posts: 15
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 Posted: Fri Apr 11, 2025 2:01 am Post subject: Package Reverse Dependency Chain Including USE Flags |
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Hello all,
I would like to map out the reverse dependency chain which causes a given package to be installed on a system, including use flags that would trigger its install. Has this been done before?
I wrote a short python script that can map the reverse dependency chain for an input package, but I am looking at a big time sink for finding if there are any use flags that triggered the inclusion of the package.
Here is the script:
| Code: |
#!/usr/bin/env python
class DependencyMap:
def __init__(self, filename):
file = open(filename)
text = file.read()
lines = text.split("\n")
self.lines = self.clean_lines(lines)
self.parents = self.find_parents()
def clean_lines(self, lines):
start_text = "pulled in by:"
end_text = ">>>"
start_flag = False
end_flag = False
for line in lines:
if not start_flag:
start_flag = start_text in line
if not start_flag:
continue
if start_flag:
end_flag = end_text in line
if end_flag:
break
yield(line)
def find_parents(self):
parents = {}
parent = (0, "",)
for line in self.lines:
if not line.strip():
continue
indent = len(line) - len(line.lstrip())
pkg = line.strip().split(" ")[0]
parent_indent, parent_pkg = parent
if not parent_indent or indent <= parent_indent:
parent = (indent, pkg,)
continue
parents.setdefault(parent_pkg, []).append(pkg)
return(parents)
def get_input_pkg(self, opts=[]):
for i,opt in enumerate(opts):
print(i,opt)
user_input = input(">>> ")
if opts:
return list(opts)[int(user_input)]
for pkg in self.parents:
if user_input in pkg:
opts.append(pkg)
opts = sorted(list(opts))
if len(opts) == 1:
return opts[0]
return self.get_input_pkg(opts)
def get_rdep_chain(self, pkg=None, _seen=[], _level=0):
if pkg is None:
pkg = self.get_input_pkg()
yield((_level,pkg,))
for pkg in self.parents.get(pkg,[]):
if pkg in _seen:
continue
if pkg != "@selected":
_seen.append(pkg)
yield from self.get_rdep_chain(pkg, _seen=_seen, _level=_level+1)
def main():
# emerge --pretend --verbose --emptytree --depclean > emerge_deps.txt
# portageq metadata / ebuild <PKG> DEPEND
depMap = DependencyMap("emerge_deps.txt")
pkg = depMap.get_input_pkg()
rdepChain = depMap.get_rdep_chain(pkg)
for level,pkg in rdepChain:
print(" "*level,pkg)
if __name__ == '__main__':
main()
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It expects an "emerge_deps.txt" file, which can be generated as follows:
| Code: |
emerge --pretend --verbose --emptytree --depclean > emerge_deps.txt
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It can generate the following example output:
| Code: |
./rdepends.py
>>> brotli
app-arch/brotli-1.1.0
app-text/dvisvgm-3.4
dev-texlive/texlive-binextra-2024_p72338-r1
app-text/texlive-2024
@selected
media-libs/libjxl-0.11.1
dev-libs/hyprgraphics-0.1.1
gui-wm/hyprland-0.46.2-r1
@selected
media-libs/woff2-1.0.2-r6
net-libs/libsoup-3.4.4
gnome-base/gvfs-1.52.3-r1
xfce-base/thunar-4.20.1
@selected
sys-apps/osinfo-db-tools-1.11.0
sys-apps/osinfo-db-20240701
sys-libs/libosinfo-1.11.0
app-emulation/virt-manager-5.0.0-r1
@selected
net-libs/nodejs-22.13.1
@selected
sys-apps/yarn-1.22.22
@selected
www-client/chromium-134.0.6998.117
@selected
www-client/firefox-128.8.0
@selected
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This is nice, I can see why a package is required all the way up to the "@selected" packages in the world file, but I would additionally like to know if the package is pulled in by a USE flag or if it is a hard dependency for the package. The USE flag rules for a package can found as follows:
| Code: |
portageq metadata / ebuild $(qlist -Iv <PKG>) DEPEND
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Example output:
| Code: |
portageq metadata / ebuild $(qlist -Iv grub) DEPEND
app-arch/xz-utils >=sys-libs/ncurses-5.2-r5:0= grub_platforms_emu? ( sdl? ( media-libs/libsdl2 ) ) device-mapper? ( >=sys-fs/lvm2-2.02.45 ) libzfs? ( sys-fs/zfs:= ) mount? ( sys-fs/fuse:3= ) truetype? ( media-libs/freetype:2= ) ppc? ( >=sys-apps/ibm-powerpc-utils-1.3.5 ) ppc64? ( >=sys-apps/ibm-powerpc-utils-1.3.5 )
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Portage parses this somehow when determining package dependencies. Is this functionality somewhat independent from Portage so I can pass the active use flags for a given package to a parser to find the triggered dependencies?
For example, I would like to to know that the bluez package is only included under pipewire because the bluetooth USE flag was enabled for pipewire, which was enabled by the desktop profile.
| Code: |
net-wireless/bluez-5.79
media-video/pipewire-1.2.7-r2
(bluetooth? ( dev-libs/glib media-libs/fdk-aac media-libs/libldac media-libs/libfreeaptx media-libs/opus media-libs/sbc >=net-wireless/bluez-4.101:= virtual/libusb:1 )
/var/db/repos/gentoo/profiles/targets/desktop/make.defaults
media-video/wireplumber-0.5.8-r2
sys-apps/xdg-desktop-portal-1.18.4-r1
x11-base/xwayland-24.1.6
gui-wm/hyprland-0.46.2-r1
@selected
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Thank you for your help, please let me know if I can clarify anything. |
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Ralphred
l33t
Joined: 31 Dec 2013
Posts: 767
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| Posted: Fri Apr 11, 2025 1:14 pm Post subject: Re: Package Reverse Dependency Chain Including USE Flags |
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| nick_0189 wrote: | | Has this been done before? |
Not that I'm aware of. There is the equery depgraph command but it's not so tailored as to be able to pass it different use flags and see how a flag switch would affect the whole dependency tree, it does show if something was triggered by a use flag (I think). IIRC it's written in perl(?). I still have a pyqt based frontend for eix* (and equery depgraph) laying around, but the depgraph function was so non-intuitive I shelved it for the "published" version; if you get this working I'd happily use it** as the core of a "show me the dependencies" GUI tab with check boxes for the optional use flags, or even a "compare the dependencies" for multiple packages selected from the search UI.
| nick_0189 wrote: | Example output: | Code: | portageq metadata / ebuild $(qlist -Iv grub) DEPEND
app-arch/xz-utils >=sys-libs/ncurses-5.2-r5:0= grub_platforms_emu? ( sdl? ( media-libs/libsdl2 ) ) device-mapper? ( >=sys-fs/lvm2-2.02.45 ) libzfs? ( sys-fs/zfs:= ) mount? ( sys-fs/fuse:3= ) truetype? ( media-libs/freetype:2= ) ppc? ( >=sys-apps/ibm-powerpc-utils-1.3.5 ) ppc64? ( >=sys-apps/ibm-powerpc-utils-1.3.5 ) |
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This doesn't look the easiest to parse, but it's certainly doable. This nesting looks particularly cumbersome to try and convey in an output... | Code: | | grub_platforms_emu? ( sdl? ( media-libs/libsdl2 ) ) |
*eix is extremely well written software, hats off to the dev(s) O7
**with your permission, OFC. |
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nick_0189
n00b
Joined: 28 Jul 2022
Posts: 15
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| Posted: Sun Apr 13, 2025 9:27 pm Post subject: |
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| Thanks for your response. I looked at equery and quse and came to the same conclusion that they could not be used for this. I'll try my hand at writing a parser for the ebuild dependencies and see how it goes, though I've never written a parser before. |
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