Re: [yocto] [RFC] Proposal: New tool to display recipe dependency trees

On 24 Nov 2025, at 17:24, Osama Abdelkader via lists.yoctoproject.org <[email protected]> wrote:
> 
> Hi All,
> 
> I would like to propose adding a new command-line tool (or BitBake subcommand) that generates
> dependency trees, including:
> 
> DEPENDS (build-time)
> RDEPENDS (runtime)
> Optional graph output (text, JSON)
> 
> Motivation
> 
> Currently, BitBake provides:
> 
> bitbake -g produces task-depends.dot (task-level, not recipe-level, must use graphviz)
> oe-pkgdata-util runtime dependency only
> bitbake -e <recipe> view variables, but manually
> Errors from the dependency resolver (if a recipe is missing)
> 
> But there is no built-in CLI tool to display a recipe dependency tree, e.g.:
> 
> bitbake-deptree dnf
> 
> dnf
> ├── libdnf
> │    ├── libsolv
> │    └── json-c
> └── sqlite3
> 
Note that the build-time and run-time dependency trees will be a _lot_ deeper than that.

The ability to mark some dependencies as “soft roots” (eg gcc-cross, glibc) and optionally stop at them would be useful.

> Is this functionality valuable upstream? Would BitBake benefit from such a tool?

Yes

> Where should it live?
> Options I see:
> 
> new BitBake subcommand (e.g. bitbake-deptree)
> extension to oe-pkgdata-util
> standalone Python tool under scripts/
> part of devtool?

I’d say this is a question for later, the question for now is “make it work”.

> Preferred output format(s)?
> Plain ASCII tree (default)
> JSON

And HTML/SVG graphs.

> Should the tool:
> 
> cover only DEPENDS (build-time)?
> include RDEPENDS with pkgdata?
> resolve virtual/ providers?

Yes to all.

> Any prior work I may have missed?

bitbake’s own taskexp (bitbake -g taskexp) is basically this with more granularity (because it’s task dependencies, not recipe) and without the drawing of an actual tree (partly because I just implemented it as a three pane window for convenience.

oe-pkgdata-browser (oe-core/scripts) and pkgexp (https://gitlab.com/rossburton/pkgexp) let you dig around the pkgdata interactively.

bitbake-whatdepends does basic processing on the dot file output from bitbake to let you see _why_ recipe A depends on recipe B.

Many people ask for this tool, so I hope you manage to implement something that works well.  I’ve started a few times, but never finished…

Ross