From bugzilla at dpdk.org  Thu Jun  4 01:10:42 2026
From: bugzilla at dpdk.org (bugzilla at dpdk.org)
Date: Wed, 03 Jun 2026 23:10:42 +0000
Subject: [DTS/framework Bug 1951] doc build causes scapy to access network
Message-ID: <bug-1951-433@http.bugs.dpdk.org/>

http://bugs.dpdk.org/show_bug.cgi?id=1951

            Bug ID: 1951
           Summary: doc build causes scapy to access network
           Product: DTS
           Version: unspecified
          Hardware: All
                OS: All
            Status: UNCONFIRMED
          Severity: normal
          Priority: Normal
         Component: framework
          Assignee: dts at dpdk.org
          Reporter: stephen at networkplumber.org
  Target Milestone: ---

Saw this warning when build docs:
WARNING: MAC address to reach destination not found. Using broadcast.

A little AI analysis turned up:

doc: DTS API doc build imports live Scapy, leaking runtime warning and reading
host network state

Description (paste into the comment field):

Building the documentation prints a Scapy runtime warning:

WARNING: Mac address to reach destination not found. Using broadcast.

The message does not come from meson, ninja, or the C compiler. The DTS
API docs are generated by Sphinx autodoc, which imports the DTS framework
to harvest docstrings; the framework imports scapy.all. Importing Scapy
triggers next-hop resolution against the host routing table (ARP/ND,
falling back to broadcast), which emits the warning.

doc/api/dts/conf.py sets autodoc_mock_imports to only the missing runtime
dependencies, via get_missing_imports(). That mocking was added so DPDK docs
could be built without DTS dependencies installed -- not to isolate import side
effects. As a result, when Scapy is installed on the build host it is not
mocked, the real module is imported by autodoc, and its runtime side effects
leak into the doc build.

The output is therefore environment-dependent: silent on a host without
Scapy (mocked), noisy on a host with Scapy (real import).

Steps to reproduce:

    Install DTS runtime deps (Scapy) on the build host.
    meson setup -Denable_docs=true build
    ninja -C build doc

Actual result:
Scapy runtime warning printed during the doc build. The build is
non-hermetic -- it reads live host routing state during docstring
extraction.

Expected result:
Doc generation must not import or execute runtime network code, and
output must not depend on which optional runtime deps happen to be
installed.

Suggested fix:
Mock the DTS runtime dependencies unconditionally in doc/api/dts/conf.py
(force scapy, and ideally the full runtime-deps set, into
autodoc_mock_imports regardless of what is installed). autodoc only needs
the modules importable for docstring extraction, never their runtime
behavior. Knocking down the Scapy logger level would hide the message but
would not fix the underlying non-hermetic import.

Fields:
Product:   DPDK
Component: doc
Version:   (set to the release where you reproduced it, e.g. 25.11 / main)
Severity:  minor


Claude is AI and can make mistakes. Pl

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