The Build-Depends specifies:

   python3-multipart (>= 0.0.13) | python3-python-multipart <!nocheck>,
   python3-multipart (<< 0.1) | python3-python-multipart <!nocheck>,

Because of the way that APT works, the second line installs
python3-python-multipart but the first line installs python3-multipart
(>> 1), because that solves the first of the two options.  This could
probably be fixed by swapping the order of the two options to:

   python3-python-multipart | python3-multipart (>= 0.0.13) <!nocheck>,
   python3-python-multipart | python3-multipart (<< 0.1) <!nocheck>,

or, since python3-python-multipart is now in testing, to the single
dependency

   python3-python-multipart


Here's a patch:
--- fastapi-0.115.5/debian/control      2024-11-29 02:00:07.000000000 +0000
+++ fastapi-0.115.5/debian/control      2025-01-14 20:46:24.000000000 +0000
@@ -13,8 +13,7 @@
                python3-flask <!nocheck>,
                python3-httpx (>= 0.23.1) <!nocheck>,
                python3-inline-snapshot <!nocheck>,
-               python3-multipart (>= 0.0.13) | python3-python-multipart <!nocheck>,
-               python3-multipart (<< 0.1) | python3-python-multipart <!nocheck>,
+               python3-python-multipart <!nocheck>,
                python3-pdm-backend,
                python3-peewee <!nocheck>,
                python3-pydantic (>= 1.8.2) <!nocheck>,


Best wishes,

   Julian

We believe that the bug you reported is fixed in the latest version of
fastapi, which is due to be installed in the Debian FTP archive.

A summary of the changes between this version and the previous one is
attached.

Thank you for reporting the bug, which will now be closed.  If you
have further comments please address them to 1093474@bugs.debian.org,
and the maintainer will reopen the bug report if appropriate.

Debian distribution maintenance software
pp.
Sandro Tosi <morph@debian.org> (supplier of updated fastapi package)

(This message was generated automatically at their request; if you
believe that there is a problem with it please contact the archive
administrators by mailing ftpmaster@ftp-master.debian.org)
Format: 1.8
Date: Mon, 14 Sep 2026 02:24:41 -0400
Source: fastapi
Architecture: source
Version: 0.141.1-1
Distribution: unstable
Urgency: medium
Maintainer: Sandro Tosi <morph@debian.org>
Changed-By: Sandro Tosi <morph@debian.org>
Closes: 1093474 1143752
Changes:
 fastapi (0.141.1-1) unstable; urgency=medium
 .
   * New upstream release
   * debian/control
     - add httpx2 to b-d, needed by tests; Closes: #1143752
     - add typer to b-d, needed by tests
     - update b-d on multipart to simply python3-python-multipart; Closes: #1093474
   * debian/pybuild.testfiles
     - install scripts/ when running tests
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 cf21894a2890fd05e2af72ed04908b4651481b0f 13113660 fastapi_0.141.1.orig.tar.xz
 eb234aaf88c26a4b2f80c52b0f76081bf7c6529c 5240 fastapi_0.141.1-1.debian.tar.xz
 21b09cb300b441b0329f45b6f3d24c8a871c9257 10910 fastapi_0.141.1-1_source.buildinfo
Checksums-Sha256:
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Files:
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