Fontbakery install blocked by lxml 4.9.1, for me (lxml 4.9.0 works)

[arrowtype]

Observed behaviour

I’m unable to install Fontbakery 0.8.9, even though I can install 0.8.8.

This seems to be because I can install lxml 4.9.0, but not 4.9.1.

When I try to install the latest fontbakery (or the latest lxml), it winds up with the following error:

Running setup.py install for lxml ... error
  error: subprocess-exited-with-error
  
  × Running setup.py install for lxml did not run successfully.
  │ exit code: 1
  ╰─> [186 lines of output]
      Building lxml version 4.9.1.

# many lines of output
 /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk/usr/include/machine/types.h:37:2: error: architecture not supported
      #error architecture not supported
       ^
      fatal error: too many errors emitted, stopping now [-ferror-limit=]
      20 errors generated.
      Compile failed: command '/usr/bin/clang' failed with exit code 1
      creating var
      creating var/folders
      creating var/folders/x0
      creating var/folders/x0/q5zt3sx15ssdz5mjcm9rgvh40000gn
      creating var/folders/x0/q5zt3sx15ssdz5mjcm9rgvh40000gn/T
      cc -I/usr/include/libxml2 -c /var/folders/x0/q5zt3sx15ssdz5mjcm9rgvh40000gn/T/xmlXPathInit1qx5d6l_.c -o var/folders/x0/q5zt3sx15ssdz5mjcm9rgvh40000gn/T/xmlXPathInit1qx5d6l_.o
      cc var/folders/x0/q5zt3sx15ssdz5mjcm9rgvh40000gn/T/xmlXPathInit1qx5d6l_.o -lxml2 -o a.out
      error: command '/usr/bin/clang' failed with exit code 1
      [end of output]
  
  note: This error originates from a subprocess, and is likely not a problem with pip.
error: legacy-install-failure

Full error message (Click to expand)

# install going well, but then...

Installing collected packages: unicodedata2, sre-yield, pyclipper, opentype-sanitizer, openstep-plist, commonmark, commandlines, appdirs, urllib3, uharfbuzz, toml, soupsieve, smmap, six, setuptools, rstr, PyYAML, pygments, pycparser, protobuf, pip, opentypespec, numpy, lxml, idna, fontTools, charset-normalizer, certifi, beziers, attrs, vharfbuzz, stringbrewer, rich, requests, pip-api, gitdb, gflanguages, fs, fontPens, fontMath, dehinter, cffsubr, cffi, booleanOperations, beautifulsoup4, axisregistry, gitpython, cmarkgfm, ufolint, ufoLib2, font-v, defcon, cu2qu, ufo2ft, glyphsLib, glyphsets, fontParts, babelfont, glyphtools, collidoscope, fontbakery
  Running setup.py install for lxml ... error
  error: subprocess-exited-with-error
  
  × Running setup.py install for lxml did not run successfully.
  │ exit code: 1
  ╰─> [186 lines of output]
      Building lxml version 4.9.1.
      Building without Cython.
      Building against libxml2 2.9.4 and libxslt 1.1.29
      running install
      /Users/stephennixon/Desktop/fontfamily-testing/venv/lib/python3.10/site-packages/setuptools/command/install.py:34: SetuptoolsDeprecationWarning: setup.py install is deprecated. Use build and pip and other standards-based tools.
        warnings.warn(
      running build
      running build_py
      creating build
      creating build/lib.macosx-10.9-universal2-cpython-310
      creating build/lib.macosx-10.9-universal2-cpython-310/lxml
      copying src/lxml/_elementpath.py -> build/lib.macosx-10.9-universal2-cpython-310/lxml
      copying src/lxml/sax.py -> build/lib.macosx-10.9-universal2-cpython-310/lxml
      copying src/lxml/pyclasslookup.py -> build/lib.macosx-10.9-universal2-cpython-310/lxml
      copying src/lxml/__init__.py -> build/lib.macosx-10.9-universal2-cpython-310/lxml
      copying src/lxml/builder.py -> build/lib.macosx-10.9-universal2-cpython-310/lxml
      copying src/lxml/doctestcompare.py -> build/lib.macosx-10.9-universal2-cpython-310/lxml
      copying src/lxml/usedoctest.py -> build/lib.macosx-10.9-universal2-cpython-310/lxml
      copying src/lxml/cssselect.py -> build/lib.macosx-10.9-universal2-cpython-310/lxml
      copying src/lxml/ElementInclude.py -> build/lib.macosx-10.9-universal2-cpython-310/lxml
      creating build/lib.macosx-10.9-universal2-cpython-310/lxml/includes
      copying src/lxml/includes/__init__.py -> build/lib.macosx-10.9-universal2-cpython-310/lxml/includes
      creating build/lib.macosx-10.9-universal2-cpython-310/lxml/html
      copying src/lxml/html/soupparser.py -> build/lib.macosx-10.9-universal2-cpython-310/lxml/html
      copying src/lxml/html/defs.py -> build/lib.macosx-10.9-universal2-cpython-310/lxml/html
      copying src/lxml/html/_setmixin.py -> build/lib.macosx-10.9-universal2-cpython-310/lxml/html
      copying src/lxml/html/clean.py -> build/lib.macosx-10.9-universal2-cpython-310/lxml/html
      copying src/lxml/html/_diffcommand.py -> build/lib.macosx-10.9-universal2-cpython-310/lxml/html
      copying src/lxml/html/html5parser.py -> build/lib.macosx-10.9-universal2-cpython-310/lxml/html
      copying src/lxml/html/__init__.py -> build/lib.macosx-10.9-universal2-cpython-310/lxml/html
      copying src/lxml/html/formfill.py -> build/lib.macosx-10.9-universal2-cpython-310/lxml/html
      copying src/lxml/html/builder.py -> build/lib.macosx-10.9-universal2-cpython-310/lxml/html
      copying src/lxml/html/ElementSoup.py -> build/lib.macosx-10.9-universal2-cpython-310/lxml/html
      copying src/lxml/html/_html5builder.py -> build/lib.macosx-10.9-universal2-cpython-310/lxml/html
      copying src/lxml/html/usedoctest.py -> build/lib.macosx-10.9-universal2-cpython-310/lxml/html
      copying src/lxml/html/diff.py -> build/lib.macosx-10.9-universal2-cpython-310/lxml/html
      creating build/lib.macosx-10.9-universal2-cpython-310/lxml/isoschematron
      copying src/lxml/isoschematron/__init__.py -> build/lib.macosx-10.9-universal2-cpython-310/lxml/isoschematron
      copying src/lxml/etree.h -> build/lib.macosx-10.9-universal2-cpython-310/lxml
      copying src/lxml/etree_api.h -> build/lib.macosx-10.9-universal2-cpython-310/lxml
      copying src/lxml/lxml.etree.h -> build/lib.macosx-10.9-universal2-cpython-310/lxml
      copying src/lxml/lxml.etree_api.h -> build/lib.macosx-10.9-universal2-cpython-310/lxml
      copying src/lxml/includes/xmlerror.pxd -> build/lib.macosx-10.9-universal2-cpython-310/lxml/includes
      copying src/lxml/includes/c14n.pxd -> build/lib.macosx-10.9-universal2-cpython-310/lxml/includes
      copying src/lxml/includes/xmlschema.pxd -> build/lib.macosx-10.9-universal2-cpython-310/lxml/includes
      copying src/lxml/includes/__init__.pxd -> build/lib.macosx-10.9-universal2-cpython-310/lxml/includes
      copying src/lxml/includes/schematron.pxd -> build/lib.macosx-10.9-universal2-cpython-310/lxml/includes
      copying src/lxml/includes/tree.pxd -> build/lib.macosx-10.9-universal2-cpython-310/lxml/includes
      copying src/lxml/includes/uri.pxd -> build/lib.macosx-10.9-universal2-cpython-310/lxml/includes
      copying src/lxml/includes/etreepublic.pxd -> build/lib.macosx-10.9-universal2-cpython-310/lxml/includes
      copying src/lxml/includes/xpath.pxd -> build/lib.macosx-10.9-universal2-cpython-310/lxml/includes
      copying src/lxml/includes/htmlparser.pxd -> build/lib.macosx-10.9-universal2-cpython-310/lxml/includes
      copying src/lxml/includes/xslt.pxd -> build/lib.macosx-10.9-universal2-cpython-310/lxml/includes
      copying src/lxml/includes/config.pxd -> build/lib.macosx-10.9-universal2-cpython-310/lxml/includes
      copying src/lxml/includes/xmlparser.pxd -> build/lib.macosx-10.9-universal2-cpython-310/lxml/includes
      copying src/lxml/includes/xinclude.pxd -> build/lib.macosx-10.9-universal2-cpython-310/lxml/includes
      copying src/lxml/includes/dtdvalid.pxd -> build/lib.macosx-10.9-universal2-cpython-310/lxml/includes
      copying src/lxml/includes/relaxng.pxd -> build/lib.macosx-10.9-universal2-cpython-310/lxml/includes
      copying src/lxml/includes/lxml-version.h -> build/lib.macosx-10.9-universal2-cpython-310/lxml/includes
      copying src/lxml/includes/etree_defs.h -> build/lib.macosx-10.9-universal2-cpython-310/lxml/includes
      creating build/lib.macosx-10.9-universal2-cpython-310/lxml/isoschematron/resources
      creating build/lib.macosx-10.9-universal2-cpython-310/lxml/isoschematron/resources/rng
      copying src/lxml/isoschematron/resources/rng/iso-schematron.rng -> build/lib.macosx-10.9-universal2-cpython-310/lxml/isoschematron/resources/rng
      creating build/lib.macosx-10.9-universal2-cpython-310/lxml/isoschematron/resources/xsl
      copying src/lxml/isoschematron/resources/xsl/XSD2Schtrn.xsl -> build/lib.macosx-10.9-universal2-cpython-310/lxml/isoschematron/resources/xsl
      copying src/lxml/isoschematron/resources/xsl/RNG2Schtrn.xsl -> build/lib.macosx-10.9-universal2-cpython-310/lxml/isoschematron/resources/xsl
      creating build/lib.macosx-10.9-universal2-cpython-310/lxml/isoschematron/resources/xsl/iso-schematron-xslt1
      copying src/lxml/isoschematron/resources/xsl/iso-schematron-xslt1/iso_abstract_expand.xsl -> build/lib.macosx-10.9-universal2-cpython-310/lxml/isoschematron/resources/xsl/iso-schematron-xslt1
      copying src/lxml/isoschematron/resources/xsl/iso-schematron-xslt1/iso_dsdl_include.xsl -> build/lib.macosx-10.9-universal2-cpython-310/lxml/isoschematron/resources/xsl/iso-schematron-xslt1
      copying src/lxml/isoschematron/resources/xsl/iso-schematron-xslt1/iso_schematron_skeleton_for_xslt1.xsl -> build/lib.macosx-10.9-universal2-cpython-310/lxml/isoschematron/resources/xsl/iso-schematron-xslt1
      copying src/lxml/isoschematron/resources/xsl/iso-schematron-xslt1/iso_svrl_for_xslt1.xsl -> build/lib.macosx-10.9-universal2-cpython-310/lxml/isoschematron/resources/xsl/iso-schematron-xslt1
      copying src/lxml/isoschematron/resources/xsl/iso-schematron-xslt1/iso_schematron_message.xsl -> build/lib.macosx-10.9-universal2-cpython-310/lxml/isoschematron/resources/xsl/iso-schematron-xslt1
      copying src/lxml/isoschematron/resources/xsl/iso-schematron-xslt1/readme.txt -> build/lib.macosx-10.9-universal2-cpython-310/lxml/isoschematron/resources/xsl/iso-schematron-xslt1
      running build_ext
      building 'lxml.etree' extension
      creating build/temp.macosx-10.9-universal2-cpython-310
      creating build/temp.macosx-10.9-universal2-cpython-310/src
      creating build/temp.macosx-10.9-universal2-cpython-310/src/lxml
      clang -Wno-unused-result -Wsign-compare -Wunreachable-code -fno-common -dynamic -DNDEBUG -g -fwrapv -O3 -Wall -arch arm64 -arch x86_64 -g -DCYTHON_CLINE_IN_TRACEBACK=0 -Isrc -Isrc/lxml/includes -I/Users/stephennixon/Desktop/fontfamily-testing/venv/include -I/Library/Frameworks/Python.framework/Versions/3.10/include/python3.10 -c src/lxml/etree.c -o build/temp.macosx-10.9-universal2-cpython-310/src/lxml/etree.o -w -flat_namespace
      In file included from src/lxml/etree.c:96:
      In file included from /Library/Frameworks/Python.framework/Versions/3.10/include/python3.10/Python.h:11:
      In file included from /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/lib/clang/11.0.3/include/limits.h:21:
      In file included from /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk/usr/include/limits.h:63:
      /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk/usr/include/sys/cdefs.h:807:2: error: Unsupported architecture
      #error Unsupported architecture
       ^
      In file included from src/lxml/etree.c:96:
      In file included from /Library/Frameworks/Python.framework/Versions/3.10/include/python3.10/Python.h:11:
      In file included from /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/lib/clang/11.0.3/include/limits.h:21:
      In file included from /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk/usr/include/limits.h:64:
      /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk/usr/include/machine/limits.h:8:2: error: architecture not supported
      #error architecture not supported
       ^
      In file included from src/lxml/etree.c:96:
      In file included from /Library/Frameworks/Python.framework/Versions/3.10/include/python3.10/Python.h:25:
      In file included from /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk/usr/include/stdio.h:64:
      In file included from /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk/usr/include/_stdio.h:71:
      In file included from /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk/usr/include/_types.h:27:
      In file included from /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk/usr/include/sys/_types.h:33:
      /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk/usr/include/machine/_types.h:34:2: error: architecture not supported
      #error architecture not supported
       ^
      In file included from src/lxml/etree.c:96:
      In file included from /Library/Frameworks/Python.framework/Versions/3.10/include/python3.10/Python.h:25:
      In file included from /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk/usr/include/stdio.h:64:
      In file included from /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk/usr/include/_stdio.h:71:
      In file included from /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk/usr/include/_types.h:27:
      /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk/usr/include/sys/_types.h:55:9: error: unknown type name '__int64_t'
      typedef __int64_t       __darwin_blkcnt_t;      /* total blocks */
              ^
      /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk/usr/include/sys/_types.h:56:9: error: unknown type name '__int32_t'; did you mean '__int128_t'?
      typedef __int32_t       __darwin_blksize_t;     /* preferred block size */
              ^
      note: '__int128_t' declared here
      /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk/usr/include/sys/_types.h:57:9: error: unknown type name '__int32_t'; did you mean '__int128_t'?
      typedef __int32_t       __darwin_dev_t;         /* dev_t */
              ^
      note: '__int128_t' declared here
      /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk/usr/include/sys/_types.h:60:9: error: unknown type name '__uint32_t'; did you mean '__uint128_t'?
      typedef __uint32_t      __darwin_gid_t;         /* [???] process and group IDs */
              ^
      note: '__uint128_t' declared here
      /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk/usr/include/sys/_types.h:61:9: error: unknown type name '__uint32_t'; did you mean '__uint128_t'?
      typedef __uint32_t      __darwin_id_t;          /* [XSI] pid_t, uid_t, or gid_t*/
              ^
      note: '__uint128_t' declared here
      /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk/usr/include/sys/_types.h:62:9: error: unknown type name '__uint64_t'
      typedef __uint64_t      __darwin_ino64_t;       /* [???] Used for 64 bit inodes */
              ^
      /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk/usr/include/sys/_types.h:68:9: error: unknown type name '__darwin_natural_t'
      typedef __darwin_natural_t __darwin_mach_port_name_t; /* Used by mach */
              ^
      /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk/usr/include/sys/_types.h:70:9: error: unknown type name '__uint16_t'; did you mean '__uint128_t'?
      typedef __uint16_t      __darwin_mode_t;        /* [???] Some file attributes */
              ^
      note: '__uint128_t' declared here
      /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk/usr/include/sys/_types.h:71:9: error: unknown type name '__int64_t'
      typedef __int64_t       __darwin_off_t;         /* [???] Used for file sizes */
              ^
      /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk/usr/include/sys/_types.h:72:9: error: unknown type name '__int32_t'; did you mean '__int128_t'?
      typedef __int32_t       __darwin_pid_t;         /* [???] process and group IDs */
              ^
      note: '__int128_t' declared here
      /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk/usr/include/sys/_types.h:73:9: error: unknown type name '__uint32_t'; did you mean '__uint128_t'?
      typedef __uint32_t      __darwin_sigset_t;      /* [???] signal set */
              ^
      note: '__uint128_t' declared here
      /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk/usr/include/sys/_types.h:74:9: error: unknown type name '__int32_t'; did you mean '__int128_t'?
      typedef __int32_t       __darwin_suseconds_t;   /* [???] microseconds */
              ^
      note: '__int128_t' declared here
      /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk/usr/include/sys/_types.h:75:9: error: unknown type name '__uint32_t'; did you mean '__uint128_t'?
      typedef __uint32_t      __darwin_uid_t;         /* [???] user IDs */
              ^
      note: '__uint128_t' declared here
      /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk/usr/include/sys/_types.h:76:9: error: unknown type name '__uint32_t'; did you mean '__uint128_t'?
      typedef __uint32_t      __darwin_useconds_t;    /* [???] microseconds */
              ^
      note: '__uint128_t' declared here
      In file included from src/lxml/etree.c:96:
      In file included from /Library/Frameworks/Python.framework/Versions/3.10/include/python3.10/Python.h:25:
      In file included from /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk/usr/include/stdio.h:64:
      In file included from /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk/usr/include/_stdio.h:71:
      /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk/usr/include/_types.h:43:9: error: unknown type name '__uint32_t'; did you mean '__uint128_t'?
      typedef __uint32_t      __darwin_wctype_t;
              ^
      note: '__uint128_t' declared here
      In file included from src/lxml/etree.c:96:
      In file included from /Library/Frameworks/Python.framework/Versions/3.10/include/python3.10/Python.h:25:
      In file included from /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk/usr/include/stdio.h:64:
      In file included from /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk/usr/include/_stdio.h:75:
      In file included from /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk/usr/include/sys/_types/_va_list.h:31:
      /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk/usr/include/machine/types.h:37:2: error: architecture not supported
      #error architecture not supported
       ^
      fatal error: too many errors emitted, stopping now [-ferror-limit=]
      20 errors generated.
      Compile failed: command '/usr/bin/clang' failed with exit code 1
      creating var
      creating var/folders
      creating var/folders/x0
      creating var/folders/x0/q5zt3sx15ssdz5mjcm9rgvh40000gn
      creating var/folders/x0/q5zt3sx15ssdz5mjcm9rgvh40000gn/T
      cc -I/usr/include/libxml2 -c /var/folders/x0/q5zt3sx15ssdz5mjcm9rgvh40000gn/T/xmlXPathInit1qx5d6l_.c -o var/folders/x0/q5zt3sx15ssdz5mjcm9rgvh40000gn/T/xmlXPathInit1qx5d6l_.o
      cc var/folders/x0/q5zt3sx15ssdz5mjcm9rgvh40000gn/T/xmlXPathInit1qx5d6l_.o -lxml2 -o a.out
      error: command '/usr/bin/clang' failed with exit code 1
      [end of output]
  
  note: This error originates from a subprocess, and is likely not a problem with pip.
error: legacy-install-failure

× Encountered error while trying to install package.
╰─> lxml

note: This is an issue with the package mentioned above, not pip.
hint: See above for output from the failure.

Resources and exact process needed to replicate

I assume this issue is due to something about my computer, but I’m not sure what that might be.

I am installing in a venv, running Python.

(venv) 
▶ python --version
Python 3.10.4
(venv) 
~/Desktop/fontfamily-testing                                                                                                                                  
▶ which python
/Users/stephennixon/Desktop/fontfamily-testing/venv/bin/python

I’m on macOS Monterey, 12.5.

What else might I try to debug this issue?

Thanks for any leads!
Thanks!

[arrowtype]

I ran into a similar architecture not supported error in another library, and searched for a solution again.

This Stack Overflow answer points out that you can set a flag to specify your computer's architecture. And this answer shows how you can determine that.

So, for me, I ran uname -a, and saw in the response included x86_64 at the end. So, I fed this into a flag, like so:

ARCHFLAGS="-arch x86_64" pip3 install -U fontbakery

And it installs successfully!

My current guess at the cause is that m1/m2 macs have a different architecture, and Python modules are starting to be written with this assumption? I don't understand the intel/m1 difference well enough to know if my guess is correct, though.

[anthrotype]

that's strange. What's the output when you run uname -m command in your Terminal? If you're running on M1/M2, you should see arm64, not x86_64. Are you using the default Terminal.app or something else (e.g. iTerm2)?
Are you perhaps using tmux? Maybe tmux is running in emulation mode and as such the sub-shells it spawns (including python itself and its subprocesses) are also run in x86_64 mode instead of the native arm64..
Try to reinstall or upgrade tmux and make sure that your tmux is compiled for the native arm64 architecture. E.g. file $(which tmux) should list "arm64" in its output.

[arrowtype]

Sorry, I wasn't clear – I am not on an m1/m2 laptop. I thought that maybe the library migrated, but I am still on intel (2019 MacBook Pro).

[anthrotype]

hm that makes even less sense that you have to provide a redundant ARCHFLAGS in order for lxml to build from source for your native x86_64 architecture...

[anthrotype]

in that case, you should probably try search https://bugs.launchpad.net/lxml or report a new bug upstream

[arrowtype]

Looks like the bug is filed at https://bugs.launchpad.net/lxml/+bug/1980575, but it isn’t clear when they might fix it.