“ERROR:root:code for hash md5 was not found” when using any hg mercurial commands

When trying to use any hg Mercurial commands on the console, I keep getting this error. I installed Python using Homebrew and I am running Mac OS Catalina v. 10.15.1.

Any reference would be appreciated. Here is the error I’m getting:

hg commit --amend
ERROR:root:code for hash md5 was not found.
Traceback (most recent call last):
  File "/usr/local/Cellar/python@2/2.7.15_3/Frameworks/Python.framework/Versions/2.7/lib/python2.7/hashlib.py", line 147, in <module>
    globals()[__func_name] = __get_hash(__func_name)
  File "/usr/local/Cellar/python@2/2.7.15_3/Frameworks/Python.framework/Versions/2.7/lib/python2.7/hashlib.py", line 97, in __get_builtin_constructor
    raise ValueError('unsupported hash type ' + name)
ValueError: unsupported hash type md5
ERROR:root:code for hash sha1 was not found.
Traceback (most recent call last):
  File "/usr/local/Cellar/python@2/2.7.15_3/Frameworks/Python.framework/Versions/2.7/lib/python2.7/hashlib.py", line 147, in <module>
    globals()[__func_name] = __get_hash(__func_name)
  File "/usr/local/Cellar/python@2/2.7.15_3/Frameworks/Python.framework/Versions/2.7/lib/python2.7/hashlib.py", line 97, in __get_builtin_constructor
    raise ValueError('unsupported hash type ' + name)
ValueError: unsupported hash type sha1
ERROR:root:code for hash sha224 was not found.
Traceback (most recent call last):
  File "/usr/local/Cellar/python@2/2.7.15_3/Frameworks/Python.framework/Versions/2.7/lib/python2.7/hashlib.py", line 147, in <module>
    globals()[__func_name] = __get_hash(__func_name)
  File "/usr/local/Cellar/python@2/2.7.15_3/Frameworks/Python.framework/Versions/2.7/lib/python2.7/hashlib.py", line 97, in __get_builtin_constructor
    raise ValueError('unsupported hash type ' + name)
ValueError: unsupported hash type sha224
ERROR:root:code for hash sha256 was not found.
Traceback (most recent call last):
  File "/usr/local/Cellar/python@2/2.7.15_3/Frameworks/Python.framework/Versions/2.7/lib/python2.7/hashlib.py", line 147, in <module>
    globals()[__func_name] = __get_hash(__func_name)
  File "/usr/local/Cellar/python@2/2.7.15_3/Frameworks/Python.framework/Versions/2.7/lib/python2.7/hashlib.py", line 97, in __get_builtin_constructor
    raise ValueError('unsupported hash type ' + name)
ValueError: unsupported hash type sha256
ERROR:root:code for hash sha384 was not found.
Traceback (most recent call last):
  File "/usr/local/Cellar/python@2/2.7.15_3/Frameworks/Python.framework/Versions/2.7/lib/python2.7/hashlib.py", line 147, in <module>
    globals()[__func_name] = __get_hash(__func_name)
  File "/usr/local/Cellar/python@2/2.7.15_3/Frameworks/Python.framework/Versions/2.7/lib/python2.7/hashlib.py", line 97, in __get_builtin_constructor
    raise ValueError('unsupported hash type ' + name)
ValueError: unsupported hash type sha384
ERROR:root:code for hash sha512 was not found.
Traceback (most recent call last):
  File "/usr/local/Cellar/python@2/2.7.15_3/Frameworks/Python.framework/Versions/2.7/lib/python2.7/hashlib.py", line 147, in <module>
    globals()[__func_name] = __get_hash(__func_name)
  File "/usr/local/Cellar/python@2/2.7.15_3/Frameworks/Python.framework/Versions/2.7/lib/python2.7/hashlib.py", line 97, in __get_builtin_constructor
    raise ValueError('unsupported hash type ' + name)
ValueError: unsupported hash type sha512
Traceback (most recent call last):
  File "/usr/local/bin/hg", line 43, in <module>
    dispatch.run()
  File "/usr/local/Cellar/mercurial/4.9/lib/python2.7/site-packages/hgdemandimport/demandimportpy2.py", line 150, in __getattr__
    self._load()
  File "/usr/local/Cellar/mercurial/4.9/lib/python2.7/site-packages/hgdemandimport/demandimportpy2.py", line 94, in _load
    _origimport, head, globals, locals, None, level)
  File "/usr/local/Cellar/mercurial/4.9/lib/python2.7/site-packages/hgdemandimport/demandimportpy2.py", line 43, in _hgextimport
    return importfunc(name, globals, *args, **kwargs)
  File "/usr/local/Cellar/mercurial/4.9/lib/python2.7/site-packages/mercurial/dispatch.py", line 625, in <module>
    class lazyaliasentry(object):
  File "/usr/local/Cellar/mercurial/4.9/lib/python2.7/site-packages/mercurial/dispatch.py", line 636, in lazyaliasentry
    @util.propertycache
  File "/usr/local/Cellar/mercurial/4.9/lib/python2.7/site-packages/hgdemandimport/demandimportpy2.py", line 150, in __getattr__
    self._load()
  File "/usr/local/Cellar/mercurial/4.9/lib/python2.7/site-packages/hgdemandimport/demandimportpy2.py", line 94, in _load
    _origimport, head, globals, locals, None, level)
  File "/usr/local/Cellar/mercurial/4.9/lib/python2.7/site-packages/hgdemandimport/demandimportpy2.py", line 43, in _hgextimport
    return importfunc(name, globals, *args, **kwargs)
  File "/usr/local/Cellar/mercurial/4.9/lib/python2.7/site-packages/mercurial/util.py", line 180, in <module>
    'md5': hashlib.md5,
  File "/usr/local/Cellar/mercurial/4.9/lib/python2.7/site-packages/hgdemandimport/demandimportpy2.py", line 151, in __getattr__
    return getattr(self._module, attr)
AttributeError: 'module' object has no attribute 'md5'

I also tried following the instruction on this issue but none of the solutions seem to work

brew link openssl --force
Warning: Refusing to link macOS-provided software: openssl@1.1
If you need to have openssl@1.1 first in your PATH run:
  echo 'export PATH="/usr/local/opt/openssl@1.1/bin:$PATH"' >> ~/.zshrc

For compilers to find openssl@1.1 you may need to set:
  export LDFLAGS="-L/usr/local/opt/openssl@1.1/lib"
  export CPPFLAGS="-I/usr/local/opt/openssl@1.1/include"

For pkg-config to find openssl@1.1 you may need to set:
  export PKG_CONFIG_PATH="/usr/local/opt/openssl@1.1/lib/pkgconfig"

Answer

Running brew reinstall python@2 didn’t work for my existing Python 2.7 virtual environments. Inside them there were still ERROR:root:code for hash sha1 was not found errors.

I encountered this problem after I ran brew upgrade openssl. And here’s the fix:

$ ls /usr/local/Cellar/openssl

…which shows

1.0.2t

According to the existing version, run:

$ brew switch openssl 1.0.2t

…which shows

Cleaning /usr/local/Cellar/openssl/1.0.2t
Opt link created for /usr/local/Cellar/openssl/1.0.2t

After that, run the following command in a Python 2.7 virtualenv:

(my-venv) $ python -c "import hashlib;m=hashlib.md5();print(m.hexdigest())"

…which shows

d41d8cd98f00b204e9800998ecf8427e

No more errors.