Using `sys.stdout` as argument breaks doc generation

[stmlange]

Expected Behavior

Doc generation works fine

Actual Behavior

python3.7 -m pdoc --html ./foo.py -o build/docs --force


Traceback (most recent call last):
  File "/usr/local/lib/python3.7/dist-packages/pdoc/__init__.py", line 122, in _render_template
    return t.render(**config).strip()
  File "/usr/lib/python3/dist-packages/mako/template.py", line 462, in render
    return runtime._render(self, self.callable_, args, data)
  File "/usr/lib/python3/dist-packages/mako/runtime.py", line 838, in _render
    **_kwargs_for_callable(callable_, data))
  File "/usr/lib/python3/dist-packages/mako/runtime.py", line 873, in _render_context
    _exec_template(inherit, lclcontext, args=args, kwargs=kwargs)
  File "/usr/lib/python3/dist-packages/mako/runtime.py", line 899, in _exec_template
    callable_(context, *args, **kwargs)
  File "/usr/local/lib/python3.7/dist-packages/pdoc/templates/html.mako", line 394, in render_body
    ${show_module(module)}
  File "/usr/local/lib/python3.7/dist-packages/pdoc/templates/html.mako", line 0, in show_module
    
  File "/usr/local/lib/python3.7/dist-packages/pdoc/templates/html.mako", line 160, in render_show_module
    ${show_func(f)}
  File "/usr/local/lib/python3.7/dist-packages/pdoc/templates/html.mako", line 101, in show_func
    <%
  File "/usr/local/lib/python3.7/dist-packages/pdoc/__init__.py", line 1085, in params
    return self._params(self.obj, annotate=annotate, link=link, module=self.module)
  File "/usr/local/lib/python3.7/dist-packages/pdoc/__init__.py", line 1137, in _params
    p = safe_default_value(p)
  File "/usr/local/lib/python3.7/dist-packages/pdoc/__init__.py", line 1110, in safe_default_value
    replacement = html.escape(replacement or p.default)
  File "/usr/lib/python3.7/html/__init__.py", line 19, in escape
    s = s.replace("&", "&amp;") # Must be done first!
AttributeError: '_io.TextIOWrapper' object has no attribute 'replace'

/usr/lib/python3/dist-packages/apport/report.py:13: DeprecationWarning: the imp module is deprecated in favour of importlib; see the module's documentation for alternative uses
  import fnmatch, glob, traceback, errno, sys, atexit, locale, imp
Traceback (most recent call last):
  File "/usr/lib/python3.7/runpy.py", line 193, in _run_module_as_main
    "__main__", mod_spec)
  File "/usr/lib/python3.7/runpy.py", line 85, in _run_code
    exec(code, run_globals)
  File "/usr/local/lib/python3.7/dist-packages/pdoc/__main__.py", line 6, in <module>
    main()
  File "/usr/local/lib/python3.7/dist-packages/pdoc/cli.py", line 489, in main
    write_files(module, ext='.html', **template_config)
  File "/usr/local/lib/python3.7/dist-packages/pdoc/cli.py", line 318, in write_files
    w.write(m.html(**kwargs))
  File "/usr/local/lib/python3.7/dist-packages/pdoc/__init__.py", line 686, in html
    html = _render_template('/html.mako', module=self, **kwargs)
  File "/usr/local/lib/python3.7/dist-packages/pdoc/__init__.py", line 122, in _render_template
    return t.render(**config).strip()
  File "/usr/lib/python3/dist-packages/mako/template.py", line 462, in render
    return runtime._render(self, self.callable_, args, data)
  File "/usr/lib/python3/dist-packages/mako/runtime.py", line 838, in _render
    **_kwargs_for_callable(callable_, data))
  File "/usr/lib/python3/dist-packages/mako/runtime.py", line 873, in _render_context
    _exec_template(inherit, lclcontext, args=args, kwargs=kwargs)
  File "/usr/lib/python3/dist-packages/mako/runtime.py", line 899, in _exec_template
    callable_(context, *args, **kwargs)
  File "_html_mako", line 127, in render_body
  File "_html_mako", line 30, in show_module
  File "_html_mako", line 396, in render_show_module
  File "_html_mako", line 311, in show_func
  File "/usr/local/lib/python3.7/dist-packages/pdoc/__init__.py", line 1085, in params
    return self._params(self.obj, annotate=annotate, link=link, module=self.module)
  File "/usr/local/lib/python3.7/dist-packages/pdoc/__init__.py", line 1137, in _params
    p = safe_default_value(p)
  File "/usr/local/lib/python3.7/dist-packages/pdoc/__init__.py", line 1110, in safe_default_value
    replacement = html.escape(replacement or p.default)
  File "/usr/lib/python3.7/html/__init__.py", line 19, in escape
    s = s.replace("&", "&amp;") # Must be done first!
AttributeError: '_io.TextIOWrapper' object has no attribute 'replace'
Error in sys.excepthook:
Traceback (most recent call last):
  File "/usr/lib/python3/dist-packages/apport_python_hook.py", line 63, in apport_excepthook
    from apport.fileutils import likely_packaged, get_recent_crashes
  File "/usr/lib/python3/dist-packages/apport/__init__.py", line 5, in <module>
    from apport.report import Report
  File "/usr/lib/python3/dist-packages/apport/report.py", line 30, in <module>
    import apport.fileutils
  File "/usr/lib/python3/dist-packages/apport/fileutils.py", line 23, in <module>
    from apport.packaging_impl import impl as packaging
  File "/usr/lib/python3/dist-packages/apport/packaging_impl.py", line 24, in <module>
    import apt
  File "/usr/lib/python3/dist-packages/apt/__init__.py", line 23, in <module>
    import apt_pkg
ModuleNotFoundError: No module named 'apt_pkg'

Original exception was:
Traceback (most recent call last):
  File "/usr/lib/python3.7/runpy.py", line 193, in _run_module_as_main
    "__main__", mod_spec)
  File "/usr/lib/python3.7/runpy.py", line 85, in _run_code
    exec(code, run_globals)
  File "/usr/local/lib/python3.7/dist-packages/pdoc/__main__.py", line 6, in <module>
    main()
  File "/usr/local/lib/python3.7/dist-packages/pdoc/cli.py", line 489, in main
    write_files(module, ext='.html', **template_config)
  File "/usr/local/lib/python3.7/dist-packages/pdoc/cli.py", line 318, in write_files
    w.write(m.html(**kwargs))
  File "/usr/local/lib/python3.7/dist-packages/pdoc/__init__.py", line 686, in html
    html = _render_template('/html.mako', module=self, **kwargs)
  File "/usr/local/lib/python3.7/dist-packages/pdoc/__init__.py", line 122, in _render_template
    return t.render(**config).strip()
  File "/usr/lib/python3/dist-packages/mako/template.py", line 462, in render
    return runtime._render(self, self.callable_, args, data)
  File "/usr/lib/python3/dist-packages/mako/runtime.py", line 838, in _render
    **_kwargs_for_callable(callable_, data))
  File "/usr/lib/python3/dist-packages/mako/runtime.py", line 873, in _render_context
    _exec_template(inherit, lclcontext, args=args, kwargs=kwargs)
  File "/usr/lib/python3/dist-packages/mako/runtime.py", line 899, in _exec_template
    callable_(context, *args, **kwargs)
  File "_html_mako", line 127, in render_body
  File "_html_mako", line 30, in show_module
  File "_html_mako", line 396, in render_show_module
  File "_html_mako", line 311, in show_func
  File "/usr/local/lib/python3.7/dist-packages/pdoc/__init__.py", line 1085, in params
    return self._params(self.obj, annotate=annotate, link=link, module=self.module)
  File "/usr/local/lib/python3.7/dist-packages/pdoc/__init__.py", line 1137, in _params
    p = safe_default_value(p)
  File "/usr/local/lib/python3.7/dist-packages/pdoc/__init__.py", line 1110, in safe_default_value
    replacement = html.escape(replacement or p.default)
  File "/usr/lib/python3.7/html/__init__.py", line 19, in escape
    s = s.replace("&", "&amp;") # Must be done first!
AttributeError: '_io.TextIOWrapper' object has no attribute 'replace'

Steps to Reproduce

1. create foo.py with the following content:

# -*- coding: utf-8 -*-
import sys


def sample(output=sys.stdout, content="┬──┬ ノ( ゜-゜ノ)\n"):
    output.write("%s\n" % (content * 100))


sample()

The offender seems to be declaring output=sys.stdout.

2. run python3.7 -m pdoc --html ./foo.py -o build/docs --force

Additional info

• pdoc version:

$ python3.7 -m pdoc --version
__main__.py 0.7.1
$ python3.7 --version
Python 3.7.3

• sounds similar to dataclasses.field breaks doc generation #116

[kernc]

• sounds similar to dataclasses.field breaks doc generation #116

It does. Can you confirm it also gets fixed by the same proposed solution?
Though it might look better to special-case sys.stdout (and friends) like os.environ is.

pdoc/pdoc/__init__.py

Lines 1100 to 1101 in 1b644f6

	if p.default is os.environ:
	replacement = 'os.environ'

[stmlange]

Thanks for the quick feedback and the pointer!

Indeed adding a special sys.stdout case to /usr/local/lib/python3.7/dist-packages/pdoc/__init__.py seems to fix the issue.

e.g.

replacement = None
if p.default is os.environ:
     replacement = 'os.environ'
elif p.default is sys.stdout:
     replacement = 'sys.stdout'

makes python3.7 -m pdoc --html ./foo.py -o build/docs --force work.