bpo-36045: builtins.help() now prefixes async for async functions (GH-12010)

Previously, it was hard to tell whether a function should be awaited. It was also incorrect (per PEP 484) to put this in the type hint for coroutine functions. Added this info to the output of builtins.help and pydoc.


https://bugs.python.org/issue36045

Lib/pydoc.py

@@ -951,6 +951,12 @@ class HTMLDoc(Doc):
                 else:
                     note = ' unbound %s method' % self.classlink(imclass,mod)
 
+        if (inspect.iscoroutinefunction(object) or
+                inspect.isasyncgenfunction(object)):
+            asyncqualifier = 'async '
+        else:
+            asyncqualifier = ''
+
         if name == realname:
             title = '<a name="%s"><strong>%s</strong></a>' % (anchor, realname)
         else:
@@ -979,8 +985,8 @@ class HTMLDoc(Doc):
         if not argspec:
             argspec = '(...)'
 
-        decl = title + self.escape(argspec) + (note and self.grey(
-               '<font face="helvetica, arial">%s</font>' % note))
+        decl = asyncqualifier + title + self.escape(argspec) + (note and
+               self.grey('<font face="helvetica, arial">%s</font>' % note))
 
         if skipdocs:
             return '<dl><dt>%s</dt></dl>\n' % decl
@@ -1382,6 +1388,12 @@ location listed above.
                 else:
                     note = ' unbound %s method' % classname(imclass,mod)
 
+        if (inspect.iscoroutinefunction(object) or
+                inspect.isasyncgenfunction(object)):
+            asyncqualifier = 'async '
+        else:
+            asyncqualifier = ''
+
         if name == realname:
             title = self.bold(realname)
         else:
@@ -1405,7 +1417,7 @@ location listed above.
                     argspec = argspec[1:-1] # remove parentheses
         if not argspec:
             argspec = '(...)'
-        decl = title + argspec + note
+        decl = asyncqualifier + title + argspec + note
 
         if skipdocs:
             return decl + '\n'