Fix #2990: linkcheck raises "Can't convert 'bytes' object to str implicitly" error if linkcheck_anchors enabled

sphinx/builders/linkcheck.py

@@ -51,6 +51,7 @@ class AnchorCheckParser(HTMLParser):
         for key, value in attrs:
             if key in ('id', 'name') and value == self.search_anchor:
                 self.found = True
+                break
 
 
 def check_anchor(response, anchor):
@@ -61,7 +62,7 @@ def check_anchor(response, anchor):
     try:
         # Read file in chunks. If we find a matching anchor, we break
         # the loop early in hopes not to have to download the whole thing.
-        for chunk in response.iter_content():
+        for chunk in response.iter_content(chunk_size=4096, decode_unicode=True):
             parser.feed(chunk)
             if parser.found:
                 break

tests/roots/test-linkcheck/conf.py

@@ -0,0 +1,4 @@
+master_doc = 'links'
+source_suffix = '.txt'
+exclude_patterns = ['_build']
+linkcheck_anchors = True

tests/roots/test-linkcheck/links.txt

@@ -0,0 +1,4 @@
+This is from CPython documentation.
+
+* Also, if there is a `default namespace <https://www.w3.org/TR/2006/REC-xml-names-20060816/#defaulting>`__, that full URI gets prepended to all of the non-prefixed tags.
+* The `SSMEDIAN <https://help.gnome.org/users/gnumeric/stable/gnumeric.html#gnumeric-function-SSMEDIAN>`_ function in the Gnome Gnumeric spreadsheet.

tests/test_build_linkcheck.py

@@ -0,0 +1,25 @@
+# -*- coding: utf-8 -*-
+"""
+    test_build_linkcheck
+    ~~~~~~~~~~~~~~~~~~~~
+
+    Test the build process with manpage builder with the test root.
+
+    :copyright: Copyright 2007-2016 by the Sphinx team, see AUTHORS.
+    :license: BSD, see LICENSE for details.
+"""
+from __future__ import print_function
+
+from util import with_app
+
+
+@with_app('linkcheck', testroot='linkcheck', freshenv=True)
+def test_all(app, status, warning):
+    app.builder.build_all()
+
+    assert (app.outdir / 'output.txt').exists()
+    content = (app.outdir / 'output.txt').text()
+
+    # expect all ok
+    assert not content
+