diff --git a/hgext/convert/subversion.py b/hgext/convert/subversion.py
--- a/hgext/convert/subversion.py
+++ b/hgext/convert/subversion.py
@@ -197,7 +197,7 @@ def issvnurl(ui, url):
         proto = 'file'
         path = os.path.abspath(url)
     if proto == 'file':
-        path = path.replace(os.sep, '/')
+        path = util.pconvert(path)
     check = protomap.get(proto, lambda *args: False)
     while '/' in path:
         if check(ui, path, proto):
diff --git a/hgext/largefiles/lfutil.py b/hgext/largefiles/lfutil.py
--- a/hgext/largefiles/lfutil.py
+++ b/hgext/largefiles/lfutil.py
@@ -303,7 +303,7 @@ def standin(filename):
     # 2) Join with '/' because that's what dirstate always uses, even on
     #    Windows. Change existing separator to '/' first in case we are
     #    passed filenames from an external source (like the command line).
-    return shortname + '/' + filename.replace(os.sep, '/')
+    return shortname + '/' + util.pconvert(filename)
 
 def isstandin(filename):
     '''Return true if filename is a big file standin. filename must be
@@ -314,7 +314,7 @@ def splitstandin(filename):
     # Split on / because that's what dirstate always uses, even on Windows.
     # Change local separator to / first just in case we are passed filenames
     # from an external source (like the command line).
-    bits = filename.replace(os.sep, '/').split('/', 1)
+    bits = util.pconvert(filename).split('/', 1)
     if len(bits) == 2 and bits[0] == shortname:
         return bits[1]
     else:
@@ -433,7 +433,7 @@ def httpsendfile(ui, filename):
 
 def unixpath(path):
     '''Return a version of path normalized for use with the lfdirstate.'''
-    return os.path.normpath(path).replace(os.sep, '/')
+    return util.pconvert(os.path.normpath(path))
 
 def islfilesrepo(repo):
     return ('largefiles' in repo.requirements and
diff --git a/mercurial/bdiff.c b/mercurial/bdiff.c
--- a/mercurial/bdiff.c
+++ b/mercurial/bdiff.c
@@ -443,7 +443,7 @@ static PyObject *fixws(PyObject *self, P
 	r = PyBytes_AsString(s);
 	rlen = PyBytes_Size(s);
 
-	w = (char *)malloc(rlen);
+	w = (char *)malloc(rlen ? rlen : 1);
 	if (!w)
 		goto nomem;
 
diff --git a/mercurial/cmdutil.py b/mercurial/cmdutil.py
--- a/mercurial/cmdutil.py
+++ b/mercurial/cmdutil.py
@@ -1224,8 +1224,8 @@ def forget(ui, repo, match, prefix, expl
             ui.status(_("skipping missing subrepository: %s\n")
                            % join(subpath))
 
-    for f in match.files():
-        if match.exact(f) or not explicitonly:
+    if not explicitonly:
+        for f in match.files():
             if f not in repo.dirstate and not os.path.isdir(match.rel(join(f))):
                 if f not in forgot:
                     if os.path.exists(match.rel(join(f))):
diff --git a/mercurial/scmutil.py b/mercurial/scmutil.py
--- a/mercurial/scmutil.py
+++ b/mercurial/scmutil.py
@@ -468,7 +468,7 @@ else:
                                _HKEY_LOCAL_MACHINE)
         if not isinstance(value, str) or not value:
             return rcpath
-        value = value.replace('/', os.sep)
+        value = util.localpath(value)
         for p in value.split(os.pathsep):
             if p.lower().endswith('mercurial.ini'):
                 rcpath.append(p)
diff --git a/tests/test-check-code-hg.t b/tests/test-check-code-hg.t
--- a/tests/test-check-code-hg.t
+++ b/tests/test-check-code-hg.t
@@ -1,9 +1,9 @@
   $ check_code="$TESTDIR"/../contrib/check-code.py
   $ cd "$TESTDIR"/..
 
-  $ "$check_code" `hg manifest` || echo 'FAILURE IS NOT AN OPTION!!!'
+  $ hg manifest | xargs "$check_code" || echo 'FAILURE IS NOT AN OPTION!!!'
 
-  $ "$check_code" --warnings --nolineno --per-file=0 `hg manifest`
+  $ hg manifest | xargs "$check_code" --warnings --nolineno --per-file=0
   contrib/check-code.py:0:
    > #    (r'^\s+[^_ \n][^_. \n]+_[^_\n]+\s*=', "don't use underbars in identifiers"),
    warning: line over 80 characters
@@ -654,4 +654,4 @@
   tests/test-walkrepo.py:0:
    >         print "Found %d repositories when I should have found 3" % (len(reposet),)
    warning: line over 80 characters
-  [1]
+  [123]
diff --git a/tests/test-subrepo-recursion.t b/tests/test-subrepo-recursion.t
--- a/tests/test-subrepo-recursion.t
+++ b/tests/test-subrepo-recursion.t
@@ -193,10 +193,14 @@ Test explicit path commands within subre
   $ hg add foo/bar/z2.txt
   $ hg status -S
   A foo/bar/z2.txt
-This is expected to forget the file, but is currently broken
   $ hg forget foo/bar/z2.txt
   $ hg status -S
   ? foo/bar/z2.txt
+  $ hg forget foo/bar/z2.txt
+  not removing foo/bar/z2.txt: file is already untracked
+  [1]
+  $ hg status -S
+  ? foo/bar/z2.txt
   $ rm foo/bar/z2.txt
 
 Log with the relationships between repo and its subrepo: