diff --git a/.hgsigs b/.hgsigs
--- a/.hgsigs
+++ b/.hgsigs
@@ -204,3 +204,4 @@ f62bb5d07848ca598aa860a517394130b61bf2ee
 07731064ac41dacdf0ec869ebd05c2e848c14fbf 0 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
 0e06a7ab9e0d5c65af4e511aee1e0342998799df 0 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
 18c17d63fdabd009e70bf994e5efb7db422f4f7f 0 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
+1d5189a57405ceca5aa244052c9f948977f4699b 0 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
diff --git a/.hgtags b/.hgtags
--- a/.hgtags
+++ b/.hgtags
@@ -217,3 +217,4 @@ f62bb5d07848ca598aa860a517394130b61bf2ee
 07731064ac41dacdf0ec869ebd05c2e848c14fbf 5.5.2
 0e06a7ab9e0d5c65af4e511aee1e0342998799df 5.6rc0
 18c17d63fdabd009e70bf994e5efb7db422f4f7f 5.6
+1d5189a57405ceca5aa244052c9f948977f4699b 5.6.1
diff --git a/contrib/chg/chg.c b/contrib/chg/chg.c
--- a/contrib/chg/chg.c
+++ b/contrib/chg/chg.c
@@ -276,6 +276,7 @@ static void execcmdserver(const struct c
 		debugmsg("closing files based on /proc contents");
 		struct dirent *de;
 		while ((de = readdir(dp))) {
+			errno = 0;
 			char *end;
 			long fd_value = strtol(de->d_name, &end, 10);
 			if (end == de->d_name) {
@@ -288,7 +289,8 @@ static void execcmdserver(const struct c
 				         de->d_name);
 				continue;
 			}
-			if (fd_value > STDERR_FILENO) {
+			if (fd_value > STDERR_FILENO && fd_value != dirfd(dp)) {
+				debugmsg("closing fd %ld", fd_value);
 				int res = close(fd_value);
 				if (res) {
 					debugmsg("tried to close fd %ld: %d "
@@ -297,6 +299,7 @@ static void execcmdserver(const struct c
 				}
 			}
 		}
+		closedir(dp);
 	}
 
 	if (putenv("CHGINTERNALMARK=") != 0)
diff --git a/mercurial/patch.py b/mercurial/patch.py
--- a/mercurial/patch.py
+++ b/mercurial/patch.py
@@ -2730,8 +2730,8 @@ def diffsinglehunk(hunklines):
 def diffsinglehunkinline(hunklines):
     """yield tokens for a list of lines in a single hunk, with inline colors"""
     # prepare deleted, and inserted content
-    a = b''
-    b = b''
+    a = bytearray()
+    b = bytearray()
     for line in hunklines:
         if line[0:1] == b'-':
             a += line[1:]
@@ -2745,8 +2745,8 @@ def diffsinglehunkinline(hunklines):
             yield t
         return
     # re-split the content into words
-    al = wordsplitter.findall(a)
-    bl = wordsplitter.findall(b)
+    al = wordsplitter.findall(bytes(a))
+    bl = wordsplitter.findall(bytes(b))
     # re-arrange the words to lines since the diff algorithm is line-based
     aln = [s if s == b'\n' else s + b'\n' for s in al]
     bln = [s if s == b'\n' else s + b'\n' for s in bl]
diff --git a/mercurial/utils/procutil.py b/mercurial/utils/procutil.py
--- a/mercurial/utils/procutil.py
+++ b/mercurial/utils/procutil.py
@@ -656,7 +656,7 @@ if pycompat.iswindows:
                 stdin.seek(0)
 
             p = subprocess.Popen(
-                tonativestr(script),
+                pycompat.rapply(tonativestr, script),
                 shell=shell,
                 env=tonativeenv(env),
                 close_fds=True,