7 files changed, 58 insertions, 8 deletions
diff --git a/lib/asn1/doc/src/notes.xml b/lib/asn1/doc/src/notes.xml
index 4d4600b3ab..e619408591 100644
--- a/lib/asn1/doc/src/notes.xml
+++ b/lib/asn1/doc/src/notes.xml
@@ -31,6 +31,27 @@
   <p>This document describes the changes made to the asn1 application.</p>
 
 
+<section><title>Asn1 2.0.1.1</title>
+
+    <section><title>Fixed Bugs and Malfunctions</title>
+      <list>
+        <item>
+	    <p>The generated decoder for the 'per' and 'uper'
+	    backends did not correctly decode ENUMERATEDs with a
+	    single value.</p>
+	    <p>The generated encoder for the 'per' and 'uper'
+	    backends generated an empty binary for a top-level type
+	    that did not need to be encoded (such as an ENUMERATED
+	    with a single value). The correct result should be a
+	    binary containing a 0 byte.</p>
+          <p>
+	    Own Id: OTP-10916 Aux Id: seq12270 </p>
+        </item>
+      </list>
+    </section>
+
+</section>
+
 <section><title>Asn1 2.0.1</title>
 
     <section><title>Fixed Bugs and Malfunctions</title>
diff --git a/lib/asn1/src/asn1ct_imm.erl b/lib/asn1/src/asn1ct_imm.erl
index 869bda5d52..4b2c3b1b65 100644
--- a/lib/asn1/src/asn1ct_imm.erl
+++ b/lib/asn1/src/asn1ct_imm.erl
@@ -61,6 +61,8 @@ optimize_alignment(Imm, Al) ->
 per_dec_boolean() ->
     {map,{get_bits,1,[1]},[{0,false},{1,true}]}.
 
+per_dec_enumerated([{V,_}], _Aligned) ->
+    {value,V};
 per_dec_enumerated(NamedList0, Aligned) ->
     Ub = length(NamedList0) - 1,
     Constraint = [{'ValueRange',{0,Ub}}],
@@ -375,6 +377,8 @@ opt_al({call,Fun,E0}, A0) ->
 opt_al({convert,Op,E0}, A0) ->
     {E,A} = opt_al(E0, A0),
     {{convert,Op,E},A};
+opt_al({value,V}=Term, A) when is_integer(V); is_atom(V) ->
+    {Term,A};
 opt_al({value,E0}, A0) ->
     {E,A} = opt_al(E0, A0),
     {{value,E},A};
@@ -391,8 +395,6 @@ opt_al({'case',Cs0}, A0) ->
 opt_al({map,E0,Cs}, A0) ->
     {E,A} = opt_al(E0, A0),
     {{map,E,Cs},A};
-opt_al('NULL'=Null, A) ->
-    {Null,A};
 opt_al(I, A) when is_integer(I) ->
     {I,A}.
 
@@ -480,8 +482,8 @@ flatten({map,E0,Cs0}, Buf0, St0) ->
     {Dst,St2} = new_var("Int", St1),
     Cs = flatten_map_cs(Cs0, E),
     {{Dst,DstBuf},Pre++[{'map',E,Cs,{Dst,DstBuf}}],St2};
-flatten({value,'NULL'}, Buf0, St0) ->
-    {{"'NULL'",Buf0},[],St0};
+flatten({value,V}, Buf0, St0) when is_atom(V) ->
+    {{"'"++atom_to_list(V)++"'",Buf0},[],St0};
 flatten({value,V0}, Buf0, St0) when is_integer(V0) ->
     {{V0,Buf0},[],St0};
 flatten({value,V0}, Buf0, St0) ->
diff --git a/lib/asn1/src/asn1rtt_per.erl b/lib/asn1/src/asn1rtt_per.erl
index 84ff809912..aa6cf4da0a 100644
--- a/lib/asn1/src/asn1rtt_per.erl
+++ b/lib/asn1/src/asn1rtt_per.erl
@@ -963,7 +963,10 @@ encode_relative_oid(Val) when is_list(Val) ->
 %%
 
 complete(L) ->
-    asn1rt_nif:encode_per_complete(L).
+    case asn1rt_nif:encode_per_complete(L) of
+	<<>> -> <<0>>;
+	Bin -> Bin
+    end.
 
 octets_to_complete(Len,Val) when Len < 256 ->
     [20,Len,Val];
diff --git a/lib/asn1/src/asn1rtt_uper.erl b/lib/asn1/src/asn1rtt_uper.erl
index ad0678f3c3..8efe9a7b0f 100644
--- a/lib/asn1/src/asn1rtt_uper.erl
+++ b/lib/asn1/src/asn1rtt_uper.erl
@@ -1016,8 +1016,11 @@ complete(InList) when is_list(InList) ->
 		Bits -> <<Res/bitstring,0:(8-Bits)>>
 	end
     end;
-complete(InList) when is_binary(InList) ->
-    InList;
+complete(Bin) when is_binary(Bin) ->
+    case Bin of
+	<<>> -> <<0>>;
+	_ -> Bin
+    end;
 complete(InList) when is_bitstring(InList) ->
     PadLen = 8 - (bit_size(InList) band 7),
     <<InList/bitstring,0:PadLen>>.
diff --git a/lib/asn1/test/asn1_SUITE_data/Prim.asn1 b/lib/asn1/test/asn1_SUITE_data/Prim.asn1
index 17a5d3490a..c3d54dbbb3 100644
--- a/lib/asn1/test/asn1_SUITE_data/Prim.asn1
+++ b/lib/asn1/test/asn1_SUITE_data/Prim.asn1
@@ -22,6 +22,8 @@ BEGIN
 
   Enum ::=  ENUMERATED {monday(1),tuesday(2),wednesday(3),thursday(4),
                         friday(5),saturday(6),sunday(7)}
+  SingleEnumVal ::= ENUMERATED {true}
+  SingleEnumValExt ::= ENUMERATED {true, ...}
 
   ObjId ::= OBJECT IDENTIFIER
   
@@ -35,4 +37,15 @@ BEGIN
 			base (2),
 			exponent (-125..128) } )
 
+  Seq ::= SEQUENCE {
+    n Null,
+    i1 INTEGER (0..63),
+    e1 SingleEnumVal,
+    i2 INTEGER (0..63),
+    e2 SingleEnumVal,
+    i3 INTEGER (0..63),
+    b Bool,
+    i4 INTEGER (0..63)
+  }    
+    
 END
diff --git a/lib/asn1/test/testPrim.erl b/lib/asn1/test/testPrim.erl
index 0d4427ba69..91fb9fffca 100644
--- a/lib/asn1/test/testPrim.erl
+++ b/lib/asn1/test/testPrim.erl
@@ -513,6 +513,14 @@ enum(Rules) ->
 		      case catch asn1_wrapper:encode('Prim','Enum',4) of Enum -> Enum end,
 		  ok
 	  end,
+
+    case Rules of
+	Per when Per =:= per; Per =:= uper ->
+	    {ok,<<0>>} = 'Prim':encode('SingleEnumVal', true),
+	    {ok,<<0>>} = 'Prim':encode('SingleEnumValExt', true);
+	ber ->
+	    ok
+    end,
     ok.
 
 
diff --git a/lib/asn1/vsn.mk b/lib/asn1/vsn.mk
index aaa060c806..3c4f3ff122 100644
--- a/lib/asn1/vsn.mk
+++ b/lib/asn1/vsn.mk
@@ -1,2 +1,2 @@
 #next version number to use is 2.0
-ASN1_VSN = 2.0.1
+ASN1_VSN = 2.0.1.1