From fd0cecaf9945e0c9eb8fedaec5dad28f701ec151 Mon Sep 17 00:00:00 2001
From: Javier Alvarado <javier@dgraph.io>
Date: Wed, 23 Jan 2019 14:50:36 -0800
Subject: [PATCH 1/2] Add angle brackets to more exported predicates.

---
 worker/export.go | 18 +++++++++++++++++-
 1 file changed, 17 insertions(+), 1 deletion(-)

diff --git a/worker/export.go b/worker/export.go
index 424c02e81f6..4385a7d8b51 100644
--- a/worker/export.go
+++ b/worker/export.go
@@ -27,6 +27,7 @@ import (
 	"strconv"
 	"strings"
 	"time"
+	"unicode"
 
 	"github.com/golang/glog"
 	"golang.org/x/net/context"
@@ -54,6 +55,18 @@ var rdfTypeMap = map[types.TypeID]string{
 	types.PasswordID: "xs:password",
 }
 
+// Having '<' and '>' around all predicates makes the exported schema harder
+// for humans to look at, so only put them on predicates containing "exotic"
+// characters (i.e. ones not in this list).
+var predNonSpecialChars = unicode.RangeTable{
+	R16: []unicode.Range16{
+		unicode.Range16{'.', '.', 1},
+		unicode.Range16{'0', '9', 1},
+		unicode.Range16{'A', 'Z', 1},
+		unicode.Range16{'a', 'z', 1},
+	},
+}
+
 func toRDF(pl *posting.List, prefix string, readTs uint64) (*bpb.KVList, error) {
 	var buf bytes.Buffer
 
@@ -142,7 +155,10 @@ func toRDF(pl *posting.List, prefix string, readTs uint64) (*bpb.KVList, error)
 func toSchema(attr string, update pb.SchemaUpdate) (*bpb.KVList, error) {
 	// bytes.Buffer never returns error for any of the writes. So, we don't need to check them.
 	var buf bytes.Buffer
-	if strings.ContainsRune(attr, ':') {
+	isSpecial := func(r rune) bool {
+		return !(unicode.In(r, &predNonSpecialChars))
+	}
+	if strings.IndexFunc(attr, isSpecial) >= 0 {
 		buf.WriteRune('<')
 		buf.WriteString(attr)
 		buf.WriteRune('>')

From 6219093c27ef3950349a1b857e17002106916df4 Mon Sep 17 00:00:00 2001
From: Javier Alvarado <javier@dgraph.io>
Date: Wed, 23 Jan 2019 15:23:55 -0800
Subject: [PATCH 2/2] Add more predicate export tests.

---
 worker/export.go      |  2 ++
 worker/export_test.go | 75 +++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 77 insertions(+)

diff --git a/worker/export.go b/worker/export.go
index 4385a7d8b51..9d9c7c76896 100644
--- a/worker/export.go
+++ b/worker/export.go
@@ -60,9 +60,11 @@ var rdfTypeMap = map[types.TypeID]string{
 // characters (i.e. ones not in this list).
 var predNonSpecialChars = unicode.RangeTable{
 	R16: []unicode.Range16{
+		// Ranges must be in order.
 		unicode.Range16{'.', '.', 1},
 		unicode.Range16{'0', '9', 1},
 		unicode.Range16{'A', 'Z', 1},
+		unicode.Range16{'_', '_', 1},
 		unicode.Range16{'a', 'z', 1},
 	},
 }
diff --git a/worker/export_test.go b/worker/export_test.go
index 75d5630659e..7469901a7bf 100644
--- a/worker/export_test.go
+++ b/worker/export_test.go
@@ -273,6 +273,81 @@ func TestToSchema(t *testing.T) {
 			},
 			expected: "<Alice:best>:string @reverse @lang . \n",
 		},
+		{
+			skv: &skv{
+				attr: "username/password",
+				schema: pb.SchemaUpdate{
+					Predicate: "",
+					ValueType: pb.Posting_STRING,
+					Directive: pb.SchemaUpdate_NONE,
+					List:      false,
+					Count:     false,
+					Upsert:    false,
+					Lang:      false,
+				},
+			},
+			expected: "<username/password>:string . \n",
+		},
+		{
+			skv: &skv{
+				attr: "B*-tree",
+				schema: pb.SchemaUpdate{
+					Predicate: "",
+					ValueType: pb.Posting_UID,
+					Directive: pb.SchemaUpdate_REVERSE,
+					List:      true,
+					Count:     false,
+					Upsert:    false,
+					Lang:      false,
+				},
+			},
+			expected: "<B*-tree>:[uid] @reverse . \n",
+		},
+		{
+			skv: &skv{
+				attr: "base_de_données",
+				schema: pb.SchemaUpdate{
+					Predicate: "",
+					ValueType: pb.Posting_STRING,
+					Directive: pb.SchemaUpdate_NONE,
+					List:      false,
+					Count:     false,
+					Upsert:    false,
+					Lang:      true,
+				},
+			},
+			expected: "<base_de_données>:string @lang . \n",
+		},
+		{
+			skv: &skv{
+				attr: "data_base",
+				schema: pb.SchemaUpdate{
+					Predicate: "",
+					ValueType: pb.Posting_STRING,
+					Directive: pb.SchemaUpdate_NONE,
+					List:      false,
+					Count:     false,
+					Upsert:    false,
+					Lang:      true,
+				},
+			},
+			expected: "data_base:string @lang . \n",
+		},
+		{
+			skv: &skv{
+				attr: "data.base",
+				schema: pb.SchemaUpdate{
+					Predicate: "",
+					ValueType: pb.Posting_STRING,
+					Directive: pb.SchemaUpdate_NONE,
+					List:      false,
+					Count:     false,
+					Upsert:    false,
+					Lang:      true,
+				},
+			},
+			expected: "data.base:string @lang . \n",
+		},
 	}
 	for _, testCase := range testCases {
 		list, err := toSchema(testCase.skv.attr, testCase.skv.schema)