restore pre-merge working set on merge --abort

bats/merge.bats

@@ -10,8 +10,6 @@ CREATE TABLE test1 (
   c2 int,
   PRIMARY KEY (pk)
 );
-SQL
-    dolt sql <<SQL
 CREATE TABLE test2 (
   pk int NOT NULL,
   c1 int,
@@ -66,6 +64,30 @@ teardown() {
     [[ "$output" =~ "add pk 1 to test1" ]] || false
 }
 
+@test "merge --abort restores working changes" {
+    dolt branch other
+
+    dolt sql -q "INSERT INTO test1 VALUES (0,10,10),(1,11,11);"
+    dolt commit -am "added rows to test1 on master"
+
+    dolt checkout other
+    dolt sql -q "INSERT INTO test1 VALUES (0,20,20),(1,21,21);"
+    dolt commit -am "added rows to test1 on other"
+
+    dolt checkout master
+    # dirty the working set with changes to test2
+    dolt sql -q "INSERT INTO test2 VALUES (9,9,9);"
+
+    dolt merge other
+    dolt merge --abort
+
+    # per Git, working set changes to test2 should remain
+    dolt sql -q "SELECT * FROM test2" -r csv
+    run dolt sql -q "SELECT * FROM test2" -r csv
+    [ "$status" -eq 0 ]
+    [[ "${lines[1]}" =~ "9,9,9" ]] || false
+}
+
 @test "squash merge" {
     dolt checkout -b merge_branch
     dolt SQL -q "INSERT INTO test1 values (0,1,2)"

go/cmd/dolt/commands/merge.go

@@ -132,7 +132,7 @@ func abortMerge(ctx context.Context, doltEnv *env.DoltEnv) errhand.VerboseError
 	err := actions.CheckoutAllTables(ctx, doltEnv.DbData())
 
 	if err == nil {
-		err = doltEnv.RepoState.ClearMerge(doltEnv.FS)
+		err = doltEnv.RepoState.AbortMerge(doltEnv.FS)
 
 		if err == nil {
 			return nil

go/libraries/doltcore/env/environment.go

@@ -427,9 +427,14 @@ func (r *repoStateWriter) SetCWBHeadRef(ctx context.Context, marshalableRef ref.
 	return nil
 }
 
+func (r *repoStateWriter) AbortMerge() error {
+	return r.dEnv.RepoState.AbortMerge(r.dEnv.FS)
+}
+
 func (r *repoStateWriter) ClearMerge() error {
 	return r.dEnv.RepoState.ClearMerge(r.dEnv.FS)
 }
+
 func (r *repoStateWriter) StartMerge(commitStr string) error {
 	return r.dEnv.RepoState.StartMerge(commitStr, r.dEnv.FS)
 }

go/libraries/doltcore/env/repo_state.go

@@ -41,6 +41,7 @@ type RepoStateWriter interface {
 	SetStagedHash(context.Context, hash.Hash) error
 	SetWorkingHash(context.Context, hash.Hash) error
 	SetCWBHeadRef(context.Context, ref.MarshalableRef) error
+	AbortMerge() error
 	ClearMerge() error
 	StartMerge(commitStr string) error
 }

go/libraries/doltcore/sqle/dfunctions/dolt_merge.go

@@ -155,7 +155,7 @@ func abortMerge(ctx *sql.Context, dbData env.DbData) error {
 		return err
 	}
 
-	err = dbData.Rsw.ClearMerge()
+	err = dbData.Rsw.AbortMerge()
 	if err != nil {
 		return err
 	}