importer: support {} format for arrays in CSV

Release note (sql change): Arrays can now be imported in a CSV file
using the {} format, similar to COPY FROM. Importing array expressions
(e.g. ARRAY[1, 2, 3]) is still supported as well.

pkg/sql/importer/import_stmt_test.go

@@ -702,6 +702,25 @@ ORDER BY table_name
 				},
 			},
 		},
+		{
+			name:   "array",
+			create: `a string, b string[]`,
+			typ:    "CSV",
+			data:   `cat,"{somevalue,anothervalue,anothervalue123}"`,
+			query: map[string][][]string{
+				`SELECT * from t`: {
+					{"cat", "{somevalue,anothervalue,anothervalue123}"},
+				},
+			},
+		},
+		{
+			name:     "array",
+			create:   `a string, b string[]`,
+			typ:      "CSV",
+			data:     `dog,{some,thing}`,
+			err:      "error parsing row 1: expected 2 fields, got 3",
+			rejected: "dog,{some,thing}\n",
+		},
 
 		// PG COPY
 		{

pkg/sql/importer/read_import_csv.go

@@ -221,11 +221,18 @@ func (c *csvRowConsumer) FillDatums(
 			var err error
 			conv.Datums[datumIdx], err = rowenc.ParseDatumStringAs(conv.VisibleColTypes[i], field.Val, conv.EvalCtx)
 			if err != nil {
-				col := conv.VisibleCols[i]
-				return newImportRowError(
-					errors.Wrapf(err, "parse %q as %s", col.GetName(), col.GetType().SQLString()),
-					strRecord(record, c.opts.Comma),
-					rowNum)
+				// Fallback to parsing as a string literal. This allows us to support
+				// both array expressions (like `ARRAY[1, 2, 3]`) and literals (like
+				// `{1, 2, 3}`).
+				var err2 error
+				conv.Datums[datumIdx], _, err2 = tree.ParseAndRequireString(conv.VisibleColTypes[i], field.Val, conv.EvalCtx)
+				if err2 != nil {
+					col := conv.VisibleCols[i]
+					return newImportRowError(
+						errors.Wrapf(errors.CombineErrors(err, err2), "parse %q as %s", col.GetName(), col.GetType().SQLString()),
+						strRecord(record, c.opts.Comma),
+						rowNum)
+				}
 			}
 		}
 		datumIdx++