Prevent NPE in CSV diff rendering when column removed (#17018) (#17377)

Backport of #17018

Fixes #16837 if a column is deleted.

services/gitdiff/csv_test.go

@@ -19,9 +19,9 @@ func TestCSVDiff(t *testing.T) {
 		diff  string
 		base  string
 		head  string
-		cells [][2]TableDiffCellType
+		cells [][]TableDiffCellType
 	}{
-		// case 0
+		// case 0 - initial commit of a csv
 		{
 			diff: `diff --git a/unittest.csv b/unittest.csv
 --- a/unittest.csv
@@ -29,11 +29,14 @@ func TestCSVDiff(t *testing.T) {
 @@ -0,0 +1,2 @@
 +col1,col2
 +a,a`,
-			base:  "",
-			head:  "col1,col2\na,a",
-			cells: [][2]TableDiffCellType{{TableDiffCellAdd, TableDiffCellAdd}, {TableDiffCellAdd, TableDiffCellAdd}},
+			base: "",
+			head: `col1,col2
+a,a`,
+			cells: [][]TableDiffCellType{
+				{TableDiffCellAdd, TableDiffCellAdd},
+				{TableDiffCellAdd, TableDiffCellAdd}},
 		},
-		// case 1
+		// case 1 - adding 1 row at end
 		{
 			diff: `diff --git a/unittest.csv b/unittest.csv
 --- a/unittest.csv
@@ -43,11 +46,17 @@ func TestCSVDiff(t *testing.T) {
 -a,a
 +a,a
 +b,b`,
-			base:  "col1,col2\na,a",
-			head:  "col1,col2\na,a\nb,b",
-			cells: [][2]TableDiffCellType{{TableDiffCellEqual, TableDiffCellEqual}, {TableDiffCellEqual, TableDiffCellEqual}, {TableDiffCellAdd, TableDiffCellAdd}},
+			base: `col1,col2
+a,a`,
+			head: `col1,col2
+a,a
+b,b`,
+			cells: [][]TableDiffCellType{
+				{TableDiffCellUnchanged, TableDiffCellUnchanged}, {TableDiffCellUnchanged, TableDiffCellUnchanged},
+				{TableDiffCellAdd, TableDiffCellAdd},
+			},
 		},
-		// case 2
+		// case 2 - row deleted
 		{
 			diff: `diff --git a/unittest.csv b/unittest.csv
 --- a/unittest.csv
@@ -56,11 +65,17 @@ func TestCSVDiff(t *testing.T) {
  col1,col2
 -a,a
  b,b`,
-			base:  "col1,col2\na,a\nb,b",
-			head:  "col1,col2\nb,b",
-			cells: [][2]TableDiffCellType{{TableDiffCellEqual, TableDiffCellEqual}, {TableDiffCellDel, TableDiffCellDel}, {TableDiffCellEqual, TableDiffCellEqual}},
+			base: `col1,col2
+a,a
+b,b`,
+			head: `col1,col2
+b,b`,
+			cells: [][]TableDiffCellType{
+				{TableDiffCellUnchanged, TableDiffCellUnchanged}, {TableDiffCellDel, TableDiffCellDel},
+				{TableDiffCellUnchanged, TableDiffCellUnchanged},
+			},
 		},
-		// case 3
+		// case 3 - row changed
 		{
 			diff: `diff --git a/unittest.csv b/unittest.csv
 --- a/unittest.csv
@@ -69,11 +84,16 @@ func TestCSVDiff(t *testing.T) {
  col1,col2
 -b,b
 +b,c`,
-			base:  "col1,col2\nb,b",
-			head:  "col1,col2\nb,c",
-			cells: [][2]TableDiffCellType{{TableDiffCellEqual, TableDiffCellEqual}, {TableDiffCellEqual, TableDiffCellChanged}},
+			base: `col1,col2
+b,b`,
+			head: `col1,col2
+b,c`,
+			cells: [][]TableDiffCellType{
+				{TableDiffCellUnchanged, TableDiffCellUnchanged},
+				{TableDiffCellUnchanged, TableDiffCellChanged},
+			},
 		},
-		// case 4
+		// case 4 - all deleted
 		{
 			diff: `diff --git a/unittest.csv b/unittest.csv
 --- a/unittest.csv
@@ -81,9 +101,88 @@ func TestCSVDiff(t *testing.T) {
 @@ -1,2 +0,0 @@
 -col1,col2
 -b,c`,
-			base:  "col1,col2\nb,c",
-			head:  "",
-			cells: [][2]TableDiffCellType{{TableDiffCellDel, TableDiffCellDel}, {TableDiffCellDel, TableDiffCellDel}},
+			base: `col1,col2
+b,c`,
+			head: "",
+			cells: [][]TableDiffCellType{
+				{TableDiffCellDel, TableDiffCellDel},
+				{TableDiffCellDel, TableDiffCellDel},
+			},
+		},
+		// case 5 - renames first column
+		{
+			diff: `diff --git a/unittest.csv b/unittest.csv
+--- a/unittest.csv
++++ b/unittest.csv
+@@ -1,3 +1,3 @@
+-col1,col2,col3
++cola,col2,col3
+ a,b,c`,
+			base: `col1,col2,col3
+a,b,c`,
+			head: `cola,col2,col3
+a,b,c`,
+			cells: [][]TableDiffCellType{
+				{TableDiffCellDel, TableDiffCellAdd, TableDiffCellUnchanged, TableDiffCellUnchanged},
+				{TableDiffCellDel, TableDiffCellAdd, TableDiffCellUnchanged, TableDiffCellUnchanged},
+			},
+		},
+		// case 6 - inserts a column after first, deletes last column
+		{
+			diff: `diff --git a/unittest.csv b/unittest.csv
+--- a/unittest.csv
++++ b/unittest.csv
+@@ -1,2 +1,2 @@
+-col1,col2,col3
+-a,b,c
++col1,col1a,col2
++a,d,b`,
+			base: `col1,col2,col3
+a,b,c`,
+			head: `col1,col1a,col2
+a,d,b`,
+			cells: [][]TableDiffCellType{
+				{TableDiffCellUnchanged, TableDiffCellAdd, TableDiffCellDel, TableDiffCellMovedUnchanged},
+				{TableDiffCellUnchanged, TableDiffCellAdd, TableDiffCellDel, TableDiffCellMovedUnchanged},
+			},
+		},
+		// case 7 - deletes first column, inserts column after last
+		{
+			diff: `diff --git a/unittest.csv b/unittest.csv
+--- a/unittest.csv
++++ b/unittest.csv
+@@ -1,2 +1,2 @@
+-col1,col2,col3
+-a,b,c
++col2,col3,col4
++b,c,d`,
+			base: `col1,col2,col3
+a,b,c`,
+			head: `col2,col3,col4
+b,c,d`,
+			cells: [][]TableDiffCellType{
+				{TableDiffCellDel, TableDiffCellUnchanged, TableDiffCellUnchanged, TableDiffCellAdd},
+				{TableDiffCellDel, TableDiffCellUnchanged, TableDiffCellUnchanged, TableDiffCellAdd},
+			},
+		},
+		// case 8 - two columns deleted, 2 added
+		{
+			diff: `diff --git a/unittest.csv b/unittest.csv
+--- a/unittest.csv
++++ b/unittest.csv
+@@ -1,2 +1,2 @@
+-col1,col2,col
+-a,b,c
++col3,col4,col5
++c,d,e`,
+			base: `col1,col2,col3
+a,b,c`,
+			head: `col3,col4,col5
+c,d,e`,
+			cells: [][]TableDiffCellType{
+				{TableDiffCellDel, TableDiffCellMovedUnchanged, TableDiffCellDel, TableDiffCellAdd, TableDiffCellAdd},
+				{TableDiffCellDel, TableDiffCellMovedUnchanged, TableDiffCellDel, TableDiffCellAdd, TableDiffCellAdd},
+			},
 		},
 	}
 
@@ -116,7 +215,7 @@ func TestCSVDiff(t *testing.T) {
 		assert.Len(t, section.Rows, len(c.cells), "case %d: should be %d rows", n, len(c.cells))
 
 		for i, row := range section.Rows {
-			assert.Len(t, row.Cells, 2, "case %d: row %d should have two cells", n, i)
+			assert.Len(t, row.Cells, len(c.cells[i]), "case %d: row %d should have %d cells", n, i, len(c.cells[i]))
 			for j, cell := range row.Cells {
 				assert.Equal(t, c.cells[i][j], cell.Type, "case %d: row %d cell %d should be equal", n, i, j)
 			}