Fix diff blob excerpt expansion (#35922)

And add comments and tests
2025-12-07 13:28:25 +00:00 · 2025-11-14 12:50:48 +08:00
parent d6dc531d4b
commit 0fb3be7f0e
3 changed files with 171 additions and 33 deletions
--- a/services/gitdiff/gitdiff_test.go
+++ b/services/gitdiff/gitdiff_test.go
@@ -983,3 +983,126 @@ func TestDiffLine_RenderBlobExcerptButtons(t *testing.T) {
 		})
 	}
 }
+
+func TestDiffLine_GetExpandDirection(t *testing.T) {
+	cases := []struct {
+		name      string
+		diffLine  *DiffLine
+		direction string
+	}{
+		{
+			name:      "NotSectionLine",
+			diffLine:  &DiffLine{Type: DiffLineAdd, SectionInfo: &DiffLineSectionInfo{}},
+			direction: "",
+		},
+		{
+			name:      "NilSectionInfo",
+			diffLine:  &DiffLine{Type: DiffLineSection, SectionInfo: nil},
+			direction: "",
+		},
+		{
+			name: "NoHiddenLines",
+			// last block stops at line 100, next block starts at line 101, so no hidden lines, no expansion.
+			diffLine: &DiffLine{
+				Type: DiffLineSection,
+				SectionInfo: &DiffLineSectionInfo{
+					LastRightIdx: 100,
+					LastLeftIdx:  100,
+					RightIdx:     101,
+					LeftIdx:      101,
+				},
+			},
+			direction: "",
+		},
+		{
+			name: "FileHead",
+			diffLine: &DiffLine{
+				Type: DiffLineSection,
+				SectionInfo: &DiffLineSectionInfo{
+					LastRightIdx: 0, // LastXxxIdx = 0 means this is the first section in the file.
+					LastLeftIdx:  0,
+					RightIdx:     1,
+					LeftIdx:      1,
+				},
+			},
+			direction: "",
+		},
+		{
+			name: "FileHeadHiddenLines",
+			diffLine: &DiffLine{
+				Type: DiffLineSection,
+				SectionInfo: &DiffLineSectionInfo{
+					LastRightIdx: 0,
+					LastLeftIdx:  0,
+					RightIdx:     101,
+					LeftIdx:      101,
+				},
+			},
+			direction: "up",
+		},
+		{
+			name: "HiddenSingleHunk",
+			diffLine: &DiffLine{
+				Type: DiffLineSection,
+				SectionInfo: &DiffLineSectionInfo{
+					LastRightIdx:  100,
+					LastLeftIdx:   100,
+					RightIdx:      102,
+					LeftIdx:       102,
+					RightHunkSize: 1234, // non-zero dummy value
+					LeftHunkSize:  5678, // non-zero dummy value
+				},
+			},
+			direction: "single",
+		},
+		{
+			name: "HiddenSingleFullHunk",
+			// the hidden lines can exactly fit into one hunk
+			diffLine: &DiffLine{
+				Type: DiffLineSection,
+				SectionInfo: &DiffLineSectionInfo{
+					LastRightIdx:  100,
+					LastLeftIdx:   100,
+					RightIdx:      100 + BlobExcerptChunkSize + 1,
+					LeftIdx:       100 + BlobExcerptChunkSize + 1,
+					RightHunkSize: 1234, // non-zero dummy value
+					LeftHunkSize:  5678, // non-zero dummy value
+				},
+			},
+			direction: "single",
+		},
+		{
+			name: "HiddenUpDownHunks",
+			diffLine: &DiffLine{
+				Type: DiffLineSection,
+				SectionInfo: &DiffLineSectionInfo{
+					LastRightIdx:  100,
+					LastLeftIdx:   100,
+					RightIdx:      100 + BlobExcerptChunkSize + 2,
+					LeftIdx:       100 + BlobExcerptChunkSize + 2,
+					RightHunkSize: 1234, // non-zero dummy value
+					LeftHunkSize:  5678, // non-zero dummy value
+				},
+			},
+			direction: "updown",
+		},
+		{
+			name: "FileTail",
+			diffLine: &DiffLine{
+				Type: DiffLineSection,
+				SectionInfo: &DiffLineSectionInfo{
+					LastRightIdx:  100,
+					LastLeftIdx:   100,
+					RightIdx:      102,
+					LeftIdx:       102,
+					RightHunkSize: 0,
+					LeftHunkSize:  0,
+				},
+			},
+			direction: "down",
+		},
+	}
+	for _, c := range cases {
+		assert.Equal(t, c.direction, c.diffLine.GetExpandDirection(), "case %s expected direction: %s", c.name, c.direction)
+	}
+}