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vole
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A free and open-source forge that lives in your Git repo.

Code

395 commit(s) on main

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update readme Keenan Nemetz · 30m ago 32290114
history blame raw 7.8 KiB
1package git
2
3import (
4 "bytes"
5 "fmt"
6 "os"
7 "path/filepath"
8 "strings"
9 "testing"
10)
11
12// TestBlobIDMatchesGit pins the one piece of object formatting this package does
13// itself. It only decides whether a blob needs writing; git still writes it.
14func TestBlobIDMatchesGit(t *testing.T) {
15 g := blobRepo(t, nil)
16 for _, content := range [][]byte{
17 nil,
18 {},
19 []byte("hello\n"),
20 {0, 1, 2, 255, '\n', 0},
21 bytes.Repeat([]byte("0123456789abcdef"), 4096),
22 } {
23 want, err := g.HashObject(content)
24 if err != nil {
25 t.Fatal(err)
26 }
27 if got := blobID(content, false); got != want {
28 t.Fatalf("blobID(%d bytes) = %s, want %s", len(content), got, want)
29 }
30 }
31}
32
33// TestBlobsBySHABinary pins the batch framing: content may contain newlines and
34// NULs, an empty blob still has a header, and asking for the same object twice
35// answers twice.
36func TestBlobsBySHABinary(t *testing.T) {
37 files := map[string][]byte{
38 "empty": {},
39 "nul": {0, '\n', 0, 255},
40 "newlines": []byte("\n\n\n"),
41 "text": []byte("no trailing newline"),
42 }
43 g := blobRepo(t, files)
44 head, err := g.RevParse("refs/heads/main")
45 if err != nil {
46 t.Fatal(err)
47 }
48 entries, err := g.LsTree(head)
49 if err != nil {
50 t.Fatal(err)
51 }
52 shas := make([]string, 0, len(entries))
53 for _, e := range entries {
54 shas = append(shas, e.SHA)
55 }
56 blobs, err := g.BlobsBySHA(append(shas, shas...))
57 if err != nil {
58 t.Fatal(err)
59 }
60 if len(blobs) != len(entries) {
61 t.Fatalf("BlobsBySHA returned %d objects, want %d", len(blobs), len(entries))
62 }
63 for _, e := range entries {
64 if !bytes.Equal(blobs[e.SHA], files[e.Name]) {
65 t.Fatalf("%s = %q, want %q", e.Name, blobs[e.SHA], files[e.Name])
66 }
67 }
68}
69
70func TestUsesSHA256(t *testing.T) {
71 if usesSHA256(nil) {
72 t.Fatal("an empty tree claimed SHA-256")
73 }
74 if usesSHA256(map[string]Entry{"a": {SHA: strings.Repeat("a", 40)}}) {
75 t.Fatal("a 40-character id claimed SHA-256")
76 }
77 if !usesSHA256(map[string]Entry{"a": {SHA: strings.Repeat("a", 64)}}) {
78 t.Fatal("a 64-character id did not claim SHA-256")
79 }
80}
81
82// TestCommitFilesIncrementalEdits checks that a change, an add, and a delete
83// produce the tree the caller asked for while leaving unrelated subtrees alone.
84func TestCommitFilesIncrementalEdits(t *testing.T) {
85 dir := filepath.Join(t.TempDir(), "r.git")
86 if err := InitBare(dir, "main"); err != nil {
87 t.Fatal(err)
88 }
89 g := Open(dir)
90 ref := "refs/heads/main"
91 if _, err := CommitFiles(g, ref, func(files map[string][]byte) error {
92 files["top.txt"] = []byte("top\n")
93 files["stable/one.txt"] = []byte("one\n")
94 files["dir/keep.txt"] = []byte("keep\n")
95 files["dir/change.txt"] = []byte("before\n")
96 files["dir/sub/gone.txt"] = []byte("gone\n")
97 return nil
98 }, "seed", "test"); err != nil {
99 t.Fatal(err)
100 }
101 before, err := g.RevParse(ref)
102 if err != nil {
103 t.Fatal(err)
104 }
105 beforeTree := treeID(t, g, before)
106 beforeRoot, err := g.LsTree(before)
107 if err != nil {
108 t.Fatal(err)
109 }
110
111 after, err := CommitFiles(g, ref, func(files map[string][]byte) error {
112 files["dir/change.txt"] = []byte("after\n")
113 files["dir/new.txt"] = []byte("new\n")
114 delete(files, "dir/sub/gone.txt")
115 return nil
116 }, "edit", "test")
117 if err != nil {
118 t.Fatal(err)
119 }
120 afterRoot, err := g.LsTree(after)
121 if err != nil {
122 t.Fatal(err)
123 }
124 root := func(entries []Entry) map[string]Entry {
125 out := map[string]Entry{}
126 for _, e := range entries {
127 out[e.Name] = e
128 }
129 return out
130 }
131 if got, want := root(afterRoot)["stable"].SHA, root(beforeRoot)["stable"].SHA; got != want {
132 t.Fatalf("unchanged subtree was rewritten: %s, want %s", got, want)
133 }
134 if root(afterRoot)["dir"].SHA == root(beforeRoot)["dir"].SHA {
135 t.Fatal("the changed subtree kept its old id")
136 }
137
138 files, err := g.FlatTree(after)
139 if err != nil {
140 t.Fatal(err)
141 }
142 want := map[string]string{
143 "top.txt": "top\n",
144 "stable/one.txt": "one\n",
145 "dir/keep.txt": "keep\n",
146 "dir/change.txt": "after\n",
147 "dir/new.txt": "new\n",
148 }
149 if len(files) != len(want) {
150 t.Fatalf("tree has %d files, want %d: %v", len(files), len(want), files)
151 }
152 for path, content := range want {
153 if got := string(files[path]); got != content {
154 t.Fatalf("%s = %q, want %q", path, got, content)
155 }
156 }
157 if _, ok := files["dir/sub/gone.txt"]; ok {
158 t.Fatal("the deleted file is still in the tree")
159 }
160 afterTree := treeID(t, g, after)
161 if afterTree == beforeTree {
162 t.Fatal("the root tree did not change")
163 }
164}
165
166// TestCommitFilesReusesTreeWhenNothingChanged guards the reuse path: a mutator
167// that writes the same bytes must not move the tree.
168func TestCommitFilesReusesTreeWhenNothingChanged(t *testing.T) {
169 dir := filepath.Join(t.TempDir(), "r.git")
170 if err := InitBare(dir, "main"); err != nil {
171 t.Fatal(err)
172 }
173 g := Open(dir)
174 ref := "refs/heads/main"
175 if _, err := CommitFiles(g, ref, func(files map[string][]byte) error {
176 files["a.txt"] = []byte("same\n")
177 files["dir/b.txt"] = []byte("same\n")
178 return nil
179 }, "seed", "test"); err != nil {
180 t.Fatal(err)
181 }
182 before := treeID(t, g, ref)
183 commit, err := CommitFiles(g, ref, func(files map[string][]byte) error {
184 files["a.txt"] = []byte("same\n")
185 files["dir/b.txt"] = []byte("same\n")
186 return nil
187 }, "no-op", "test")
188 if err != nil {
189 t.Fatal(err)
190 }
191 after := treeID(t, g, commit)
192 if after != before {
193 t.Fatalf("tree moved from %s to %s without a content change", before, after)
194 }
195}
196
197// TestCommitFilesStaysProportionalToTheChange is the regression test for the
198// thousands of git processes a one-file write used to start. GIT_TRACE counts
199// every child git, and a changed file at depth two needs a bounded handful.
200func TestCommitFilesStaysProportionalToTheChange(t *testing.T) {
201 dir := filepath.Join(t.TempDir(), "r.git")
202 if err := InitBare(dir, "main"); err != nil {
203 t.Fatal(err)
204 }
205 g := Open(dir)
206 ref := "refs/heads/main"
207 seed := map[string][]byte{}
208 for i := 0; i < 200; i++ {
209 seed[fmt.Sprintf("runs/r%03d/1/record.md", i)] = []byte("record\n")
210 }
211 seed["issues/change/issue.md"] = []byte("before\n")
212 if _, err := CommitFiles(g, ref, func(files map[string][]byte) error {
213 for path, content := range seed {
214 files[path] = content
215 }
216 return nil
217 }, "seed", "test"); err != nil {
218 t.Fatal(err)
219 }
220
221 trace := filepath.Join(t.TempDir(), "git.trace")
222 traced := *g
223 traced.ExtraEnv = append(traced.ExtraEnv, "GIT_TRACE="+trace)
224 if _, err := CommitFiles(&traced, ref, func(files map[string][]byte) error {
225 files["issues/change/issue.md"] = []byte("after\n")
226 return nil
227 }, "change", "test"); err != nil {
228 t.Fatal(err)
229 }
230 data, err := os.ReadFile(trace)
231 if err != nil {
232 t.Fatal(err)
233 }
234 // rev-parse, ls-tree, one cat-file --batch, one hash-object, three mktree
235 // (issues/change, issues, root), commit-tree, update-ref. A full rewrite
236 // starts one git per file and per directory: over 400 here.
237 const limit = 20
238 if starts := bytes.Count(data, []byte("built-in: git ")); starts > limit {
239 t.Fatalf("one changed file started %d git processes (limit %d):\n%s", starts, limit, data)
240 }
241}
242
243func treeID(t *testing.T, g *Repo, rev string) string {
244 t.Helper()
245 out, err := g.Run(nil, "rev-parse", "--verify", rev+"^{tree}")
246 if err != nil {
247 t.Fatal(err)
248 }
249 return strings.TrimSpace(string(out))
250}
251
252func BenchmarkCommitFilesOneFile(b *testing.B) {
253 dir := filepath.Join(b.TempDir(), "r.git")
254 if err := InitBare(dir, "main"); err != nil {
255 b.Fatal(err)
256 }
257 g := Open(dir)
258 ref := "refs/heads/main"
259 const unrelated = 2000
260 if _, err := CommitFiles(g, ref, func(files map[string][]byte) error {
261 for i := 0; i < unrelated; i++ {
262 files[fmt.Sprintf("runs/r%04d/1/record.md", i)] = []byte("record\n")
263 }
264 return nil
265 }, "seed", "bench"); err != nil {
266 b.Fatal(err)
267 }
268 b.ResetTimer()
269 for i := 0; i < b.N; i++ {
270 content := []byte(fmt.Sprintf("change %d\n", i))
271 if _, err := CommitFiles(g, ref, func(files map[string][]byte) error {
272 files["issues/one/issue.md"] = content
273 return nil
274 }, "change", "bench"); err != nil {
275 b.Fatal(err)
276 }
277 }
278}
279