veryroundbird.house
1package git
2
3import (
4 "bytes"
5 "fmt"
6 "log"
7 "os"
8 "os/exec"
9 "slices"
10 "strings"
11
12 "github.com/bluekeyes/go-gitdiff/gitdiff"
13 "github.com/go-git/go-git/v5/plumbing"
14 "github.com/go-git/go-git/v5/plumbing/object"
15 "tangled.sh/tangled.sh/core/patchutil"
16 "tangled.sh/tangled.sh/core/types"
17)
18
19func (g *GitRepo) Diff() (*types.NiceDiff, error) {
20 c, err := g.r.CommitObject(g.h)
21 if err != nil {
22 return nil, fmt.Errorf("commit object: %w", err)
23 }
24
25 patch := &object.Patch{}
26 commitTree, err := c.Tree()
27 parent := &object.Commit{}
28 if err == nil {
29 parentTree := &object.Tree{}
30 if c.NumParents() != 0 {
31 parent, err = c.Parents().Next()
32 if err == nil {
33 parentTree, err = parent.Tree()
34 if err == nil {
35 patch, err = parentTree.Patch(commitTree)
36 if err != nil {
37 return nil, fmt.Errorf("patch: %w", err)
38 }
39 }
40 }
41 } else {
42 patch, err = parentTree.Patch(commitTree)
43 if err != nil {
44 return nil, fmt.Errorf("patch: %w", err)
45 }
46 }
47 }
48
49 diffs, _, err := gitdiff.Parse(strings.NewReader(patch.String()))
50 if err != nil {
51 log.Println(err)
52 }
53
54 nd := types.NiceDiff{}
55 for _, d := range diffs {
56 ndiff := types.Diff{}
57 ndiff.Name.New = d.NewName
58 ndiff.Name.Old = d.OldName
59 ndiff.IsBinary = d.IsBinary
60 ndiff.IsNew = d.IsNew
61 ndiff.IsDelete = d.IsDelete
62 ndiff.IsCopy = d.IsCopy
63 ndiff.IsRename = d.IsRename
64
65 for _, tf := range d.TextFragments {
66 ndiff.TextFragments = append(ndiff.TextFragments, *tf)
67 for _, l := range tf.Lines {
68 switch l.Op {
69 case gitdiff.OpAdd:
70 nd.Stat.Insertions += 1
71 case gitdiff.OpDelete:
72 nd.Stat.Deletions += 1
73 }
74 }
75 }
76
77 nd.Diff = append(nd.Diff, ndiff)
78 }
79
80 nd.Stat.FilesChanged = len(diffs)
81 nd.Commit.This = c.Hash.String()
82 nd.Commit.PGPSignature = c.PGPSignature
83 nd.Commit.Committer = c.Committer
84 nd.Commit.Tree = c.TreeHash.String()
85
86 if parent.Hash.IsZero() {
87 nd.Commit.Parent = ""
88 } else {
89 nd.Commit.Parent = parent.Hash.String()
90 }
91 nd.Commit.Author = c.Author
92 nd.Commit.Message = c.Message
93
94 if v, ok := c.ExtraHeaders["change-id"]; ok {
95 nd.Commit.ChangedId = string(v)
96 }
97
98 return &nd, nil
99}
100
101func (g *GitRepo) DiffTree(commit1, commit2 *object.Commit) (*types.DiffTree, error) {
102 tree1, err := commit1.Tree()
103 if err != nil {
104 return nil, err
105 }
106
107 tree2, err := commit2.Tree()
108 if err != nil {
109 return nil, err
110 }
111
112 diff, err := object.DiffTree(tree1, tree2)
113 if err != nil {
114 return nil, err
115 }
116
117 patch, err := diff.Patch()
118 if err != nil {
119 return nil, err
120 }
121
122 diffs, _, err := gitdiff.Parse(strings.NewReader(patch.String()))
123 if err != nil {
124 return nil, err
125 }
126
127 return &types.DiffTree{
128 Rev1: commit1.Hash.String(),
129 Rev2: commit2.Hash.String(),
130 Patch: patch.String(),
131 Diff: diffs,
132 }, nil
133}
134
135// FormatPatch generates a git-format-patch output between two commits,
136// and returns the raw format-patch series, a parsed FormatPatch and an error.
137func (g *GitRepo) formatSinglePatch(base, commit2 plumbing.Hash, extraArgs ...string) (string, *types.FormatPatch, error) {
138 var stdout bytes.Buffer
139
140 args := []string{
141 "-C",
142 g.path,
143 "format-patch",
144 fmt.Sprintf("%s..%s", base.String(), commit2.String()),
145 "--stdout",
146 }
147 args = append(args, extraArgs...)
148
149 cmd := exec.Command("git", args...)
150 cmd.Stdout = &stdout
151 cmd.Stderr = os.Stderr
152 err := cmd.Run()
153 if err != nil {
154 return "", nil, err
155 }
156
157 formatPatch, err := patchutil.ExtractPatches(stdout.String())
158 if err != nil {
159 return "", nil, err
160 }
161
162 if len(formatPatch) > 1 {
163 return "", nil, fmt.Errorf("running format-patch on single commit produced more than on patch")
164 }
165
166 return stdout.String(), &formatPatch[0], nil
167}
168
169func (g *GitRepo) MergeBase(commit1, commit2 *object.Commit) (*object.Commit, error) {
170 isAncestor, err := commit1.IsAncestor(commit2)
171 if err != nil {
172 return nil, err
173 }
174
175 if isAncestor {
176 return commit1, nil
177 }
178
179 mergeBase, err := commit1.MergeBase(commit2)
180 if err != nil {
181 return nil, err
182 }
183
184 if len(mergeBase) == 0 {
185 return nil, fmt.Errorf("failed to find a merge-base")
186 }
187
188 return mergeBase[0], nil
189}
190
191func (g *GitRepo) ResolveRevision(revStr string) (*object.Commit, error) {
192 rev, err := g.r.ResolveRevision(plumbing.Revision(revStr))
193 if err != nil {
194 return nil, fmt.Errorf("resolving revision %s: %w", revStr, err)
195 }
196
197 commit, err := g.r.CommitObject(*rev)
198 if err != nil {
199
200 return nil, fmt.Errorf("getting commit for %s: %w", revStr, err)
201 }
202
203 return commit, nil
204}
205
206func (g *GitRepo) commitsBetween(newCommit, oldCommit *object.Commit) ([]*object.Commit, error) {
207 var commits []*object.Commit
208 current := newCommit
209
210 for {
211 if current.Hash == oldCommit.Hash {
212 break
213 }
214
215 commits = append(commits, current)
216
217 if len(current.ParentHashes) == 0 {
218 return nil, fmt.Errorf("old commit %s not found in history of new commit %s", oldCommit.Hash, newCommit.Hash)
219 }
220
221 parent, err := current.Parents().Next()
222 if err != nil {
223 return nil, fmt.Errorf("error getting parent: %w", err)
224 }
225
226 current = parent
227 }
228
229 return commits, nil
230}
231
232func (g *GitRepo) FormatPatch(base, commit2 *object.Commit) (string, []types.FormatPatch, error) {
233 // get list of commits between commir2 and base
234 commits, err := g.commitsBetween(commit2, base)
235 if err != nil {
236 return "", nil, fmt.Errorf("failed to get commits: %w", err)
237 }
238
239 // reverse the list so we start from the oldest one and go up to the most recent one
240 slices.Reverse(commits)
241
242 var allPatchesContent strings.Builder
243 var allPatches []types.FormatPatch
244
245 for _, commit := range commits {
246 changeId := ""
247 if val, ok := commit.ExtraHeaders["change-id"]; ok {
248 changeId = string(val)
249 }
250
251 var parentHash plumbing.Hash
252 if len(commit.ParentHashes) > 0 {
253 parentHash = commit.ParentHashes[0]
254 } else {
255 parentHash = plumbing.NewHash("4b825dc642cb6eb9a060e54bf8d69288fbee4904") // git empty tree hash
256 }
257
258 var additionalArgs []string
259 if changeId != "" {
260 additionalArgs = append(additionalArgs, "--add-header", fmt.Sprintf("Change-Id: %s", changeId))
261 }
262
263 stdout, patch, err := g.formatSinglePatch(parentHash, commit.Hash, additionalArgs...)
264 if err != nil {
265 return "", nil, fmt.Errorf("failed to format patch for commit %s: %w", commit.Hash.String(), err)
266 }
267
268 allPatchesContent.WriteString(stdout)
269 allPatchesContent.WriteString("\n")
270
271 allPatches = append(allPatches, *patch)
272 }
273
274 return allPatchesContent.String(), allPatches, nil
275}