1. 1//! Git worktree isolation: each isolated run gets its own worktree + branch
2. 2//! off HEAD, so mutations never touch the user's checkout.
3. 3
4. 4use std::path::{Path, PathBuf};
5. 5use std::process::Command;
6. 6
7. 7#[derive(Debug, thiserror::Error)]
8. 8pub enum WorktreeError {
9. 9 #[error("not a git repository")]
10. 10 NotARepo,
11. 11 #[error("git failed: {0}")]
12. 12 Git(String),
13. 13 #[error("io error: {0}")]
14. 14 Io(#[from] std::io::Error),
15. 15}
16. 16
17. 17fn git(repo: &Path, args: &[&str]) -> Result<String, WorktreeError> {
18. 18 let out = Command::new("git")
19. 19 .current_dir(repo)
20. 20 .args(args)
21. 21 .output()
22. 22 .map_err(WorktreeError::Io)?;
23. 23 if !out.status.success() {
24. 24 return Err(WorktreeError::Git(
25. 25 String::from_utf8_lossy(&out.stderr).trim().to_string(),
26. 26 ));
27. 27 }
28. 28 Ok(String::from_utf8_lossy(&out.stdout).trim().to_string())
29. 29}
30. 30
31. 31pub fn is_git_repo(cwd: &Path) -> bool {
32. 32 Command::new("git")
33. 33 .current_dir(cwd)
34. 34 .args(["rev-parse", "--is-inside-work-tree"])
35. 35 .output()
36. 36 .map(|o| o.status.success())
37. 37 .unwrap_or(false)
38. 38}
39. 39
40. 40pub struct Worktree {
41. 41 pub path: PathBuf,
42. 42 pub branch: String,
43. 43}
44. 44
45. 45/// Creates `.vak/worktrees/<run_id>` on branch `vak/<run_id>`.
46. 46pub fn create(repo: &Path, run_id: &str) -> Result<Worktree, WorktreeError> {
47. 47 if !is_git_repo(repo) {
48. 48 return Err(WorktreeError::NotARepo);
49. 49 }
50. 50 let path = repo.join(".vak/worktrees").join(run_id);
51. 51 if let Some(parent) = path.parent() {
52. 52 std::fs::create_dir_all(parent)?;
53. 53 }
54. 54 let branch = format!("vak/{run_id}");
55. 55 git(
56. 56 repo,
57. 57 &[
58. 58 "worktree",
59. 59 "add",
60. 60 "-b",
61. 61 &branch,
62. 62 path.to_string_lossy().as_ref(),
63. 63 "HEAD",
64. 64 ],
65. 65 )?;
66. 66 Ok(Worktree { path, branch })
67. 67}
68. 68
69. 69/// Removes the worktree and its branch (uncommitted changes are discarded —
70. 70/// callers should surface that before calling).
71. 71pub fn remove(repo: &Path, wt: &Worktree) -> Result<(), WorktreeError> {
72. 72 git(
73. 73 repo,
74. 74 &[
75. 75 "worktree",
76. 76 "remove",
77. 77 "--force",
78. 78 wt.path.to_string_lossy().as_ref(),
79. 79 ],
80. 80 )?;
81. 81 git(repo, &["branch", "-D", &wt.branch])?;
82. 82 Ok(())
83. 83}
84. 84