1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171

// Copyright 2024 Google LLC
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// https://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or https://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.

//! Utilities for running `git` commands.

use crate::cmd::{get_cmd_stdout_utf8, run_cmd, RunCommandError};
use std::ffi::OsStr;
use std::fmt::{self, Display, Formatter};
use std::path::{Path, PathBuf};
use std::process::Command;
use std::{env, io};

/// Error returned by [`Repo::open`] and [`Repo::open_path`].
#[derive(Debug)]
pub enum RepoOpenError {
    /// Failed to get current directory.
    CurrentDir(io::Error),

    /// The directory does not have a `.git` subdirectory.
    GitDirMissing(PathBuf),
}

impl Display for RepoOpenError {
    fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {
        write!(f, "failed to open git repo: ")?;
        match self {
            Self::CurrentDir(err) => {
                write!(f, "failed to get current dir: {err}")
            }
            Self::GitDirMissing(path) => {
                write!(f, "{} does not exist", path.display())
            }
        }
    }
}

impl std::error::Error for RepoOpenError {}

/// Git repo.
#[derive(Clone, Debug, Eq, PartialEq, Ord, PartialOrd, Hash)]
pub struct Repo(PathBuf);

impl Repo {
    /// Get a `Repo` for the current directory.
    ///
    /// This will fail if the current directory does not contain a
    /// `.git` subdirectory.
    pub fn open() -> Result<Self, RepoOpenError> {
        let path = env::current_dir().map_err(RepoOpenError::CurrentDir)?;
        Self::open_path(path)
    }

    /// Get a `Repo` for the given path.
    ///
    /// This will fail if the `path` does not contain a `.git`
    /// subdirectory.
    pub fn open_path<P>(path: P) -> Result<Self, RepoOpenError>
    where
        P: Into<PathBuf>,
    {
        let path = path.into();

        // Check that this is a git repo. This is just to help fail
        // quickly if the path is wrong; it isn't checking that the git
        // repo is valid or anything.
        //
        // Also, there are various special types of git checkouts so
        // it's quite possible this check is wrong for special
        // circumstances, but for a typical CI release process it should
        // be fine.
        let git_dir = path.join(".git");
        if !git_dir.exists() {
            return Err(RepoOpenError::GitDirMissing(git_dir));
        }

        Ok(Self(path))
    }

    /// Get the repo path.
    pub fn path(&self) -> &Path {
        &self.0
    }

    /// Create a git command with the given args.
    fn get_git_command<I, S>(&self, args: I) -> Command
    where
        I: IntoIterator<Item = S>,
        S: AsRef<OsStr>,
    {
        let mut cmd = Command::new("git");
        cmd.arg("-C");
        cmd.arg(self.path());
        cmd.args(args);
        cmd
    }

    /// Get the subject of the commit message for the given commit.
    pub fn get_commit_message_body(
        &self,
        commit_sha: &str,
    ) -> Result<String, RunCommandError> {
        let cmd = self.get_git_command([
            "log",
            "-1",
            // Only get the body of the commit message.
            "--format=format:%b",
            commit_sha,
        ]);
        let output = get_cmd_stdout_utf8(cmd)?;
        Ok(output)
    }

    /// Get the subject of the commit message for the given commit.
    pub fn get_commit_message_subject(
        &self,
        commit_sha: &str,
    ) -> Result<String, RunCommandError> {
        let cmd = self.get_git_command([
            "log",
            "-1",
            // Only get the subject of the commit message.
            "--format=format:%s",
            commit_sha,
        ]);
        let output = get_cmd_stdout_utf8(cmd)?;
        Ok(output)
    }

    /// Fetch git tags from the remote.
    pub fn fetch_git_tags(&self) -> Result<(), RunCommandError> {
        let cmd = self.get_git_command(["fetch", "--tags"]);
        run_cmd(cmd)?;
        Ok(())
    }

    /// Check if a git tag exists locally.
    ///
    /// All git tags were fetched at the start of auto-release, so checking locally
    /// is sufficient.
    pub fn does_git_tag_exist(
        &self,
        tag: &str,
    ) -> Result<bool, RunCommandError> {
        let cmd = self.get_git_command(["tag", "--list", tag]);
        let output = get_cmd_stdout_utf8(cmd)?;

        Ok(output.lines().any(|line| line == tag))
    }

    /// Create a git tag locally and push it.
    pub fn make_and_push_git_tag(
        &self,
        tag: &str,
        commit_sha: &str,
    ) -> Result<(), RunCommandError> {
        // Create the tag.
        let cmd = self.get_git_command(["tag", tag, commit_sha]);
        run_cmd(cmd)?;

        // Push it.
        let cmd = self.get_git_command(["push", "--tags"]);
        run_cmd(cmd)?;

        Ok(())
    }
}