ai_usagebar/copilot/
credentials.rs

1//! Obtain a GitHub OAuth token from the official GitHub CLI without handling
2//! its credential files ourselves.
3
4use std::io;
5use std::process::{Command, Stdio};
6
7use crate::error::{AppError, Result};
8use crate::vendor::vendor_secret_env_vars_to_remove;
9
10/// Where the GitHub CLI records a completed login. Its existence is the
11/// cheapest honest answer to "is Copilot signed in": the token itself only
12/// comes back from `gh auth token`, and a status list that runs a subprocess
13/// per provider is not a status list.
14///
15/// This follows `gh`'s own documented precedence exactly, because a path we
16/// invent is a wrong answer on somebody's machine: `GH_CONFIG_DIR`, then
17/// `$XDG_CONFIG_HOME/gh`, then `%AppData%\GitHub CLI` on Windows, then
18/// `~/.config/gh`.
19pub fn default_hosts_path() -> Result<std::path::PathBuf> {
20    hosts_path_with(
21        |name| std::env::var_os(name).filter(|value| !value.is_empty()),
22        crate::cache::home_dir()?,
23    )
24}
25
26/// Test seam for [`default_hosts_path`]: the environment and the home
27/// directory are the production inputs, so they are injected rather than read.
28pub fn hosts_path_with(
29    environment: impl Fn(&str) -> Option<std::ffi::OsString>,
30    home: std::path::PathBuf,
31) -> Result<std::path::PathBuf> {
32    if let Some(dir) = environment("GH_CONFIG_DIR") {
33        return Ok(std::path::PathBuf::from(dir).join("hosts.yml"));
34    }
35    if let Some(dir) = environment("XDG_CONFIG_HOME") {
36        return Ok(std::path::PathBuf::from(dir).join("gh").join("hosts.yml"));
37    }
38    if cfg!(windows)
39        && let Some(dir) = environment("AppData")
40    {
41        return Ok(std::path::PathBuf::from(dir)
42            .join("GitHub CLI")
43            .join("hosts.yml"));
44    }
45    Ok(home.join(".config").join("gh").join("hosts.yml"))
46}
47
48/// The deliberately narrow process description used to obtain the current
49/// GitHub CLI OAuth token. Keeping it data makes the subprocess boundary
50/// inspectable in tests and prevents a shell from entering this path.
51#[derive(Debug, Clone, PartialEq, Eq)]
52pub struct GhAuthTokenCommand {
53    pub program: std::path::PathBuf,
54    pub args: [&'static str; 2],
55    pub env_remove: Vec<&'static str>,
56}
57
58impl GhAuthTokenCommand {
59    /// `gh` has no canonical install path across distributions, so unlike
60    /// `grok` it is looked up on `PATH` by default. That makes the binary an
61    /// ambient choice, which is why `[copilot] gh_binary` exists: point it at
62    /// the trusted executable and the lookup stops being ambient.
63    pub fn standard(gh_binary: Option<&std::path::Path>) -> Self {
64        Self {
65            program: gh_binary.map_or_else(|| std::path::PathBuf::from("gh"), Into::into),
66            args: ["auth", "token"],
67            // `gh auth token` must use its saved OAuth login, rather than an
68            // arbitrary provider token inherited from this process.
69            env_remove: vendor_secret_env_vars_to_remove(&[]),
70        }
71    }
72}
73
74#[derive(Debug, Clone, PartialEq, Eq)]
75pub struct GhAuthTokenOutput {
76    pub success: bool,
77    pub stdout: Vec<u8>,
78}
79
80/// Injectable command boundary. Tests supply a fake runner, so they never
81/// execute `gh`, inspect a real GitHub config directory, or use ambient env.
82pub trait GhAuthTokenRunner {
83    fn run(&self, command: &GhAuthTokenCommand) -> io::Result<GhAuthTokenOutput>;
84}
85
86pub struct SystemGhAuthTokenRunner;
87
88impl GhAuthTokenRunner for SystemGhAuthTokenRunner {
89    fn run(&self, command: &GhAuthTokenCommand) -> io::Result<GhAuthTokenOutput> {
90        let mut process = Command::new(&command.program);
91        process
92            .args(command.args)
93            .stdin(Stdio::null())
94            .stdout(Stdio::piped())
95            .stderr(Stdio::null());
96        for variable in &command.env_remove {
97            process.env_remove(variable);
98        }
99        let output = process.output()?;
100        Ok(GhAuthTokenOutput {
101            success: output.status.success(),
102            stdout: output.stdout,
103        })
104    }
105}
106
107pub fn resolve_with(
108    runner: &impl GhAuthTokenRunner,
109    gh_binary: Option<&std::path::Path>,
110) -> Result<String> {
111    let command = GhAuthTokenCommand::standard(gh_binary);
112    let output = match runner.run(&command) {
113        Ok(output) => output,
114        Err(error) if error.kind() == io::ErrorKind::NotFound => {
115            return Err(login_error(
116                "GitHub CLI (`gh`) is not installed. Install it, then run",
117            ));
118        }
119        Err(_) => return Err(login_error("GitHub CLI could not be started. Run")),
120    };
121    if !output.success {
122        return Err(login_error("GitHub CLI is not logged in. Run"));
123    }
124    let token = String::from_utf8(output.stdout)
125        .ok()
126        .map(|value| value.trim().to_string())
127        .filter(|value| !value.is_empty())
128        .ok_or_else(|| login_error("GitHub CLI returned no OAuth token. Run"))?;
129    Ok(token)
130}
131
132fn login_error(prefix: &str) -> AppError {
133    AppError::Credentials(format!(
134        "GitHub Copilot: {prefix} `gh auth login --web`, then select GitHub Copilot as the primary provider in Settings."
135    ))
136}
137
138#[cfg(test)]
139mod tests {
140    use super::*;
141    use std::cell::RefCell;
142
143    struct FakeRunner {
144        result: io::Result<GhAuthTokenOutput>,
145        command: RefCell<Option<GhAuthTokenCommand>>,
146    }
147
148    impl GhAuthTokenRunner for FakeRunner {
149        fn run(&self, command: &GhAuthTokenCommand) -> io::Result<GhAuthTokenOutput> {
150            *self.command.borrow_mut() = Some(command.clone());
151            self.result
152                .as_ref()
153                .map(Clone::clone)
154                .map_err(|error| io::Error::new(error.kind(), "fake gh failure"))
155        }
156    }
157
158    #[test]
159    fn runs_only_fixed_gh_auth_token_command_and_returns_trimmed_token() {
160        let runner = FakeRunner {
161            result: Ok(GhAuthTokenOutput {
162                success: true,
163                stdout: b"test-github-oauth-token\n".to_vec(),
164            }),
165            command: RefCell::new(None),
166        };
167
168        assert_eq!(
169            resolve_with(&runner, None).unwrap(),
170            "test-github-oauth-token"
171        );
172        let command = runner.command.into_inner().unwrap();
173        assert_eq!(command.program, std::path::Path::new("gh"));
174        assert_eq!(command.args, ["auth", "token"]);
175        assert!(command.env_remove.contains(&"ZAI_API_KEY"));
176        assert!(command.env_remove.contains(&"GITHUB_COPILOT_TOKEN"));
177        assert!(command.env_remove.contains(&"GH_TOKEN"));
178        assert!(command.env_remove.contains(&"GITHUB_TOKEN"));
179    }
180
181    /// `gh` has no canonical path, so `PATH` is the sensible default — but it
182    /// is still an ambient choice about which binary runs on every refresh.
183    /// `[copilot] gh_binary` is how a user pins it, so the setting has to
184    /// actually reach the spawned command.
185    /// `gh`'s own precedence, in order. A path we invent instead is a wrong
186    /// answer on somebody's machine: an XDG user's login would read as absent
187    /// and report Copilot as never signed in.
188    #[test]
189    fn hosts_path_follows_the_github_cli_precedence() {
190        use std::ffi::OsString;
191        use std::path::PathBuf;
192        let home = PathBuf::from("/home/u");
193        let only = |wanted: &'static str, value: &'static str| {
194            move |name: &str| (name == wanted).then(|| OsString::from(value))
195        };
196
197        assert_eq!(
198            hosts_path_with(only("GH_CONFIG_DIR", "/cfg/gh"), home.clone()).unwrap(),
199            PathBuf::from("/cfg/gh/hosts.yml"),
200            "GH_CONFIG_DIR is used verbatim, with no `gh` segment appended"
201        );
202        assert_eq!(
203            hosts_path_with(only("XDG_CONFIG_HOME", "/xdg"), home.clone()).unwrap(),
204            PathBuf::from("/xdg/gh/hosts.yml")
205        );
206        assert_eq!(
207            hosts_path_with(|_| None, home.clone()).unwrap(),
208            home.join(".config").join("gh").join("hosts.yml"),
209            "with nothing set, the home convention"
210        );
211
212        // GH_CONFIG_DIR outranks XDG_CONFIG_HOME.
213        let both = |name: &str| match name {
214            "GH_CONFIG_DIR" => Some(OsString::from("/cfg/gh")),
215            "XDG_CONFIG_HOME" => Some(OsString::from("/xdg")),
216            _ => None,
217        };
218        assert_eq!(
219            hosts_path_with(both, home.clone()).unwrap(),
220            PathBuf::from("/cfg/gh/hosts.yml")
221        );
222
223        // `AppData` is Windows-only and ranks below XDG, so it must not
224        // capture a Linux or macOS machine that happens to have it set.
225        let appdata =
226            hosts_path_with(only("AppData", "C:/Users/u/AppData/Roaming"), home.clone()).unwrap();
227        if cfg!(windows) {
228            assert_eq!(
229                appdata,
230                PathBuf::from("C:/Users/u/AppData/Roaming/GitHub CLI/hosts.yml")
231            );
232        } else {
233            assert_eq!(appdata, home.join(".config").join("gh").join("hosts.yml"));
234        }
235    }
236
237    #[test]
238    fn a_configured_gh_binary_replaces_the_path_lookup() {
239        let pinned = std::path::Path::new("/opt/github/bin/gh");
240        assert_eq!(
241            GhAuthTokenCommand::standard(Some(pinned)).program,
242            pinned,
243            "a pinned binary must be used verbatim"
244        );
245        assert_eq!(
246            GhAuthTokenCommand::standard(None).program,
247            std::path::Path::new("gh"),
248            "unset still means the PATH lookup"
249        );
250        // The rest of the boundary is fixed either way.
251        for command in [
252            GhAuthTokenCommand::standard(Some(pinned)),
253            GhAuthTokenCommand::standard(None),
254        ] {
255            assert_eq!(command.args, ["auth", "token"]);
256            assert!(command.env_remove.contains(&"GITHUB_TOKEN"));
257        }
258    }
259
260    #[test]
261    fn login_failure_never_echoes_gh_output() {
262        let runner = FakeRunner {
263            result: Ok(GhAuthTokenOutput {
264                success: false,
265                stdout: b"private-token-or-error".to_vec(),
266            }),
267            command: RefCell::new(None),
268        };
269
270        let error = resolve_with(&runner, None).unwrap_err().to_string();
271        assert!(error.contains("gh auth login --web"));
272        assert!(!error.contains("private-token-or-error"));
273    }
274}
ai_usagebar/copilot/credentials.rs

ai_usagebar/copilot/
credentials.rs
