Resolve default branch name when branching

Author: Kobzol

src/branching.rs

@@ -18,7 +18,8 @@ impl Context {
             return Ok(());
         };
         let mut token = github.token("rust-lang/rust")?;
-        let bump_commit = branchpoint(&mut token, "master")?;
+        let repo = token.repository()?;
+        let bump_commit = branchpoint(&mut token, &repo.default_branch)?;
         let prebump_sha = bump_commit.parents[0].sha.clone();
         let beta_sha = token.get_ref("heads/beta")?;
 

src/github.rs

@@ -411,6 +411,17 @@ impl RepositoryClient<'_> {
         self.client.without_body().send_with_response::<GitFile>()
     }
 
+    /// Returns information about the current repository
+    pub(crate) fn repository(&mut self) -> anyhow::Result<Repository> {
+        self.start_new_request()?;
+        self.client.get(true)?;
+        self.client.url(&format!(
+            "https://api.github.com/repos/{repo}",
+            repo = self.repo,
+        ))?;
+        self.client.without_body().send_with_response::<Repository>()
+    }
+
     pub(crate) fn merge_pr(&mut self, pr: u32) -> anyhow::Result<()> {
         self.start_new_request()?;
         self.client.put(true)?;
@@ -496,6 +507,11 @@ impl GitFile {
     }
 }
 
+#[derive(Debug, serde::Deserialize)]
+pub(crate) struct Repository {
+    pub(crate) default_branch: String
+}
+
 #[derive(Copy, Clone)]
 pub(crate) struct CreateTag<'a> {
     pub(crate) commit: &'a str,