git blame: Display GitHub avatars in blame tooltips, if available (#10767)

Release Notes:

- Added GitHub avatars to tooltips that appear when hovering over a `git
blame` entry (either inline or in the blame gutter).

Demo:



https://github.com/zed-industries/zed/assets/1185253/295c5aee-3a4e-46aa-812d-495439d8840d

crates/util/src/github.rs

@@ -1,6 +1,7 @@
 use crate::http::HttpClient;
 use anyhow::{anyhow, bail, Context, Result};
 use futures::AsyncReadExt;
+use isahc::{config::Configurable, AsyncBody, Request};
 use serde::Deserialize;
 use std::sync::Arc;
 use url::Url;
@@ -26,6 +27,89 @@ pub struct GithubReleaseAsset {
     pub browser_download_url: String,
 }
 
+#[derive(Debug, Deserialize)]
+struct CommitDetails {
+    commit: Commit,
+    author: Option<User>,
+}
+
+#[derive(Debug, Deserialize)]
+struct Commit {
+    author: Author,
+}
+
+#[derive(Debug, Deserialize)]
+struct Author {
+    name: String,
+    email: String,
+    date: String,
+}
+
+#[derive(Debug, Deserialize)]
+struct User {
+    pub login: String,
+    pub id: u64,
+    pub node_id: String,
+    pub avatar_url: String,
+    pub gravatar_id: String,
+}
+
+#[derive(Debug)]
+pub struct GitHubAuthor {
+    pub id: u64,
+    pub email: String,
+    pub avatar_url: String,
+}
+
+pub async fn fetch_github_commit_author(
+    repo_owner: &str,
+    repo: &str,
+    commit: &str,
+    client: &Arc<dyn HttpClient>,
+) -> Result<Option<GitHubAuthor>> {
+    let url = format!("https://api.github.com/repos/{repo_owner}/{repo}/commits/{commit}");
+
+    let mut request = Request::get(&url)
+        .redirect_policy(isahc::config::RedirectPolicy::Follow)
+        .header("Content-Type", "application/json");
+
+    if let Ok(github_token) = std::env::var("GITHUB_TOKEN") {
+        request = request.header("Authorization", format!("Bearer {}", github_token));
+    }
+
+    let mut response = client
+        .send(request.body(AsyncBody::default())?)
+        .await
+        .with_context(|| format!("error fetching GitHub commit details at {:?}", url))?;
+
+    let mut body = Vec::new();
+    response.body_mut().read_to_end(&mut body).await?;
+
+    if response.status().is_client_error() {
+        let text = String::from_utf8_lossy(body.as_slice());
+        bail!(
+            "status error {}, response: {text:?}",
+            response.status().as_u16()
+        );
+    }
+
+    let body_str = std::str::from_utf8(&body)?;
+
+    serde_json::from_str::<CommitDetails>(body_str)
+        .map(|github_commit| {
+            if let Some(author) = github_commit.author {
+                Some(GitHubAuthor {
+                    id: author.id,
+                    avatar_url: author.avatar_url,
+                    email: github_commit.commit.author.email,
+                })
+            } else {
+                None
+            }
+        })
+        .context("deserializing GitHub commit details failed")
+}
+
 pub async fn latest_github_release(
     repo_name_with_owner: &str,
     require_assets: bool,