hive-forge: rewrite bash CLI helper as a rust binary (closes #280)

hive-forge/src/verbs/tree_sha.rs

@@ -0,0 +1,40 @@
+//! `tree-sha <ref> [repo]` — print the tree SHA of the commit at a
+//! branch name or commit SHA.
+
+use anyhow::Result;
+use clap::Args as ClapArgs;
+use serde_json::Value;
+
+use crate::client::Client;
+
+#[derive(ClapArgs)]
+pub struct Args {
+    /// Branch name or commit SHA.
+    reference: String,
+    /// Repo override.
+    repo: Option<String>,
+}
+
+pub fn run(client: &Client, args: Args) -> Result<()> {
+    let repo = client.repo(args.repo.as_deref());
+    // Try branch first; the bash helper silently treats failure as
+    // "not a branch, use the reference as a commit sha directly".
+    let commit_sha = match client.get_json(&format!("/repos/{repo}/branches/{}", args.reference)) {
+        Ok(v) => v
+            .get("commit")
+            .and_then(|c| c.get("id"))
+            .and_then(Value::as_str)
+            .unwrap_or(&args.reference)
+            .to_owned(),
+        Err(_) => args.reference.clone(),
+    };
+    let commit = client.get_json(&format!("/repos/{repo}/git/commits/{commit_sha}"))?;
+    let sha = commit
+        .get("tree")
+        .and_then(|t| t.get("sha"))
+        .and_then(Value::as_str)
+        .or_else(|| commit.get("sha").and_then(Value::as_str))
+        .unwrap_or("");
+    println!("{sha}");
+    Ok(())
+}