Add a --tag option to the clone-sdk command (#369)

* Add a --tag option to the clone-sdk command

* Update changelog

* Update README

CHANGELOG.md

@@ -13,7 +13,9 @@ Special thanks to external contributors for this release: @CharlyCst ([#347]).
 - [relayer-cli]
     - Merge light clients config in relayer config and add commands to add/remove light clients ([#348])
     - CLI for client update message ([#277])
-- [proto-compiler] Refactor and allow specifying a commit at which the Cosmos SDK should be checked out ([#366])
+- [proto-compiler]
+    - Refactor and allow specifying a commit at which the Cosmos SDK should be checked out ([#366])
+    - Add a `--tag` option to the `clone-sdk` command to check out a tag instead of a commit ([#369])
 - [ibc-proto] Refactor and allow specifying a commit at which the Cosmos SDK should be checked out ([#366])
 
 [#274]: https://github.com/informalsystems/ibc-rs/issues/274
@@ -22,6 +24,7 @@ Special thanks to external contributors for this release: @CharlyCst ([#347]).
 [#336]: https://github.com/informalsystems/ibc-rs/issues/336
 [#348]: https://github.com/informalsystems/ibc-rs/pulls/348
 [#366]: https://github.com/informalsystems/ibc-rs/issues/366
+[#369]: https://github.com/informalsystems/ibc-rs/pulls/369
 
 ### IMPROVEMENTS
 

proto-compiler/README.md

@@ -4,15 +4,32 @@ The `ibc-proto-compiler` is a simple command-line tool to automate the compilati
 
 ## Usage
 
-From within the `proto-compiler` directory, run the following command to clone the Cosmos SDK repository:
+### Clone the Cosmos SDK
+
+From within the `proto-compiler` directory, run the following command to clone the Cosmos SDK repository, and check out a specific commit:
 
 ```bash
-$ cargo run -- clone-sdk --commit ce3994020a0d5c246016c8832ba4a668e8b7c77b --out /tmp/sdk
+$ cargo run -- clone-sdk --out /tmp/sdk --commit ce3994020a0d5c246016c8832ba4a668e8b7c77b
 ```
 
+Note: the full commit hash must be specified.
+
+Alternatively, one can check out a tag with the `--tag` option:
+
+```bash
+$ cargo run -- clone-sdk --out /tmp/sdk --tag v0.39.1-rc3 
+```
+
+If neither `--commit` nor `--tag` is specified, then the default main branch will be checked out.
+
+### Generate Rust sources from Protubuf definitions
+
 To generate the Rust sources from the Protobuf definitions, and copy them to the `src/prost` folder `ibc-proto` crate within the `ibc-rs` project:
 
 ```bash
 $ cargo run -- compile --sdk /tmp/sdk --out ../proto/src/prost
 ```
 
+Additionally, this command will output the commit hash at which the Cosmos SDK is checked out into `$out/COSMOS_SDK_COMMIT`.
+
+This value is exposed via the `ibc_proto::COSMOS_SDK_VERSION` constant in the `ibc-proto` library.

proto-compiler/src/cmd/clone.rs

@@ -11,13 +11,27 @@ pub struct CloneCmd {
     /// commit to checkout
     #[argh(option, short = 'c')]
     commit: Option<String>,
+
+    /// tag to checkout
+    #[argh(option, short = 't')]
+    tag: Option<String>,
+
     /// where to checkout the repository
     #[argh(option, short = 'o')]
     path: PathBuf,
 }
 
 impl CloneCmd {
+    pub fn validate(&self) {
+        if self.commit.is_some() && self.tag.is_some() {
+            println!("[error] The --commit and --tag options are mutually exclusive.");
+            process::exit(1);
+        }
+    }
+
     pub fn run(&self) {
+        self.validate();
+
         let repo = if self.path.exists() {
             println!(
                 "[info ] Found Cosmos SDK source at '{}'",
@@ -33,35 +47,77 @@ impl CloneCmd {
 
             let url = "https://github.com/cosmos/cosmos-sdk";
 
-            Repository::clone(url, &self.path).unwrap_or_else(|e| {
+            let repo = Repository::clone(url, &self.path).unwrap_or_else(|e| {
                 println!("[error] Failed to clone the repository: {}", e);
                 process::exit(1)
-            })
+            });
+
+            println!("[info ] Cloned at '{}'", self.path.display());
+
+            repo
         };
 
         if let Some(ref rev) = self.commit {
             checkout_commit(&repo, rev).unwrap_or_else(|e| {
-                println!("[error] Failed to checkout {}: {}", rev, e);
+                println!("[error] Failed to checkout commit {}: {}", rev, e);
+                process::exit(1)
+            });
+        } else if let Some(ref tag) = self.tag {
+            checkout_tag(&repo, tag).unwrap_or_else(|e| {
+                println!("[error] Failed to checkout tag {}: {}", tag, e);
                 process::exit(1)
             });
-
-            println!("[info ] HEAD is at {}", rev);
         }
-
-        println!("[info ] Cloned at '{}'", self.path.display());
     }
 }
 
 fn checkout_commit(repo: &Repository, rev: &str) -> Result<(), git2::Error> {
     let oid = Oid::from_str(rev)?;
     let commit = repo.find_commit(oid)?;
-    repo.branch(rev, &commit, false)?;
 
+    // Create a new branch `rev` that points to `commit`
+    repo.branch(rev, &commit, true)?;
+
+    // Checkout the newly created branch
     let treeish = format!("refs/heads/{}", rev);
     let object = repo.revparse_single(&treeish)?;
-
     repo.checkout_tree(&object, None)?;
     repo.set_head(&treeish)?;
 
+    println!("[info ] Checked out commit {}", rev);
+
+    Ok(())
+}
+
+fn checkout_tag(repo: &Repository, tag_name: &str) -> Result<(), git2::Error> {
+    // Find a tag with name `tag_name`
+    let tag = repo
+        .references()?
+        .into_iter()
+        .flatten()
+        .filter(|r| r.is_tag())
+        .flat_map(|r| r.peel_to_tag())
+        .find(|t| t.name() == Some(tag_name));
+
+    if let Some(tag) = tag {
+        // Get the commit this tag points to
+        let target_oid = tag.target()?.id();
+        let commit = repo.find_commit(target_oid)?;
+
+        // Create a new branch `tag_name` that points to `commit`
+        repo.branch(tag_name, &commit, true)?;
+
+        // Checkout the newly created branch
+        let rev = format!("refs/heads/{}", tag_name);
+        let obj = repo.revparse_single(&rev)?;
+        repo.checkout_tree(&obj, None)?;
+        repo.set_head(&rev)?;
+
+        println!("[info ] Checked out tag {}", tag_name);
+    } else {
+        println!("[error] Could not find tag {}", tag_name);
+        process::exit(1);
+    }
+
     Ok(())
 }