Rename tool to rustc-josh-sync and add a few fixes

Cargo.toml

@@ -1,11 +1,11 @@
 [package]
-name = "josh-sync"
+name = "rustc-josh-sync"
 version = "0.1.0"
 edition = "2024"
 
 [[bin]]
-path = "src/bin/josh_sync.rs"
-name = "josh-sync"
+path = "src/bin/rustc_josh_sync.rs"
+name = "rustc-josh-sync"
 
 [dependencies]
 anyhow = "1"

README.md

@@ -3,36 +3,36 @@ This repository contains a binary utility for performing [Josh](https://github.c
 synchronizations (pull and push) of Josh subtrees in the [rust-lang/rust](https://github.com/rust-lang/rust) repository.
 
 ## Installation
-You can install the binary `josh-sync` tool using the following command:
+You can install the binary `rustc-josh-sync` tool using the following command:
 
 ```bash
 $ cargo install --locked --git https://github.com/rust-lang/josh-sync
 ```
 
 ## Creating config file
 
-First, create a configuration file for a given subtree repo using `josh-sync init`. The config will be created under the path `josh-sync.toml`. Modify the file to fill in the name of the subtree repository (e.g. `stdarch`) and its relative path in the main `rust-lang/rust` repository (e.g. `library/stdarch`).
+First, create a configuration file for a given subtree repo using `rustc-josh-sync init`. The config will be created under the path `josh-sync.toml`. Modify the file to fill in the name of the subtree repository (e.g. `stdarch`) and its relative path in the main `rust-lang/rust` repository (e.g. `library/stdarch`).
 
 If you need to specify a more complex Josh `filter`, use `filter` field in the configuration file instead of the `path` field.
 
-The `init` command will also create an empty `rust-version` file that stores the last upstream `rustc` SHA that was synced in the subtree.
+The `init` command will also create an empty `rust-version` file (if it doesn't already exist) that stores the last upstream `rustc` SHA that was synced in the subtree.
 
 ## Performing pull
 
 A pull operation fetches changes to the subtree subdirectory that were performed in `rust-lang/rust` and merges them into the subtree repository. After performing a pull, a pull request is sent against the *subtree repository*. We *pull from rustc*.
 
 1) Checkout the latest default branch of the subtree
 2) Create a new branch that will be used for the subtree PR, e.g. `pull`
-3) Run `josh-sync pull`
+3) Run `rustc-josh-sync pull`
 4) Send a PR to the subtree repository
-    - Note that `josh-sync` can do this for you if you have the [gh](https://cli.github.com/) CLI tool installed.
+    - Note that `rustc-josh-sync` can do this for you if you have the [gh](https://cli.github.com/) CLI tool installed.
 
 ## Performing push
 
 A push operation takes changes performed in the subtree repository and merges them into the subtree subdirectory of the `rust-lang/rust` repository. After performing a push, a push request is sent against the *rustc repository*. We *push to rustc*.
 
 1) Checkout the latest default branch of the subtree
-2) Run `josh-sync pull <your-github-username> <branch>`
+2) Run `rustc-josh-sync pull <your-github-username> <branch>`
     - The branch with the push contents will be created in `https://github.com/<your-github-username>/rust` fork, in the `<branch>` branch.
 3) Send a PR to `rustc`
 
@@ -56,5 +56,5 @@ You may observe "Nothing to pull" even if you *know* rustc-pull has something to
 To minimize the likelihood of this happening, you may wish to keep a separate *minimal* git config that *only* has `[user]` entries from global git config, then repoint system git to use the minimal git config instead. E.g.
 
 ```
-GIT_CONFIG_GLOBAL=/path/to/minimal/gitconfig GIT_CONFIG_SYSTEM='' josh-sync ...
+GIT_CONFIG_GLOBAL=/path/to/minimal/gitconfig GIT_CONFIG_SYSTEM='' rustc-josh-sync ...
 ```

josh-sync.example.toml

@@ -1,3 +1,10 @@
-org = "rust-lang"
+# GitHub org of the repository (optional, `rust-lang` is the default)
+#org = "rust-lang"
+# Name of the repository
 repo = "stdarch"
+# Path where the subtree is located in rust-lang/rust
 path = "library/stdarch"
+
+# Optionally, you can specify the complete Josh filter for complex cases
+# Note that this option is mutually exclusive with `path`
+#filter = ...

src/bin/josh_sync.rs → src/bin/rustc_josh_sync.rs

@@ -57,9 +57,14 @@ fn main() -> anyhow::Result<()> {
                 .write(Path::new(DEFAULT_CONFIG_PATH))
                 .context("cannot write config")?;
             println!("Created config file at {DEFAULT_CONFIG_PATH}");
-            std::fs::write(DEFAULT_RUST_VERSION_PATH, "")
-                .context("cannot write rust-version file")?;
-            println!("Created empty rust-version file at {DEFAULT_RUST_VERSION_PATH}");
+
+            if !Path::new(DEFAULT_RUST_VERSION_PATH).is_file() {
+                std::fs::write(DEFAULT_RUST_VERSION_PATH, "")
+                    .context("cannot write rust-version file")?;
+                println!("Created empty rust-version file at {DEFAULT_RUST_VERSION_PATH}");
+            } else {
+                println!("{DEFAULT_RUST_VERSION_PATH} already exists, not doing anything with it");
+            }
         }
         Command::Pull {
             config_path,