enhancement: Add option to specify rust-toolchain.toml path (#47)

Author: Kubaryt

README.md

@@ -49,7 +49,7 @@ First, all items specified in the toolchain file are installed.
 Afterward, the `components` and `target` specified via inputs are installed in addition to the items from the toolchain file.
 
 | Name                     | Description                                                                                                             | Default       |
-| ------------------------ | ----------------------------------------------------------------------------------------------------------------------- | ------------- |
+|--------------------------|-------------------------------------------------------------------------------------------------------------------------| ------------- |
 | `toolchain`              | Comma-separated list of Rustup toolchain specifier e.g. `stable`, `nightly`, `1.42.0`. The last version is the default. | stable        |
 | `target`                 | Additional target support to install e.g. `wasm32-unknown-unknown`                                                      |               |
 | `components`             | Comma-separated string of additional components to install e.g. `clippy, rustfmt`                                       |               |
@@ -66,6 +66,7 @@ Afterward, the `components` and `target` specified via inputs are installed in a
 | `matcher`                | Enable problem matcher to surface build messages and formatting issues                                                  | true          |
 | `rustflags`              | Set the value of `RUSTFLAGS` (set to empty string to avoid overwriting existing flags)                                  | "-D warnings" |
 | `override`               | Setup the last installed toolchain as the default via `rustup override`                                                 | true          |
+| `rust-toolchain-dir`     | Path from root directory to directory with the rust toolchain file (if its not in the root of the repository)           |               |
 
 [`Swatinem/rust-cache`]: https://github.com/Swatinem/rust-cache
 

action.yml

@@ -69,6 +69,9 @@ inputs:
     description: "Setup the last installed toolchain as the default via `rustup override`"
     required: false
     default: "true"
+  rust-toolchain-dir:
+    description: "Specify path from root directory to the directory to search for rust-toolchain.toml file. By default root directory will be used."
+    required: false
 
 outputs:
   rustc-version:
@@ -163,14 +166,18 @@ runs:
         targets: ${{inputs.target}}
         components: ${{inputs.components}}
         override: ${{inputs.override}}
+        rust_toolchain_dir: ${{inputs.rust-toolchain-dir}}
       shell: bash
       run: |
-        if [[ -z "$toolchain" && ( -f "rust-toolchain" || -f "rust-toolchain.toml" ) ]]
+        if [[ -z "$toolchain" && ( -f "rust-toolchain" || -f "rust-toolchain.toml" || -f "$rust_toolchain_dir/rust-toolchain.toml") ]]
         then
           # Install the toolchain as specified in the file
           # rustup show is the old way that implicitly installed a toolchain
           # rustup toolchain install is the new explicit way
           # https://github.com/rust-lang/rustup/issues/3635#issuecomment-2343511297
+          if [[ -n "$rust_toolchain_dir" ]]; then
+              cd "$rust_toolchain_dir"
+          fi
           rustup show active-toolchain || rustup toolchain install
           if [[ -n $components ]]; then
             rustup component add ${components//,/ }