Fix CI (#727)

- Replace `::add-path::` CI command with environment files
- Placate Clippy
- Consolidate cache actions

.github/workflows/build.yaml

@@ -10,12 +10,6 @@ on:
     branches:
     - master
 
-env:
-  # Increment to invalidate github actions caches if they become corrupt.
-  # Errors of the form "can't find crate for `snafu_derive` which `snafu` depends on"
-  # can usually be fixed by incrementing this value.
-  CACHE_KEY_PREFIX: 4
-
 jobs:
   all:
     name: All
@@ -48,25 +42,16 @@ jobs:
       if: matrix.os == 'macos-latest'
       run: |
         brew install gnu-tar
-        echo "::add-path::/usr/local/opt/gnu-tar/libexec/gnubin"
+        echo /usr/local/opt/gnu-tar/libexec/gnubin > $GITHUB_PATH
 
-    - name: Cache cargo registry
+    - name: Cache Cargo
       uses: actions/cache@v1
       with:
-        path: ~/.cargo/registry
-        key: ${{ env.CACHE_KEY_PREFIX }}-${{ runner.os }}-cargo-registry-${{ hashFiles('**/Cargo.lock') }}
-
-    - name: Cache cargo index
-      uses: actions/cache@v1
-      with:
-        path: ~/.cargo/git
-        key: ${{ env.CACHE_KEY_PREFIX }}-${{ runner.os }}-cargo-index-${{ hashFiles('**/Cargo.lock') }}
-
-    - name: Cache cargo build
-      uses: actions/cache@v1
-      with:
-        path: target
-        key: ${{ env.CACHE_KEY_PREFIX }}-${{ runner.os }}-cargo-build-target-${{ hashFiles('**/Cargo.lock') }}
+        path: |
+          ~/.cargo/registry
+          ~/.cargo/git
+          target
+        key: ${{ runner.os }}-cargo-${{ hashFiles('**/Cargo.lock') }}
 
     - name: Install Main Toolchain
       uses: actions-rs/toolchain@v1

src/lib.rs

@@ -1,7 +1,6 @@
 #![deny(clippy::all, clippy::pedantic, clippy::restriction)]
 #![allow(
   clippy::blanket_clippy_restriction_lints,
-  clippy::option_if_let_else,
   clippy::comparison_chain,
   clippy::else_if_without_else,
   clippy::enum_glob_use,
@@ -19,7 +18,9 @@
   clippy::missing_inline_in_public_items,
   clippy::needless_pass_by_value,
   clippy::non_ascii_literal,
+  clippy::option_if_let_else,
   clippy::panic,
+  clippy::panic_in_result_fn,
   clippy::pattern_type_mismatch,
   clippy::print_stdout,
   clippy::shadow_unrelated,
@@ -27,6 +28,7 @@
   clippy::struct_excessive_bools,
   clippy::too_many_lines,
   clippy::unreachable,
+  clippy::unwrap_in_result,
   clippy::unwrap_used,
   clippy::use_debug,
   clippy::wildcard_enum_match_arm,

src/recipe.rs

@@ -234,7 +234,7 @@ impl<'src, D> Recipe<'src, D> {
           command = &command[1..];
         }
 
-        if command == "" {
+        if command.is_empty() {
           continue;
         }
 

src/shebang.rs

@@ -19,7 +19,7 @@ impl<'line> Shebang<'line> {
     let interpreter = pieces.next().unwrap_or("");
     let argument = pieces.next();
 
-    if interpreter == "" {
+    if interpreter.is_empty() {
       return None;
     }