Add optional eslint to the rustdoc-js test target

Author: JohnHeitmann

config.toml.example

@@ -144,6 +144,10 @@
 # target when running tests, otherwise this can be omitted.
 #nodejs = "node"
 
+# The eslint executable to use. Note that this is only used for linting js files
+# during the test phase. It can be omitted.
+#eslint = "eslint"
+
 # Python interpreter to use for various tasks throughout the build, notably
 # rustdoc tests, the lldb python interpreter, and some dist bits and pieces.
 # Note that Python 2 is currently required.

src/bootstrap/config.rs

@@ -136,6 +136,7 @@ pub struct Config {
     pub libdir: Option<PathBuf>,
     pub mandir: Option<PathBuf>,
     pub codegen_tests: bool,
+    pub eslint: Option<PathBuf>,
     pub nodejs: Option<PathBuf>,
     pub gdb: Option<PathBuf>,
     pub python: Option<PathBuf>,
@@ -202,6 +203,7 @@ struct Build {
     gdb: Option<String>,
     locked_deps: Option<bool>,
     vendor: Option<bool>,
+    eslint: Option<String>,
     nodejs: Option<String>,
     python: Option<String>,
     full_bootstrap: Option<bool>,
@@ -444,6 +446,7 @@ impl Config {
         };
 
 
+        config.eslint = build.eslint.map(PathBuf::from);
         config.nodejs = build.nodejs.map(PathBuf::from);
         config.gdb = build.gdb.map(PathBuf::from);
         config.python = build.python.map(PathBuf::from);

src/bootstrap/test.rs

@@ -609,6 +609,14 @@ impl Step for RustdocJS {
                 "No nodejs found, skipping \"src/test/rustdoc-js\" tests"
             );
         }
+
+        if let Some(ref eslint) = builder.config.eslint {
+            let mut command = Command::new(eslint);
+            command.args(&["src/librustdoc/html/static"]);
+            builder.run(&mut command);
+        } else {
+            builder.info("No eslint found, skipping js linting");
+        }
     }
 }