Rollup merge of #87035 - GuillaumeGomez:fix-implementors-display, r=notriddle

Fix implementors display

Part of https://github.com/rust-lang/rust/issues/86632.

This PR does a few things:
 * It fixes of the JS rendered implementors.
 * It generates anchors for JS rendered implementors to make it coherent with the others.
 * It adds a test to ensure that we won't have the same issue again.
 * It changes the way we render the rustdoc-gui crates to simplify it a bit and also to allow to have dependencies without going through compiletest.

Before:

![Screenshot from 2021-07-10 13-30-13](https://user-images.githubusercontent.com/3050060/125174172-b4048700-e1c3-11eb-8f0e-c46081371d4f.png)

After:

![Screenshot from 2021-07-10 21-11-15](https://user-images.githubusercontent.com/3050060/125174173-b49d1d80-e1c3-11eb-8740-1dbbff70c2eb.png)

I plan to add the `[src]` links in another PR because this one is already big enough.

cc `@Mark-Simulacrum` (for the bootstrap changes)

r? `@Nemo157`

.gitignore

@@ -72,4 +72,7 @@ __pycache__/
 **node_modules
 **package-lock.json
 
+## Rustdoc GUI tests
+src/test/rustdoc-gui/src/**.lock
+
 # Before adding new lines, see the comment at the top.

src/bootstrap/test.rs

@@ -907,27 +907,25 @@ impl Step for RustdocGUI {
         // We remove existing folder to be sure there won't be artifacts remaining.
         let _ = fs::remove_dir_all(&out_dir);
 
-        let mut nb_generated = 0;
+        let src_path = "src/test/rustdoc-gui/src";
         // We generate docs for the libraries present in the rustdoc-gui's src folder.
-        let libs_dir = builder.build.src.join("src/test/rustdoc-gui/src");
-        for entry in libs_dir.read_dir().expect("read_dir call failed") {
-            let entry = entry.expect("invalid entry");
-            let path = entry.path();
-            if path.extension().map(|e| e == "rs").unwrap_or(false) {
-                let mut command = builder.rustdoc_cmd(self.compiler);
-                command.arg(path).arg("-o").arg(&out_dir);
-                builder.run(&mut command);
-                nb_generated += 1;
-            }
-        }
-        assert!(nb_generated > 0, "no documentation was generated...");
+        let mut cargo = Command::new(&builder.initial_cargo);
+        cargo
+            .arg("doc")
+            .arg("--workspace")
+            .arg("--target-dir")
+            .arg(&out_dir)
+            .env("RUSTDOC", builder.rustdoc(self.compiler))
+            .env("RUSTC", builder.rustc(self.compiler))
+            .current_dir(&builder.build.src.join(src_path));
+        builder.run(&mut cargo);
 
         // We now run GUI tests.
         let mut command = Command::new(&nodejs);
         command
             .arg(builder.build.src.join("src/tools/rustdoc-gui/tester.js"))
             .arg("--doc-folder")
-            .arg(out_dir)
+            .arg(out_dir.join("doc"))
             .arg("--tests-folder")
             .arg(builder.build.src.join("src/test/rustdoc-gui"));
         for path in &builder.paths {

src/librustdoc/html/static/js/main.js

@@ -683,6 +683,9 @@ function hideThemeButtonState() {
             });
         }
 
+        var currentNbImpls = implementors.getElementsByClassName("impl").length;
+        var traitName = document.querySelector("h1.fqn > .in-band > .trait").textContent;
+        var baseIdName = "impl-" + traitName + "-";
         var libs = Object.getOwnPropertyNames(imp);
         for (var i = 0, llength = libs.length; i < llength; ++i) {
             if (libs[i] === window.currentCrate) { continue; }
@@ -705,6 +708,7 @@ function hideThemeButtonState() {
 
                 var code = document.createElement("code");
                 code.innerHTML = struct.text;
+                addClass(code, "in-band");
 
                 onEachLazy(code.getElementsByTagName("a"), function(elem) {
                     var href = elem.getAttribute("href");
@@ -714,12 +718,18 @@ function hideThemeButtonState() {
                     }
                 });
 
-                var display = document.createElement("h3");
+                var currentId = baseIdName + currentNbImpls;
+                var anchor = document.createElement("a");
+                anchor.href = "#" + currentId;
+                addClass(anchor, "anchor");
+
+                var display = document.createElement("div");
+                display.id = currentId;
                 addClass(display, "impl");
-                display.innerHTML = "<span class=\"in-band\"><table class=\"table-display\">" +
-                    "<tbody><tr><td><code>" + code.outerHTML + "</code></td><td></td></tr>" +
-                    "</tbody></table></span>";
+                display.appendChild(anchor);
+                display.appendChild(code);
                 list.appendChild(display);
+                currentNbImpls += 1;
             }
         }
     };

src/test/rustdoc-gui/implementors.goml

@@ -0,0 +1,16 @@
+// The goal of this test is to check that the external trait implementors, generated with JS,
+// have the same display than the "local" ones.
+goto: file://|DOC_PATH|/implementors/trait.Whatever.html
+assert: "#implementors-list"
+// There are supposed to be two implementors listed.
+assert-count: ("#implementors-list > .impl", 2)
+// Now we check that both implementors have an anchor, an ID and a similar DOM.
+assert: ("#implementors-list > .impl:nth-child(1) > a.anchor")
+assert-attribute: ("#implementors-list > .impl:nth-child(1)", {"id": "impl-Whatever"})
+assert-attribute: ("#implementors-list > .impl:nth-child(1) > a.anchor", {"href": "#impl-Whatever"})
+assert: "#implementors-list > .impl:nth-child(1) > code.in-band"
+
+assert: ("#implementors-list > .impl:nth-child(2) > a.anchor")
+assert-attribute: ("#implementors-list > .impl:nth-child(2)", {"id": "impl-Whatever-1"})
+assert-attribute: ("#implementors-list > .impl:nth-child(2) > a.anchor", {"href": "#impl-Whatever-1"})
+assert: "#implementors-list > .impl:nth-child(2) > code.in-band"

src/test/rustdoc-gui/src/Cargo.lock

@@ -0,0 +1,18 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+version = 3
+
+[[package]]
+name = "implementors"
+version = "0.1.0"
+
+[[package]]
+name = "lib2"
+version = "0.1.0"
+dependencies = [
+ "implementors",
+]
+
+[[package]]
+name = "test_docs"
+version = "0.1.0"

src/test/rustdoc-gui/src/Cargo.toml

@@ -0,0 +1,6 @@
+[workspace]
+members = [
+    "test_docs",
+    "lib2",
+    "implementors",
+]

src/test/rustdoc-gui/src/implementors/Cargo.toml

@@ -0,0 +1,7 @@
+[package]
+name = "implementors"
+version = "0.1.0"
+edition = "2018"
+
+[lib]
+path = "lib.rs"

src/test/rustdoc-gui/src/implementors/lib.rs

@@ -0,0 +1,7 @@
+pub trait Whatever {
+    fn method() {}
+}
+
+pub struct Struct;
+
+impl Whatever for Struct {}

src/test/rustdoc-gui/src/lib2/Cargo.toml

@@ -0,0 +1,10 @@
+[package]
+name = "lib2"
+version = "0.1.0"
+edition = "2018"
+
+[lib]
+path = "lib.rs"
+
+[dependencies]
+implementors = { path = "../implementors" }

src/test/rustdoc-gui/src/lib2/lib.rs

@@ -31,3 +31,5 @@ impl Trait for Foo {
     type X = u32;
     const Y: u32 = 0;
 }
+
+impl implementors::Whatever for Foo {}

src/test/rustdoc-gui/src/lib2/src/lib.rs

@@ -0,0 +1,7 @@
+#[cfg(test)]
+mod tests {
+    #[test]
+    fn it_works() {
+        assert_eq!(2 + 2, 4);
+    }
+}

src/test/rustdoc-gui/src/test_docs/Cargo.toml

@@ -0,0 +1,7 @@
+[package]
+name = "test_docs"
+version = "0.1.0"
+edition = "2018"
+
+[lib]
+path = "lib.rs"