From b87c231fc3347d98bbc03cac536c050239a7abe0 Mon Sep 17 00:00:00 2001
From: josh rotenberg <joshrotenberg@gmail.com>
Date: Sun, 4 Jul 2021 14:44:23 -0700
Subject: [PATCH] first pass at 2021 support

---
 src/book/mod.rs                              |  4 +++
 src/config.rs                                | 23 ++++++++++++++++
 src/renderer/html_handlebars/hbs_renderer.rs | 28 +++++++++++++++++++-
 src/theme/book.js                            | 11 +++++---
 4 files changed, 61 insertions(+), 5 deletions(-)

diff --git a/src/book/mod.rs b/src/book/mod.rs
index 286234bd..7f1159b4 100644
--- a/src/book/mod.rs
+++ b/src/book/mod.rs
@@ -274,6 +274,10 @@ impl MDBook {
                         RustEdition::E2018 => {
                             cmd.args(&["--edition", "2018"]);
                         }
+                        RustEdition::E2021 => {
+                            cmd.args(&["--edition", "2021"])
+                                .args(&["-Z", "unstable-options"]);
+                        }
                     }
                 }
 
diff --git a/src/config.rs b/src/config.rs
index c384192c..bf4aabbb 100644
--- a/src/config.rs
+++ b/src/config.rs
@@ -467,6 +467,9 @@ pub struct RustConfig {
 #[derive(Debug, Copy, Clone, PartialEq, Serialize, Deserialize)]
 /// Rust edition to use for the code.
 pub enum RustEdition {
+    /// The 2021 edition of Rust
+    #[serde(rename = "2021")]
+    E2021,
     /// The 2018 edition of Rust
     #[serde(rename = "2018")]
     E2018,
@@ -855,6 +858,26 @@ mod tests {
         assert_eq!(got.rust, rust_should_be);
     }
 
+    #[test]
+    fn edition_2021() {
+        let src = r#"
+        [book]
+        title = "mdBook Documentation"
+        description = "Create book from markdown files. Like Gitbook but implemented in Rust"
+        authors = ["Mathieu David"]
+        src = "./source"
+        [rust]
+        edition = "2021"
+        "#;
+
+        let rust_should_be = RustConfig {
+            edition: Some(RustEdition::E2021),
+        };
+
+        let got = Config::from_str(src).unwrap();
+        assert_eq!(got.rust, rust_should_be);
+    }
+
     #[test]
     fn load_arbitrary_output_type() {
         #[derive(Debug, Deserialize, PartialEq)]
diff --git a/src/renderer/html_handlebars/hbs_renderer.rs b/src/renderer/html_handlebars/hbs_renderer.rs
index 80b06bf8..02b7da46 100644
--- a/src/renderer/html_handlebars/hbs_renderer.rs
+++ b/src/renderer/html_handlebars/hbs_renderer.rs
@@ -836,13 +836,15 @@ fn add_playground_pre(
                 {
                     let contains_e2015 = classes.contains("edition2015");
                     let contains_e2018 = classes.contains("edition2018");
-                    let edition_class = if contains_e2015 || contains_e2018 {
+                    let contains_e2021 = classes.contains("edition2021");
+                    let edition_class = if contains_e2015 || contains_e2018 || contains_e2021 {
                         // the user forced edition, we should not overwrite it
                         ""
                     } else {
                         match edition {
                             Some(RustEdition::E2015) => " edition2015",
                             Some(RustEdition::E2018) => " edition2018",
+                            Some(RustEdition::E2021) => " edition2021",
                             None => "",
                         }
                     };
@@ -1064,4 +1066,28 @@ mod tests {
             assert_eq!(&*got, *should_be);
         }
     }
+    #[test]
+    fn add_playground_edition2021() {
+        let inputs = [
+            ("<code class=\"language-rust\">x()</code>",
+             "<pre class=\"playground\"><code class=\"language-rust edition2021\">\n<span class=\"boring\">#![allow(unused)]\n</span><span class=\"boring\">fn main() {\n</span>x()\n<span class=\"boring\">}\n</span></code></pre>"),
+            ("<code class=\"language-rust\">fn main() {}</code>",
+             "<pre class=\"playground\"><code class=\"language-rust edition2021\">fn main() {}\n</code></pre>"),
+            ("<code class=\"language-rust edition2015\">fn main() {}</code>",
+             "<pre class=\"playground\"><code class=\"language-rust edition2015\">fn main() {}\n</code></pre>"),
+            ("<code class=\"language-rust edition2018\">fn main() {}</code>",
+             "<pre class=\"playground\"><code class=\"language-rust edition2018\">fn main() {}\n</code></pre>"),
+        ];
+        for (src, should_be) in &inputs {
+            let got = add_playground_pre(
+                src,
+                &Playground {
+                    editable: true,
+                    ..Playground::default()
+                },
+                Some(RustEdition::E2021),
+            );
+            assert_eq!(&*got, *should_be);
+        }
+    }
 }
diff --git a/src/theme/book.js b/src/theme/book.js
index 5e386369..4d395821 100644
--- a/src/theme/book.js
+++ b/src/theme/book.js
@@ -108,16 +108,19 @@ function playground_text(playground) {
 
         let text = playground_text(code_block);
         let classes = code_block.querySelector('code').classList;
-        let has_2018 = classes.contains("edition2018");
-        let edition = has_2018 ? "2018" : "2015";
-
+        let edition = "2015";
+        if(classes.contains("edition2018")) {
+            edition = "2018";
+        } else if(classes.contains("edition2021")) {
+            edition = "2021";
+        }
         var params = {
             version: "stable",
             optimize: "0",
             code: text,
             edition: edition
         };
-
+        alert(params.edition);
         if (text.indexOf("#![feature") !== -1) {
             params.version = "nightly";
         }