rust-lang · ehuss · Aug 13, 2025 · Aug 13, 2025
diff --git a/crates/mdbook-core/src/config.rs b/crates/mdbook-core/src/config.rs
@@ -411,7 +411,7 @@ pub enum RustEdition {
 }
 
 /// Configuration for the HTML renderer.
-#[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
+#[derive(Default, Debug, Clone, PartialEq, Serialize, Deserialize)]
 #[serde(default, rename_all = "kebab-case", deny_unknown_fields)]
 #[non_exhaustive]
 pub struct HtmlConfig {
@@ -426,8 +426,6 @@ pub struct HtmlConfig {
     pub smart_punctuation: bool,
     /// Should mathjax be enabled?
     pub mathjax_support: bool,
-    /// Whether to fonts.css and respective font files to the output directory.
-    pub copy_fonts: bool,
     /// Additional CSS stylesheets to include in the rendered page's `<head>`.
     pub additional_css: Vec<PathBuf>,
     /// Additional JS scripts to include at the bottom of the rendered page's
@@ -481,36 +479,6 @@ pub struct HtmlConfig {
     pub hash_files: bool,
 }
 
-impl Default for HtmlConfig {
-    fn default() -> HtmlConfig {
-        HtmlConfig {
-            theme: None,
-            default_theme: None,
-            preferred_dark_theme: None,
-            smart_punctuation: false,
-            mathjax_support: false,
-            copy_fonts: true,
-            additional_css: Vec::new(),
-            additional_js: Vec::new(),
-            fold: Fold::default(),
-            playground: Playground::default(),
-            code: Code::default(),
-            print: Print::default(),
-            no_section_label: false,
-            search: None,
-            git_repository_url: None,
-            git_repository_icon: None,
-            edit_url_template: None,
-            input_404: None,
-            site_url: None,
-            cname: None,
-            live_reload_endpoint: None,
-            redirect: HashMap::new(),
-            hash_files: false,
-        }
-    }
-}
-
 impl HtmlConfig {
     /// Returns the directory of theme from the provided root directory. If the
     /// directory is not present it will append the default directory of "theme"

diff --git a/crates/mdbook-html/front-end/templates/index.hbs b/crates/mdbook-html/front-end/templates/index.hbs
@@ -34,9 +34,7 @@
 
         <!-- Fonts -->
         <link rel="stylesheet" href="{{ resource "FontAwesome/css/font-awesome.css" }}">
-        {{#if copy_fonts}}
         <link rel="stylesheet" href="{{ resource "fonts/fonts.css" }}">
-        {{/if}}
 
         <!-- Highlight.js Stylesheets -->
         <link rel="stylesheet" id="highlight-css" href="{{ resource "highlight.css" }}">

diff --git a/crates/mdbook-html/front-end/templates/toc.html.hbs b/crates/mdbook-html/front-end/templates/toc.html.hbs
@@ -29,9 +29,7 @@
         {{/if}}
         <!-- Fonts -->
         <link rel="stylesheet" href="{{ resource "FontAwesome/css/font-awesome.css" }}">
-        {{#if copy_fonts}}
         <link rel="stylesheet" href="{{ resource "fonts/fonts.css" }}">
-        {{/if}}
         <!-- Custom theme stylesheets -->
         {{#each additional_css}}
         <link rel="stylesheet" href="{{ resource this }}">

diff --git a/crates/mdbook-html/src/html_handlebars/hbs_renderer.rs b/crates/mdbook-html/src/html_handlebars/hbs_renderer.rs
@@ -557,11 +557,6 @@ fn make_data(
         data.insert("mathjax_support".to_owned(), json!(true));
     }
 
-    // This `matches!` checks for a non-empty file.
-    if html_config.copy_fonts || matches!(theme.fonts_css.as_deref(), Some([_, ..])) {
-        data.insert("copy_fonts".to_owned(), json!(true));
-    }
-
     // Add check to see if there is an additional style
     if !html_config.additional_css.is_empty() {
         let mut css = Vec::new();

diff --git a/crates/mdbook-html/src/html_handlebars/static_files.rs b/crates/mdbook-html/src/html_handlebars/static_files.rs
@@ -3,7 +3,7 @@
 use super::helpers::resources::ResourceHelper;
 use crate::theme::{self, Theme, playground_editor};
 use anyhow::{Context, Result};
-use log::{debug, warn};
+use log::debug;
 use mdbook_core::config::HtmlConfig;
 use mdbook_core::utils;
 use std::borrow::Cow;
@@ -84,7 +84,7 @@ impl StaticFiles {
             theme::FONT_AWESOME_WOFF2,
         );
         this.add_builtin("FontAwesome/fonts/FontAwesome.ttf", theme::FONT_AWESOME_TTF);
-        if html_config.copy_fonts && theme.fonts_css.is_none() {
+        if theme.fonts_css.is_none() {
             this.add_builtin("fonts/fonts.css", theme::fonts::CSS);
             for (file_name, contents) in theme::fonts::LICENSES.iter() {
                 this.add_builtin(file_name, contents);
@@ -101,13 +101,6 @@ impl StaticFiles {
                 this.add_builtin("fonts/fonts.css", fonts_css);
             }
         }
-        if !html_config.copy_fonts && theme.fonts_css.is_none() {
-            warn!(
-                "output.html.copy-fonts is deprecated.\n\
-                This book appears to have copy-fonts=false in book.toml without a fonts.css file.\n\
-                Add an empty `theme/fonts/fonts.css` file to squelch this warning."
-            );
-        }
 
         let playground_config = &html_config.playground;
 

diff --git a/guide/src/format/configuration/renderers.md b/guide/src/format/configuration/renderers.md
@@ -99,7 +99,6 @@ default-theme = "light"
 preferred-dark-theme = "navy"
 smart-punctuation = true
 mathjax-support = false
-copy-fonts = true
 additional-css = ["custom.css", "custom2.css"]
 additional-js = ["custom.js"]
 no-section-label = false
@@ -127,10 +126,6 @@ The following configuration options are available:
   Defaults to `false`.
 - **mathjax-support:** Adds support for [MathJax](../mathjax.md). Defaults to
   `false`.
-- **copy-fonts:** (**Deprecated**) If `true` (the default), mdBook uses its built-in fonts which are copied to the output directory.
-  If `false`, the built-in fonts will not be used.
-  This option is deprecated. If you want to define your own custom fonts,
-  create a `theme/fonts/fonts.css` file and store the fonts in the `theme/fonts/` directory.
 - **additional-css:** If you need to slightly change the appearance of your book
   without overwriting the whole style, you can specify a set of stylesheets that
   will be loaded after the default ones where you can surgically change the

diff --git a/tests/testsuite/theme.rs b/tests/testsuite/theme.rs
@@ -139,45 +139,26 @@ book/fonts/myfont.woff
         );
 }
 
-// copy-fonts=false, no theme, deprecated
+// Empty fonts.css should not copy the default fonts.
 #[test]
-fn copy_fonts_false_no_theme() {
-    BookTest::from_dir("theme/copy_fonts_false_no_theme")
+fn empty_fonts_css() {
+    BookTest::from_dir("theme/empty_fonts_css")
         .run("build", |cmd| {
             cmd.expect_stderr(str![[r#"
 [TIMESTAMP] [INFO] (mdbook_driver::mdbook): Book building has started
 [TIMESTAMP] [INFO] (mdbook_driver::mdbook): Running the html backend
-[TIMESTAMP] [WARN] (mdbook_html::html_handlebars::static_files): output.html.copy-fonts is deprecated.
-This book appears to have copy-fonts=false in book.toml without a fonts.css file.
-Add an empty `theme/fonts/fonts.css` file to squelch this warning.
 [TIMESTAMP] [INFO] (mdbook_html::html_handlebars::hbs_renderer): HTML book written to `[ROOT]/book`
 
 "#]]);
         })
-        .check_file_doesnt_contain("book/index.html", "fonts.css")
-        .check_file_list("book/fonts", str![[""]]);
-}
-
-// copy-fonts=false, empty fonts.css
-#[test]
-fn copy_fonts_false_with_empty_fonts_css() {
-    BookTest::from_dir("theme/copy_fonts_false_with_empty_fonts_css")
-        .run("build", |cmd| {
-            cmd.expect_stderr(str![[r#"
-[TIMESTAMP] [INFO] (mdbook_driver::mdbook): Book building has started
-[TIMESTAMP] [INFO] (mdbook_driver::mdbook): Running the html backend
-[TIMESTAMP] [INFO] (mdbook_html::html_handlebars::hbs_renderer): HTML book written to `[ROOT]/book`
-
-"#]]);
-        })
-        .check_file_doesnt_contain("book/index.html", "fonts.css")
+        .check_file_contains("book/index.html", "fonts.css")
         .check_file_list("book/fonts", str![[""]]);
 }
 
-// copy-fonts=false, fonts.css has contents
+// Custom fonts.css file shouldn't copy default fonts.
 #[test]
-fn copy_fonts_false_with_fonts_css() {
-    BookTest::from_dir("theme/copy_fonts_false_with_fonts_css")
+fn custom_fonts_css() {
+    BookTest::from_dir("theme/custom_fonts_css")
         .run("build", |cmd| {
             cmd.expect_stderr(str![[r#"
 [TIMESTAMP] [INFO] (mdbook_driver::mdbook): Book building has started

diff --git a/tests/testsuite/theme/copy_fonts_false_no_theme/book.toml b/tests/testsuite/theme/copy_fonts_false_no_theme/book.toml
diff --git a/tests/testsuite/theme/copy_fonts_false_with_empty_fonts_css/book.toml b/tests/testsuite/theme/copy_fonts_false_with_empty_fonts_css/book.toml
diff --git a/tests/testsuite/theme/copy_fonts_false_with_fonts_css/book.toml b/tests/testsuite/theme/copy_fonts_false_with_fonts_css/book.toml
diff --git a/tests/testsuite/theme/copy_fonts_false_with_fonts_css/src/SUMMARY.md b/tests/testsuite/theme/copy_fonts_false_with_fonts_css/src/SUMMARY.md
diff --git a/tests/testsuite/theme/custom_fonts_css/book.toml b/tests/testsuite/theme/custom_fonts_css/book.toml
@@ -0,0 +1,2 @@
+[book]
+title = "custom_fonts_css"
diff --git a/.../copy_fonts_false_no_theme/src/SUMMARY.md → ...ite/theme/custom_fonts_css/src/SUMMARY.md b/.../copy_fonts_false_no_theme/src/SUMMARY.md → ...ite/theme/custom_fonts_css/src/SUMMARY.md
diff --git a/...alse_with_fonts_css/theme/fonts/fonts.css → ...me/custom_fonts_css/theme/fonts/fonts.css b/...alse_with_fonts_css/theme/fonts/fonts.css → ...me/custom_fonts_css/theme/fonts/fonts.css
diff --git a/...se_with_fonts_css/theme/fonts/myfont.woff → .../custom_fonts_css/theme/fonts/myfont.woff b/...se_with_fonts_css/theme/fonts/myfont.woff → .../custom_fonts_css/theme/fonts/myfont.woff
diff --git a/tests/testsuite/theme/empty_fonts_css/book.toml b/tests/testsuite/theme/empty_fonts_css/book.toml
@@ -0,0 +1,2 @@
+[book]
+title = "empty_fonts_css"
diff --git a/...false_with_empty_fonts_css/src/SUMMARY.md → ...uite/theme/empty_fonts_css/src/SUMMARY.md b/...false_with_empty_fonts_css/src/SUMMARY.md → ...uite/theme/empty_fonts_css/src/SUMMARY.md
diff --git a/...ith_empty_fonts_css/theme/fonts/fonts.css → ...eme/empty_fonts_css/theme/fonts/fonts.css b/...ith_empty_fonts_css/theme/fonts/fonts.css → ...eme/empty_fonts_css/theme/fonts/fonts.css