From 660b57e1fb5b2bc99b3db0dce48b8f903ab08cc6 Mon Sep 17 00:00:00 2001
From: Rob Parrett <robparrett@gmail.com>
Date: Fri, 20 Dec 2024 06:37:12 -0700
Subject: [PATCH] Add optional config for extra paths to watch for changes

---
 components/config/src/config/mod.rs            | 18 ++++++++++++++++++
 .../getting-started/configuration.md           |  4 ++++
 src/cmd/serve.rs                               | 14 +++++++++++++-
 src/fs_utils.rs                                |  3 ++-
 4 files changed, 37 insertions(+), 2 deletions(-)

diff --git a/components/config/src/config/mod.rs b/components/config/src/config/mod.rs
index 88d949fc21..4dbe4f51fe 100644
--- a/components/config/src/config/mod.rs
+++ b/components/config/src/config/mod.rs
@@ -102,6 +102,8 @@ pub struct Config {
     pub generate_sitemap: bool,
     /// Enables the generation of robots.txt
     pub generate_robots_txt: bool,
+    /// A list of extra paths to watch for changes
+    pub extra_watch_paths: Vec<String>,
 }
 
 #[derive(Serialize)]
@@ -123,6 +125,7 @@ pub struct SerializedConfig<'a> {
     search: search::SerializedSearch<'a>,
     generate_sitemap: bool,
     generate_robots_txt: bool,
+    extra_watch_paths: &'a [String],
 }
 
 impl Config {
@@ -340,6 +343,7 @@ impl Config {
             search: self.search.serialize(),
             generate_sitemap: self.generate_sitemap,
             generate_robots_txt: self.generate_robots_txt,
+            extra_watch_paths: &self.extra_watch_paths,
         }
     }
 }
@@ -405,6 +409,7 @@ impl Default for Config {
             extra: HashMap::new(),
             generate_sitemap: true,
             generate_robots_txt: true,
+            extra_watch_paths: Vec::new(),
         }
     }
 }
@@ -804,6 +809,19 @@ ignored_files = ["*.{graphml,iso}", "*.py?", "**/{target,temp_folder}"]
         assert!(g.is_match("content/poetry/zen.py2"));
     }
 
+    #[test]
+    fn non_empty_extra_watch_paths_results_in_vector_of_extra_watch_paths() {
+        let config_str = r#"
+title = "My site"
+base_url = "example.com"
+extra_watch_paths = ["a", "b"]
+        "#;
+
+        let config = Config::parse(config_str).unwrap();
+        let v = config.extra_watch_paths;
+        assert_eq!(v, vec!["a", "b"]);
+    }
+
     #[test]
     fn link_checker_skip_anchor_prefixes() {
         let config_str = r#"
diff --git a/docs/content/documentation/getting-started/configuration.md b/docs/content/documentation/getting-started/configuration.md
index 2565e0913f..d462eff8d7 100644
--- a/docs/content/documentation/getting-started/configuration.md
+++ b/docs/content/documentation/getting-started/configuration.md
@@ -12,6 +12,7 @@ If you are not familiar with TOML, have a look at [the TOML spec](https://github
 ⚠️ If you add keys to your `config.toml`, you must pay attention to which TOML section it belongs to. A TOML section starts with a header, e.g. `[search]`, and ends at the next section or EOF.
 
 Here are the current `config.toml` sections:
+
 1. main (unnamed)
 2. markdown
 3. link_checker
@@ -106,6 +107,9 @@ generate_sitemap = true
 # When set to "false", robots.txt is not generated
 generate_robots_txt = true
 
+# Extra paths to watch for changes, relative to config.toml
+extra_watch_paths = []
+
 # Configuration of the Markdown rendering
 [markdown]
 # When set to "true", all code blocks are highlighted.
diff --git a/src/cmd/serve.rs b/src/cmd/serve.rs
index eb2b75dd26..8fce546c4d 100644
--- a/src/cmd/serve.rs
+++ b/src/cmd/serve.rs
@@ -462,7 +462,7 @@ pub fn serve(
     // An array of (path, WatchMode, RecursiveMode) where the path is watched for changes,
     // the WatchMode value indicates whether this path must exist for zola serve to operate,
     // and the RecursiveMode value indicates whether to watch nested directories.
-    let watch_this = vec![
+    let mut watch_this = vec![
         // The first entry is ultimtely to watch config.toml in a more robust manner on Linux when
         // the file changes by way of a caching strategy used by editors such as vim.
         // https://github.com/getzola/zola/issues/2266
@@ -473,6 +473,12 @@ pub fn serve(
         ("templates", WatchMode::Optional, RecursiveMode::Recursive),
         ("themes", WatchMode::Condition(site.config.theme.is_some()), RecursiveMode::Recursive),
     ];
+    watch_this.extend(
+        site.config
+            .extra_watch_paths
+            .iter()
+            .map(|path| (path.as_str(), WatchMode::Required, RecursiveMode::Recursive)),
+    );
 
     // Setup watchers
     let (tx, rx) = channel();
@@ -810,6 +816,12 @@ pub fn serve(
                                 site = s;
                             }
                         }
+                        ChangeKind::Unknown => {
+                            // Probably a user-defined watch location. We can't know exactly what to update.
+                            if let Some(s) = recreate_site() {
+                                site = s;
+                            }
+                        }
                     };
                     messages::report_elapsed_time(start);
                 }
diff --git a/src/fs_utils.rs b/src/fs_utils.rs
index 9cd3da8a75..c4e8c699f6 100644
--- a/src/fs_utils.rs
+++ b/src/fs_utils.rs
@@ -17,6 +17,7 @@ pub enum ChangeKind {
     StaticFiles,
     Sass,
     Config,
+    Unknown,
 }
 
 /// This enum abstracts over the fine-grained group of enums in `notify`.
@@ -156,7 +157,7 @@ fn detect_change_kind(pwd: &Path, path: &Path, config_path: &Path) -> (ChangeKin
     } else if path == config_path {
         ChangeKind::Config
     } else {
-        unreachable!("Got a change in an unexpected path: {}", partial_path.display());
+        ChangeKind::Unknown
     };
 
     (change_kind, partial_path)