Merge pull request #2801 from HollowMan6/btreemap

Keep preprocessors/backends execution order deterministic

Author: ehuss

crates/mdbook-core/src/config.rs

@@ -48,7 +48,7 @@ use crate::utils::log_backtrace;
 use anyhow::{Context, Error, Result, bail};
 use log::{debug, trace};
 use serde::{Deserialize, Serialize};
-use std::collections::HashMap;
+use std::collections::{BTreeMap, HashMap};
 use std::env;
 use std::fs::File;
 use std::io::Read;
@@ -214,15 +214,15 @@ impl Config {
     }
 
     /// Returns the configuration for all preprocessors.
-    pub fn preprocessors<'de, T: Deserialize<'de>>(&self) -> Result<HashMap<String, T>> {
+    pub fn preprocessors<'de, T: Deserialize<'de>>(&self) -> Result<BTreeMap<String, T>> {
         self.preprocessor
             .clone()
             .try_into()
             .with_context(|| "Failed to read preprocessors")
     }
 
     /// Returns the configuration for all renderers.
-    pub fn outputs<'de, T: Deserialize<'de>>(&self) -> Result<HashMap<String, T>> {
+    pub fn outputs<'de, T: Deserialize<'de>>(&self) -> Result<BTreeMap<String, T>> {
         self.output
             .clone()
             .try_into()

crates/mdbook-driver/src/mdbook/tests.rs

@@ -47,12 +47,10 @@ fn config_defaults_to_link_and_index_preprocessor_if_not_set() {
     // make sure we haven't got anything in the `preprocessor` table
     assert!(cfg.preprocessors::<toml::Value>().unwrap().is_empty());
 
-    let got = determine_preprocessors(&cfg, Path::new(""));
+    let got = determine_preprocessors(&cfg, Path::new("")).unwrap();
 
-    assert!(got.is_ok());
-    assert_eq!(got.as_ref().unwrap().len(), 2);
-    assert_eq!(got.as_ref().unwrap()[0].name(), "index");
-    assert_eq!(got.as_ref().unwrap()[1].name(), "links");
+    let names: Vec<_> = got.values().map(|p| p.name()).collect();
+    assert_eq!(names, ["index", "links"]);
 }
 
 #[test]
@@ -252,3 +250,35 @@ fn preprocessor_should_run_falls_back_to_supports_renderer_method() {
     let got = preprocessor_should_run(&BoolPreprocessor(should_be), &html, &cfg).unwrap();
     assert_eq!(got, should_be);
 }
+
+// Default is to sort preprocessors alphabetically.
+#[test]
+fn preprocessor_sorted_by_name() {
+    let cfg_str = r#"
+        [preprocessor.xyz]
+        [preprocessor.abc]
+        "#;
+
+    let cfg = Config::from_str(cfg_str).unwrap();
+
+    let got = determine_preprocessors(&cfg, Path::new("")).unwrap();
+
+    let names: Vec<_> = got.values().map(|p| p.name()).collect();
+    assert_eq!(names, ["abc", "index", "links", "xyz"]);
+}
+
+// Default is to sort renderers alphabetically.
+#[test]
+fn renderers_sorted_by_name() {
+    let cfg_str = r#"
+        [output.xyz]
+        [output.abc]
+        "#;
+
+    let cfg = Config::from_str(cfg_str).unwrap();
+
+    let got = determine_renderers(&cfg).unwrap();
+
+    let names: Vec<_> = got.values().map(|p| p.name()).collect();
+    assert_eq!(names, ["abc", "xyz"]);
+}