feat: improve InvalidIndexFile error to mention index file names

lychee-bin/tests/cli.rs

@@ -2546,12 +2546,12 @@ mod cli {
     fn test_index_files_specified() {
         let input = fixtures_path().join("filechecker/dir_links.md");
 
-        // passing `--index-files index.html` should reject all links
+        // passing `--index-files index.html,index.htm` should reject all links
         // to /empty_dir because it doesn't have the index file
         let result = main_command()
-            .arg(input)
+            .arg(&input)
             .arg("--index-files")
-            .arg("index.html")
+            .arg("index.html,index.htm")
             .arg("--verbose")
             .assert()
             .failure();
@@ -2561,7 +2561,18 @@ mod cli {
         result
             .stdout(contains("Cannot find index file").count(empty_dir_links))
             .stdout(contains("/empty_dir").count(empty_dir_links))
+            .stdout(contains("(index.html, or index.htm)").count(empty_dir_links))
             .stdout(contains(format!("{index_dir_links} OK")));
+
+        // within the error message, formatting of the index file name list should
+        // omit empty names.
+        main_command()
+            .arg(&input)
+            .arg("--index-files")
+            .arg(",index.html,,,index.htm,")
+            .assert()
+            .failure()
+            .stdout(contains("(index.html, or index.htm)").count(empty_dir_links));
     }
 
     #[test]
@@ -2601,7 +2612,7 @@ mod cli {
         // passing an empty list to --index-files should reject /all/
         // directory links.
         let result = main_command()
-            .arg(input)
+            .arg(&input)
             .arg("--index-files")
             .arg("")
             .assert()
@@ -2610,6 +2621,17 @@ mod cli {
         let num_dir_links = 4;
         result
             .stdout(contains("Cannot find index file").count(num_dir_links))
+            .stdout(contains("No directory links are allowed").count(num_dir_links))
+            .stdout(contains("0 OK"));
+
+        // ... as should passing a number of empty index file names
+        main_command()
+            .arg(&input)
+            .arg("--index-files")
+            .arg(",,,,,")
+            .assert()
+            .failure()
+            .stdout(contains("No directory links are allowed").count(num_dir_links))
             .stdout(contains("0 OK"));
     }
 

lychee-lib/src/checker/file.rs

@@ -229,6 +229,15 @@ impl FileChecker {
             None => &[".".to_owned()],
         };
 
+        let invalid_index_error = || {
+            // Drop empty index file names. These will never be accepted as valid
+            // index files, and doing this makes cleaner error reporting.
+            let mut names = index_names_to_try.to_vec();
+            names.retain(|x| !x.is_empty());
+
+            ErrorKind::InvalidIndexFile(names)
+        };
+
         index_names_to_try
             .iter()
             .find_map(|filename| {
@@ -242,7 +251,7 @@ impl FileChecker {
                 let path = dir_path.join(filename);
                 exists(&path).then_some(path)
             })
-            .ok_or_else(|| ErrorKind::InvalidIndexFile(dir_path.to_path_buf()))
+            .ok_or_else(invalid_index_error)
     }
 
     /// Checks a resolved file, optionally verifying fragments for HTML files.

lychee-lib/src/types/error.rs

@@ -70,9 +70,9 @@ pub enum ErrorKind {
     #[error("Cannot find fragment")]
     InvalidFragment(Uri),
 
-    /// The given directory is missing a required index file
+    /// Cannot resolve local directory link using the configured index files
     #[error("Cannot find index file within directory")]
-    InvalidIndexFile(PathBuf),
+    InvalidIndexFile(Vec<String>),
 
     /// The given path cannot be converted to a URI
     #[error("Invalid path to URL conversion: {0}")]
@@ -330,9 +330,11 @@ impl ErrorKind {
             ErrorKind::StatusCodeSelectorError(status_code_selector_error) => Some(format!(
                 "Status code selector error: {status_code_selector_error}. Check accept configuration",
             )),
-            ErrorKind::InvalidIndexFile(_path) => Some(
-                "Index file not found in directory. Check if index.html or other index files exist".to_string()
-            ),
+            ErrorKind::InvalidIndexFile(index_files) => match &index_files[..] {
+                [] => "No directory links are allowed because index_files is defined and empty".to_string(),
+                [name] => format!("An index file ({name}) is required"),
+                [init @ .., tail] => format!("An index file ({}, or {}) is required", init.join(", "), tail),
+            }.into()
         }
     }