write reload unit test

helix-core/src/history.rs

@@ -118,7 +118,7 @@ impl Revision {
 }
 
 // Temporarily 3 for review.
-const HEADER_TAG: &str = "Helix Undofile 3\n";
+const HEADER_TAG: &str = "Helix Undofile 4\n";
 
 fn get_hash<R: Read>(reader: &mut R) -> std::io::Result<[u8; 20]> {
     const BUF_SIZE: usize = 8192;
@@ -155,6 +155,7 @@ impl History {
         write_u64(writer, mtime)?;
         writer.write_all(&get_hash(&mut std::fs::File::open(path)?)?)?;
 
+        // Append new revisions to the end of the file.
         write_usize(writer, self.revisions.len())?;
         writer.seek(SeekFrom::End(0))?;
         for rev in &self.revisions[last_saved_revision..] {

helix-loader/src/lib.rs

@@ -70,7 +70,7 @@ pub fn local_config_dirs() -> Vec<PathBuf> {
 }
 
 pub fn cache_dir() -> PathBuf {
-    let mut path = if cfg!(feature = "integration") {
+    let mut path = if cfg!(feature = "integration") || cfg!(test) {
         std::env::temp_dir()
     } else {
         // TODO: allow env var override

helix-view/Cargo.toml

@@ -52,4 +52,6 @@ clipboard-win = { version = "4.5", features = ["std"] }
 libc = "0.2"
 
 [dev-dependencies]
+quickcheck = { version = "1", default-features = false }
+tempfile = "3"
 helix-tui = { path = "../helix-tui" }

helix-view/src/document.rs

@@ -636,6 +636,7 @@ impl Document {
                         .into_std()
                         .await;
                     tokio::task::spawn_blocking(move || -> anyhow::Result<()> {
+                        // Truncate the file if it's not a valid undofile.
                         if History::deserialize(&mut std::fs::File::open(&undofile_path)?, &path)
                             .is_ok()
                         {
@@ -1386,7 +1387,8 @@ impl Display for FormatterError {
 
 #[cfg(test)]
 mod test {
-    use arc_swap::ArcSwap;
+    use arc_swap::{access::Map, ArcSwap};
+    use quickcheck::Gen;
 
     use super::*;
 
@@ -1556,6 +1558,98 @@ mod test {
         );
     }
 
+    #[tokio::test(flavor = "multi_thread")]
+    async fn reload_history() {
+        let test_fn: fn(Vec<String>) -> bool = |changes| -> bool {
+            let len = changes.len() / 3;
+            let mut original = Rope::new();
+            let mut iter = changes.into_iter();
+
+            let changes_a: Vec<_> = iter
+                .by_ref()
+                .take(len)
+                .map(|c| {
+                    let c = Rope::from(c);
+                    let transaction = helix_core::diff::compare_ropes(&original, &c);
+                    original = c;
+                    transaction
+                })
+                .collect();
+            let mut original_concurrent = original.clone();
+
+            let changes_b: Vec<_> = iter
+                .by_ref()
+                .take(len)
+                .map(|c| {
+                    let c = Rope::from(c);
+                    let transaction = helix_core::diff::compare_ropes(&original, &c);
+                    original = c;
+                    transaction
+                })
+                .collect();
+            let changes_c: Vec<_> = iter
+                .take(len)
+                .map(|c| {
+                    let c = Rope::from(c);
+                    let transaction = helix_core::diff::compare_ropes(&original_concurrent, &c);
+                    original_concurrent = c;
+                    transaction
+                })
+                .collect();
+
+            let file = tempfile::NamedTempFile::new().unwrap();
+            let mut config = Config::default();
+            config.persistent_undo = true;
+
+            let view_id = ViewId::default();
+            let config = Arc::new(ArcSwap::new(Arc::new(config)));
+            let mut doc_1 = Document::open(file.path(), None, None, config.clone()).unwrap();
+            doc_1.ensure_view_init(view_id);
+
+            // Make changes & save document A
+            for c in changes_a {
+                doc_1.apply(&c, view_id);
+            }
+            helix_lsp::block_on(doc_1.save::<PathBuf>(None, true).unwrap()).unwrap();
+
+            let mut doc_2 = Document::open(file.path(), None, None, config.clone()).unwrap();
+            let mut doc_3 = Document::open(file.path(), None, None, config.clone()).unwrap();
+            doc_2.ensure_view_init(view_id);
+            doc_3.ensure_view_init(view_id);
+
+            // Make changes in A and B at the same time.
+            for c in changes_b {
+                doc_1.apply(&c, view_id);
+            }
+
+            for c in changes_c {
+                doc_2.apply(&c, view_id);
+            }
+            helix_lsp::block_on(doc_2.save::<PathBuf>(None, true).unwrap()).unwrap();
+
+            doc_1.load_history().unwrap();
+            doc_3.load_history().unwrap();
+
+            assert_eq!(doc_2.history.get_mut(), doc_3.history.get_mut());
+
+            helix_lsp::block_on(doc_1.save::<PathBuf>(None, true).unwrap()).unwrap();
+            doc_2.load_history().unwrap();
+            doc_3.load_history().unwrap();
+            doc_1.history.get_mut() == doc_2.history.get_mut()
+                && doc_1.history.get_mut() == doc_3.history.get_mut()
+        };
+        let handles: Vec<_> = (0..100)
+            .map(|_| {
+                tokio::task::spawn_blocking(move || {
+                    quickcheck::QuickCheck::new()
+                        .max_tests(1)
+                        .quickcheck(test_fn);
+                })
+            })
+            .collect();
+        futures_util::future::try_join_all(handles).await.unwrap();
+    }
+
     macro_rules! decode {
         ($name:ident, $label:expr, $label_override:expr) => {
             #[test]