Auto merge of #14025 - Veykril:changekind-fix, r=jonas-schievink

fix: Fix process-changes not deduplicating changes correctly

probably fixes https://github.com/rust-lang/rust-analyzer/issues/12873 (will close it with this nevertheless as its not really reproducible)

crates/proc-macro-api/src/lib.rs

@@ -121,7 +121,7 @@ impl ProcMacroServer {
     }
 
     pub fn load_dylib(&self, dylib: MacroDylib) -> Result<Vec<ProcMacro>, ServerError> {
-        let _p = profile::span("ProcMacroClient::by_dylib_path");
+        let _p = profile::span("ProcMacroClient::load_dylib");
         let macros =
             self.process.lock().unwrap_or_else(|e| e.into_inner()).find_proc_macros(&dylib.path)?;
 

crates/rust-analyzer/src/global_state.rs

@@ -3,7 +3,7 @@
 //!
 //! Each tick provides an immutable snapshot of the state as `WorldSnapshot`.
 
-use std::{sync::Arc, time::Instant};
+use std::{mem, sync::Arc, time::Instant};
 
 use crossbeam_channel::{unbounded, Receiver, Sender};
 use flycheck::FlycheckHandle;
@@ -197,29 +197,41 @@ impl GlobalState {
             // We need to fix up the changed events a bit, if we have a create or modify for a file
             // id that is followed by a delete we actually no longer observe the file text from the
             // create or modify which may cause problems later on
+            let mut collapsed_create_delete = false;
             changed_files.dedup_by(|a, b| {
                 use vfs::ChangeKind::*;
 
+                let has_collapsed_create_delete = mem::replace(&mut collapsed_create_delete, false);
+
                 if a.file_id != b.file_id {
                     return false;
                 }
 
-                match (a.change_kind, b.change_kind) {
+                // true => delete the second element (a), we swap them here as they are inverted by dedup_by
+                match (b.change_kind, a.change_kind) {
                     // duplicate can be merged
                     (Create, Create) | (Modify, Modify) | (Delete, Delete) => true,
                     // just leave the create, modify is irrelevant
-                    (Create, Modify) => {
-                        std::mem::swap(a, b);
+                    (Create, Modify) => true,
+                    // modify becomes irrelevant if the file is deleted
+                    (Modify, Delete) => {
+                        mem::swap(a, b);
+                        true
+                    }
+                    // Remove the create message, and in the following loop, also remove the delete
+                    (Create, Delete) => {
+                        collapsed_create_delete = true;
+                        b.change_kind = Delete;
+                        true
+                    }
+                    // trailing delete from earlier
+                    (Delete, Create | Modify) if has_collapsed_create_delete => {
+                        b.change_kind = Create;
                         true
                     }
-                    // modify becomes irrelevant if the file is deleted
-                    (Modify, Delete) => true,
-                    // we should fully remove this occurrence,
-                    // but leaving just a delete works as well
-                    (Create, Delete) => true,
                     // this is equivalent to a modify
                     (Delete, Create) => {
-                        a.change_kind = Modify;
+                        b.change_kind = Modify;
                         true
                     }
                     // can't really occur
@@ -227,7 +239,9 @@ impl GlobalState {
                     (Delete, Modify) => false,
                 }
             });
-
+            if collapsed_create_delete {
+                changed_files.pop();
+            }
             for file in &changed_files {
                 if let Some(path) = vfs.file_path(file.file_id).as_path() {
                     let path = path.to_path_buf();

crates/rust-analyzer/src/reload.rs

@@ -362,7 +362,7 @@ impl GlobalState {
             let loader = &mut self.loader;
             let mem_docs = &self.mem_docs;
             let mut load = move |path: &AbsPath| {
-                let _p = profile::span("GlobalState::load");
+                let _p = profile::span("switch_workspaces::load");
                 let vfs_path = vfs::VfsPath::from(path.to_path_buf());
                 if !mem_docs.contains(&vfs_path) {
                     let contents = loader.handle.load_sync(path);
@@ -584,10 +584,10 @@ pub(crate) fn load_proc_macro(
     path: &AbsPath,
     dummy_replace: &[Box<str>],
 ) -> ProcMacroLoadResult {
+    let server = server.map_err(ToOwned::to_owned)?;
     let res: Result<Vec<_>, String> = (|| {
         let dylib = MacroDylib::new(path.to_path_buf())
             .map_err(|io| format!("Proc-macro dylib loading failed: {io}"))?;
-        let server = server.map_err(ToOwned::to_owned)?;
         let vec = server.load_dylib(dylib).map_err(|e| format!("{e}"))?;
         if vec.is_empty() {
             return Err("proc macro library returned no proc macros".to_string());

crates/vfs/src/lib.rs

@@ -75,6 +75,7 @@ pub struct Vfs {
 }
 
 /// Changed file in the [`Vfs`].
+#[derive(Debug)]
 pub struct ChangedFile {
     /// Id of the changed file
     pub file_id: FileId,
@@ -161,9 +162,9 @@ impl Vfs {
         let file_id = self.alloc_file_id(path);
         let change_kind = match (&self.get(file_id), &contents) {
             (None, None) => return false,
+            (Some(old), Some(new)) if old == new => return false,
             (None, Some(_)) => ChangeKind::Create,
             (Some(_), None) => ChangeKind::Delete,
-            (Some(old), Some(new)) if old == new => return false,
             (Some(_), Some(_)) => ChangeKind::Modify,
         };