conflict moved to db

Cargo.lock

@@ -492,6 +492,7 @@ dependencies = [
  "diesel_derives",
  "itoa",
  "pq-sys",
+ "uuid",
 ]
 
 [[package]]
@@ -679,6 +680,7 @@ dependencies = [
  "enum_delegate",
  "env_logger",
  "futures",
+ "hex",
  "once_cell",
  "pretty_assertions",
  "rand",
@@ -688,6 +690,7 @@ dependencies = [
  "tokio",
  "tracing",
  "url",
+ "uuid",
 ]
 
 [[package]]
@@ -924,6 +927,12 @@ version = "0.3.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "d77f7ec81a6d05a3abb01ab6eb7590f6083d08449fe5a1c8b1e620283546ccb7"
 
+[[package]]
+name = "hex"
+version = "0.4.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7f24254aa9a54b5c858eaee2f5bccdb46aaf0e486a595ed5fd8f86ba55232a70"
+
 [[package]]
 name = "http"
 version = "0.2.11"
@@ -2276,11 +2285,12 @@ dependencies = [
 
 [[package]]
 name = "uuid"
-version = "1.5.0"
+version = "1.6.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "88ad59a7560b41a70d191093a945f0b87bc1deeda46fb237479708a1d6b6cdfc"
+checksum = "5e395fcf16a7a3d8127ec99782007af141946b4795001f876d54fb0d55978560"
 dependencies = [
  "getrandom",
+ "serde",
 ]
 
 [[package]]

Cargo.toml

@@ -10,19 +10,21 @@ async-trait = "0.1.74"
 axum = "0.6.20"
 axum-macros = "0.3.8"
 chrono = { version = "0.4.31", features = ["serde"] }
-diesel = {version = "2.1.4", features = ["postgres", "chrono"] }
+diesel = {version = "2.1.4", features = ["postgres", "chrono", "uuid"] }
 diesel-derive-newtype = "2.1.0"
 diesel_migrations = "2.1.0"
 diffy = "0.3.0"
 enum_delegate = "0.2.0"
 env_logger = { version = "0.10.1", default-features = false }
 futures = "0.3.29"
+hex = "0.4.3"
 rand = "0.8.5"
 serde = "1.0.192"
 sha2 = "0.10.8"
 tokio = { version = "1.34.0", features = ["full"] }
 tracing = "0.1.40"
 url = "2.4.1"
+uuid = { version = "1.6.1", features = ["serde"] }
 
 [dev-dependencies]
 once_cell = "1.18.0"

migrations/2023-11-28-150402_article/down.sql

@@ -1,3 +1,4 @@
+drop table conflict;
 drop table edit;
 drop table article;
 drop table instance_follow;

migrations/2023-11-28-150402_article/up.sql

@@ -28,9 +28,16 @@ create table article (
 
 create table edit (
     id serial primary key,
+    hash uuid not null,
     ap_id varchar(255) not null unique,
     diff text not null,
     article_id int REFERENCES article ON UPDATE CASCADE ON DELETE CASCADE NOT NULL,
-    version text not null,
+    previous_version_id uuid not null
-    previous_version text not null
+);
-)
+
+create table conflict (
+    id uuid primary key,
+    diff text not null,
+    article_id int REFERENCES article ON UPDATE CASCADE ON DELETE CASCADE NOT NULL,
+    previous_version_id uuid not null
+);

src/api.rs

@@ -1,7 +1,9 @@
 use crate::database::article::{ArticleView, DbArticle, DbArticleForm};
-use crate::database::edit::{DbEdit, EditVersion};
+use crate::database::conflict::{ApiConflict, DbConflict, DbConflictForm};
+use crate::database::edit::{DbEdit, DbEditForm};
 use crate::database::instance::{DbInstance, InstanceView};
-use crate::database::{DbConflict, MyDataHandle};
+use crate::database::version::EditVersion;
+use crate::database::MyDataHandle;
 use crate::error::MyResult;
 use crate::federation::activities::create_article::CreateArticle;
 use crate::federation::activities::follow::Follow;
@@ -9,14 +11,12 @@ use crate::federation::activities::submit_article_update;
 use crate::utils::generate_article_version;
 use activitypub_federation::config::Data;
 use activitypub_federation::fetch::object_id::ObjectId;
-use anyhow::anyhow;
 use axum::extract::Query;
 use axum::routing::{get, post};
 use axum::{Form, Json, Router};
 use axum_macros::debug_handler;
 use diffy::create_patch;
 use futures::future::try_join_all;
-use rand::random;
 use serde::{Deserialize, Serialize};
 use url::Url;
 
@@ -60,8 +60,7 @@ async fn create_article(
         instance_id: local_instance.id,
         local: true,
     };
-    dbg!(&form.ap_id);
+    let article = DbArticle::create(&form, &data.db_connection)?;
-    let article = dbg!(DbArticle::create(&form, &data.db_connection))?;
 
     CreateArticle::send_to_followers(article.clone(), &data).await?;
 
@@ -77,17 +76,9 @@ pub struct EditArticleData {
     pub new_text: String,
     /// The version that this edit is based on, ie [DbArticle.latest_version] or
     /// [ApiConflict.previous_version]
-    pub previous_version: EditVersion,
+    pub previous_version_id: EditVersion,
     /// If you are resolving a conflict, pass the id to delete conflict from the database
-    pub resolve_conflict_id: Option<i32>,
+    pub resolve_conflict_id: Option<EditVersion>,
-}
-
-#[derive(Clone, Debug, Serialize, Deserialize, PartialEq)]
-pub struct ApiConflict {
-    pub id: i32,
-    pub three_way_merge: String,
-    pub article_id: ObjectId<DbArticle>,
-    pub previous_version: EditVersion,
 }
 
 /// Edit an existing article (local or remote).
@@ -105,21 +96,17 @@ async fn edit_article(
     Form(edit_form): Form<EditArticleData>,
 ) -> MyResult<Json<Option<ApiConflict>>> {
     // resolve conflict if any
-    if let Some(resolve_conflict_id) = &edit_form.resolve_conflict_id {
+    if let Some(resolve_conflict_id) = edit_form.resolve_conflict_id {
-        let mut lock = data.conflicts.lock().unwrap();
+        DbConflict::delete(resolve_conflict_id, &data.db_connection)?;
-        if !lock.iter().any(|c| &c.id == resolve_conflict_id) {
-            return Err(anyhow!("invalid resolve conflict"))?;
-        }
-        lock.retain(|c| &c.id != resolve_conflict_id);
     }
     let original_article = DbArticle::read_view(edit_form.article_id, &data.db_connection)?;
 
-    if edit_form.previous_version == original_article.latest_version {
+    if edit_form.previous_version_id == original_article.latest_version {
         // No intermediate changes, simply submit new version
         submit_article_update(
             &data,
             edit_form.new_text.clone(),
-            edit_form.previous_version,
+            edit_form.previous_version_id,
             &original_article.article,
         )
         .await?;
@@ -128,20 +115,18 @@ async fn edit_article(
         // There have been other changes since this edit was initiated. Get the common ancestor
         // version and generate a diff to find out what exactly has changed.
         let ancestor =
-            generate_article_version(&original_article.edits, &edit_form.previous_version)?;
+            generate_article_version(&original_article.edits, &edit_form.previous_version_id)?;
         let patch = create_patch(&ancestor, &edit_form.new_text);
 
-        let db_conflict = DbConflict {
+        let previous_version = DbEdit::read(&edit_form.previous_version_id, &data.db_connection)?;
-            id: random(),
+        let form = DbConflictForm {
+            id: EditVersion::new(&patch.to_string())?,
             diff: patch.to_string(),
-            article_id: original_article.article.ap_id.clone(),
+            article_id: original_article.article.id,
-            previous_version: edit_form.previous_version,
+            previous_version_id: previous_version.hash,
         };
-        {
+        let conflict = DbConflict::create(&form, &data.db_connection)?;
-            let mut lock = data.conflicts.lock().unwrap();
+        Ok(Json(conflict.to_api_conflict(&data).await?))
-            lock.push(db_conflict.clone());
-        }
-        Ok(Json(db_conflict.to_api_conflict(&data).await?))
     }
 }
 
@@ -186,8 +171,8 @@ async fn resolve_article(
     data: Data<MyDataHandle>,
 ) -> MyResult<Json<ArticleView>> {
     let article: DbArticle = ObjectId::from(query.id).dereference(&data).await?;
-    let edits = DbEdit::for_article(&article, &data.db_connection)?;
+    let edits = DbEdit::read_for_article(&article, &data.db_connection)?;
-    let latest_version = edits.last().unwrap().version.clone();
+    let latest_version = edits.last().unwrap().hash.clone();
     Ok(Json(ArticleView {
         article,
         edits,
@@ -226,7 +211,7 @@ async fn follow_instance(
 /// Get a list of all unresolved edit conflicts.
 #[debug_handler]
 async fn edit_conflicts(data: Data<MyDataHandle>) -> MyResult<Json<Vec<ApiConflict>>> {
-    let conflicts = { data.conflicts.lock().unwrap().to_vec() };
+    let conflicts = DbConflict::list(&data.db_connection)?;
     let conflicts: Vec<ApiConflict> = try_join_all(conflicts.into_iter().map(|c| {
         let data = data.reset_request_count();
         async move { c.to_api_conflict(&data).await }
@@ -289,10 +274,18 @@ async fn fork_article(
 
     // copy edits to new article
     // TODO: convert to sql
-    let edits = DbEdit::for_article(&original_article, &data.db_connection)?;
+    let edits = DbEdit::read_for_article(&original_article, &data.db_connection)?;
     for e in edits {
-        let form = e.copy_to_local_fork(&article)?;
+        let ap_id = DbEditForm::generate_ap_id(&article, &e.hash)?;
-        DbEdit::create(&form, &data.db_connection)?;
+        // TODO: id gives db unique violation
+        let form = DbEditForm {
+            ap_id,
+            diff: e.diff,
+            article_id: article.id,
+            hash: e.hash,
+            previous_version_id: e.previous_version_id,
+        };
+        dbg!(DbEdit::create(&form, &data.db_connection))?;
     }
 
     CreateArticle::send_to_followers(article.clone(), &data).await?;

src/database/article.rs

@@ -1,4 +1,4 @@
-use crate::database::edit::{DbEdit, EditVersion};
+use crate::database::edit::DbEdit;
 
 use crate::database::schema::article;
 use crate::error::MyResult;
@@ -6,7 +6,7 @@ use crate::federation::objects::edits_collection::DbEditCollection;
 use activitypub_federation::fetch::collection_id::CollectionId;
 use activitypub_federation::fetch::object_id::ObjectId;
 use diesel::pg::PgConnection;
-use diesel::BelongingToDsl;
+
 use diesel::ExpressionMethods;
 use diesel::{
     insert_into, AsChangeset, BoolExpressionMethods, Identifiable, Insertable,
@@ -14,6 +14,7 @@ use diesel::{
 };
 use serde::{Deserialize, Serialize};
 
+use crate::database::version::EditVersion;
 use std::ops::DerefMut;
 use std::sync::Mutex;
 
@@ -86,8 +87,7 @@ impl DbArticle {
             article::table.find(id).get_result(conn.deref_mut())?
         };
         let latest_version = article.latest_edit_version(conn)?;
-        let mut conn = conn.lock().unwrap();
+        let edits: Vec<DbEdit> = DbEdit::read_for_article(&article, conn)?;
-        let edits: Vec<DbEdit> = DbEdit::belonging_to(&article).get_results(conn.deref_mut())?;
         Ok(ArticleView {
             article,
             edits,
@@ -137,9 +137,8 @@ impl DbArticle {
 
     // TODO: shouldnt have to read all edits from db
     pub fn latest_edit_version(&self, conn: &Mutex<PgConnection>) -> MyResult<EditVersion> {
-        let mut conn = conn.lock().unwrap();
+        let edits: Vec<DbEdit> = DbEdit::read_for_article(self, conn)?;
-        let edits: Vec<DbEdit> = DbEdit::belonging_to(&self).get_results(conn.deref_mut())?;
+        match edits.last().map(|e| e.hash.clone()) {
-        match edits.last().map(|e| e.version.clone()) {
             Some(latest_version) => Ok(latest_version),
             None => Ok(EditVersion::default()),
         }

src/database/conflict.rs

@@ -0,0 +1,108 @@
+use crate::database::article::DbArticle;
+use crate::database::edit::DbEdit;
+use crate::database::schema::conflict;
+use crate::database::version::EditVersion;
+use crate::database::MyDataHandle;
+use crate::error::MyResult;
+use crate::federation::activities::submit_article_update;
+use crate::utils::generate_article_version;
+use activitypub_federation::config::Data;
+
+use diesel::{
+    delete, insert_into, Identifiable, Insertable, PgConnection, QueryDsl, Queryable, RunQueryDsl,
+    Selectable,
+};
+use diffy::{apply, merge, Patch};
+use serde::{Deserialize, Serialize};
+use std::ops::DerefMut;
+use std::sync::Mutex;
+
+/// A local only object which represents a merge conflict. It is created
+/// when a local user edit conflicts with another concurrent edit.
+#[derive(Clone, Debug, Serialize, Deserialize, PartialEq, Queryable, Selectable, Identifiable)]
+#[diesel(table_name = conflict, check_for_backend(diesel::pg::Pg), belongs_to(DbArticle, foreign_key = article_id))]
+pub struct DbConflict {
+    pub id: EditVersion,
+    pub diff: String,
+    pub article_id: i32,
+    pub previous_version_id: EditVersion,
+}
+
+#[derive(Clone, Debug, Serialize, Deserialize, PartialEq)]
+pub struct ApiConflict {
+    pub id: EditVersion,
+    pub three_way_merge: String,
+    pub article_id: i32,
+    pub previous_version_id: EditVersion,
+}
+
+#[derive(Debug, Clone, Insertable)]
+#[diesel(table_name = conflict, check_for_backend(diesel::pg::Pg))]
+pub struct DbConflictForm {
+    pub id: EditVersion,
+    pub diff: String,
+    pub article_id: i32,
+    pub previous_version_id: EditVersion,
+}
+
+impl DbConflict {
+    pub fn create(form: &DbConflictForm, conn: &Mutex<PgConnection>) -> MyResult<Self> {
+        let mut conn = conn.lock().unwrap();
+        Ok(insert_into(conflict::table)
+            .values(form)
+            .get_result(conn.deref_mut())?)
+    }
+    pub fn list(conn: &Mutex<PgConnection>) -> MyResult<Vec<Self>> {
+        let mut conn = conn.lock().unwrap();
+        Ok(conflict::table.get_results(conn.deref_mut())?)
+    }
+
+    /// Delete a merge conflict after it is resolved.
+    pub fn delete(id: EditVersion, conn: &Mutex<PgConnection>) -> MyResult<Self> {
+        let mut conn = conn.lock().unwrap();
+        // TODO: should throw error on invalid id param
+        Ok(delete(conflict::table.find(id)).get_result(conn.deref_mut())?)
+    }
+
+    pub async fn to_api_conflict(
+        &self,
+        data: &Data<MyDataHandle>,
+    ) -> MyResult<Option<ApiConflict>> {
+        let article = DbArticle::read(self.article_id, &data.db_connection)?;
+        // Make sure to get latest version from origin so that all conflicts can be resolved
+        let original_article = article.ap_id.dereference_forced(data).await?;
+
+        // create common ancestor version
+        let edits = DbEdit::read_for_article(&original_article, &data.db_connection)?;
+        let ancestor = generate_article_version(&edits, &self.previous_version_id)?;
+
+        let patch = Patch::from_str(&self.diff)?;
+        // apply self.diff to ancestor to get `ours`
+        let ours = apply(&ancestor, &patch)?;
+        match merge(&ancestor, &ours, &original_article.text) {
+            Ok(new_text) => {
+                // patch applies cleanly so we are done
+                // federate the change
+                submit_article_update(
+                    data,
+                    new_text,
+                    self.previous_version_id.clone(),
+                    &original_article,
+                )
+                .await?;
+                DbConflict::delete(self.id.clone(), &data.db_connection)?;
+                Ok(None)
+            }
+            Err(three_way_merge) => {
+                // there is a merge conflict, user needs to do three-way-merge
+                Ok(Some(ApiConflict {
+                    id: self.id.clone(),
+                    three_way_merge,
+                    article_id: original_article.id,
+                    previous_version_id: original_article
+                        .latest_edit_version(&data.db_connection)?,
+                }))
+            }
+        }
+    }
+}

src/database/edit.rs

@@ -1,80 +1,71 @@
 use crate::database::schema::edit;
+use crate::database::version::EditVersion;
 use crate::database::DbArticle;
 use crate::error::MyResult;
 use activitypub_federation::fetch::object_id::ObjectId;
+use diesel::ExpressionMethods;
 use diesel::{
-    insert_into, AsChangeset, Identifiable, Insertable, PgConnection, Queryable, RunQueryDsl,
+    insert_into, AsChangeset, Insertable, PgConnection, QueryDsl, Queryable, RunQueryDsl,
     Selectable,
 };
-use diesel::{Associations, BelongingToDsl};
-use diesel_derive_newtype::DieselNewType;
 use diffy::create_patch;
 use serde::{Deserialize, Serialize};
-use sha2::{Digest, Sha224};
 use std::ops::DerefMut;
 use std::sync::Mutex;
 
 /// Represents a single change to the article.
-#[derive(
+#[derive(Clone, Debug, Serialize, Deserialize, PartialEq, Queryable, Selectable)]
-    Clone,
+#[diesel(table_name = edit, check_for_backend(diesel::pg::Pg))]
-    Debug,
-    Serialize,
-    Deserialize,
-    PartialEq,
-    Queryable,
-    Selectable,
-    Identifiable,
-    Associations,
-)]
-#[diesel(table_name = edit, check_for_backend(diesel::pg::Pg), belongs_to(DbArticle, foreign_key = article_id))]
 pub struct DbEdit {
+    // TODO: we could use hash as primary key, but that gives errors on forking because
+    //       the same edit is used for multiple articles
     pub id: i32,
+    /// UUID built from sha224 hash of diff
+    pub hash: EditVersion,
     pub ap_id: ObjectId<DbEdit>,
     pub diff: String,
     pub article_id: i32,
-    pub version: EditVersion,
+    /// First edit of an article always has `EditVersion::default()` here
-    // TODO: could be an Option<DbEdit.id> instead
+    pub previous_version_id: EditVersion,
-    pub previous_version: EditVersion,
 }
 
 #[derive(Debug, Clone, Insertable, AsChangeset)]
 #[diesel(table_name = edit, check_for_backend(diesel::pg::Pg))]
 pub struct DbEditForm {
+    pub hash: EditVersion,
     pub ap_id: ObjectId<DbEdit>,
     pub diff: String,
     pub article_id: i32,
-    pub version: EditVersion,
+    pub previous_version_id: EditVersion,
-    pub previous_version: EditVersion,
 }
 
 impl DbEditForm {
     pub fn new(
         original_article: &DbArticle,
         updated_text: &str,
-        previous_version: EditVersion,
+        previous_version_id: EditVersion,
     ) -> MyResult<Self> {
         let diff = create_patch(&original_article.text, updated_text);
-        let (ap_id, hash) = Self::generate_ap_id_and_hash(original_article, diff.to_bytes())?;
+        let version = EditVersion::new(&diff.to_string())?;
+        let ap_id = Self::generate_ap_id(original_article, &version)?;
         Ok(DbEditForm {
+            hash: version,
             ap_id,
             diff: diff.to_string(),
             article_id: original_article.id,
-            version: EditVersion(hash),
+            previous_version_id,
-            previous_version,
         })
     }
 
-    fn generate_ap_id_and_hash(
+    pub(crate) fn generate_ap_id(
         article: &DbArticle,
-        diff: Vec<u8>,
+        version: &EditVersion,
-    ) -> MyResult<(ObjectId<DbEdit>, String)> {
+    ) -> MyResult<ObjectId<DbEdit>> {
-        let mut sha224 = Sha224::new();
+        Ok(ObjectId::parse(&format!(
-        sha224.update(diff);
+            "{}/{}",
-        let hash = format!("{:X}", sha224.finalize());
+            article.ap_id,
-        Ok((
+            version.hash()
-            ObjectId::parse(&format!("{}/{}", article.ap_id, hash))?,
+        ))?)
-            hash,
-        ))
     }
 }
 
@@ -88,31 +79,20 @@ impl DbEdit {
             .set(form)
             .get_result(conn.deref_mut())?)
     }
-
+    pub fn read(version: &EditVersion, conn: &Mutex<PgConnection>) -> MyResult<Self> {
-    pub fn for_article(article: &DbArticle, conn: &Mutex<PgConnection>) -> MyResult<Vec<Self>> {
         let mut conn = conn.lock().unwrap();
-        Ok(DbEdit::belonging_to(&article).get_results(conn.deref_mut())?)
+        Ok(edit::table
-    }
+            .filter(edit::dsl::hash.eq(version))
-    pub fn copy_to_local_fork(self, article: &DbArticle) -> MyResult<DbEditForm> {
+            .get_result(conn.deref_mut())?)
-        let (ap_id, _) =
-            DbEditForm::generate_ap_id_and_hash(article, self.diff.clone().into_bytes())?;
-        Ok(DbEditForm {
-            ap_id,
-            diff: self.diff,
-            article_id: article.id,
-            version: self.version,
-            previous_version: self.previous_version,
-        })
-    }
     }
 
-#[derive(Clone, Debug, Serialize, Deserialize, PartialEq, DieselNewType)]
+    pub fn read_for_article(
-pub struct EditVersion(pub String);
+        article: &DbArticle,
-
+        conn: &Mutex<PgConnection>,
-impl Default for EditVersion {
+    ) -> MyResult<Vec<Self>> {
-    fn default() -> Self {
+        let mut conn = conn.lock().unwrap();
-        let sha224 = Sha224::new();
+        Ok(edit::table
-        let hash = format!("{:X}", sha224.finalize());
+            .filter(edit::dsl::article_id.eq(article.id))
-        EditVersion(hash)
+            .get_results(conn.deref_mut())?)
     }
 }

src/database/mod.rs

@@ -1,90 +1,27 @@
-use crate::api::ApiConflict;
 use crate::database::article::DbArticle;
-use crate::database::edit::DbEdit;
-use crate::error::MyResult;
-use crate::federation::activities::submit_article_update;
-use crate::utils::generate_article_version;
-use activitypub_federation::config::Data;
-use activitypub_federation::fetch::object_id::ObjectId;
-use diesel::PgConnection;
-use diffy::{apply, merge, Patch};
-use edit::EditVersion;
 
+use diesel::PgConnection;
 use std::ops::Deref;
 use std::sync::{Arc, Mutex};
 
 pub mod article;
+pub mod conflict;
 pub mod edit;
 pub mod instance;
 mod schema;
+pub mod version;
 
 #[derive(Clone)]
 pub struct MyData {
     pub db_connection: Arc<Mutex<PgConnection>>,
-    pub fake_db: Arc<FakeDatabase>,
 }
 
 impl Deref for MyData {
-    type Target = Arc<FakeDatabase>;
+    type Target = Arc<Mutex<PgConnection>>;
 
     fn deref(&self) -> &Self::Target {
-        &self.fake_db
+        &self.db_connection
     }
 }
+
 pub type MyDataHandle = MyData;
-
-pub struct FakeDatabase {
-    pub conflicts: Mutex<Vec<DbConflict>>,
-}
-
-#[derive(Clone, Debug)]
-pub struct DbConflict {
-    pub id: i32,
-    pub diff: String,
-    pub article_id: ObjectId<DbArticle>,
-    pub previous_version: EditVersion,
-}
-
-impl DbConflict {
-    pub async fn to_api_conflict(
-        &self,
-        data: &Data<MyDataHandle>,
-    ) -> MyResult<Option<ApiConflict>> {
-        // Make sure to get latest version from origin so that all conflicts can be resolved
-        let original_article = self.article_id.dereference_forced(&data).await?;
-
-        // create common ancestor version
-        let edits = DbEdit::for_article(&original_article, &data.db_connection)?;
-        let ancestor = generate_article_version(&edits, &self.previous_version)?;
-
-        let patch = Patch::from_str(&self.diff)?;
-        // apply self.diff to ancestor to get `ours`
-        let ours = apply(&ancestor, &patch)?;
-        match dbg!(merge(&ancestor, &ours, &original_article.text)) {
-            Ok(new_text) => {
-                // patch applies cleanly so we are done
-                // federate the change
-                submit_article_update(
-                    data,
-                    new_text,
-                    self.previous_version.clone(),
-                    &original_article,
-                )
-                .await?;
-                // remove conflict from db
-                let mut lock = data.conflicts.lock().unwrap();
-                lock.retain(|c| c.id != self.id);
-                Ok(None)
-            }
-            Err(three_way_merge) => {
-                // there is a merge conflict, user needs to do three-way-merge
-                Ok(Some(ApiConflict {
-                    id: self.id,
-                    three_way_merge,
-                    article_id: original_article.ap_id.clone(),
-                    previous_version: original_article.latest_edit_version(&data.db_connection)?,
-                }))
-            }
-        }
-    }
-}

src/database/schema.rs

@@ -12,15 +12,24 @@ diesel::table! {
     }
 }
 
+diesel::table! {
+    conflict (id) {
+        id -> Uuid,
+        diff -> Text,
+        article_id -> Int4,
+        previous_version_id -> Uuid,
+    }
+}
+
 diesel::table! {
     edit (id) {
         id -> Int4,
+        hash -> Uuid,
         #[max_length = 255]
         ap_id -> Varchar,
         diff -> Text,
         article_id -> Int4,
-        version -> Text,
+        previous_version_id -> Uuid,
-        previous_version -> Text,
     }
 }
 
@@ -49,6 +58,7 @@ diesel::table! {
 }
 
 diesel::joinable!(article -> instance (instance_id));
+diesel::joinable!(conflict -> article (article_id));
 diesel::joinable!(edit -> article (article_id));
 
-diesel::allow_tables_to_appear_in_same_query!(article, edit, instance, instance_follow,);
+diesel::allow_tables_to_appear_in_same_query!(article, conflict, edit, instance, instance_follow,);

src/database/version.rs

@@ -0,0 +1,43 @@
+use crate::error::MyResult;
+use std::hash::Hash;
+
+use diesel_derive_newtype::DieselNewType;
+use serde::{Deserialize, Serialize};
+use sha2::{Digest, Sha256};
+use uuid::Uuid;
+
+/// The version hash of a specific edit. Generated by taking an SHA256 hash of the diff
+/// and using the first 16 bytes so that it fits into UUID.
+#[derive(Clone, Debug, Serialize, Deserialize, PartialEq, Eq, Hash, DieselNewType)]
+pub struct EditVersion(Uuid);
+
+impl EditVersion {
+    pub fn new(diff: &str) -> MyResult<Self> {
+        let mut sha256 = Sha256::new();
+        sha256.update(diff);
+        let hash_bytes = sha256.finalize();
+        let uuid = Uuid::from_slice(&hash_bytes.as_slice()[..16])?;
+        Ok(EditVersion(uuid))
+    }
+
+    pub fn hash(&self) -> String {
+        hex::encode(self.0.into_bytes())
+    }
+}
+
+impl Default for EditVersion {
+    fn default() -> Self {
+        EditVersion::new("").unwrap()
+    }
+}
+
+#[test]
+fn test_edit_versions() -> MyResult<()> {
+    let default = EditVersion::default();
+    assert_eq!("e3b0c44298fc1c149afbf4c8996fb924", default.hash());
+
+    let version = EditVersion::new("test")?;
+    assert_eq!("9f86d081884c7d659a2feaa0c55ad015", version.hash());
+
+    Ok(())
+}

src/federation/activities/mod.rs

@@ -1,6 +1,7 @@
 use crate::database::article::DbArticle;
-use crate::database::edit::{DbEdit, DbEditForm, EditVersion};
+use crate::database::edit::{DbEdit, DbEditForm};
 use crate::database::instance::DbInstance;
+use crate::database::version::EditVersion;
 use crate::database::MyDataHandle;
 use crate::error::Error;
 use crate::federation::activities::update_local_article::UpdateLocalArticle;
@@ -30,12 +31,12 @@ pub async fn submit_article_update(
     } else {
         // dont insert edit into db, might be invalid in case of conflict
         let edit = DbEdit {
-            id: 0,
+            id: -1,
+            hash: form.hash,
             ap_id: form.ap_id,
             diff: form.diff,
             article_id: form.article_id,
-            version: form.version,
+            previous_version_id: form.previous_version_id,
-            previous_version: form.previous_version,
         };
         let instance = DbInstance::read(original_article.instance_id, &data.db_connection)?;
         UpdateRemoteArticle::send(edit, instance, data).await?;

src/federation/activities/reject.rs

@@ -1,4 +1,6 @@
+use crate::database::conflict::{DbConflict, DbConflictForm};
 use crate::database::instance::DbInstance;
+use crate::database::version::EditVersion;
 use crate::database::MyDataHandle;
 use crate::error::MyResult;
 use crate::federation::objects::edit::ApubEdit;
@@ -8,11 +10,7 @@ use activitypub_federation::{
     config::Data, fetch::object_id::ObjectId, protocol::helpers::deserialize_one_or_many,
     traits::ActivityHandler,
 };
-use rand::random;
 
-use crate::database::article::DbArticle;
-use crate::database::DbConflict;
-use crate::federation::activities::update_local_article::UpdateLocalArticle;
 use serde::{Deserialize, Serialize};
 use url::Url;
 
@@ -68,16 +66,15 @@ impl ActivityHandler for RejectEdit {
     }
 
     async fn receive(self, data: &Data<Self::DataType>) -> Result<(), Self::Error> {
-        dbg!(&self);
         // cant convert this to DbEdit as it tries to apply patch and fails
-        let mut lock = data.conflicts.lock().unwrap();
+        let article = self.object.object.dereference(data).await?;
-        let conflict = DbConflict {
+        let form = DbConflictForm {
-            id: random(),
+            id: EditVersion::new(&self.object.content)?,
             diff: self.object.content,
-            article_id: self.object.object,
+            article_id: article.id,
-            previous_version: self.object.previous_version,
+            previous_version_id: self.object.previous_version,
         };
-        lock.push(conflict);
+        DbConflict::create(&form, &data.db_connection)?;
         Ok(())
     }
 }

src/federation/objects/article.rs

@@ -1,6 +1,6 @@
 use crate::database::article::DbArticleForm;
-use crate::database::edit::EditVersion;
 use crate::database::instance::DbInstance;
+use crate::database::version::EditVersion;
 use crate::database::{article::DbArticle, MyDataHandle};
 use crate::error::Error;
 use crate::federation::objects::edits_collection::DbEditCollection;

src/federation/objects/edit.rs

@@ -1,5 +1,6 @@
 use crate::database::article::DbArticle;
-use crate::database::edit::{DbEdit, DbEditForm, EditVersion};
+use crate::database::edit::{DbEdit, DbEditForm};
+use crate::database::version::EditVersion;
 use crate::database::MyDataHandle;
 use crate::error::Error;
 use activitypub_federation::config::Data;
@@ -44,9 +45,8 @@ impl Object for DbEdit {
             kind: EditType::Edit,
             id: self.ap_id,
             content: self.diff,
-            version: self.version,
+            version: self.hash,
-            // TODO: this is wrong
+            previous_version: self.previous_version_id,
-            previous_version: self.previous_version,
             object: article.ap_id,
         })
     }
@@ -65,8 +65,8 @@ impl Object for DbEdit {
             ap_id: json.id,
             diff: json.content,
             article_id: article.id,
-            version: json.version,
+            hash: json.version,
-            previous_version: json.previous_version,
+            previous_version_id: json.previous_version,
         };
         let edit = DbEdit::create(&form, &data.db_connection)?;
         Ok(edit)

src/lib.rs

@@ -1,6 +1,6 @@
 use crate::api::api_routes;
 use crate::database::instance::{DbInstance, DbInstanceForm};
-use crate::database::{FakeDatabase, MyData};
+use crate::database::MyData;
 use crate::error::MyResult;
 use crate::federation::routes::federation_routes;
 use crate::utils::generate_activity_id;
@@ -28,10 +28,6 @@ mod utils;
 const MIGRATIONS: EmbeddedMigrations = embed_migrations!("migrations");
 
 pub async fn start(hostname: &str, database_url: &str) -> MyResult<()> {
-    let fake_db = Arc::new(FakeDatabase {
-        conflicts: Mutex::new(vec![]),
-    });
-
     let db_connection = Arc::new(Mutex::new(PgConnection::establish(database_url)?));
     db_connection
         .lock()
@@ -39,10 +35,7 @@ pub async fn start(hostname: &str, database_url: &str) -> MyResult<()> {
         .run_pending_migrations(MIGRATIONS)
         .unwrap();
 
-    let data = MyData {
+    let data = MyData { db_connection };
-        db_connection,
-        fake_db,
-    };
     let config = FederationConfig::builder()
         .domain(hostname)
         .app_data(data)

src/utils.rs

@@ -1,5 +1,5 @@
 use crate::database::edit::DbEdit;
-use crate::database::edit::EditVersion;
+use crate::database::version::EditVersion;
 use crate::error::MyResult;
 use anyhow::anyhow;
 use diffy::{apply, Patch};
@@ -31,7 +31,7 @@ pub fn generate_article_version(edits: &Vec<DbEdit>, version: &EditVersion) -> M
     for e in edits {
         let patch = Patch::from_str(&e.diff)?;
         generated = apply(&generated, &patch)?;
-        if &e.version == version {
+        if &e.hash == version {
             return Ok(generated);
         }
     }

tests/common.rs

@@ -1,12 +1,14 @@
+use anyhow::anyhow;
 use fediwiki::api::{
-    ApiConflict, CreateArticleData, EditArticleData, FollowInstance, GetArticleData, ResolveObject,
+    CreateArticleData, EditArticleData, FollowInstance, GetArticleData, ResolveObject,
 };
 use fediwiki::database::article::ArticleView;
+use fediwiki::database::conflict::ApiConflict;
 use fediwiki::database::instance::DbInstance;
 use fediwiki::error::MyResult;
 use fediwiki::start;
 use once_cell::sync::Lazy;
-use reqwest::Client;
+use reqwest::{Client, RequestBuilder, StatusCode};
 use serde::de::Deserialize;
 use serde::ser::Serialize;
 use std::env::current_dir;
@@ -142,7 +144,7 @@ pub async fn create_article(hostname: &str, title: String) -> MyResult<ArticleVi
     let edit_form = EditArticleData {
         article_id: article.article.id,
         new_text: TEST_ARTICLE_DEFAULT_TEXT.to_string(),
-        previous_version: article.latest_version,
+        previous_version_id: article.latest_version,
         resolve_conflict_id: None,
     };
     edit_article(hostname, &edit_form).await
@@ -157,13 +159,10 @@ pub async fn edit_article_with_conflict(
     hostname: &str,
     edit_form: &EditArticleData,
 ) -> MyResult<Option<ApiConflict>> {
-    Ok(CLIENT
+    let req = CLIENT
         .patch(format!("http://{}/api/v1/article", hostname))
-        .form(edit_form)
+        .form(edit_form);
-        .send()
+    handle_json_res(req).await
-        .await?
-        .json()
-        .await?)
 }
 
 pub async fn edit_article(hostname: &str, edit_form: &EditArticleData) -> MyResult<ArticleView> {
@@ -184,25 +183,34 @@ where
     T: for<'de> Deserialize<'de>,
     R: Serialize,
 {
-    let mut res = CLIENT.get(format!("http://{}/api/v1/{}", hostname, endpoint));
+    let mut req = CLIENT.get(format!("http://{}/api/v1/{}", hostname, endpoint));
     if let Some(query) = query {
-        res = res.query(&query);
+        req = req.query(&query);
     }
-    let alpha_instance: T = res.send().await?.json().await?;
+    handle_json_res(req).await
-    Ok(alpha_instance)
 }
 
 pub async fn post<T: Serialize, R>(hostname: &str, endpoint: &str, form: &T) -> MyResult<R>
 where
     R: for<'de> Deserialize<'de>,
 {
-    Ok(CLIENT
+    let req = CLIENT
         .post(format!("http://{}/api/v1/{}", hostname, endpoint))
-        .form(form)
+        .form(form);
-        .send()
+    handle_json_res(req).await
-        .await?
+}
-        .json()
+
-        .await?)
+async fn handle_json_res<T>(req: RequestBuilder) -> MyResult<T>
+where
+    T: for<'de> Deserialize<'de>,
+{
+    let res = req.send().await?;
+    if res.status() == StatusCode::OK {
+        Ok(res.json().await?)
+    } else {
+        let text = res.text().await?;
+        Err(anyhow!("Post API response {text}").into())
+    }
 }
 
 pub async fn follow_instance(api_instance: &str, follow_instance: &str) -> MyResult<()> {

tests/test.rs

@@ -7,12 +7,11 @@ use crate::common::{
     get_query, post, TestData, TEST_ARTICLE_DEFAULT_TEXT,
 };
 use common::get;
-use fediwiki::api::{
+use fediwiki::api::{EditArticleData, ForkArticleData, ResolveObject, SearchArticleData};
-    ApiConflict, EditArticleData, ForkArticleData, ResolveObject, SearchArticleData,
-};
 use fediwiki::database::article::{ArticleView, DbArticle};
 use fediwiki::error::MyResult;
 
+use fediwiki::database::conflict::ApiConflict;
 use fediwiki::database::instance::{DbInstance, InstanceView};
 use pretty_assertions::{assert_eq, assert_ne};
 use url::Url;
@@ -42,7 +41,7 @@ async fn test_create_read_and_edit_article() -> MyResult<()> {
     let edit_form = EditArticleData {
         article_id: create_res.article.id,
         new_text: "Lorem Ipsum 2".to_string(),
-        previous_version: get_res.latest_version,
+        previous_version_id: get_res.latest_version,
         resolve_conflict_id: None,
     };
     let edit_res = edit_article(&data.alpha.hostname, &edit_form).await?;
@@ -125,7 +124,7 @@ async fn test_synchronize_articles() -> MyResult<()> {
     let edit_form = EditArticleData {
         article_id: create_res.article.id,
         new_text: "Lorem Ipsum 2\n".to_string(),
-        previous_version: create_res.latest_version,
+        previous_version_id: create_res.latest_version,
         resolve_conflict_id: None,
     };
     edit_article(&data.alpha.hostname, &edit_form).await?;
@@ -179,7 +178,7 @@ async fn test_edit_local_article() -> MyResult<()> {
     let edit_form = EditArticleData {
         article_id: create_res.article.id,
         new_text: "Lorem Ipsum 2".to_string(),
-        previous_version: get_res.latest_version,
+        previous_version_id: get_res.latest_version,
         resolve_conflict_id: None,
     };
     let edit_res = edit_article(&data.beta.hostname, &edit_form).await?;
@@ -225,7 +224,7 @@ async fn test_edit_remote_article() -> MyResult<()> {
     let edit_form = EditArticleData {
         article_id: create_res.article.id,
         new_text: "Lorem Ipsum 2".to_string(),
-        previous_version: get_res.latest_version,
+        previous_version_id: get_res.latest_version,
         resolve_conflict_id: None,
     };
     let edit_res = edit_article(&data.alpha.hostname, &edit_form).await?;
@@ -265,7 +264,7 @@ async fn test_local_edit_conflict() -> MyResult<()> {
     let edit_form = EditArticleData {
         article_id: create_res.article.id,
         new_text: "Lorem Ipsum\n".to_string(),
-        previous_version: create_res.latest_version.clone(),
+        previous_version_id: create_res.latest_version.clone(),
         resolve_conflict_id: None,
     };
     let edit_res = edit_article(&data.alpha.hostname, &edit_form).await?;
@@ -276,7 +275,7 @@ async fn test_local_edit_conflict() -> MyResult<()> {
     let edit_form = EditArticleData {
         article_id: create_res.article.id,
         new_text: "Ipsum Lorem\n".to_string(),
-        previous_version: create_res.latest_version,
+        previous_version_id: create_res.latest_version,
         resolve_conflict_id: None,
     };
     let edit_res = edit_article_with_conflict(&data.alpha.hostname, &edit_form)
@@ -292,7 +291,7 @@ async fn test_local_edit_conflict() -> MyResult<()> {
     let edit_form = EditArticleData {
         article_id: create_res.article.id,
         new_text: "Lorem Ipsum and Ipsum Lorem\n".to_string(),
-        previous_version: edit_res.previous_version,
+        previous_version_id: edit_res.previous_version_id,
         resolve_conflict_id: Some(edit_res.id),
     };
     let edit_res = edit_article(&data.alpha.hostname, &edit_form).await?;
@@ -333,7 +332,7 @@ async fn test_federated_edit_conflict() -> MyResult<()> {
     let edit_form = EditArticleData {
         article_id: create_res.article.id,
         new_text: "Lorem Ipsum\n".to_string(),
-        previous_version: create_res.latest_version.clone(),
+        previous_version_id: create_res.latest_version.clone(),
         resolve_conflict_id: None,
     };
     let edit_res = edit_article(&data.alpha.hostname, &edit_form).await?;
@@ -350,7 +349,7 @@ async fn test_federated_edit_conflict() -> MyResult<()> {
     let edit_form = EditArticleData {
         article_id: create_res.article.id,
         new_text: "aaaa\n".to_string(),
-        previous_version: create_res.latest_version,
+        previous_version_id: create_res.latest_version,
         resolve_conflict_id: None,
     };
     let edit_res = edit_article(&data.gamma.hostname, &edit_form).await?;
@@ -367,8 +366,8 @@ async fn test_federated_edit_conflict() -> MyResult<()> {
     let edit_form = EditArticleData {
         article_id: create_res.article.id,
         new_text: "aaaa\n".to_string(),
-        previous_version: conflicts[0].previous_version.clone(),
+        previous_version_id: conflicts[0].previous_version_id.clone(),
-        resolve_conflict_id: Some(conflicts[0].id),
+        resolve_conflict_id: Some(conflicts[0].id.clone()),
     };
     let edit_res = edit_article(&data.gamma.hostname, &edit_form).await?;
     assert_eq!(edit_form.new_text, edit_res.article.text);
@@ -395,7 +394,7 @@ async fn test_overlapping_edits_no_conflict() -> MyResult<()> {
     let edit_form = EditArticleData {
         article_id: create_res.article.id,
         new_text: "my\nexample\ntext\n".to_string(),
-        previous_version: create_res.latest_version.clone(),
+        previous_version_id: create_res.latest_version.clone(),
         resolve_conflict_id: None,
     };
     let edit_res = edit_article(&data.alpha.hostname, &edit_form).await?;
@@ -406,7 +405,7 @@ async fn test_overlapping_edits_no_conflict() -> MyResult<()> {
     let edit_form = EditArticleData {
         article_id: create_res.article.id,
         new_text: "some\nexample\narticle\n".to_string(),
-        previous_version: create_res.latest_version,
+        previous_version_id: create_res.latest_version,
         resolve_conflict_id: None,
     };
     let edit_res = edit_article(&data.alpha.hostname, &edit_form).await?;
@@ -448,7 +447,7 @@ async fn test_fork_article() -> MyResult<()> {
     assert_eq!(resolved_article.text, forked_article.text);
     assert_eq!(resolve_res.edits.len(), fork_res.edits.len());
     assert_eq!(resolve_res.edits[0].diff, fork_res.edits[0].diff);
-    assert_eq!(resolve_res.edits[0].version, fork_res.edits[0].version);
+    assert_eq!(resolve_res.edits[0].hash, fork_res.edits[0].hash);
     assert_ne!(resolve_res.edits[0].id, fork_res.edits[0].id);
     assert_eq!(resolve_res.latest_version, fork_res.latest_version);
     assert_ne!(resolved_article.ap_id, forked_article.ap_id);