implement transaction

README.md

@@ -110,6 +110,29 @@ let movies = await client->findMovies({
 
 There's just one thing to notice in relation to regular EdgeQL - we require you to put a comment at the top of your query with a `@name` annotation, naming the query. This is because we need to be able to discern which query is which in the current ReScript file, since you can put as many queries as you want in the same ReScript file.
 
+### Using transactions
+
+There's a `transaction` function emitted for each EdgeQL query. You can use that to do your operation in a transaction:
+
+```rescript
+let client = EdgeDB.Client.make()
+
+// Remember to define your EdgeQL using a module, so you get easy access to all generated functions.
+module InsertMovie = %edgeql(`
+  # @name insertMovie
+  insert Movie {
+      title := <str>$title,
+      status :=  <PublishStatus>$status
+  }`)
+
+await client->EdgeDB.Client.transaction(async tx => {
+  await tx->InsertMovie.transaction({
+    title: "Jalla Jalla",
+    status: #Published
+  })
+})
+```
+
 ### Cardinality
 
 EdgeDB and `rescript-edgedb` automatically manages the cardinality of each query for you. That means that you can always trust the return types of your query. For example, adding `limit 1` to the `findMovies` query above would make the return types `option<movie>` instead of `array<movie>`.
@@ -127,10 +150,10 @@ Yes, you should. This ensures building the project doesn't _have_ to rely on a r
 
 ## WIP
 
-- [ ] Simple transactions support
-- [ ] CLI to statically prevent overfetching
+- [x] Simple transactions support
+- [x] CLI to statically prevent overfetching
 - [ ] Improve CLI docs
-- [ ] Test/example project
+- [x] Test/example project
 - [ ] Figure out publishing
 - [ ] Generate docs using new ReScript doc generation
 

cli/EdgeDbGenerator.res

@@ -414,6 +414,14 @@ ${params.types.distinctTypes->Set.values->Iterator.toArray->Array.joinWith("\n\n
           : ""}${extraInFnArgs}): ${returnType} => {
     client->EdgeDB.QueryHelpers.${method}(queryText${hasArgs ? ", ~args" : ""}${extraInFnApply})
   }
+
+  let transaction = (transaction: EdgeDB.Transaction.t${hasArgs
+          ? `, args: args`
+          : ""}${extraInFnArgs}): ${returnType} => {
+    transaction->EdgeDB.TransactionHelpers.${method}(queryText${hasArgs
+          ? ", ~args"
+          : ""}${extraInFnApply})
+  }
 }\n\n`,
     )
   })

dbTestProject/src/Movies.res

@@ -35,3 +35,21 @@ let movieByTitle = (client, ~title) => {
     title: title,
   })
 }
+
+let _ = %edgeql(`
+  # @name AddActor
+  insert Person {
+    name := <str>$name
+  }
+`)
+
+// Workaround until new release of rescript-embed-lang
+let addActor = Movies__edgeDb.AddActor.transaction
+
+let _ = %edgeql(`
+  # @name RemoveActor
+  delete Person filter .id = <uuid>$id
+`)
+
+// Workaround until new release of rescript-embed-lang
+let removeActor = Movies__edgeDb.RemoveActor.transaction

dbTestProject/test/TestProject.test.res

@@ -35,6 +35,33 @@ describe("fetching data", () => {
       await client->Movies.movieByTitle(~title="The Great Adventure 2"),
     )->Expect.toMatchSnapshot
   })
+
+  testAsync("running in a transaction", async () => {
+    let res = await client->EdgeDB.Client.transaction(
+      async transaction => {
+        await transaction->Movies.addActor({name: "Bruce Willis"})
+      },
+    )
+
+    expect(
+      switch res {
+      | Ok({id}) =>
+        let removed = await client->EdgeDB.Client.transaction(
+          async transaction => {
+            await transaction->Movies.removeActor({id: id})
+          },
+        )
+        switch removed {
+        | Some({id}) =>
+          // Just for the unused CLI output
+          let _id = id
+        | None => ()
+        }
+        id->String.length > 2
+      | Error(_) => false
+      },
+    )->Expect.toBe(true)
+  })
 })
 
 test("run unused selections CLI", () => {

package.json

@@ -5,7 +5,7 @@
   "main": "src/EdgeDB.mjs",
   "bin": "dist/Cli.js",
   "scripts": {
-    "test": "bun test test/",
+    "test": "bun test test/*.test.mjs",
     "build:res": "rescript",
     "build": "npm run build:res && esbuild --external:edgedb --external:chokidar --platform=node --bundle cli/Cli.mjs --outfile=dist/Cli.js"
   },

src/EdgeDB.res

@@ -1,8 +1,6 @@
 module Transaction = {
   type t
 
-  @module("edgedb") external make: unit => t = "createClient"
-
   @send external execute: (t, string, ~args: 'args=?) => promise<unit> = "execute"
 
   @send external query: (t, string, ~args: 'args=?) => promise<array<'result>> = "query"
@@ -400,3 +398,28 @@ module QueryHelpers = {
     | exception Exn.Error(err) => Error(err->Error.fromExn)
     }
 }
+
+module TransactionHelpers = {
+  /** Returns all found items as an array. */
+  let many = (client, query, ~args=?) => Transaction.query(client, query, ~args)
+
+  /** Returns a single item, if one was found. */
+  let single = async (client, query, ~args=?, ~onError=?) =>
+    switch await Transaction.querySingle(client, query, ~args) {
+    | Value(v) => Some(v)
+    | Null => None
+    | exception Exn.Error(err) =>
+      switch onError {
+      | None => ()
+      | Some(onError) => onError(err->Error.fromExn)
+      }
+      None
+    }
+
+  /** Assumes exactly one item is going to be found, and errors if that's not the case. */
+  let singleRequired = async (client, query, ~args=?) =>
+    switch await Transaction.queryRequiredSingle(client, query, ~args) {
+    | v => Ok(v)
+    | exception Exn.Error(err) => Error(err->Error.fromExn)
+    }
+}

test/__snapshots__/EdgeDbGeneratorTests.test.mjs.snap

@@ -1,36 +1,5 @@
 // Bun Snapshot v1, https://goo.gl/fbAQLP
 
-exports[`generate file 1`] = `
-{
-  "contents": 
-"// @sourceHash 43efb7cecb4f08bcf22e679cf6cdeed5
-module FindMovie = {
-  let queryText = \`select Movie {
-          title,
-          status,
-          actors: {
-              name,
-              age
-          }
-      } filter 
-          .title = <str>$movieTitle\`
-
-  type args = {movieTitle: string}
-
-  type response = {title: string, status: [#Published | #Unpublished]}
-
-  let query = (client: EdgeDB.Client.t, args: args): promise<result<response, EdgeDB.Error.errorFromOperation>> => {
-    client->EdgeDB.QueryHelpers.singleRequired(queryText, ~args)
-  }
-}
-
-"
-,
-  "hash": "43efb7cecb4f08bcf22e679cf6cdeed5",
-  "path": "SomeQueryFile__edgeDb.res",
-}
-`;
-
 exports[`extracting queries from ReScript documents it can extract from docs #1 1`] = `
 "select Movie {
         title,
@@ -73,3 +42,38 @@ exports[`extracting queries from ReScript documents it can extract from docs #2
         } filter 
             .id = <uuid>$userId"
 `;
+
+exports[`generate file 1`] = `
+{
+  "contents": 
+"// @sourceHash b71c2e4fb6a0ba65311c5fce81401d7a
+module FindMovie = {
+  let queryText = \`select Movie {
+          title,
+          status,
+          actors: {
+              name,
+              age
+          }
+      } filter 
+          .title = <str>$movieTitle\`
+
+  type args = {movieTitle: string}
+
+  type response = {title: string, status: [#Published | #Unpublished]}
+
+  let query = (client: EdgeDB.Client.t, args: args): promise<result<response, EdgeDB.Error.errorFromOperation>> => {
+    client->EdgeDB.QueryHelpers.singleRequired(queryText, ~args)
+  }
+
+  let transaction = (transaction: EdgeDB.Transaction.t, args: args): promise<result<response, EdgeDB.Error.errorFromOperation>> => {
+    transaction->EdgeDB.TransactionHelpers.singleRequired(queryText, ~args)
+  }
+}
+
+"
+,
+  "hash": "b71c2e4fb6a0ba65311c5fce81401d7a",
+  "path": "SomeQueryFile__edgeDb.res",
+}
+`;