refactor(db-mongodb,drizzle): reduce race condition window between retrieving and using a session (#14653)

## Description

Moves `getSession` (MongoDB) and `getTransaction` (Drizzle) calls to
immediately before database operations.

## Why

When sessions are retrieved early in a function but used much later,
there's a race condition window: if a parallel operation commits/ends
that session before we use it, we get `MongoExpiredSessionError`. By
retrieving the session right before use, we minimize this window.

This alone significantly reduced transaction errors in #14651. By
retrieving sessions closer to use, if a parallel operation commits the
transaction before we retrieve it, we get `undefined` instead of an
expired session. Operations then run without a session (which succeeds)
rather than attempting to use an expired session (which errors).

**Example:**

```ts
// Before - 50+ line window where session could be ended by parallel operation
const session = await getSession(this, req)
const query = await buildQuery(...)     // Line 1
transform(data)                         // Line 2
// ... 48 more lines
await Model.find(query, { session })    // Line 50 - session might be expired!
```

```ts
// After - retrieve right before use
const query = await buildQuery(...)
transform(data)
const session = await getSession(this, req)  // Get it now
await Model.find(query, { session })         // Use immediately
```

Author: AlessioGr

packages/db-mongodb/src/count.ts

@@ -15,10 +15,6 @@ export const count: Count = async function count(
 ) {
   const { collectionConfig, Model } = getCollection({ adapter: this, collectionSlug })
 
-  const options: CountOptions = {
-    session: await getSession(this, req),
-  }
-
   let hasNearConstraint = false
 
   if (where) {
@@ -37,6 +33,10 @@ export const count: Count = async function count(
   // useEstimatedCount is faster, but not accurate, as it ignores any filters. It is thus set to true if there are no filters.
   const useEstimatedCount = hasNearConstraint || !query || Object.keys(query).length === 0
 
+  const options: CountOptions = {
+    session: await getSession(this, req),
+  }
+
   if (!useEstimatedCount && Object.keys(query).length === 0 && this.disableIndexHints !== true) {
     // Improve the performance of the countDocuments query which is used if useEstimatedCount is set to false by adding
     // a hint. By default, if no hint is provided, MongoDB does not use an indexed field to count the returned documents,

packages/db-mongodb/src/countGlobalVersions.ts

@@ -15,10 +15,6 @@ export const countGlobalVersions: CountGlobalVersions = async function countGlob
 ) {
   const { globalConfig, Model } = getGlobal({ adapter: this, globalSlug, versions: true })
 
-  const options: CountOptions = {
-    session: await getSession(this, req),
-  }
-
   let hasNearConstraint = false
 
   if (where) {
@@ -36,6 +32,10 @@ export const countGlobalVersions: CountGlobalVersions = async function countGlob
   // useEstimatedCount is faster, but not accurate, as it ignores any filters. It is thus set to true if there are no filters.
   const useEstimatedCount = hasNearConstraint || !query || Object.keys(query).length === 0
 
+  const options: CountOptions = {
+    session: await getSession(this, req),
+  }
+
   if (!useEstimatedCount && Object.keys(query).length === 0 && this.disableIndexHints !== true) {
     // Improve the performance of the countDocuments query which is used if useEstimatedCount is set to false by adding
     // a hint. By default, if no hint is provided, MongoDB does not use an indexed field to count the returned documents,

packages/db-mongodb/src/countVersions.ts

@@ -19,10 +19,6 @@ export const countVersions: CountVersions = async function countVersions(
     versions: true,
   })
 
-  const options: CountOptions = {
-    session: await getSession(this, req),
-  }
-
   let hasNearConstraint = false
 
   if (where) {
@@ -40,6 +36,10 @@ export const countVersions: CountVersions = async function countVersions(
   // useEstimatedCount is faster, but not accurate, as it ignores any filters. It is thus set to true if there are no filters.
   const useEstimatedCount = hasNearConstraint || !query || Object.keys(query).length === 0
 
+  const options: CountOptions = {
+    session: await getSession(this, req),
+  }
+
   if (!useEstimatedCount && Object.keys(query).length === 0 && this.disableIndexHints !== true) {
     // Improve the performance of the countDocuments query which is used if useEstimatedCount is set to false by adding
     // a hint. By default, if no hint is provided, MongoDB does not use an indexed field to count the returned documents,

packages/db-mongodb/src/create.ts

@@ -15,12 +15,6 @@ export const create: Create = async function create(
 ) {
   const { collectionConfig, customIDType, Model } = getCollection({ adapter: this, collectionSlug })
 
-  const options: CreateOptions = {
-    session: await getSession(this, req),
-    // Timestamps are manually added by the write transform
-    timestamps: false,
-  }
-
   let doc
 
   if (!data.createdAt) {
@@ -47,6 +41,12 @@ export const create: Create = async function create(
     }
   }
 
+  const options: CreateOptions = {
+    session: await getSession(this, req),
+    // Timestamps are manually added by the write transform
+    timestamps: false,
+  }
+
   try {
     ;[doc] = await Model.create([data], options)
   } catch (error) {

packages/db-mongodb/src/createGlobalVersion.ts

@@ -22,12 +22,6 @@ export const createGlobalVersion: CreateGlobalVersion = async function createGlo
 ) {
   const { globalConfig, Model } = getGlobal({ adapter: this, globalSlug, versions: true })
 
-  const options = {
-    session: await getSession(this, req),
-    // Timestamps are manually added by the write transform
-    timestamps: false,
-  }
-
   const data = {
     autosave,
     createdAt,
@@ -50,6 +44,12 @@ export const createGlobalVersion: CreateGlobalVersion = async function createGlo
     operation: 'write',
   })
 
+  const options = {
+    session: await getSession(this, req),
+    // Timestamps are manually added by the write transform
+    timestamps: false,
+  }
+
   let [doc] = await Model.create([data], options, req)
 
   await Model.updateMany(

packages/db-mongodb/src/createVersion.ts

@@ -27,12 +27,6 @@ export const createVersion: CreateVersion = async function createVersion(
     versions: true,
   })
 
-  const options = {
-    session: await getSession(this, req),
-    // Timestamps are manually added by the write transform
-    timestamps: false,
-  }
-
   const data = {
     autosave,
     createdAt,
@@ -56,6 +50,12 @@ export const createVersion: CreateVersion = async function createVersion(
     operation: 'write',
   })
 
+  const options = {
+    session: await getSession(this, req),
+    // Timestamps are manually added by the write transform
+    timestamps: false,
+  }
+
   let [doc] = await Model.create([data], options, req)
 
   const parentQuery = {

packages/db-mongodb/src/deleteMany.ts

@@ -14,16 +14,16 @@ export const deleteMany: DeleteMany = async function deleteMany(
 ) {
   const { collectionConfig, Model } = getCollection({ adapter: this, collectionSlug })
 
-  const options: DeleteOptions = {
-    session: await getSession(this, req),
-  }
-
   const query = await buildQuery({
     adapter: this,
     collectionSlug,
     fields: collectionConfig.flattenedFields,
     where,
   })
 
+  const options: DeleteOptions = {
+    session: await getSession(this, req),
+  }
+
   await Model.deleteMany(query, options)
 }

packages/db-mongodb/src/deleteOne.ts

@@ -15,6 +15,13 @@ export const deleteOne: DeleteOne = async function deleteOne(
 ) {
   const { collectionConfig, Model } = getCollection({ adapter: this, collectionSlug })
 
+  const query = await buildQuery({
+    adapter: this,
+    collectionSlug,
+    fields: collectionConfig.flattenedFields,
+    where,
+  })
+
   const options: MongooseUpdateQueryOptions = {
     projection: buildProjectionFromSelect({
       adapter: this,
@@ -24,13 +31,6 @@ export const deleteOne: DeleteOne = async function deleteOne(
     session: await getSession(this, req),
   }
 
-  const query = await buildQuery({
-    adapter: this,
-    collectionSlug,
-    fields: collectionConfig.flattenedFields,
-    where,
-  })
-
   if (returning === false) {
     await Model.deleteOne(query, options)?.lean()
     return null

packages/db-mongodb/src/deleteVersions.ts

@@ -36,14 +36,14 @@ export const deleteVersions: DeleteVersions = async function deleteVersions(
     throw new APIError('Either collection or globalSlug must be passed.')
   }
 
-  const session = await getSession(this, req)
-
   const query = await buildQuery({
     adapter: this,
     fields,
     locale,
     where,
   })
 
+  const session = await getSession(this, req)
+
   await VersionsModel.deleteMany(query, { session })
 }

packages/db-mongodb/src/find.ts

@@ -34,8 +34,6 @@ export const find: Find = async function find(
 ) {
   const { collectionConfig, Model } = getCollection({ adapter: this, collectionSlug })
 
-  const session = await getSession(this, req)
-
   let hasNearConstraint = false
 
   if (where) {
@@ -66,6 +64,8 @@ export const find: Find = async function find(
     where,
   })
 
+  const session = await getSession(this, req)
+
   // useEstimatedCount is faster, but not accurate, as it ignores any filters. It is thus set to true if there are no filters.
   const useEstimatedCount = hasNearConstraint || !query || Object.keys(query).length === 0
   const paginationOptions: PaginateOptions = {