Unable to drop unique index on collection field after schema modification

[akshdev1998]

Prerequisites

• I have written a descriptive issue title
• I have searched existing issues to ensure the bug has not already been reported

Mongoose version

8.7.0

Node.js version

v22.6.0

MongoDB server version

6.9.0

Typescript version (if applicable)

No response

Description

Prerequisites

• I have written a descriptive issue title[x] I have searched existing issues to ensure the bug has not already been reported

Mongoose version

8.7.0

Node.js version

22.6.0

MongoDB server version

6.9.0

Typescript version (if applicable)

5.6.2

Description

Description: I encountered an issue where I was unable to drop the unique index on the employeeId field in my MongoDB collection, even after modifying the schema to remove the unique constraint. The behavior suggests that the unique index on the employeeId field remained intact despite my attempts to remove it.

Steps to Reproduce

Steps to Reproduce:

1. Create a schema with a unique index on employeeId.
2. Try to drop the index using Mongoose.
3. Change the schema name.
4. Attempt to drop the index again.

Steps to Reproduce

Steps to Reproduce:

1. Create a schema with a unique index on employeeId.
2. Try to drop the index using Mongoose.
3. Change the schema name.
4. Attempt to drop the index again.

Expected Behavior

Expected Behavior:
The index on employeeId should be dropped successfully.

Actual Behavior:
The index could not be dropped, and the schema modification was ineffective.

Code Example:

const XrInteractionSchema = new mongoose.Schema({
  employeeId: { type: String, unique: true },
  // other fields
});
// for taking this issue
```javascript
const XrInteractionSchema = new mongoose.Schema({
  employeeId: { type: String, },
  // other fields
});

[vkarpov15]

Can you please clarify how you're doing "Try to drop the index using Mongoose." - are you just removing the index from your schema, are you using syncIndexes(), are you doing something else?

[akshdev1998]

I am removed indexes from the schema but still it is giving referencing old schema... so the issue with this

First i save with unique true

const XrInteractionSchema = new mongoose.Schema({ employeeId: { type: String, unique: true }, // other fields });

Final Schema is this but mongodb is referencing previous code

const XrInteractionSchema = new mongoose.Schema({ employeeId: { type: String, }, // other fields });

SO WHY IT IS HAPPENING