[bug]: Next test-set ID incorrectly uses numeric suffix from custom metadata names #4377

Problem Summary

When a test-set is recorded with custom metadata ending in a number, that number incorrectly influences the next auto-generated test-set-N ID, causing it to skip ahead unexpectedly.

Example

Code:

pkg.NextID([]string{"test-set-0", "checkout-flow-999"}, "test-set-")

Expected Output:

test-set-1

Actual Output:

test-set-1000

Why This Happens

The allocator extracts numeric suffixes from all strings in the input list, not just those matching the requested prefix. When it encounters checkout-flow-999, it treats 999 as a candidate ID for the test-set- sequence, causing the next ID to incorrectly jump to 1000.

User-Level Impact

keploy record -c "<app cmd>" --metadata "name=checkout-flow-999"
keploy record -c "<app cmd>"

The second recording may create:

keploy/test-set-1000

Instead of the expected:

keploy/test-set-1

Root Cause

The ID parsing logic in pkg.NextID() and pkg.LastID() extracts numeric suffixes without first filtering by the requested prefix.

Affected Files

• pkg/service/record/record.go
• pkg/util.go

Likely Fix Area

• pkg.NextID() — Filter candidate IDs to only those starting with the provided prefix before extracting numeric suffixes
• pkg.LastID() — Same parsing pattern; requires the same fix

Solution Approach

Modify the ID extraction logic to:

1. Filter strings to match prefix + numeric pattern only
2. Extract the numeric part from matching IDs
3. Return the next sequential number