Publishing fails with 'duplicate version' for servers not visible in API

[olgasafonova]

Bug Description

When trying to publish io.github.olgasafonova/productplan-mcp-server version 4.7.0, the registry returns:

Error: invalid version: cannot publish duplicate version

However, querying the API returns 404:

curl https://registry.modelcontextprotocol.io/v0.1/servers/io.github.olgasafonova%2Fproductplan-mcp-server
# Returns: 404 Not Found

Root Cause Analysis

Looking at the source code, there's a mismatch between the duplicate check and the public API:

CheckVersionExists (duplicate check):

SELECT EXISTS(SELECT 1 FROM servers WHERE server_name = $1 AND version = $2)

GetServerByName (public API):

SELECT ... FROM servers WHERE server_name = $1 AND is_latest = true

The duplicate check doesn't filter by is_latest, so if a version exists with is_latest = false, it will:

• Block new publishes (version exists in table)
• Return 404 on API (no is_latest = true record)

Expected Behavior

Either:

1. The duplicate check should only consider is_latest = true versions, OR
2. There should be a way to republish/overwrite versions, OR
3. A more helpful error message explaining the server exists but isn't visible

Steps to Reproduce

1. Attempt to publish io.github.olgasafonova/productplan-mcp-server version 4.7.0
2. Get 'duplicate version' error
3. Query API - get 404

Environment

• mcp-publisher CLI (latest)
• GitHub OAuth authentication