[MCP]: Prerelease installs can resolve incompatible httpx 1.0.dev builds for codeclone[mcp] #24

CodeClone version

2.0.0b6

MCP category

Packaging / launcher / transport

MCP client or host

uv tool / uv pip prerelease install flow for codeclone[mcp]; affects codeclone-mcp startup before any client-specific tool call.

What happened?

Installing the optional MCP extra with a prerelease-enabled resolver can select httpx 1.0.dev* through the MCP dependency graph. That build is incompatible with the current MCP runtime expectations and causes codeclone-mcp startup/import failure.

The base codeclone package is unaffected. Non-prerelease installs resolve a compatible stable httpx release and work as expected. The failure matters because CodeClone beta install instructions commonly use --pre, so this can affect the documented MCP install path.

What should happen instead?

The codeclone[mcp] extra should remain installable even when the outer installer uses --pre for CodeClone itself.

CodeClone should constrain the optional MCP extra to a stable compatible httpx range, e.g. httpx>=0.27.1,<1, so prerelease install flows do not accidentally resolve incompatible httpx 1.0.dev* builds.

Reproduction or request sequence

{
  "commands": [
    "uv tool install --pre \"codeclone[mcp]\"",
    "codeclone-mcp --help"
  ],
  "observed": "The MCP launcher can fail during import/startup when httpx 1.0.dev* is resolved.",
  "representative_error": "AttributeError: module 'httpx' has no attribute 'TransportError'",
  "expected": "codeclone-mcp starts normally and uses a stable httpx 0.x release."
}

Additional context

Planned/fixed in 2.0.0b7 as a packaging-only hotfix by adding a direct httpx>=0.27.1,<1 constraint to the optional MCP extra.

This does not change MCP tool schemas, report contracts, baseline/cache semantics, or runtime behavior once the server starts. It only makes the documented prerelease install path deterministic and safe.