Summary

When uv sync --frozen is run against a workspace, credentials embedded in
[tool.uv.sources] entries that live in workspace-member pyproject.toml
files are silently dropped. The same entries work correctly under uv lock
and uv sync (without --frozen). For private git deps this manifests as
fatal: could not read Username for 'https://github.com': terminal prompts disabled.

Minimal reproducible example

repo/
├── pyproject.toml              # workspace root; declares members; no [tool.uv.sources]
├── uv.lock
└── nested/
    └── pyproject.toml          # [tool.uv.sources]
                                # example = { git = "https://user:password@github.com/organization/repository", tag = "v1" }

Root pyproject.toml:

[project]
name = "root"
version = "0"
requires-python = ">=3.12"
dependencies = ["example"]

[tool.uv.workspace]
members = ["nested"]

nested/pyproject.toml:

[project]
name = "nested"
version = "0"
requires-python = ">=3.12"
dependencies = ["example"]

[tool.uv.sources]
example = { git = "https://user:password@github.com/organization/repository", tag = "v1" }

Steps:

1. uv lock from the repo root — succeeds; lockfile correctly records
   git+https://github.com/organization/repository@<commit> with no credentials (per
   the redaction behavior introduced in Redact registry credentials in lockfile #5803).

2. uv sync --frozen from the repo root — fails:

   × Failed to download and build `example @ git+https://github.com/organization/repository@<commit>`
   ├─▶ Git operation failed
   ├─▶ failed to clone into: /root/.cache/uv/git-v0/db/...
   ├─▶ failed to fetch commit `<commit>`
   ╰─▶ process didn't exit successfully:
       `/usr/bin/git fetch --force --update-head-ok 'https://github.com/organization/repository' ...`
       (exit status: 128)
       --- stderr
       fatal: could not read Username for 'https://github.com': terminal prompts disabled
   

Workaround: move the credentialed [tool.uv.sources] entry into the
workspace-root pyproject.toml, or configure git directly via
git config --global url.<auth>.insteadOf <bare> / GIT_ASKPASS / .netrc.

Root cause

Under --frozen, project discovery is intentionally scoped to the root only:

store_credentials_from_target then iterates target.sources(), which walks
workspace.sources() plus each loaded member's [tool.uv.sources]:

With MemberDiscovery::None, members aren't loaded, so member-level
[tool.uv.sources] are invisible to store_credentials_from_target, and
GIT_STORE never gets the credentials. GitSource::fetch then runs against
the bare URL:

Expected behavior

uv sync --frozen should respect credentials defined in any workspace
member's [tool.uv.sources], consistently with uv lock and uv sync
without --frozen. The lockfile already records workspace membership, so
credentials can be collected from each member's pyproject.toml on disk
without doing full member discovery / validation.

Related

• Redact registry credentials in lockfile #5803 — Redact registry credentials in lockfile (established that creds in
  pyproject.toml must be re-applied at install time; this issue is a
  follow-up where re-application is incomplete for workspaces under
  --frozen).
• Provide an way to provide Git authentication for tool.uv.sources #8529 — Provide a way to provide Git authentication for tool.uv.sources
  (broader umbrella; this issue is the concrete --frozen subset).

Platform

macOS 26 arm64

Version

uv 0.11.14 (3fdfdc7 2026-05-12 aarch64-apple-darwin)

Python version

Python 3.14.2