[tobiasraabe]

Changes

Ubuntu 26.04 installs Graphviz 14.1.2. The Python 3.11 lowest-dependency job selects PyGraphviz 1.12, which fails to compile because its gvRenderData wrapper passes unsigned int * where Graphviz expects size_t *. This blocks the merge-queue checks for #1028 before the lowest-dependency tests start.

Raise the Linux test dependency minimum to PyGraphviz 2.0, the first release containing the upstream compatibility fix: pygraphviz/pygraphviz#603. Refresh the corresponding lockfile requirement; the locked package remains at 2.0.3.

Validation

• just lint passed.
• uv lock --check passed.
• uv pip compile with Python 3.11, Linux x86_64, --resolution lowest-direct, and --only-binary :all: selects PyGraphviz 2.0.
• Linux Python 3.11.16 / PyGraphviz 2.0, lowest dependency resolution: pytest tests/test_dag_command.py -q passed (21 tests). Local Linux is Ubuntu 22.04; Ubuntu 26.04 validation runs in CI.

Todo

• Review whether documentation needs updating: no public API or runtime dependency change.
• Review the changelog: omitted because this only changes the test environment minimum.