2026.4.2

What's Changed

• Add CC to extra_env_vars for OS.UNKNOWN by @connorjward in #5116
• Fix release workflow by @connorjward in #5120
• Fix argument ordering in a SLATE test by @connorjward in #5113
• Enable setting the base for a PR using labels by @connorjward in #5121
• Fix compositions with RestrictedFunctionSpace by @pbrubeck in #5126
• Restructure CI configs to allow for more coverage by @connorjward in #5117
• Add schedule for PETSc Firedrake '26 by @pbrubeck in #5128
• Fix push testing CI workflow by @connorjward in #5131
• Fix multidomain form data by @pbrubeck in #5132
• Fix coarse_mat_type in notebook by @pbrubeck in #5138
• Links to Firedrake26 tutorial notebooks by @pbrubeck in #5149
• Fix Real + interior facet for PCPatch by @connorjward in #5142
• AuxiliaryOperatorSNES by @JHopeCollins in #5119
• docs: Update Jack's page on Rwanda workshop by @JDBetteridge in #5160
• firedrake-run-split-tests: fall back when GNU parallel is missing by @cpjordan in #5147
• Add outer timeout for mpi testing by @cpjordan in #5150
• Fix SLATE test for pytest 9.1.0 by @connorjward in #5179
• Add Irksome to firedrake-zenodo as an optional component by @connorjward in #5182
• Assemble interpolates with Indexed arguments by @leo-collins in #5166
• Demo about Reynolds-robust Navier-Stokes by @pefarrell in #5163
• Fix Adjoint + Fieldsplit by @pbrubeck in #5197
• Add concept of 'retired' configs to firedrake-configure by @connorjward in #5153
• Fixes for irksome zenodo releases by @connorjward in #5196
• Increase docs build retention from 1 to 5 days by @connorjward in #5198
• Remove misleading link to Jupyter website by @connorjward in #5202
• replace notebooks with jupytext by @danshapero in #5195
• Tweak mesh size used in Re-robust Navier-Stokes demo by @pefarrell in #5200
• Fix linkcheck by @connorjward in #5222
• Allow in place operators to modify coordinates by @dham in #5214
• AGENTS.md by @pbrubeck in #5219
• Improve firedrake-run-split-tests by @connorjward in #5232
• SLATE: Fix codegen for elimination of 1x1 block by @pbrubeck in #5205
• Add information about hwloc env variable that breaks users installs by @connorjward in #5229
• Refactor test parameterization for some IO tests by @connorjward in #5203
• firedrake-configure: scope apt HDF5 to --with-hdf5-* and declare zlib1g-dev by @timCorintis in #5240
• Support 64-bit integer builds by @leo-collins in #5259
• Make the PETSc/wheel optimisation flags overridable in firedrake-configure by @timCorintis in #5253
• Do not use LDFLAGS+= in firedrake-configure, it doesn't exist by @connorjward in #5280
• fix flaky test by @leo-collins in #5282
• Fixes for BDDC by @pbrubeck in #5152
• Fix Netgen permutation by @pbrubeck in #5034
• Fix for complex BDDC by @pbrubeck in #5286
• Skip adaptive BDDC elasticity test in complex mode; fix skipcomplex reason display by @pbrubeck in #5291
• Fix firedrake-configure for macOS netCDF build failure by @connorjward in #5299
• macos fix firedrake-configure again (--download-pnetcdf) by @connorjward in #5303
• Fix linting of Dockerfile by @connorjward in #5304
• Increase iteration counts for flaky test by @connorjward in #5307
• Speed up our slowest test by @connorjward in #5318
• Add a demo on Carstensen-Gedicke lower bounds for the Dirichlet Poisson eigenproblem by @pefarrell in #5308
• Quash some warnings by @connorjward in #5316
• Increase default timeout for firedrake-run-split-tests to 1 hour by @connorjward in #5330
• Fix HypreADS for fieldsplit by @connorjward in #5328
• Fix DG injection for symmetric tensors by @pbrubeck in #5351
• zero initial guess for Riesz Map solve by @JHopeCollins in #5357
• Add Fedora 44 community arch by @connorjward in #5352
• Fix linkcheck by @connorjward in #5359
• Fix linkcheck by @connorjward in #5369
• Constrain Cython to <3.3.0 due to petsc4py build error by @connorjward in #5376
• Cap islpy below 2026.2 on release by @pbrubeck in #5378
• check periodicity from unique mesh in ASMExtrudedStarPC by @JHopeCollins in #5384
• Add AC to team website by @achanbour in #5387
• Fix docs makefile to automatically regenerate authors list by @achanbour in #5388
• AGENTS.md: more patterns/antipatterns by @pbrubeck in #5344
• Fix repeated assembly of Real one forms by @connorjward in #5393
• Remove dead link by @connorjward in #5397
• Fix macOS for release by @connorjward in #5389
• plotting extruded meshes by @danshapero in #5368
• Update PETSc version to 3.25.5 for release by @connorjward in #5417
• Minor firedrake-zenodo fixups by @connorjward in #5419
• Use libsupermesh release by @connorjward in #5422
• Add pygraphviz back to CI and Docker by @connorjward in #5423
• RieszMap: allow passing options_prefix for solver by @JHopeCollins in #5424

New Contributors

• @timCorintis made their first contribution in #5240

Full Changelog: 2026.4.1...2026.4.2