From afc0170e62720a075d8a2a1b99cb636091b1c48f Mon Sep 17 00:00:00 2001
From: lmoresi <louis.moresi@anu.edu.au>
Date: Wed, 22 Apr 2026 09:24:18 +1000
Subject: [PATCH 1/2] Copy .petsc-version to new worktrees

worktree_create symlinks petsc-custom/petsc/ (the build) but not
petsc-custom/.petsc-version (the version pin).  The activation
script needs this file to derive PETSC_ARCH.  Without it, worktrees
fall back to the default version and ./uw build fails or links
against the wrong PETSc.

Copy (not symlink) so each worktree can independently pin a
different PETSc version via ./uw petsc switch.

Underworld development team with AI support from Claude Code (https://claude.com/claude-code)
---
 uw | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/uw b/uw
index eebb537fe..f8e241f36 100755
--- a/uw
+++ b/uw
@@ -1164,6 +1164,14 @@ worktree_create() {
         echo -e "    ${GREEN}✓${NC} petsc-custom/petsc → main repo (shared)"
     fi
 
+    # .petsc-version — copy (not symlink) so each worktree can pin its own
+    # PETSc version independently.  Initialised from the main repo's current
+    # version; the worktree can later run ./uw petsc switch to diverge.
+    if [ -f "$main_repo/petsc-custom/.petsc-version" ]; then
+        cp "$main_repo/petsc-custom/.petsc-version" "$wt_path/petsc-custom/.petsc-version"
+        echo -e "    ${GREEN}✓${NC} .petsc-version copied ($(cat "$main_repo/petsc-custom/.petsc-version"))"
+    fi
+
     # .pixi-env — copy so ./uw knows which environment to use
     if [ -f "$main_repo/.pixi-env" ]; then
         cp "$main_repo/.pixi-env" "$wt_path/.pixi-env"

From 9dd52c4e713827377d86dda6f10a3777dfbd5be3 Mon Sep 17 00:00:00 2001
From: lmoresi <louis.moresi@anu.edu.au>
Date: Wed, 22 Apr 2026 15:49:09 +1000
Subject: [PATCH 2/2] Clarify .petsc-version comment: shared source tree
 limitation

The PETSc source is symlinked, so ./uw petsc switch in a worktree
affects all worktrees.  The .petsc-version copy lets worktrees
select different already-built arch directories, not independently
switch the source checkout.

Underworld development team with AI support from Claude Code (https://claude.com/claude-code)
---
 uw | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/uw b/uw
index f8e241f36..00abd5d8a 100755
--- a/uw
+++ b/uw
@@ -1164,9 +1164,11 @@ worktree_create() {
         echo -e "    ${GREEN}✓${NC} petsc-custom/petsc → main repo (shared)"
     fi
 
-    # .petsc-version — copy (not symlink) so each worktree can pin its own
-    # PETSc version independently.  Initialised from the main repo's current
-    # version; the worktree can later run ./uw petsc switch to diverge.
+    # .petsc-version — copy (not symlink) so each worktree can select a
+    # different already-built PETSC_ARCH (e.g. petsc-324-uw-openmpi vs
+    # petsc-325-uw-openmpi).  Built arch directories coexist in the
+    # shared PETSc source tree; .petsc-version just picks which one
+    # the activation script uses for PETSC_ARCH.
     if [ -f "$main_repo/petsc-custom/.petsc-version" ]; then
         cp "$main_repo/petsc-custom/.petsc-version" "$wt_path/petsc-custom/.petsc-version"
         echo -e "    ${GREEN}✓${NC} .petsc-version copied ($(cat "$main_repo/petsc-custom/.petsc-version"))"