fix(packaging): meshbay-common clears its compiled bytecode before an upgrade

The postinst compiles __pycache__ directories the package does not own; on
the next upgrade they kept dpkg from removing directories the new version no
longer ships, and it warned. preinst/prerm (deb) and %pre/%preun (rpm)
remove them first.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

3 files changed, 41 insertions, 0 deletions

diff --git a/packaging/deb/meshbay-common/DEBIAN/preinst b/packaging/deb/meshbay-common/DEBIAN/preinst
new file mode 100755
index 0000000..16af2f8
--- /dev/null
+++ b/packaging/deb/meshbay-common/DEBIAN/preinst
@@ -0,0 +1,14 @@
+#!/bin/sh
+set -e
+
+# The postinst compiles bytecode next to every module, into __pycache__
+# directories the package does not own. Left in place, they keep dpkg from
+# removing a directory the new version no longer ships, and it warns.
+case "$1" in
+    upgrade)
+        find /opt/meshbay-common/venv -depth -type d -name __pycache__ \
+            -exec rm -rf {} + 2>/dev/null || true
+        ;;
+esac
+
+#DEBHELPER#
diff --git a/packaging/deb/meshbay-common/DEBIAN/prerm b/packaging/deb/meshbay-common/DEBIAN/prerm
new file mode 100755
index 0000000..e7b665b
--- /dev/null
+++ b/packaging/deb/meshbay-common/DEBIAN/prerm
@@ -0,0 +1,13 @@
+#!/bin/sh
+set -e
+
+# Bytecode the postinst compiled is not the package's: removed here, so that
+# dpkg can remove the directories it was written into.
+case "$1" in
+    remove|upgrade|deconfigure)
+        find /opt/meshbay-common/venv -depth -type d -name __pycache__ \
+            -exec rm -rf {} + 2>/dev/null || true
+        ;;
+esac
+
+#DEBHELPER#
diff --git a/packaging/rpm/meshbay-common.spec b/packaging/rpm/meshbay-common.spec
index 948de9a..147dc17 100644
--- a/packaging/rpm/meshbay-common.spec
+++ b/packaging/rpm/meshbay-common.spec
@@ -17,6 +17,20 @@ Installs to /opt/meshbay-common/venv/.
 %install
 cp -a %{_staging_root}/* %{buildroot}/
 
+# Bytecode written at run time into __pycache__ is not the package's, and would
+# keep rpm from removing a directory the new version no longer ships.
+%pre
+if [ "$1" -ge 2 ]; then
+    find /opt/meshbay-common/venv -depth -type d -name __pycache__ \
+        -exec rm -rf {} + 2>/dev/null || true
+fi
+
+%preun
+if [ "$1" -eq 0 ]; then
+    find /opt/meshbay-common/venv -depth -type d -name __pycache__ \
+        -exec rm -rf {} + 2>/dev/null || true
+fi
+
 %files
 /opt/meshbay-common