Add update+upgrade (U&U) test infrastructure: 0.1.0->stable update script,

test/install/load.sql three-mode loader, dependency-guard anchor, and a
permanent schema-qualification pgTAP assertion

Implements advanced-extension-testing.md checklist items 1-6 on top of
PR #17 (reconcile-object-functions):

- PGXNTOOL_ENABLE_TEST_INSTALL / PGXNTOOL_ENABLE_VERIFY_RESULTS set
  explicitly; TEST_LOAD_SOURCE (fresh/update/existing) + TEST_UPDATE_FROM/TO
  make vars, parse-time validated, propagated as placeholder GUCs via
  PGOPTIONS; `make test-update` wrapper.
- test/install/load.sql: single committed-once installer for the extension,
  covering all three load modes, including a drop-first reset (with
  pg_temp.drop_role() for the extension's own global roles) and an
  existing-mode presence/version assertion.
- sql/object_reference--0.1.0--stable.sql: hand-authored update script (there
  was previously no update path at all from the only real historical release
  to current). Recreates every function/view that changed via the same
  private-helper-schema bootstrap/teardown convention the fresh install uses,
  so the update path is verified byte-for-byte structurally identical to a
  fresh install (function bodies, comments, ACLs, table/view columns).
- Makefile: DATA += sql/object_reference--0.1.0.sql (pgxntool#48 workaround,
  needed for CREATE EXTENSION ... VERSION '0.1.0' to work at all); a
  conditional count_nulls install step for the update-mode floor only (0.1.0's
  own install script still needs it, even though current object_reference no
  longer requires it).
- test/finish.sql: one permanent pgTAP assertion (modeled on
  pg_count_nulls'/extension_tools' own schema-qualification checks) proving
  object_reference/_object_reference are never resolved via search_path.
- Moved the pre-existing raw-source-load sanity check (test/sql/zzz_build.sql)
  to test/build/, pgxntool's own test-build feature: it needs a schema-free
  database to create `object_reference` manually in, which the committed-once
  installer above no longer provides in the shared main-suite database.

Dependency-guard anchor for a future existing-mode CI job: a view typed on
_object_reference.object's row type (object_reference-owned, never dropped or
redefined by the update script) blocks a non-CASCADE DROP EXTENSION; manually
proven to block the drop (and to keep blocking it after the update path) as
part of this PR's own verification, not committed as CI machinery yet.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

Author: jnasbyupgrade

Makefile

@@ -1,17 +1,107 @@
+# Committed-once install of the extension (test/install/load.sql), run before
+# the main pgTAP suite in its own pg_regress session so its state persists
+# (committed) into every per-test file. Must be set (and set to exactly
+# "yes"/"no", not auto-detected) BEFORE base.mk is included below, since
+# base.mk reads it at parse time.
+PGXNTOOL_ENABLE_TEST_INSTALL = yes
+
+# Safeguard for `make results`: refuses to copy test/results/*.out over
+# test/expected/*.out while a real regression is showing. This is already
+# pgxntool's own default, but set it explicitly so that stays true even if a
+# future pgxntool default ever changes.
+PGXNTOOL_ENABLE_VERIFY_RESULTS = yes
+
+# TEST_LOAD_SOURCE selects how test/install/load.sql installs the extension:
+#   - fresh (default): CREATE EXTENSION object_reference (current version).
+#   - update: CREATE EXTENSION at TEST_UPDATE_FROM (default 0.1.0, the only
+#     real historical PGXN release) then ALTER EXTENSION UPDATE -- to
+#     TEST_UPDATE_TO if set, otherwise to the current default_version
+#     ("stable"). Running the SAME suite with the SAME expected output
+#     against the updated database verifies it behaves identically to a
+#     fresh install.
+#   - existing: the extension is ALREADY installed in the target database (by
+#     a binary pg_upgrade, or an ALTER EXTENSION UPDATE done outside the
+#     suite). load.sql does not touch it; it only asserts presence + current
+#     version. Pair with CONTRIB_TESTDB=<db> and
+#     EXTRA_REGRESS_OPTS=--use-existing so pg_regress runs against that
+#     database instead of dropping and recreating a throwaway one.
+#
+# The mode (and the update from/to versions) are signalled to load.sql via
+# placeholder GUCs. pg_regress does not forward make variables, but the psql
+# processes it spawns inherit the environment, so PGOPTIONS reaches load.sql.
+#
+# The GUCs are exported UNCONDITIONALLY, so load.sql can read them WITHOUT
+# missing_ok and fail loudly if they did not propagate. Relying on an absent
+# GUC to mean "fresh" is unsafe: a silent break anywhere in the
+# make -> PGOPTIONS -> env -> psql chain would quietly run the wrong mode.
+#
+# TEST_LOAD_SOURCE must be exactly `fresh`, `update` or `existing`; anything
+# else is a hard error at parse time (so e.g. `make test
+# TEST_LOAD_SOURCE=typo` fails fast rather than defaulting).
+TEST_LOAD_SOURCE ?= fresh
+ifeq ($(filter $(TEST_LOAD_SOURCE),fresh update existing),)
+$(error TEST_LOAD_SOURCE must be 'fresh', 'update' or 'existing', got '$(TEST_LOAD_SOURCE)')
+endif
+
+# update-mode version range (read by load.sql only in update mode). Empty
+# TEST_UPDATE_TO means "update to the current default_version" (stable).
+TEST_UPDATE_FROM ?= 0.1.0
+TEST_UPDATE_TO ?=
+
+export PGOPTIONS := $(PGOPTIONS) -c object_reference.test_load_mode=$(TEST_LOAD_SOURCE) -c object_reference.test_update_from=$(TEST_UPDATE_FROM) -c object_reference.test_update_to=$(TEST_UPDATE_TO)
+
+# Convenience wrapper: `make test-update` == `make test TEST_LOAD_SOURCE=update`.
+# Must recurse (a fresh $(MAKE)) rather than depend on `test`, so the
+# parse-time TEST_LOAD_SOURCE conditional above re-evaluates with update set.
+.PHONY: test-update
+test-update:
+	$(MAKE) test TEST_LOAD_SOURCE=update
+
 include pgxntool/base.mk
 
+# pgxntool's base.mk DATA wildcard ($(EXTENSION__CURRENT_VERSION__FILES)
+# $(wildcard sql/*--*--*.sql)) only picks up the CURRENT version file and
+# two-dash update-diff scripts -- it never matches a one-dash historical
+# full-install file like sql/object_reference--0.1.0.sql, so `make install`
+# would silently never place it in the extension directory and `CREATE
+# EXTENSION object_reference VERSION '0.1.0'` (needed by TEST_UPDATE_FROM
+# above) would fail with "extension control file ... does not exist".
+# Same gap already filed upstream: Postgres-Extensions/pgxntool#48.
+DATA += sql/object_reference--0.1.0.sql
+
 testdeps: $(wildcard test/*.sql test/helpers/*.sql) # Be careful not to include directories in this
 testdeps: test_factory
 
 install: cat_tools
 
+# 0.1.0 (TEST_UPDATE_FROM's default -- the update-mode floor, see above) needs
+# count_nulls too: its install script's _object_oid.null_count trigger calls
+# count_nulls' not_null_count_trigger(), and object_reference.control's
+# `requires` (cat_tools only -- count_nulls was dropped once the reg*
+# pseudotype removal made that trigger unnecessary) no longer CASCADEs it in.
+# Only needed for update-mode testing against that floor -- current
+# object_reference has no runtime dependency on count_nulls at all -- so this
+# is conditional, not folded into the unconditional `install: cat_tools` above.
+ifeq ($(TEST_LOAD_SOURCE),update)
+install: count_nulls
+endif
+
+.PHONY: count_nulls
+count_nulls: $(DESTDIR)$(datadir)/extension/count_nulls.control
+$(DESTDIR)$(datadir)/extension/count_nulls.control:
+	pgxn install count_nulls
+
 # pgxntool's check-stale-expected target (added in pgxntool 2.2.0) depends on
 # installcheck but is listed before install in TEST_DEPS, and Make evaluates a
 # target's prerequisites in file-parse order across stanzas -- so plain
 # `make test` ran installcheck before install ever happened. Force installcheck
 # to require install locally until that's fixed upstream.
 installcheck: install
 
+# Clean the cruft pg_regress writes into test/install/ (the self-comparing
+# result .out and its diff), which is listed in test/install/.gitignore.
+extra_clean += $(addprefix test/install/,$(shell grep -v '^\#' test/install/.gitignore 2>/dev/null))
+
 test: dump_test
 extra_clean += $(wildcard test/dump/*.log)
 dump_test: test/dump/run.sh test/helpers/object_table.sql $(wildcard test/dump/*.sql)