Add CI check for unecessary template tests

When the regression tests output differs between PG versions we create a
template test (aka *.sql.in) and add several different output files for
each supported version.

Over time we support new PG version and deprecate older ones, for
example nowadays we're working on PG16 support and removed PG12 so we
need to check if we still need template files.

.github/workflows/code_style.yaml

@@ -124,3 +124,7 @@ jobs:
     - name: Check for missing gitignore entries for template test files
       if: always()
       run: ./scripts/check_missing_gitignore_for_template_tests.sh
+    - name: Check for unecessary template test files
+      if: always()
+      run: ./scripts/check_unecessary_template_tests.sh
+

scripts/check_unecessary_template_tests.sh

@@ -0,0 +1,17 @@
+#!/bin/bash
+
+ERROR=0
+
+for FILE in $(git ls-files | grep '\.sql\.in')
+do
+  DIRNAME=$(dirname "${FILE}" | sed 's/sql/expected/g')
+  TESTNAME=$(basename "${FILE}" .sql.in)
+
+  if diff --from-file ${DIRNAME}/${TESTNAME}-*.out > /dev/null 2>&1; then
+      echo "ERROR: all template output test files are equal: \"${DIRNAME}/${TESTNAME}-*.out\""
+      echo "HINT: Please turn template test file \"${FILE}\" into a regular test file"
+      ERROR=1
+  fi
+done
+
+exit ${ERROR}

tsl/test/sql/.gitignore

@@ -28,7 +28,6 @@
 /modify_exclusion-*.sql
 /plan_skip_scan-*.sql
 /remote-copy-*sv
-/telemetry_stats-*.sql
 /transparent_decompression-*.sql
 /transparent_decompression_ordered_index-*.sql
 /merge_append_partially_compressed-*.sql

tsl/test/sql/CMakeLists.txt

@@ -88,6 +88,10 @@ if(CMAKE_BUILD_TYPE MATCHES Debug)
     transparent_decompression_join_index.sql
     feature_flags.sql)
 
+  if(USE_TELEMETRY)
+    list(APPEND TEST_FILES telemetry_stats.sql)
+  endif()
+
   if(ENABLE_MULTINODE_TESTS)
     list(
       APPEND
@@ -203,9 +207,6 @@ if(CMAKE_BUILD_TYPE MATCHES Debug)
       dist_partial_agg.sql.in
       dist_query.sql.in)
   endif()
-  if(USE_TELEMETRY)
-    list(APPEND TEST_TEMPLATES telemetry_stats.sql.in)
-  endif()
 endif(CMAKE_BUILD_TYPE MATCHES Debug)
 
 # Check if PostgreSQL was compiled with JIT support