From ef506078b533f9feeaa1da0d6630e2bc893658d8 Mon Sep 17 00:00:00 2001
From: shahramn <shahram.najm@ecmwf.int>
Date: Mon, 23 Dec 2024 11:58:06 +0000
Subject: [PATCH] GRIB message validity checker: Sections

---
 .../grib_accessor_class_message_is_valid.cc   | 23 +++++++++++++++++++
 tests/grib_check_message_validity.sh          | 17 ++++++++++++--
 2 files changed, 38 insertions(+), 2 deletions(-)

diff --git a/src/accessor/grib_accessor_class_message_is_valid.cc b/src/accessor/grib_accessor_class_message_is_valid.cc
index 9a0bdbea7..a937502e7 100644
--- a/src/accessor/grib_accessor_class_message_is_valid.cc
+++ b/src/accessor/grib_accessor_class_message_is_valid.cc
@@ -9,6 +9,7 @@
  */
 
 #include "grib_accessor_class_message_is_valid.h"
+#include <cstdio>
 
 grib_accessor_message_is_valid_t _grib_accessor_message_is_valid{};
 grib_accessor* grib_accessor_message_is_valid = &_grib_accessor_message_is_valid;
@@ -103,8 +104,30 @@ static int check_geoiterator(grib_handle* h)
     return err;
 }
 
+static int check_sections(grib_handle* h)
+{
+    int err = 0;
+    long edition = 0;
+    err = grib_get_long_internal(h, "edition", &edition);
+    if (err) return err;
+    if (edition == 2) {
+        // sections 3 thru to 8 should exist
+        // section 2 is optional
+        for (size_t i=3; i<9; ++i) {
+            char sname[16] = {0,};
+            snprintf(sname, sizeof(sname), "section_%zu", i);
+            if (!grib_is_defined(h, sname)) {
+                grib_context_log(h->context, GRIB_LOG_ERROR, "Section %zu is missing!", i);
+                return GRIB_INVALID_MESSAGE;
+            }
+        }
+    }
+    return GRIB_SUCCESS;
+}
+
 typedef int (*proj_func)(grib_handle*);
 static proj_func check_functions[] = {
+    check_sections,
     check_field_values,
     check_grid_pl_array,
     check_geoiterator
diff --git a/tests/grib_check_message_validity.sh b/tests/grib_check_message_validity.sh
index 828ade584..d23df8d6c 100755
--- a/tests/grib_check_message_validity.sh
+++ b/tests/grib_check_message_validity.sh
@@ -14,8 +14,18 @@ tempGrib=temp.$label.grib
 tempText=temp.$label.txt
 tempFilt=temp.$label.filt
 
-sample=$ECCODES_SAMPLES_PATH/reduced_gg_pl_32_grib2.tmpl
-grib_check_key_equals $sample   isMessageValid 1
+grib_check_key_equals $ECCODES_SAMPLES_PATH/reduced_gg_pl_32_grib2.tmpl isMessageValid 1
+grib_check_key_equals $ECCODES_SAMPLES_PATH/GRIB2.tmpl isMessageValid 1
+
+
+# Bad sections
+# ---------------
+# Correct key order: NV=6,PVPresent=1
+${tools_dir}/grib_set -s PVPresent=1,NV=6 $ECCODES_SAMPLES_PATH/reduced_gg_pl_128_grib2.tmpl $tempGrib
+grib_check_key_equals $tempGrib isMessageValid 0 2>$tempText
+grep -q "Section 5 is missing" $tempText
+grep -q "Error instantiating iterator gaussian_reduced" $tempText
+
 
 # Check regular lat/lon
 # ------------------------------
@@ -26,6 +36,7 @@ grep -q "Regular grid Geoiterator" $tempText
 
 # Check reduced Gaussian grid Ni
 # ------------------------------
+sample=$ECCODES_SAMPLES_PATH/reduced_gg_pl_32_grib2.tmpl
 cat >$tempFilt<<EOF
    set Ni = 0; # illegal
    assert ( isMessageValid == 0 );
@@ -39,8 +50,10 @@ grep -q "Invalid Ni" $tempText
 grib_check_key_equals $tempGrib isMessageValid 0
 grib_check_key_equals $sample   isMessageValid 1
 
+
 # Check reduced Gaussian grid pl
 # ------------------------------
+sample=$ECCODES_SAMPLES_PATH/reduced_gg_pl_32_grib2.tmpl
 cat >$tempFilt<<EOF
    meta pl_elem4 element(pl, 4);
    set pl_elem4 = 0;