From 7e4add8c3a86cf53a630041ccde8ae03154458f7 Mon Sep 17 00:00:00 2001
From: Emanuele Danovaro <emanuele.danovaro@ecmwf.int>
Date: Thu, 5 Mar 2026 09:06:44 +0100
Subject: [PATCH] gather levelist value as double - preserve numerical type if
 gathering native levelist

---
 src/metkit/codes/GRIBDecoder.cc |  33 +++++++++++-
 tests/CMakeLists.txt            |   3 ++
 tests/pl.grib                   | Bin 0 -> 3120 bytes
 tests/sol.grib                  | Bin 0 -> 7200 bytes
 tests/test_codes_decoder.cc     |  88 ++++++++++++++++++++++++++++++++
 5 files changed, 122 insertions(+), 2 deletions(-)
 create mode 100644 tests/pl.grib
 create mode 100644 tests/sol.grib

diff --git a/src/metkit/codes/GRIBDecoder.cc b/src/metkit/codes/GRIBDecoder.cc
index e66ddb9f..9a4f6a58 100644
--- a/src/metkit/codes/GRIBDecoder.cc
+++ b/src/metkit/codes/GRIBDecoder.cc
@@ -37,6 +37,13 @@ bool GRIBDecoder::match(const eckit::message::Message& msg) const {
                          (p[0] == 'B' and p[1] == 'U' and p[2] == 'D' and p[3] == 'G'));
 }
 
+namespace {
+bool isInteger(double val) {
+    double intpart;
+    return std::modf(val, &intpart) == 0.0;
+}
+}  // namespace
+
 
 void GRIBDecoder::getMetadata(const eckit::message::Message& msg, eckit::message::MetadataGatherer& gather,
                               const eckit::message::GetMetadataOptions& options) const {
@@ -59,14 +66,36 @@ void GRIBDecoder::getMetadata(const eckit::message::Message& msg, eckit::message
 
         switch (options.valueRepresentation) {
             case eckit::message::ValueRepresentation::String: {
-                gather.setValue(name, k.getString());
+                // TODO - remove as soon as https://jira.ecmwf.int/browse/ECC-2113 is fixed
+                if (k.name() == "levelist") {
+                    double val = k.getDouble();
+                    if (isInteger(val)) {
+                        gather.setValue(name, eckit::translate<std::string>(static_cast<long>(val)));
+                    }
+                    else {
+                        gather.setValue(name, eckit::translate<std::string>(val));
+                    }
+                }
+                else {
+                    gather.setValue(name, k.getString());
+                }
                 break;
             }
             case eckit::message::ValueRepresentation::Native: {
                 std::visit(
                     [&](auto&& v) {
                         using Type = std::decay_t<decltype(v)>;
-                        if constexpr (std::is_same_v<Type, std::string> || std::is_arithmetic_v<Type>) {
+                        // TODO - remove as soon as https://jira.ecmwf.int/browse/ECC-2113 is fixed
+                        if (k.name() == "levelist") {
+                            double val = k.getDouble();
+                            if (isInteger(val)) {
+                                gather.setValue(name, static_cast<long>(val));
+                            }
+                            else {
+                                gather.setValue(name, val);
+                            }
+                        }
+                        else if constexpr (std::is_same_v<Type, std::string> || std::is_arithmetic_v<Type>) {
                             gather.setValue(name, std::forward<decltype(v)>(v));
                         }
                         else if constexpr (std::is_same_v<Type, std::vector<uint8_t>>) {
diff --git a/tests/CMakeLists.txt b/tests/CMakeLists.txt
index 20e5a00b..719a4663 100644
--- a/tests/CMakeLists.txt
+++ b/tests/CMakeLists.txt
@@ -25,6 +25,9 @@ ecbuild_get_test_multidata( TARGET metkit_get_odb_data
                                   multiodb2.odb
                             NOCHECK )
 
+configure_file(pl.grib pl.grib COPYONLY)
+configure_file(sol.grib sol.grib COPYONLY)
+
 add_custom_target(soft_link_expand_test_data ALL
                   COMMAND ${CMAKE_COMMAND} -E create_symlink "${CMAKE_CURRENT_SOURCE_DIR}/expand" "${CMAKE_CURRENT_BINARY_DIR}/expand")
 
diff --git a/tests/pl.grib b/tests/pl.grib
new file mode 100644
index 0000000000000000000000000000000000000000..1523bf956a91c938b282df8fad47559248567d45
GIT binary patch
literal 3120
zcmZ<{@^t$DpMi-144628lqe%Z5(9%G10(w@W)_ezBM=KR0VzfXP8LQ30|P^#fCn>3
zY7vNF_>T&JB0@mS36o+uvIWFsFlYfXM4bOJFdFKDF-TAeYz2_<e;&{jkW~yRAd(4U
zCXgk{3M7CQIj6r_*ucfWAOPetu(ACII?R)u{j1z-Yop+_M8BlBQR?1DY#*7r7)>=a
z)P14$Q^t+Ii6sPRg}h@?vO#Toon7VCG(E2nGhS0y`zlWrk6#`=b~h~IwX@|D!bQ@P
z8=sf<m&sKrrripj<q#D(E1@X$b;8E@mIS`2N%7|+Gn@U}#oO%aBpcFO4%FVrvd-+O
zI@+jGlT_wi+E6yTO0jlg!?YfszWVO}y%+l@H49eVtzFa{+FsFZ)nU=%*__ZetIM=w
zTc>?_UX5#&ZT0rD30Ws{7ZvZUoKUUTys3F%LsZ?|#^rUV>r|^Y=LY0X%2G&Hh+mXa
zkY$~3UldsB-yl@`sqRV5+{&4y%q6kKJ1XT%b@F~^duQ9_2bOFoTUwpn7}Ap3mecXC
z=XCeG_K22Ub!W@Z6zt6Q%Fs>Um^mfasmP%GPn|$>di%fbcYWo3v$}7$O{niO2LkuO
zm<~V@J(><i(*Y<Qh>Vs8qvZiG9h?|V2czkLfr0(PXgU~82Mi2;3Zv<Op6LJpQC5*H

literal 0
HcmV?d00001

diff --git a/tests/sol.grib b/tests/sol.grib
new file mode 100644
index 0000000000000000000000000000000000000000..3a1a242411317b0492a8f8e5938e9f38ecf4c719
GIT binary patch
literal 7200
zcmeI0KWJ)a7{=efC%GUcy?DXGp-Af>#lgYbT5ymeTni3T971sj#UX=33Jw_@94t6E
zI0!d`&<qZtIAn0h;1H-o28Rp|85}Y=WN^sfkU>Zv+p$aM-g81!j-GSA?|q-=_waom
ze){o;*H;nx`#3nn+dHOTh*HD{kFhV`5-H>4=R!<rdSm?l+xOoS1wAEtvnvYD2Cx4<
za9MJH%l$Y0^B-UDKhtmc@b1??7yFY$JRpiwf<j8-X=%z(mU5J*0u`x5WvWn>YIIC>
zI-v%gQj^Z8Md#F}4t1$VeHze^E@(uTG^Q(>&^1lzhGuk2bGoAi-P4jDXhn~-rYG9a
zGi~XGc1&!1$T2?RI43ydB&Rsd8P0N!^IYH}m$=Lou5yi!xy~ot;8Sk$8MpYH+uY$U
z_qfjk9`Xf`_>#wb#S^~fDc|snZ+Xslyx@CY@&m8<k=Ojh8-C_3zwk~-Ob#U`M-rEW
zgp!n$q$ML+$w^)cQk0UEr6N_S$+6VsL>h7`O*xa6oJ(6e(v_a{WgtVjkda)<SgvFu
z*D{qGnaQop<xUoIFH3oll|0H?o@67>vXvLvDXHn9#`H+zn$S>_n$ompG^;tyYe9=z
z(y~^xsx>{<x}Io5PqnFM+R}4vYe&1<)4mRLs24iYOC9T#PV`!*dZRPF)w$m3Lhp5{
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z?aW$sZf)yW*Lv2sfer1#Ms{gqyRwO0+thAsX16xCJ6qVjE$zWp_GoK+vW-34)?RGq
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zU--x`ee730@oS&@jnDkn=YHo4zxSm-_{txB?N7e(XW#mZ?*a-eI1FOJQ4kLjK^P>1
zRFDobK{m(*`JfOKgHliqDnS*06?`h;Oab5I@QVz7nZgwzu8iXjG2F=l@*VEH#S=Do
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ziE}t|24_y;&<UJ6hGR!??hp>{!^vGZx(#Qy;P57#-hkulaDEL0sDK0|5TO7v<UoiF
zNRa|DLXaa4g2X@)1Dtmt%NB&$fHZ3mX9e;sL7)XlGzXDpAk!3tnt)Ve5NiZ-4MDIz
zNY(|>+8|pCglmFy4G^ym^3_1V3P@N25epz=4us5rlqnE11Ucg%XbdDZB*YG6-GZ<i
zkai8?u0Y-;2)qD^=OFS7WS)Z16OeigVvj)XAqd_F$-C46)z3lqGf@5%v_Ap$k3s(`
zQlN}9C?XZ|NQW#^B8{|2A~h0752CMZpDg-TUVlfb?4yc4?qB$$;C281h3|ukzS*Ds
z=lCp%2O`4)q!9VRcQ`&oIT%Jc80BD;gHaAfIrzWI!F?u1Id~VX2cz|1v>uGsgVB2M
m6I~A?2BRE|_C=$8(P&>Z+82%XML*en(R~i?cTWG)zUW`05$@yw

literal 0
HcmV?d00001

diff --git a/tests/test_codes_decoder.cc b/tests/test_codes_decoder.cc
index 34c209e4..304ec960 100644
--- a/tests/test_codes_decoder.cc
+++ b/tests/test_codes_decoder.cc
@@ -16,6 +16,7 @@
 #include <vector>
 
 #include "eckit/config/LocalConfiguration.h"
+#include "eckit/io/FileHandle.h"
 #include "eckit/io/MemoryHandle.h"
 #include "eckit/message/Message.h"
 #include "eckit/message/Reader.h"
@@ -454,6 +455,93 @@ CASE("test codessplitter unstr_latlot.tmpl String") {
     }
 }
 
+CASE("test levelist String") {
+    eckit::FileHandle f("pl.grib");
+
+    eckit::message::Reader reader(f);
+    eckit::message::Message msg;
+
+    std::vector<std::string> expect{"0", "0.02", "0.2", "2", "20", "200"};
+    for (size_t i = 0; i < expect.size(); ++i) {
+        msg = reader.next();
+        EXPECT(msg);
+
+        MetadataSetter md;
+        eckit::message::TypedSetter<MetadataSetter> gatherer{md};
+        eckit::message::GetMetadataOptions mdOpts{};
+        mdOpts.valueRepresentation = eckit::message::ValueRepresentation::String;
+        msg.getMetadata(gatherer, mdOpts);
+        { MD_EXPECT_STRING(md, "levelist", expect[i]); }
+    }
+    msg = reader.next();
+    EXPECT(!msg);
+}
+
+CASE("test levelist Native") {
+    eckit::FileHandle f("pl.grib");
+
+    eckit::message::Reader reader(f);
+    eckit::message::Message msg;
+
+    std::vector<double> expect{0, 0.02, 0.2, 2, 20, 200};
+    for (size_t i = 0; i < expect.size(); ++i) {
+        msg = reader.next();
+        EXPECT(msg);
+
+        MetadataSetter md;
+        eckit::message::TypedSetter<MetadataSetter> gatherer{md};
+        eckit::message::GetMetadataOptions mdOpts{};
+        mdOpts.valueRepresentation = eckit::message::ValueRepresentation::Native;
+        msg.getMetadata(gatherer, mdOpts);
+        { MD_EXPECT_DOUBLE(md, "levelist", expect[i]); }
+    }
+    msg = reader.next();
+    EXPECT(!msg);
+}
+
+CASE("test levelist String") {
+    eckit::FileHandle f("sol.grib");
+
+    eckit::message::Reader reader(f);
+    eckit::message::Message msg;
+
+    std::vector<std::string> expect{"0.02", "0.2", "2", "20"};
+    for (size_t i = 0; i < expect.size(); ++i) {
+        msg = reader.next();
+        EXPECT(msg);
+
+        MetadataSetter md;
+        eckit::message::TypedSetter<MetadataSetter> gatherer{md};
+        eckit::message::GetMetadataOptions mdOpts{};
+        mdOpts.valueRepresentation = eckit::message::ValueRepresentation::String;
+        msg.getMetadata(gatherer, mdOpts);
+        { MD_EXPECT_STRING(md, "levelist", expect[i]); }
+    }
+    msg = reader.next();
+    EXPECT(!msg);
+}
+
+CASE("test levelist Native") {
+    eckit::FileHandle f("sol.grib");
+
+    eckit::message::Reader reader(f);
+    eckit::message::Message msg;
+
+    std::vector<double> expect{0.02, 0.2, 2, 20};
+    for (size_t i = 0; i < expect.size(); ++i) {
+        msg = reader.next();
+        EXPECT(msg);
+
+        MetadataSetter md;
+        eckit::message::TypedSetter<MetadataSetter> gatherer{md};
+        eckit::message::GetMetadataOptions mdOpts{};
+        mdOpts.valueRepresentation = eckit::message::ValueRepresentation::Native;
+        msg.getMetadata(gatherer, mdOpts);
+        { MD_EXPECT_DOUBLE(md, "levelist", expect[i]); }
+    }
+    msg = reader.next();
+    EXPECT(!msg);
+}
 
 //----------------------------------------------------------------------------------------------------------------------