WKT2_2018: always export ID of SOURCECRS/TARGETCRS and STEPs

even if there is one on upper node

This is a particular logic allowed by paragraph 7.3.3 Identifier
of OGC 18-010r6

7 files changed, 145 insertions, 60 deletions

diff --git a/include/proj/io.hpp b/include/proj/io.hpp
index ace8ad9d..5386ca6c 100644
--- a/include/proj/io.hpp
+++ b/include/proj/io.hpp
@@ -261,6 +261,13 @@ class PROJ_GCC_DLL WKTFormatter {
     PROJ_INTERNAL void popOutputId();
     PROJ_INTERNAL bool outputId() const;
 
+    PROJ_INTERNAL void pushHasId(bool hasId);
+    PROJ_INTERNAL void popHasId();
+
+    PROJ_INTERNAL void pushDisableUsage();
+    PROJ_INTERNAL void popDisableUsage();
+    PROJ_INTERNAL bool outputUsage() const;
+
     PROJ_INTERNAL void
     pushAxisLinearUnit(const common::UnitOfMeasureNNPtr &unit);
     PROJ_INTERNAL void popAxisLinearUnit();
diff --git a/src/iso19111/common.cpp b/src/iso19111/common.cpp
index 4b947dc9..d46da0da 100644
--- a/src/iso19111/common.cpp
+++ b/src/iso19111/common.cpp
@@ -1073,7 +1073,7 @@ void ObjectUsage::setProperties(
 
 void ObjectUsage::baseExportToWKT(WKTFormatter *formatter) const {
     const bool isWKT2 = formatter->version() == WKTFormatter::Version::WKT2;
-    if (isWKT2 && formatter->outputId()) {
+    if (isWKT2 && formatter->outputUsage()) {
         auto l_domains = domains();
         if (!l_domains.empty()) {
             if (formatter->use2018Keywords()) {
diff --git a/src/iso19111/coordinateoperation.cpp b/src/iso19111/coordinateoperation.cpp
index 80c1a572..d7f138a4 100644
--- a/src/iso19111/coordinateoperation.cpp
+++ b/src/iso19111/coordinateoperation.cpp
@@ -7639,6 +7639,53 @@ void Transformation::_exportToWKT(io::WKTFormatter *formatter) const {
 
 // ---------------------------------------------------------------------------
 
+static void exportSourceCRSAndTargetCRSToWKT(const CoordinateOperation *co,
+                                             io::WKTFormatter *formatter) {
+    auto l_sourceCRS = co->sourceCRS();
+    assert(l_sourceCRS);
+    auto l_targetCRS = co->targetCRS();
+    assert(l_targetCRS);
+    const bool isWKT2 = formatter->version() == io::WKTFormatter::Version::WKT2;
+    const bool canExportCRSId =
+        (isWKT2 && formatter->use2018Keywords() &&
+         !(formatter->idOnTopLevelOnly() && formatter->topLevelHasId()));
+
+    const bool hasDomains = !co->domains().empty();
+    if (hasDomains) {
+        formatter->pushDisableUsage();
+    }
+
+    formatter->startNode(io::WKTConstants::SOURCECRS, false);
+    if (canExportCRSId && !l_sourceCRS->identifiers().empty()) {
+        // fake that top node has no id, so that the sourceCRS id is
+        // considered
+        formatter->pushHasId(false);
+        l_sourceCRS->_exportToWKT(formatter);
+        formatter->popHasId();
+    } else {
+        l_sourceCRS->_exportToWKT(formatter);
+    }
+    formatter->endNode();
+
+    formatter->startNode(io::WKTConstants::TARGETCRS, false);
+    if (canExportCRSId && !l_targetCRS->identifiers().empty()) {
+        // fake that top node has no id, so that the targetCRS id is
+        // considered
+        formatter->pushHasId(false);
+        l_targetCRS->_exportToWKT(formatter);
+        formatter->popHasId();
+    } else {
+        l_targetCRS->_exportToWKT(formatter);
+    }
+    formatter->endNode();
+
+    if (hasDomains) {
+        formatter->popDisableUsage();
+    }
+}
+
+// ---------------------------------------------------------------------------
+
 void SingleOperation::exportTransformationToWKT(
     io::WKTFormatter *formatter) const {
     const bool isWKT2 = formatter->version() == io::WKTFormatter::Version::WKT2;
@@ -7647,11 +7694,6 @@ void SingleOperation::exportTransformationToWKT(
             "Transformation can only be exported to WKT2");
     }
 
-    auto l_sourceCRS = sourceCRS();
-    assert(l_sourceCRS);
-    auto l_targetCRS = targetCRS();
-    assert(l_targetCRS);
-
     if (formatter->abridgedTransformation()) {
         formatter->startNode(io::WKTConstants::ABRIDGEDTRANSFORMATION,
                              !identifiers().empty());
@@ -7672,13 +7714,7 @@ void SingleOperation::exportTransformationToWKT(
     }
 
     if (!formatter->abridgedTransformation()) {
-        formatter->startNode(io::WKTConstants::SOURCECRS, false);
-        l_sourceCRS->_exportToWKT(formatter);
-        formatter->endNode();
-
-        formatter->startNode(io::WKTConstants::TARGETCRS, false);
-        l_targetCRS->_exportToWKT(formatter);
-        formatter->endNode();
+        exportSourceCRSAndTargetCRSToWKT(this, formatter);
     }
 
     method()->_exportToWKT(formatter);
@@ -9337,20 +9373,34 @@ void ConcatenatedOperation::_exportToWKT(io::WKTFormatter *formatter) const {
         }
     }
 
-    formatter->startNode(io::WKTConstants::SOURCECRS, false);
-    sourceCRS()->_exportToWKT(formatter);
-    formatter->endNode();
+    exportSourceCRSAndTargetCRSToWKT(this, formatter);
 
-    formatter->startNode(io::WKTConstants::TARGETCRS, false);
-    targetCRS()->_exportToWKT(formatter);
-    formatter->endNode();
+    const bool canExportOperationId =
+        !(formatter->idOnTopLevelOnly() && formatter->topLevelHasId());
+
+    const bool hasDomains = !domains().empty();
+    if (hasDomains) {
+        formatter->pushDisableUsage();
+    }
 
     for (const auto &operation : operations()) {
         formatter->startNode(io::WKTConstants::STEP, false);
-        operation->_exportToWKT(formatter);
+        if (canExportOperationId && !operation->identifiers().empty()) {
+            // fake that top node has no id, so that the operation id is
+            // considered
+            formatter->pushHasId(false);
+            operation->_exportToWKT(formatter);
+            formatter->popHasId();
+        } else {
+            operation->_exportToWKT(formatter);
+        }
         formatter->endNode();
     }
 
+    if (hasDomains) {
+        formatter->popDisableUsage();
+    }
+
     ObjectUsage::baseExportToWKT(formatter);
     formatter->endNode();
 }
diff --git a/src/iso19111/io.cpp b/src/iso19111/io.cpp
index 78b18719..578234b4 100644
--- a/src/iso19111/io.cpp
+++ b/src/iso19111/io.cpp
@@ -141,6 +141,7 @@ struct WKTFormatter::Private {
     std::vector<bool> stackHasChild_{};
     std::vector<bool> stackHasId_{false};
     std::vector<bool> stackEmptyKeyword_{};
+    std::vector<bool> stackDisableUsage_{};
     std::vector<bool> outputUnitStack_{true};
     std::vector<bool> outputIdStack_{true};
     std::vector<UnitOfMeasureNNPtr> axisLinearUnitStack_{
@@ -272,6 +273,11 @@ const std::string &WKTFormatter::toString() const {
     if (d->outputUnitStack_.size() != 1)
         throw FormattingException(
             "Unbalanced pushOutputUnit() / popOutputUnit()");
+    if (d->stackHasId_.size() != 1)
+        throw FormattingException("Unbalanced pushHasId() / popHasId()");
+    if (!d->stackDisableUsage_.empty())
+        throw FormattingException(
+            "Unbalanced pushDisableUsage() / popDisableUsage()");
 
     return d->result_;
 }
@@ -556,6 +562,28 @@ bool WKTFormatter::outputId() const {
 
 // ---------------------------------------------------------------------------
 
+void WKTFormatter::pushHasId(bool hasId) { d->stackHasId_.push_back(hasId); }
+
+// ---------------------------------------------------------------------------
+
+void WKTFormatter::popHasId() { d->stackHasId_.pop_back(); }
+
+// ---------------------------------------------------------------------------
+
+void WKTFormatter::pushDisableUsage() { d->stackDisableUsage_.push_back(true); }
+
+// ---------------------------------------------------------------------------
+
+void WKTFormatter::popDisableUsage() { d->stackDisableUsage_.pop_back(); }
+
+// ---------------------------------------------------------------------------
+
+bool WKTFormatter::outputUsage() const {
+    return outputId() && d->stackDisableUsage_.empty();
+}
+
+// ---------------------------------------------------------------------------
+
 void WKTFormatter::pushAxisLinearUnit(const UnitOfMeasureNNPtr &unit) {
     d->axisLinearUnitStack_.push_back(unit);
 }
diff --git a/test/cli/testprojinfo_out.dist b/test/cli/testprojinfo_out.dist
index ee9aeca7..eaa10689 100644
--- a/test/cli/testprojinfo_out.dist
+++ b/test/cli/testprojinfo_out.dist
@@ -193,10 +193,6 @@ COORDINATEOPERATION["Ballpark geographic offset from NAD27 to NAD83",
                 AXIS["geodetic longitude (Lon)",east,
                     ORDER[2],
                     ANGLEUNIT["degree",0.0174532925199433]],
-            USAGE[
-                SCOPE["unknown"],
-                AREA["North America - NAD27"],
-                BBOX[7.15,167.65,83.17,-47.74]],
             ID["EPSG",4267]]],
     TARGETCRS[
         GEOGCRS["NAD83",
@@ -212,10 +208,6 @@ COORDINATEOPERATION["Ballpark geographic offset from NAD27 to NAD83",
                 AXIS["geodetic longitude (Lon)",east,
                     ORDER[2],
                     ANGLEUNIT["degree",0.0174532925199433]],
-            USAGE[
-                SCOPE["unknown"],
-                AREA["North America - NAD83"],
-                BBOX[14.92,167.65,86.46,-47.74]],
             ID["EPSG",4269]]],
     METHOD["Geographic2D offsets",
         ID["EPSG",9619]],
@@ -265,7 +257,8 @@ COORDINATEOPERATION["NAD27 to NAD83 (3)",
                     ANGLEUNIT["degree",0.0174532925199433]],
                 AXIS["geodetic longitude (Lon)",east,
                     ORDER[2],
-                    ANGLEUNIT["degree",0.0174532925199433]]]],
+                    ANGLEUNIT["degree",0.0174532925199433]],
+            ID["EPSG",4267]]],
     TARGETCRS[
         GEOGCRS["NAD83",
             DATUM["North American Datum 1983",
@@ -279,7 +272,8 @@ COORDINATEOPERATION["NAD27 to NAD83 (3)",
                     ANGLEUNIT["degree",0.0174532925199433]],
                 AXIS["geodetic longitude (Lon)",east,
                     ORDER[2],
-                    ANGLEUNIT["degree",0.0174532925199433]]]],
+                    ANGLEUNIT["degree",0.0174532925199433]],
+            ID["EPSG",4269]]],
     METHOD["NTv1",
         ID["EPSG",9614]],
     PARAMETERFILE["Latitude and longitude difference file","ntv1_can.dat"],
@@ -313,7 +307,8 @@ COORDINATEOPERATION["NAD27 to NAD83 (4)",
                     ANGLEUNIT["degree",0.0174532925199433]],
                 AXIS["geodetic longitude (Lon)",east,
                     ORDER[2],
-                    ANGLEUNIT["degree",0.0174532925199433]]]],
+                    ANGLEUNIT["degree",0.0174532925199433]],
+            ID["EPSG",4267]]],
     TARGETCRS[
         GEOGCRS["NAD83",
             DATUM["North American Datum 1983",
@@ -327,7 +322,8 @@ COORDINATEOPERATION["NAD27 to NAD83 (4)",
                     ANGLEUNIT["degree",0.0174532925199433]],
                 AXIS["geodetic longitude (Lon)",east,
                     ORDER[2],
-                    ANGLEUNIT["degree",0.0174532925199433]]]],
+                    ANGLEUNIT["degree",0.0174532925199433]],
+            ID["EPSG",4269]]],
     METHOD["NTv2",
         ID["EPSG",9615]],
     PARAMETERFILE["Latitude and longitude difference file","ntv2_0.gsb"],
@@ -361,7 +357,8 @@ COORDINATEOPERATION["NAD27 to NAD83 (1)",
                     ANGLEUNIT["degree",0.0174532925199433]],
                 AXIS["geodetic longitude (Lon)",east,
                     ORDER[2],
-                    ANGLEUNIT["degree",0.0174532925199433]]]],
+                    ANGLEUNIT["degree",0.0174532925199433]],
+            ID["EPSG",4267]]],
     TARGETCRS[
         GEOGCRS["NAD83",
             DATUM["North American Datum 1983",
@@ -375,7 +372,8 @@ COORDINATEOPERATION["NAD27 to NAD83 (1)",
                     ANGLEUNIT["degree",0.0174532925199433]],
                 AXIS["geodetic longitude (Lon)",east,
                     ORDER[2],
-                    ANGLEUNIT["degree",0.0174532925199433]]]],
+                    ANGLEUNIT["degree",0.0174532925199433]],
+            ID["EPSG",4269]]],
     METHOD["CTABLE2"],
     PARAMETERFILE["Latitude and longitude difference file","conus"],
     OPERATIONACCURACY[0.15],
@@ -408,7 +406,8 @@ COORDINATEOPERATION["NAD27 to NAD83 (2)",
                     ANGLEUNIT["degree",0.0174532925199433]],
                 AXIS["geodetic longitude (Lon)",east,
                     ORDER[2],
-                    ANGLEUNIT["degree",0.0174532925199433]]]],
+                    ANGLEUNIT["degree",0.0174532925199433]],
+            ID["EPSG",4267]]],
     TARGETCRS[
         GEOGCRS["NAD83",
             DATUM["North American Datum 1983",
@@ -422,7 +421,8 @@ COORDINATEOPERATION["NAD27 to NAD83 (2)",
                     ANGLEUNIT["degree",0.0174532925199433]],
                 AXIS["geodetic longitude (Lon)",east,
                     ORDER[2],
-                    ANGLEUNIT["degree",0.0174532925199433]]]],
+                    ANGLEUNIT["degree",0.0174532925199433]],
+            ID["EPSG",4269]]],
     METHOD["CTABLE2"],
     PARAMETERFILE["Latitude and longitude difference file","alaska"],
     OPERATIONACCURACY[0.5],
@@ -455,7 +455,8 @@ COORDINATEOPERATION["NAD27 to NAD83 (5)",
                     ANGLEUNIT["degree",0.0174532925199433]],
                 AXIS["geodetic longitude (Lon)",east,
                     ORDER[2],
-                    ANGLEUNIT["degree",0.0174532925199433]]]],
+                    ANGLEUNIT["degree",0.0174532925199433]],
+            ID["EPSG",4267]]],
     TARGETCRS[
         GEOGCRS["NAD83",
             DATUM["North American Datum 1983",
@@ -469,7 +470,8 @@ COORDINATEOPERATION["NAD27 to NAD83 (5)",
                     ANGLEUNIT["degree",0.0174532925199433]],
                 AXIS["geodetic longitude (Lon)",east,
                     ORDER[2],
-                    ANGLEUNIT["degree",0.0174532925199433]]]],
+                    ANGLEUNIT["degree",0.0174532925199433]],
+            ID["EPSG",4269]]],
     METHOD["NTv1",
         ID["EPSG",9614]],
     PARAMETERFILE["Latitude and longitude difference file","GS2783v1.QUE"],
@@ -503,7 +505,8 @@ COORDINATEOPERATION["NAD27 to NAD83 (6)",
                     ANGLEUNIT["degree",0.0174532925199433]],
                 AXIS["geodetic longitude (Lon)",east,
                     ORDER[2],
-                    ANGLEUNIT["degree",0.0174532925199433]]]],
+                    ANGLEUNIT["degree",0.0174532925199433]],
+            ID["EPSG",4267]]],
     TARGETCRS[
         GEOGCRS["NAD83",
             DATUM["North American Datum 1983",
@@ -517,7 +520,8 @@ COORDINATEOPERATION["NAD27 to NAD83 (6)",
                     ANGLEUNIT["degree",0.0174532925199433]],
                 AXIS["geodetic longitude (Lon)",east,
                     ORDER[2],
-                    ANGLEUNIT["degree",0.0174532925199433]]]],
+                    ANGLEUNIT["degree",0.0174532925199433]],
+            ID["EPSG",4269]]],
     METHOD["NTv2",
         ID["EPSG",9615]],
     PARAMETERFILE["Latitude and longitude difference file","QUE27-83.gsb"],
@@ -552,10 +556,6 @@ COORDINATEOPERATION["Ballpark geographic offset from NAD27 to NAD83",
                 AXIS["geodetic longitude (Lon)",east,
                     ORDER[2],
                     ANGLEUNIT["degree",0.0174532925199433]],
-            USAGE[
-                SCOPE["unknown"],
-                AREA["North America - NAD27"],
-                BBOX[7.15,167.65,83.17,-47.74]],
             ID["EPSG",4267]]],
     TARGETCRS[
         GEOGCRS["NAD83",
@@ -571,10 +571,6 @@ COORDINATEOPERATION["Ballpark geographic offset from NAD27 to NAD83",
                 AXIS["geodetic longitude (Lon)",east,
                     ORDER[2],
                     ANGLEUNIT["degree",0.0174532925199433]],
-            USAGE[
-                SCOPE["unknown"],
-                AREA["North America - NAD83"],
-                BBOX[14.92,167.65,86.46,-47.74]],
             ID["EPSG",4269]]],
     METHOD["Geographic2D offsets",
         ID["EPSG",9619]],
@@ -712,7 +708,8 @@ COORDINATEOPERATION["RH2000 height to SWEREF99",
             VDATUM["Rikets hojdsystem 2000"],
             CS[vertical,1],
                 AXIS["gravity-related height (H)",up,
-                    LENGTHUNIT["metre",1]]]],
+                    LENGTHUNIT["metre",1]],
+            ID["EPSG",5613]]],
     TARGETCRS[
         GEOGCRS["SWEREF99 (3D)",
             DATUM["SWEREF99",
@@ -729,7 +726,8 @@ COORDINATEOPERATION["RH2000 height to SWEREF99",
                     ANGLEUNIT["degree minute second hemisphere",0.0174532925199433]],
                 AXIS["ellipsoidal height (h)",up,
                     ORDER[3],
-                    LENGTHUNIT["metre",1]]]],
+                    LENGTHUNIT["metre",1]],
+            ID["EPSG",4377]]],
     METHOD["GravityRelatedHeight to Geographic3D",
         ID["PROJ","HEIGHT_TO_GEOGRAPHIC3D"]],
     PARAMETERFILE["Geoid (height correction) model file","SWEN17_RH2000.gtx"],
diff --git a/test/unit/test_factory.cpp b/test/unit/test_factory.cpp
index 944e0ebe..f4c560d5 100644
--- a/test/unit/test_factory.cpp
+++ b/test/unit/test_factory.cpp
@@ -734,7 +734,8 @@ TEST(factory, AuthorityFactory_createCoordinateOperation_helmert_15_CF) {
         "                    LENGTHUNIT[\"metre\",1]],\n"
         "                AXIS[\"(Z)\",geocentricZ,\n"
         "                    ORDER[3],\n"
-        "                    LENGTHUNIT[\"metre\",1]]]],\n"
+        "                    LENGTHUNIT[\"metre\",1]],\n"
+        "            ID[\"EPSG\",5332]]],\n"
         "    TARGETCRS[\n"
         "        GEODCRS[\"GDA94\",\n"
         "            DATUM[\"Geocentric Datum of Australia 1994\",\n"
@@ -751,7 +752,8 @@ TEST(factory, AuthorityFactory_createCoordinateOperation_helmert_15_CF) {
         "                    LENGTHUNIT[\"metre\",1]],\n"
         "                AXIS[\"(Z)\",geocentricZ,\n"
         "                    ORDER[3],\n"
-        "                    LENGTHUNIT[\"metre\",1]]]],\n"
+        "                    LENGTHUNIT[\"metre\",1]],\n"
+        "            ID[\"EPSG\",4938]]],\n"
         "    METHOD[\"Time-dependent Coordinate Frame rotation (geocen)\",\n"
         "        ID[\"EPSG\",1056]],\n"
         "    PARAMETER[\"X-axis translation\",-84.68,\n"
@@ -885,7 +887,8 @@ TEST(
         "                    ANGLEUNIT[\"degree\",0.0174532925199433]],\n"
         "                AXIS[\"geodetic longitude (Lon)\",east,\n"
         "                    ORDER[2],\n"
-        "                    ANGLEUNIT[\"degree\",0.0174532925199433]]]],\n"
+        "                    ANGLEUNIT[\"degree\",0.0174532925199433]],\n"
+        "            ID[\"EPSG\",4749]]],\n"
         "    TARGETCRS[\n"
         "        GEOGCRS[\"NEA74 Noumea\",\n"
         "            DATUM[\"NEA74 Noumea\",\n"
@@ -899,7 +902,8 @@ TEST(
         "                    ANGLEUNIT[\"degree\",0.0174532925199433]],\n"
         "                AXIS[\"geodetic longitude (Lon)\",east,\n"
         "                    ORDER[2],\n"
-        "                    ANGLEUNIT[\"degree\",0.0174532925199433]]]],\n"
+        "                    ANGLEUNIT[\"degree\",0.0174532925199433]],\n"
+        "            ID[\"EPSG\",4644]]],\n"
         "    METHOD[\"NTv2\",\n"
         "        ID[\"EPSG\",9615]],\n"
         "    PARAMETERFILE[\"Latitude and longitude difference "
@@ -953,7 +957,8 @@ TEST(factory, AuthorityFactory_createCoordinateOperation_other_transformation) {
         "                    ANGLEUNIT[\"degree\",0.0174532925199433]],\n"
         "                AXIS[\"geodetic longitude (Lon)\",east,\n"
         "                    ORDER[2],\n"
-        "                    ANGLEUNIT[\"degree\",0.0174532925199433]]]],\n"
+        "                    ANGLEUNIT[\"degree\",0.0174532925199433]],\n"
+        "            ID[\"EPSG\",4818]]],\n"
         "    TARGETCRS[\n"
         "        GEOGCRS[\"S-JTSK\",\n"
         "            DATUM[\"System of the Unified Trigonometrical Cadastral "
@@ -968,7 +973,8 @@ TEST(factory, AuthorityFactory_createCoordinateOperation_other_transformation) {
         "                    ANGLEUNIT[\"degree\",0.0174532925199433]],\n"
         "                AXIS[\"geodetic longitude (Lon)\",east,\n"
         "                    ORDER[2],\n"
-        "                    ANGLEUNIT[\"degree\",0.0174532925199433]]]],\n"
+        "                    ANGLEUNIT[\"degree\",0.0174532925199433]],\n"
+        "            ID[\"EPSG\",4156]]],\n"
         "    METHOD[\"Longitude rotation\",\n"
         "        ID[\"EPSG\",9601]],\n"
         "    PARAMETER[\"Longitude offset\",-17.6666666666667,\n"
diff --git a/test/unit/test_operation.cpp b/test/unit/test_operation.cpp
index 9111b862..848fb23b 100644
--- a/test/unit/test_operation.cpp
+++ b/test/unit/test_operation.cpp
@@ -442,7 +442,6 @@ TEST(operation, concatenated_operation) {
     {
         auto formatter =
             WKTFormatter::create(WKTFormatter::Convention::WKT2_2018);
-        formatter->setOutputId(false);
         src_wkt = GeographicCRS::EPSG_4326->exportToWKT(formatter.get());
     }
 
@@ -450,7 +449,6 @@ TEST(operation, concatenated_operation) {
     {
         auto formatter =
             WKTFormatter::create(WKTFormatter::Convention::WKT2_2018);
-        formatter->setOutputId(false);
         dst_wkt = GeographicCRS::EPSG_4979->exportToWKT(formatter.get());
     }
 
@@ -458,7 +456,6 @@ TEST(operation, concatenated_operation) {
     {
         auto formatter =
             WKTFormatter::create(WKTFormatter::Convention::WKT2_2018);
-        formatter->setOutputId(false);
         step1_wkt = transf_1->exportToWKT(formatter.get());
     }
 
@@ -466,7 +463,6 @@ TEST(operation, concatenated_operation) {
     {
         auto formatter =
             WKTFormatter::create(WKTFormatter::Convention::WKT2_2018);
-        formatter->setOutputId(false);
         step2_wkt = transf_2->exportToWKT(formatter.get());
     }