Deprecate methods for constructing CRS from Postgis srids

Constructing CRS using Postgis srids is highly discouraged, and instead CRSes should always be constructed using auth:id codes or WKT strings. QGIS 4.0: The logic should be isolated into the postgres provider alone, and not exposed to stable API (cherry picked from commit c76813c)
qgis · Dec 20, 2019 · c72565e · c72565e
1 parent 3121990
commit c72565e
Show file tree

Hide file tree

Showing 16 changed files with 98 additions and 134 deletions.
diff --git a/python/core/auto_generated/qgscoordinatereferencesystem.sip.in b/python/core/auto_generated/qgscoordinatereferencesystem.sip.in
@@ -349,13 +349,18 @@ and refer to QGIS internal CRS IDs.
 %End
 
 
-    bool createFromSrid( long srid );
+ bool createFromSrid( long srid ) /Deprecated/;
 %Docstring
 Sets this CRS by lookup of the given PostGIS SRID in the CRS database.
 
 :param srid: The PostGIS SRID for the desired spatial reference system.
 
 :return: ``True`` on success else ``False``
+
+.. deprecated::
+   Use alternative methods for SRS construction instead -- this
+method was specifically created for use by the postgres provider alone,
+and using it elsewhere will lead to subtle bugs.
 %End
 
     bool createFromWkt( const QString &wkt );

diff --git a/src/core/qgscoordinatereferencesystem.cpp b/src/core/qgscoordinatereferencesystem.cpp
@@ -249,7 +249,7 @@ bool QgsCoordinateReferenceSystem::createFromId( const long id, CrsType type )
       result = createFromSrsId( id );
       break;
     case PostgisCrsId:
-      result = createFromSrid( id );
+      result = createFromPostgisSrid( id );
       break;
     case EpsgCrsId:
       result = createFromOgcWmsCrs( QStringLiteral( "EPSG:%1" ).arg( id ) );
@@ -289,7 +289,7 @@ bool QgsCoordinateReferenceSystem::createFromString( const QString &definition )
     else if ( authName == QLatin1String( "postgis" ) )
     {
       const long id = match.captured( 2 ).toLong();
-      result = createFromId( id, PostgisCrsId );
+      result = createFromPostgisSrid( id );
     }
     else if ( authName == QLatin1String( "esri" ) || authName == QLatin1String( "osgeo" ) || authName == QLatin1String( "ignf" ) || authName == QLatin1String( "zangi" ) || authName == QLatin1String( "iau2000" ) )
     {
@@ -495,6 +495,11 @@ void QgsCoordinateReferenceSystem::validate()
 }
 
 bool QgsCoordinateReferenceSystem::createFromSrid( const long id )
+{
+  return createFromPostgisSrid( id );
+}
+
+bool QgsCoordinateReferenceSystem::createFromPostgisSrid( const long id )
 {
   QgsReadWriteLocker locker( sSrIdCacheLock, QgsReadWriteLocker::Read );
   if ( !sDisableSrIdCache )
@@ -3292,7 +3297,7 @@ QStringList QgsCoordinateReferenceSystem::recentProjections()
       if ( ! crs.isValid() )
       {
         // Couldn't create from EPSG, try the Proj4 string instead
-        if ( i >= projectionsProj4.size() || !crs.createFromProj4( projectionsProj4.at( i ) ) )
+        if ( i >= projectionsProj4.size() || !crs.createFromProj( projectionsProj4.at( i ) ) )
         {
           // No? Skip this entry
           continue;

diff --git a/src/core/qgscoordinatereferencesystem.h b/src/core/qgscoordinatereferencesystem.h
@@ -208,7 +208,7 @@ class CORE_EXPORT QgsCoordinateReferenceSystem
     enum CrsType
     {
       InternalCrsId,  //!< Internal ID used by QGIS in the local SQLite database
-      PostgisCrsId,   //!< SRID used in PostGIS
+      PostgisCrsId,   //!< SRID used in PostGIS. DEPRECATED -- DO NOT USE
       EpsgCrsId       //!< EPSG code
     };
 
@@ -364,8 +364,12 @@ class CORE_EXPORT QgsCoordinateReferenceSystem
      * Sets this CRS by lookup of the given PostGIS SRID in the CRS database.
      * \param srid The PostGIS SRID for the desired spatial reference system.
      * \returns TRUE on success else FALSE
+     *
+     * \deprecated Use alternative methods for SRS construction instead -- this
+     * method was specifically created for use by the postgres provider alone,
+     * and using it elsewhere will lead to subtle bugs.
      */
-    bool createFromSrid( long srid );
+    Q_DECL_DEPRECATED bool createFromSrid( long srid ) SIP_DEPRECATED;
 
     /**
      * Sets this CRS using a WKT definition.
@@ -942,6 +946,9 @@ class CORE_EXPORT QgsCoordinateReferenceSystem
     static bool sDisableStringCache;
 
     friend class TestQgsCoordinateReferenceSystem;
+    friend class QgsPostgresProvider;
+
+    bool createFromPostgisSrid( const long id );
 };
 
 Q_DECLARE_METATYPE( QgsCoordinateReferenceSystem )

diff --git a/src/providers/db2/qgsdb2provider.cpp b/src/providers/db2/qgsdb2provider.cpp
@@ -548,12 +548,6 @@ QgsCoordinateReferenceSystem QgsDb2Provider::crs() const
 {
   if ( !mCrs.isValid() && mSRId > 0 )
   {
-    mCrs.createFromSrid( mSRId );
-    if ( mCrs.isValid() )
-    {
-      return mCrs;
-    }
-
     // try to load crs from the database tables as a fallback
     QSqlQuery query = QSqlQuery( mDatabase );
     query.setForwardOnly( true );

diff --git a/src/providers/gpx/qgsgpxprovider.cpp b/src/providers/gpx/qgsgpxprovider.cpp
@@ -534,7 +534,7 @@ QString QgsGPXProvider::description() const
 
 QgsCoordinateReferenceSystem QgsGPXProvider::crs() const
 {
-  return QgsCoordinateReferenceSystem( GEOSRID, QgsCoordinateReferenceSystem::PostgisCrsId ); // use WGS84
+  return QgsCoordinateReferenceSystem( QStringLiteral( "EPSG:4326" ) );
 }
 
 QgsDataProvider *QgsGpxProviderMetadata::createProvider( const QString &uri, const QgsDataProvider::ProviderOptions &options )

diff --git a/src/providers/postgres/qgspostgresprovider.cpp b/src/providers/postgres/qgspostgresprovider.cpp
@@ -4305,7 +4305,9 @@ QgsCoordinateReferenceSystem QgsPostgresProvider::crs() const
 {
   QgsCoordinateReferenceSystem srs;
   int srid = mRequestedSrid.isEmpty() ? mDetectedSrid.toInt() : mRequestedSrid.toInt();
-  srs.createFromSrid( srid );
+
+  // TODO QGIS 4 - move the logic from createFromSridInternal to sit within the postgres provider alone
+  srs.createFromPostgisSrid( srid );
   if ( !srs.isValid() )
   {
     static QMutex sMutex;