Resolve env vars when looking up documentation files.

Fixes: lp:1729276
* https://bugs.launchpad.net/kicad/+bug/1729276

common/common.cpp

@@ -39,6 +39,7 @@
 #include <wx/config.h>
 #include <wx/utils.h>
 #include <wx/stdpaths.h>
+#include <wx/url.h>
 
 #include <pgm_base.h>
 
@@ -264,6 +265,20 @@ const wxString ExpandEnvVarSubstitutions( const wxString& aString )
     return wxExpandEnvVars( aString );
 }
 
+
+const wxString ResolveUriByEnvVars( const wxString& aUri )
+{
+    // URL-like URI: return as is.
+    wxURL url( aUri );
+    if( url.GetError() == wxURL_NOERR )
+        return aUri;
+
+    // Otherwise, the path points to a local file. Resolve environment
+    // variables if any.
+    return ExpandEnvVarSubstitutions( aUri );
+}
+
+
 bool EnsureFileDirectoryExists( wxFileName*     aTargetFullFileName,
                                 const wxString& aBaseFilename,
                                 REPORTER*       aReporter )

eeschema/dialogs/dialog_edit_component_in_schematic.cpp

@@ -599,18 +599,6 @@ void DIALOG_EDIT_COMPONENT_IN_SCHEMATIC::deleteFieldButtonHandler( wxCommandEven
     m_skipCopyFromPanel = false;
 }
 
-static wxString resolveUriByEnvVars( const wxString& aUri )
-{
-    // URL-like URI: return as is.
-    wxURL url( aUri );
-    if( url.GetError() == wxURL_NOERR )
-    {
-        return aUri;
-    }
-    // Otherwise, the path points to a local file. Resolve environment
-    // variables if any.
-    return ExpandEnvVarSubstitutions( aUri );
-}
 
 void DIALOG_EDIT_COMPONENT_IN_SCHEMATIC::showButtonHandler( wxCommandEvent& event )
 {
@@ -619,7 +607,7 @@ void DIALOG_EDIT_COMPONENT_IN_SCHEMATIC::showButtonHandler( wxCommandEvent& even
     if( fieldNdx == DATASHEET )
     {
         wxString datasheet_uri = fieldValueTextCtrl->GetValue();
-        datasheet_uri = resolveUriByEnvVars( datasheet_uri );
+        datasheet_uri = ResolveUriByEnvVars( datasheet_uri );
         GetAssociatedDocument( this, datasheet_uri );
     }
     else if( fieldNdx == FOOTPRINT )

eeschema/dialogs/dialog_edit_libentry_fields_in_lib.cpp

@@ -502,6 +502,7 @@ void DIALOG_EDIT_LIBENTRY_FIELDS_IN_LIB::showButtonHandler( wxCommandEvent& even
     if( fieldNdx == DATASHEET )
     {
         wxString datasheet_uri = fieldValueTextCtrl->GetValue();
+        datasheet_uri = ResolveUriByEnvVars( datasheet_uri );
         GetAssociatedDocument( this, datasheet_uri );
     }
     else if( fieldNdx == FOOTPRINT )

eeschema/schedit.cpp

@@ -285,8 +285,8 @@ void SCH_EDIT_FRAME::Process_Special_Functions( wxCommandEvent& event )
         // Ensure the struct is a component (could be a piece of a component, like Field, text..)
         if( item && item->Type() == SCH_COMPONENT_T )
         {
-            wxString text = static_cast<SCH_COMPONENT*>( item )->
+            wxString text = static_cast<SCH_COMPONENT*>( item )->GetField( DATASHEET )->GetText();
-                                    GetField( DATASHEET )->GetFullyQualifiedText();
+            text = ResolveUriByEnvVars( text );
 
             if( !text.IsEmpty() )
                 GetAssociatedDocument( this, text );

include/common.h

@@ -316,6 +316,13 @@ wxString GetKicadConfigPath();
  */
 const wxString ExpandEnvVarSubstitutions( const wxString& aString );
 
+/**
+ * Function ResolveUriByEnvVars
+ * replaces any environment variables in file-path uris (leaving network-path
+ * uris alone).
+ */
+const wxString ResolveUriByEnvVars( const wxString& aUri );
+
 
 #ifdef __WXMAC__
 /**