Decode Error in ChargeParamDisRes if #ConsumptionCost == 3

[TGruett]

Describe the bug

Hi,
I encountered a decode error (-110, EXI_ERROR__ARRAY_OUT_OF_BOUNDS) in a ChargeParameterDiscoveryResponse (ISO-2).
I figured out that it depends on the number of ConsumptionCost elements. If there are 3 of them in the message (the maximum permitted by the specification), I get this error. I'm pretty sure this didn't happen a few months ago. Maybe one of the last PRs is responsible for that?
I have not investigated this problem any further yet.

To Reproduce

Example Message:

EXI 8098022AAAAAAAAAAAAAAA90A000001200003403C18501E088000454D85B195CC815185C9A5999880D4D400C0D8040141185014000CC18830A02A00051418501600024A4A000010081861E80608284C3A81081209C0018000008000200C0000430441380

XML

<?xml version="1.0" encoding="UTF-8"?><ns7:V2G_Message xmlns:ns7="urn:iso:15118:2:2013:MsgDef" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:ns3="http://www.w3.org/2001/XMLSchema" xmlns:ns4="http://www.w3.org/2000/09/xmldsig#" xmlns:ns5="urn:iso:15118:2:2013:MsgBody" xmlns:ns6="urn:iso:15118:2:2013:MsgDataTypes" xmlns:ns8="urn:iso:15118:2:2013:MsgHeader">
  <ns7:Header>
    <ns8:SessionID>AAAAAAAAAAAAAAAA</ns8:SessionID>
  </ns7:Header>
  <ns7:Body>
    <ns5:ChargeParameterDiscoveryRes>
      <ns5:ResponseCode>OK</ns5:ResponseCode>
      <ns5:EVSEProcessing>Finished</ns5:EVSEProcessing>
      <ns6:SAScheduleList>
        <ns6:SAScheduleTuple>
          <ns6:SAScheduleTupleID>10</ns6:SAScheduleTupleID>
          <ns6:PMaxSchedule>
            <ns6:PMaxScheduleEntry>
              <ns6:RelativeTimeInterval>
                <ns6:start>0</ns6:start>
                <ns6:duration>2000</ns6:duration>
              </ns6:RelativeTimeInterval>
              <ns6:PMax>
                <ns6:Multiplier>3</ns6:Multiplier>
                <ns6:Unit>W</ns6:Unit>
                <ns6:Value>30</ns6:Value>
              </ns6:PMax>
            </ns6:PMaxScheduleEntry>
          </ns6:PMaxSchedule>
          <ns6:SalesTariff>
            <ns6:SalesTariffID>1</ns6:SalesTariffID>
            <ns6:SalesTariffDescription>Sales Tariff 55</ns6:SalesTariffDescription>
            <ns6:NumEPriceLevels>3</ns6:NumEPriceLevels>
            <ns6:SalesTariffEntry>
              <ns6:RelativeTimeInterval>
                <ns6:start>600</ns6:start>
                <ns6:duration>20</ns6:duration>
              </ns6:RelativeTimeInterval>
              <ns6:ConsumptionCost>
                <ns6:startValue>
                  <ns6:Multiplier>3</ns6:Multiplier>
                  <ns6:Unit>W</ns6:Unit>
                  <ns6:Value>20</ns6:Value>
                </ns6:startValue>
                <ns6:Cost>
                  <ns6:costKind>relativePricePercentage</ns6:costKind>
                  <ns6:amount>51</ns6:amount>
                  <ns6:amountMultiplier>0</ns6:amountMultiplier>
                </ns6:Cost>
              </ns6:ConsumptionCost>
              <ns6:ConsumptionCost>
                <ns6:startValue>
                  <ns6:Multiplier>3</ns6:Multiplier>
                  <ns6:Unit>W</ns6:Unit>
                  <ns6:Value>21</ns6:Value>
                </ns6:startValue>
                <ns6:Cost>
                  <ns6:costKind>relativePricePercentage</ns6:costKind>
                  <ns6:amount>10</ns6:amount>
                </ns6:Cost>
              </ns6:ConsumptionCost>
              <ns6:ConsumptionCost>
                <ns6:startValue>
                  <ns6:Multiplier>3</ns6:Multiplier>
                  <ns6:Unit>W</ns6:Unit>
                  <ns6:Value>22</ns6:Value>
                </ns6:startValue>
                <ns6:Cost>
                  <ns6:costKind>relativePricePercentage</ns6:costKind>
                  <ns6:amount>9</ns6:amount>
                </ns6:Cost>
              </ns6:ConsumptionCost>
            </ns6:SalesTariffEntry>
          </ns6:SalesTariff>
        </ns6:SAScheduleTuple>
      </ns6:SAScheduleList>
      <ns6:DC_EVSEChargeParameter>
        <ns6:DC_EVSEStatus>
          <ns6:NotificationMaxDelay>0</ns6:NotificationMaxDelay>
          <ns6:EVSENotification>None</ns6:EVSENotification>
          <ns6:EVSEIsolationStatus>No_IMD</ns6:EVSEIsolationStatus>
          <ns6:EVSEStatusCode>EVSE_Ready</ns6:EVSEStatusCode>
        </ns6:DC_EVSEStatus>
        <ns6:EVSEMaximumCurrentLimit>
          <ns6:Multiplier>0</ns6:Multiplier>
          <ns6:Unit>A</ns6:Unit>
          <ns6:Value>500</ns6:Value>
        </ns6:EVSEMaximumCurrentLimit>
        <ns6:EVSEMaximumPowerLimit>
          <ns6:Multiplier>1</ns6:Multiplier>
          <ns6:Unit>W</ns6:Unit>
          <ns6:Value>15000</ns6:Value>
        </ns6:EVSEMaximumPowerLimit>
        <ns6:EVSEMaximumVoltageLimit>
          <ns6:Multiplier>-1</ns6:Multiplier>
          <ns6:Unit>V</ns6:Unit>
          <ns6:Value>10000</ns6:Value>
        </ns6:EVSEMaximumVoltageLimit>
        <ns6:EVSEMinimumCurrentLimit>
          <ns6:Multiplier>-3</ns6:Multiplier>
          <ns6:Unit>A</ns6:Unit>
          <ns6:Value>0</ns6:Value>
        </ns6:EVSEMinimumCurrentLimit>
        <ns6:EVSEMinimumVoltageLimit>
          <ns6:Multiplier>-3</ns6:Multiplier>
          <ns6:Unit>V</ns6:Unit>
          <ns6:Value>0</ns6:Value>
        </ns6:EVSEMinimumVoltageLimit>
        <ns6:EVSEPeakCurrentRipple>
          <ns6:Multiplier>-3</ns6:Multiplier>
          <ns6:Unit>A</ns6:Unit>
          <ns6:Value>0</ns6:Value>
        </ns6:EVSEPeakCurrentRipple>
        <ns6:EVSEEnergyToBeDelivered>
          <ns6:Multiplier>-1</ns6:Multiplier>
          <ns6:Unit>Wh</ns6:Unit>
          <ns6:Value>5000</ns6:Value>
        </ns6:EVSEEnergyToBeDelivered>
      </ns6:DC_EVSEChargeParameter>
    </ns5:ChargeParameterDiscoveryRes>
  </ns7:Body>
</ns7:V2G_Message>

Anything else?

No response

[barsnick]

Thanks for the report.

It seems to me that the calculation of next_grammar_id_breakout is incorrect under certain circumstances:

cbexigen/src/cbexigen/base_coder_classes.py

Line 816 in 871fcb3

grammar_detail.next_grammar_out = grammars[idx_grammar + 1].grammar_id

cbexigen/src/cbexigen/decoder_classes.py

Line 433 in 871fcb3

next_grammar_id_breakout = detail.next_grammar_out

[barsnick]

This grammar calculation looks correct, but the resulting code isn't:

INFO:iso2_msgDefDecoder:Grammar for SalesTariffEntryType
INFO:iso2_msgDefDecoder:// Element: definition=complex; name={urn:iso:15118:2:2013:MsgDataTypes}SalesTariffEntry; type={urn:iso:15118:2:2013:MsgDataTypes}SalesTariffEntryType; base type=EntryType; content type=ELEMENT-ONLY;
//          abstract=False; final=False; derivation=extension;
INFO:iso2_msgDefDecoder:// Particle: RelativeTimeInterval, RelativeTimeIntervalType (0, 1); TimeInterval, IntervalType (0, 1); EPriceLevel, unsignedByte (0, 1); ConsumptionCost, ConsumptionCostType (0, 3);
INFO:iso2_msgDefDecoder:// Grammar: ID=32; read/write bits=2; START (RelativeTimeInterval), START (TimeInterval)
INFO:root:Handling ConsumptionCost as arrays, _max = 3
INFO:iso2_msgDefDecoder:// Grammar: ID=33; read/write bits=2; END Element, START (EPriceLevel), START (ConsumptionCost)
INFO:iso2_msgDefDecoder:// Grammar: ID=34; read/write bits=2; LOOP (ConsumptionCost), END Element
INFO:root:Handling ConsumptionCost as arrays, _max = 3
INFO:iso2_msgDefDecoder:// Grammar: ID=35; read/write bits=2; END Element, START (ConsumptionCost)
INFO:iso2_msgDefDecoder:// Grammar: ID=36; read/write bits=2; LOOP (ConsumptionCost), END Element
INFO:iso2_msgDefDecoder:// Grammar: ID=3; read/write bits=1; END Element
INFO:iso2_msgDefDecoder:// Grammar: ID=4; read/write bits=0; ERROR Element
INFO:iso2_msgDefDecoder:
INFO:iso2_msgDefDecoder:Grammar ID=32, eventCode=0, decode=IntervalType (Particle 'RelativeTimeInterval'), next ID=33
INFO:iso2_msgDefDecoder:Grammar ID=32, eventCode=1, decode=IntervalType (Particle 'TimeInterval'), next ID=33
INFO:iso2_msgDefDecoder:Grammar ID=33, eventCode=0, decode=unsignedShort (Particle 'EPriceLevel'), next ID=35
INFO:iso2_msgDefDecoder:Grammar ID=33, eventCode=1, decode=ConsumptionCostType (Particle 'ConsumptionCost'), next ID=34
INFO:iso2_msgDefDecoder:Grammar ID=33, eventCode=2, END Element, next ID=4
INFO:iso2_msgDefDecoder:Grammar ID=34, eventCode=0, decode=ConsumptionCostType (Particle 'ConsumptionCost'), next ID=34
INFO:iso2_msgDefDecoder:Grammar ID=34, eventCode=1, END Element, next ID=4
INFO:iso2_msgDefDecoder:Grammar ID=35, eventCode=0, decode=ConsumptionCostType (Particle 'ConsumptionCost'), next ID=36
INFO:iso2_msgDefDecoder:Grammar ID=35, eventCode=1, END Element, next ID=4
INFO:iso2_msgDefDecoder:Grammar ID=36, eventCode=0, decode=ConsumptionCostType (Particle 'ConsumptionCost'), next ID=36
INFO:iso2_msgDefDecoder:Grammar ID=36, eventCode=1, END Element, next ID=4
INFO:iso2_msgDefDecoder:Grammar ID=3, eventCode=0, END Element, next ID=4

(Two occurrences of ConsumptionCostType START + ConsumptionCostType LOOP; one if it follows the TimeInterval choice, the other if it follows EPriceLevel. Each optionally goes to END.)

---

Related: Grammar 163 in this context is incorrect, it does not handle the particle following VendorSpecificDataContainer.
164 ist correct:

INFO:iso20_WPT_Decoder:Grammar for WPT_FinePositioningSetupReqType
INFO:iso20_WPT_Decoder:// Element: definition=complex; name={urn:iso:std:iso:15118:-20:WPT}WPT_FinePositioningSetupReq; type={urn:iso:std:iso:15118:-20:WPT}WPT_FinePositioningSetupReqType; base type=V2GRequestType; content type=ELEMENT-ONLY;
//          abstract=False; final=False; derivation=extension;
INFO:iso20_WPT_Decoder:// Particle: Header, MessageHeaderType (1, 1); EVProcessing, processingType (1, 1); EVDeviceFinePositioningMethodList, WPT_FinePositioningMethodListType (1, 1); EVDevicePairingMeth
odList, WPT_PairingMethodListType (1, 1); EVDeviceAlignmentCheckMethodList, WPT_AlignmentCheckMethodListType (1, 1); NaturalOffset, unsignedShort (1, 1); VendorSpecificDataContainer, WPT_DataContainerTyp
e (0, 16); LF_SystemSetupData, WPT_LF_SystemSetupDataType (0, 1);
INFO:iso20_WPT_Decoder:// Grammar: ID=157; read/write bits=1; START (Header)
INFO:iso20_WPT_Decoder:// Grammar: ID=158; read/write bits=1; START (EVProcessing)
INFO:iso20_WPT_Decoder:// Grammar: ID=159; read/write bits=1; START (EVDeviceFinePositioningMethodList)
INFO:iso20_WPT_Decoder:// Grammar: ID=160; read/write bits=1; START (EVDevicePairingMethodList)
INFO:iso20_WPT_Decoder:// Grammar: ID=161; read/write bits=1; START (EVDeviceAlignmentCheckMethodList)
INFO:iso20_WPT_Decoder:// Grammar: ID=162; read/write bits=1; START (NaturalOffset)
INFO:root:Handling VendorSpecificDataContainer as arrays, _max = 16
INFO:iso20_WPT_Decoder:// Grammar: ID=163; read/write bits=2; END Element, START (VendorSpecificDataContainer)
INFO:iso20_WPT_Decoder:// Grammar: ID=164; read/write bits=2; LOOP (VendorSpecificDataContainer), END Element, START (LF_SystemSetupData)
INFO:iso20_WPT_Decoder:// Grammar: ID=165; read/write bits=2; END Element, START (LF_SystemSetupData)
INFO:iso20_WPT_Decoder:// Grammar: ID=2; read/write bits=1; END Element
INFO:iso20_WPT_Decoder:// Grammar: ID=3; read/write bits=0; ERROR Element
INFO:iso20_WPT_Decoder:
INFO:iso20_WPT_Decoder:Grammar ID=157, eventCode=0, decode=MessageHeaderType (Particle 'Header'), next ID=158
INFO:iso20_WPT_Decoder:Grammar ID=158, eventCode=0, decode=string (Particle 'EVProcessing'), next ID=159
INFO:iso20_WPT_Decoder:Grammar ID=159, eventCode=0, decode=WPT_FinePositioningMethodListType (Particle 'EVDeviceFinePositioningMethodList'), next ID=160
INFO:iso20_WPT_Decoder:Grammar ID=160, eventCode=0, decode=WPT_PairingMethodListType (Particle 'EVDevicePairingMethodList'), next ID=161
INFO:iso20_WPT_Decoder:Grammar ID=161, eventCode=0, decode=WPT_AlignmentCheckMethodListType (Particle 'EVDeviceAlignmentCheckMethodList'), next ID=162
INFO:iso20_WPT_Decoder:Grammar ID=162, eventCode=0, decode=unsignedInt (Particle 'NaturalOffset'), next ID=163
INFO:iso20_WPT_Decoder:Grammar ID=163, eventCode=0, decode=base64Binary (Particle 'VendorSpecificDataContainer'), next ID=164
INFO:iso20_WPT_Decoder:Grammar ID=163, eventCode=1, END Element, next ID=3
INFO:iso20_WPT_Decoder:Grammar ID=164, eventCode=0, decode=base64Binary (Particle 'VendorSpecificDataContainer'), next ID=165
INFO:iso20_WPT_Decoder:Grammar ID=164, eventCode=1, decode=WPT_LF_SystemSetupDataType (Particle 'LF_SystemSetupData'), next ID=2
INFO:iso20_WPT_Decoder:Grammar ID=164, eventCode=2, END Element, next ID=3
INFO:iso20_WPT_Decoder:Grammar ID=165, eventCode=0, decode=WPT_LF_SystemSetupDataType (Particle 'LF_SystemSetupData'), next ID=2
INFO:iso20_WPT_Decoder:Grammar ID=165, eventCode=1, END Element, next ID=3
INFO:iso20_WPT_Decoder:Grammar ID=2, eventCode=0, END Element, next ID=3