modify the document of api

examples/all-clusters-app/all-clusters-common/include/operational-state-delegate-impl.h

@@ -52,6 +52,8 @@ class GenericOperationalStateDelegateImpl : public Delegate
     /**
      * Fills in the provided MutableCharSpan with the phase at index `index` if there is one,
      * or returns CHIP_ERROR_NOT_FOUND if the index is out of range for the list of phases.
+     * If fills in the provided MutableCharSpan with the phase at index `0` and returns CHIP_ERROR_NOT_FOUND,
+     * it represents PhaseList attribute is an empty list, the SDK will set PhaseList attribute value to null.
      * Note: This is used by the SDK to populate the phase list attribute. If the contents of this list changes, the
      * device SHALL call the Instance's ReportPhaseListChange method to report that this attribute has changed.
      * @param index The index of the phase, with 0 representing the first phase.

examples/all-clusters-app/ameba/main/include/OperationalStateManager.h

@@ -56,6 +56,8 @@ class GenericOperationalStateDelegateImpl : public Delegate
     /**
      * Fills in the provided MutableCharSpan with the phase at index `index` if there is one,
      * or returns CHIP_ERROR_NOT_FOUND if the index is out of range for the list of phases.
+     * If fills in the provided MutableCharSpan with the phase at index `0` and returns CHIP_ERROR_NOT_FOUND,
+     * it represents PhaseList attribute is an empty list, the SDK will set PhaseList attribute value to null.
      * Note: This is used by the SDK to populate the phase list attribute. If the contents of this list changes, the
      * device SHALL call the Instance's ReportPhaseListChange method to report that this attribute has changed.
      * @param index The index of the phase, with 0 representing the first phase.

examples/chef/common/chef-rvc-operational-state-delegate.h

@@ -52,6 +52,8 @@ class GenericOperationalStateDelegateImpl : public Delegate
     /**
      * Fills in the provided MutableCharSpan with the phase at index `index` if there is one,
      * or returns CHIP_ERROR_NOT_FOUND if the index is out of range for the list of phases.
+     * If fills in the provided MutableCharSpan with the phase at index `0` and returns CHIP_ERROR_NOT_FOUND,
+     * it represents PhaseList attribute is an empty list, the SDK will set PhaseList attribute value to null.
      * Note: This is used by the SDK to populate the phase list attribute. If the contents of this list changes, the
      * device SHALL call the Instance's ReportPhaseListChange method to report that this attribute has changed.
      * @param index The index of the phase, with 0 representing the first phase.

examples/dishwasher-app/dishwasher-common/include/operational-state-delegate-impl.h

@@ -52,6 +52,8 @@ class OperationalStateDelegate : public Delegate
      * Get the list of supported operational phases.
      * Fills in the provided MutableCharSpan with the phase at index `index` if there is one,
      * or returns CHIP_ERROR_NOT_FOUND if the index is out of range for the list of phases.
+     * If fills in the provided MutableCharSpan with the phase at index `0` and returns CHIP_ERROR_NOT_FOUND,
+     * it represents PhaseList attribute is an empty list, the SDK will set PhaseList attribute value to null.
      * @param index The index of the phase, with 0 representing the first phase.
      * @param operationalPhase  The MutableCharSpan is filled.
      */

examples/microwave-oven-app/microwave-oven-common/include/microwave-oven-device.h

@@ -113,6 +113,8 @@ class ExampleMicrowaveOvenDevice : public MicrowaveOvenControl::Delegate,
     /**
      * Fills in the provided MutableCharSpan with the phase at index `index` if there is one,
      * or returns CHIP_ERROR_NOT_FOUND if the index is out of range for the list of phases.
+     * If fills in the provided MutableCharSpan with the phase at index `0` and returns CHIP_ERROR_NOT_FOUND,
+     * it represents PhaseList attribute is an empty list, the SDK will set PhaseList attribute value to null.
      * Note: This is used by the SDK to populate the phase list attribute. If the contents of this list changes, the
      * device SHALL call the Instance's ReportPhaseListChange method to report that this attribute has changed.
      * @param index The index of the phase, with 0 representing the first phase.

examples/rvc-app/rvc-common/include/rvc-operational-state-delegate.h

@@ -75,6 +75,8 @@ class RvcOperationalStateDelegate : public OperationalState::Delegate
     /**
      * Fills in the provided MutableCharSpan with the phase at index `index` if there is one,
      * or returns CHIP_ERROR_NOT_FOUND if the index is out of range for the list of phases.
+     * If fills in the provided MutableCharSpan with the phase at index `0` and returns CHIP_ERROR_NOT_FOUND,
+     * it represents PhaseList attribute is an empty list, the SDK will set PhaseList attribute value to null.
      * Note: This is used by the SDK to populate the phase list attribute. If the contents of this list changes, the
      * device SHALL call the Instance's ReportPhaseListChange method to report that this attribute has changed.
      * @param index The index of the phase, with 0 representing the first phase.

src/app/clusters/operational-state-server/operational-state-server.h

@@ -269,6 +269,8 @@ class Delegate
     /**
      * Fills in the provided MutableCharSpan with the phase at index `index` if there is one,
      * or returns CHIP_ERROR_NOT_FOUND if the index is out of range for the list of phases.
+     * If fills in the provided MutableCharSpan with the phase at index `0` and returns CHIP_ERROR_NOT_FOUND,
+     * it represents PhaseList attribute is an empty list, the SDK will set PhaseList attribute value to null.
      * Note: This is used by the SDK to populate the phase list attribute. If the contents of this list changes, the
      * device SHALL call the Instance's ReportPhaseListChange method to report that this attribute has changed.
      * @param index The index of the phase, with 0 representing the first phase.