Ignore MinItems and MaxItems diff in nested block

.changelog/118.txt

@@ -0,0 +1,3 @@
+```release-note:bug
+tf5muxserver+tf6muxserver: Allow differing provider schema block `MinItems` and `MaxItems` as terraform-plugin-framework does not use those fields for configuration validation
+```

tf5muxserver/mux_server_test.go

@@ -547,6 +547,54 @@ func TestNewMuxServer(t *testing.T) {
 				}).ProviderServer,
 			},
 		},
+		"nested block MinItems and MaxItems diff are ignored": {
+			servers: []func() tfprotov5.ProviderServer{
+				(&tf5testserver.TestServer{
+					ProviderSchema: &tfprotov5.Schema{
+						Version: 1,
+						Block: &tfprotov5.SchemaBlock{
+							Version: 1,
+							BlockTypes: []*tfprotov5.SchemaNestedBlock{
+								{
+									TypeName: "feature",
+									Nesting:  tfprotov5.SchemaNestedBlockNestingModeList,
+									Block: &tfprotov5.SchemaBlock{
+										Version:         1,
+										Description:     "features to enable on the provider",
+										DescriptionKind: tfprotov5.StringKindPlain,
+										Attributes:      []*tfprotov5.SchemaAttribute{},
+									},
+									MinItems: 1,
+									MaxItems: 2,
+								},
+							},
+						},
+					},
+				}).ProviderServer,
+				(&tf5testserver.TestServer{
+					ProviderSchema: &tfprotov5.Schema{
+						Version: 1,
+						Block: &tfprotov5.SchemaBlock{
+							Version: 1,
+							BlockTypes: []*tfprotov5.SchemaNestedBlock{
+								{
+									TypeName: "feature",
+									Nesting:  tfprotov5.SchemaNestedBlockNestingModeList,
+									Block: &tfprotov5.SchemaBlock{
+										Version:         1,
+										Description:     "features to enable on the provider",
+										DescriptionKind: tfprotov5.StringKindPlain,
+										Attributes:      []*tfprotov5.SchemaAttribute{},
+									},
+									MinItems: 0,
+									MaxItems: 0,
+								},
+							},
+						},
+					},
+				}).ProviderServer,
+			},
+		},
 	}
 
 	for name, testCase := range testCases {

tf5muxserver/schema_equality.go

@@ -15,6 +15,7 @@ var schemaCmpOptions = []cmp.Option{
 	cmpopts.SortSlices(func(i, j *tfprotov5.SchemaNestedBlock) bool {
 		return i.TypeName < j.TypeName
 	}),
+	cmpopts.IgnoreFields(tfprotov5.SchemaNestedBlock{}, "MinItems", "MaxItems"),
 }
 
 // schemaDiff outputs the difference between schemas while accounting for

tf6muxserver/mux_server_test.go

@@ -547,6 +547,54 @@ func TestNewMuxServer(t *testing.T) {
 				}).ProviderServer,
 			},
 		},
+		"nested block MinItems and MaxItems diff are ignored": {
+			servers: []func() tfprotov6.ProviderServer{
+				(&tf6testserver.TestServer{
+					ProviderSchema: &tfprotov6.Schema{
+						Version: 1,
+						Block: &tfprotov6.SchemaBlock{
+							Version: 1,
+							BlockTypes: []*tfprotov6.SchemaNestedBlock{
+								{
+									TypeName: "feature",
+									Nesting:  tfprotov6.SchemaNestedBlockNestingModeList,
+									Block: &tfprotov6.SchemaBlock{
+										Version:         1,
+										Description:     "features to enable on the provider",
+										DescriptionKind: tfprotov6.StringKindPlain,
+										Attributes:      []*tfprotov6.SchemaAttribute{},
+									},
+									MinItems: 1,
+									MaxItems: 2,
+								},
+							},
+						},
+					},
+				}).ProviderServer,
+				(&tf6testserver.TestServer{
+					ProviderSchema: &tfprotov6.Schema{
+						Version: 1,
+						Block: &tfprotov6.SchemaBlock{
+							Version: 1,
+							BlockTypes: []*tfprotov6.SchemaNestedBlock{
+								{
+									TypeName: "feature",
+									Nesting:  tfprotov6.SchemaNestedBlockNestingModeList,
+									Block: &tfprotov6.SchemaBlock{
+										Version:         1,
+										Description:     "features to enable on the provider",
+										DescriptionKind: tfprotov6.StringKindPlain,
+										Attributes:      []*tfprotov6.SchemaAttribute{},
+									},
+									MinItems: 0,
+									MaxItems: 0,
+								},
+							},
+						},
+					},
+				}).ProviderServer,
+			},
+		},
 	}
 
 	for name, testCase := range testCases {

tf6muxserver/schema_equality.go

@@ -15,6 +15,7 @@ var schemaCmpOptions = []cmp.Option{
 	cmpopts.SortSlices(func(i, j *tfprotov6.SchemaNestedBlock) bool {
 		return i.TypeName < j.TypeName
 	}),
+	cmpopts.IgnoreFields(tfprotov6.SchemaNestedBlock{}, "MinItems", "MaxItems"),
 }
 
 // schemaDiff outputs the difference between schemas while accounting for

website/docs/plugin/mux/combining-protocol-version-5-providers.mdx

@@ -27,7 +27,7 @@ The following provider server implementations are supported:
 
 To be combined, provider servers must meet the following requirements:
 
-* All provider schemas must match.
+* All provider schemas  (except block `MinItems`/`MaxItems`) must match.
 * All provider meta schemas must match.
 * Only one provider may implement each resource and data source.