Partially unknown provider functions arguments fixed (opentofu#2127) (opentofu#2133) (opentofu#2134)

Signed-off-by: Christian Mesh <[email protected]>

Author: cam72cam

CHANGELOG.md

@@ -1,12 +1,16 @@
-## 1.7.5 (unreleased)
+## 1.7.6 (unreleased)
+
+## 1.7.5
+
+BUG FIXES:
+* Provider functions will now handle partially unknown arguments per the tfplugin spec ([#2127](https://github.com/opentofu/opentofu/pull/2127))
 
 ## 1.7.4
 
 ENHANCEMENTS:
 * Made `tofu plan` with `generate-config-out` flag replace JSON strings with `jsonencode` functions calls. ([#1595](https://github.com/opentofu/opentofu/pull/1595))
 
 BUG FIXES:
-
 * `tofu init` will no longer return a supurious "Backend configuration changed" error when re-initializing a working directory with identical settings, backend configuration contains references to variables or local values, and when the `-backend-config` command line option is used. That combination previously caused OpenTofu to incorrectly treat the backend configuration as invalid. ([#2055](https://github.com/opentofu/opentofu/pull/2055))
 * configuration generation should no longer fail when generating sensitive properties
 * Provider defined functions are now supported better in child modules

internal/plugin/grpc_provider.go

@@ -766,9 +766,22 @@ func (p *GRPCProvider) CallFunction(r providers.CallFunctionRequest) (resp provi
 			} else {
 				// This should be unreachable
 				resp.Error = fmt.Errorf("invalid CallFunctionRequest: too many arguments passed to non-variadic function %s", r.Name)
+				return resp
 			}
 		}
 
+		if !paramSpec.AllowUnknownValues && !arg.IsWhollyKnown() {
+			// Unlike the standard in cty, AllowUnknownValues == false does not just apply to
+			// the root of the value (IsKnown) and instead also applies to values inside collections
+			// and structures (IsWhollyKnown).
+			// This is documented in the tfplugin proto file comments.
+			//
+			// The standard cty logic can be found in:
+			// https://github.com/zclconf/go-cty/blob/ea922e7a95ba2be57897697117f318670e066d22/cty/function/function.go#L288-L290
+			resp.Result = cty.UnknownVal(spec.Return)
+			return resp
+		}
+
 		if arg.IsNull() {
 			if paramSpec.AllowNullValue {
 				continue

internal/plugin6/grpc_provider.go

@@ -755,9 +755,22 @@ func (p *GRPCProvider) CallFunction(r providers.CallFunctionRequest) (resp provi
 			} else {
 				// This should be unreachable
 				resp.Error = fmt.Errorf("invalid CallFunctionRequest: too many arguments passed to non-variadic function %s", r.Name)
+				return resp
 			}
 		}
 
+		if !paramSpec.AllowUnknownValues && !arg.IsWhollyKnown() {
+			// Unlike the standard in cty, AllowUnknownValues == false does not just apply to
+			// the root of the value (IsKnown) and instead also applies to values inside collections
+			// and structures (IsWhollyKnown).
+			// This is documented in the tfplugin proto file comments.
+			//
+			// The standard cty logic can be found in:
+			// https://github.com/zclconf/go-cty/blob/ea922e7a95ba2be57897697117f318670e066d22/cty/function/function.go#L288-L290
+			resp.Result = cty.UnknownVal(spec.Return)
+			return resp
+		}
+
 		if arg.IsNull() {
 			if paramSpec.AllowNullValue {
 				continue

internal/providers/provider.go

@@ -170,7 +170,10 @@ type FunctionParameterSpec struct {
 	// Null values alowed for the parameter
 	AllowNullValue bool
 	// Unknown Values allowed for the parameter
-	// Implies the Return type of the function is also Unknown
+	// Individual provider implementations may interpret this as a
+	// check using IsWhollyKnown instead cty's default of IsKnown.
+	// If the input is not wholly known, the result should be
+	// cty.UnknownVal(spec.returnType)
 	AllowUnknownValues bool
 	// Human-readable documentation for the parameter
 	Description string