configs: parse the "providers" map for module calls

This was accidentally missed on the first pass of module call decoding.
As before, this is a map from child provider config address to parent
provider config address, allowing the set of providers to be projected in
arbitrary ways into a child module.

configs/module_call.go

@@ -1,6 +1,8 @@
 package configs
 
 import (
+	"fmt"
+
 	"github.com/hashicorp/hcl2/gohcl"
 	"github.com/hashicorp/hcl2/hcl"
 	"github.com/hashicorp/hcl2/hcl/hclsyntax"
@@ -21,6 +23,8 @@ type ModuleCall struct {
 	Count   hcl.Expression
 	ForEach hcl.Expression
 
+	Providers []PassedProviderConfig
+
 	DependsOn []hcl.Traversal
 
 	DeclRange hcl.Range
@@ -76,9 +80,49 @@ func decodeModuleBlock(block *hcl.Block, override bool) (*ModuleCall, hcl.Diagno
 		mc.DependsOn = append(mc.DependsOn, deps...)
 	}
 
+	if attr, exists := content.Attributes["providers"]; exists {
+		seen := make(map[string]hcl.Range)
+		pairs, pDiags := hcl.ExprMap(attr.Expr)
+		diags = append(diags, pDiags...)
+		for _, pair := range pairs {
+			key, keyDiags := decodeProviderConfigRef(pair.Key, "providers")
+			diags = append(diags, keyDiags...)
+			value, valueDiags := decodeProviderConfigRef(pair.Value, "providers")
+			diags = append(diags, valueDiags...)
+			if keyDiags.HasErrors() || valueDiags.HasErrors() {
+				continue
+			}
+
+			matchKey := key.String()
+			if prev, exists := seen[matchKey]; exists {
+				diags = append(diags, &hcl.Diagnostic{
+					Severity: hcl.DiagError,
+					Summary:  "Duplicate provider address",
+					Detail:   fmt.Sprintf("A provider configuration was already passed to %s at %s. Each child provider configuration can be assigned only once.", matchKey, prev),
+					Subject:  pair.Value.Range().Ptr(),
+				})
+				continue
+			}
+
+			rng := hcl.RangeBetween(pair.Key.Range(), pair.Value.Range())
+			seen[matchKey] = rng
+			mc.Providers = append(mc.Providers, PassedProviderConfig{
+				InChild:  key,
+				InParent: value,
+			})
+		}
+	}
+
 	return mc, diags
 }
 
+// PassedProviderConfig represents a provider config explicitly passed down to
+// a child module, possibly giving it a new local address in the process.
+type PassedProviderConfig struct {
+	InChild  *ProviderConfigRef
+	InParent *ProviderConfigRef
+}
+
 var moduleBlockSchema = &hcl.BodySchema{
 	Attributes: []hcl.AttributeSchema{
 		{
@@ -97,5 +141,8 @@ var moduleBlockSchema = &hcl.BodySchema{
 		{
 			Name: "depends_on",
 		},
+		{
+			Name: "providers",
+		},
 	},
 }

configs/module_call_test.go

@@ -0,0 +1,137 @@
+package configs
+
+import (
+	"io/ioutil"
+	"testing"
+
+	"github.com/go-test/deep"
+	"github.com/hashicorp/hcl2/hcl"
+)
+
+func TestLoadModuleCall(t *testing.T) {
+	src, err := ioutil.ReadFile("test-fixtures/valid-files/module-calls.tf")
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	parser := testParser(map[string]string{
+		"module-calls.tf": string(src),
+	})
+
+	file, diags := parser.LoadConfigFile("module-calls.tf")
+	if len(diags) != 0 {
+		t.Errorf("Wrong number of diagnostics %d; want 0", len(diags))
+		for _, diag := range diags {
+			t.Logf("- %s", diag)
+		}
+		return
+	}
+
+	gotModules := file.ModuleCalls
+	wantModules := []*ModuleCall{
+		{
+			Name:       "foo",
+			SourceAddr: "./foo",
+			SourceSet:  true,
+			SourceAddrRange: hcl.Range{
+				Filename: "module-calls.tf",
+				Start:    hcl.Pos{Line: 3, Column: 12, Byte: 27},
+				End:      hcl.Pos{Line: 3, Column: 19, Byte: 34},
+			},
+			DeclRange: hcl.Range{
+				Filename: "module-calls.tf",
+				Start:    hcl.Pos{Line: 2, Column: 1, Byte: 1},
+				End:      hcl.Pos{Line: 2, Column: 13, Byte: 13},
+			},
+		},
+		{
+			Name:       "bar",
+			SourceAddr: "hashicorp/bar/aws",
+			SourceSet:  true,
+			SourceAddrRange: hcl.Range{
+				Filename: "module-calls.tf",
+				Start:    hcl.Pos{Line: 8, Column: 12, Byte: 113},
+				End:      hcl.Pos{Line: 8, Column: 31, Byte: 132},
+			},
+			DeclRange: hcl.Range{
+				Filename: "module-calls.tf",
+				Start:    hcl.Pos{Line: 7, Column: 1, Byte: 87},
+				End:      hcl.Pos{Line: 7, Column: 13, Byte: 99},
+			},
+		},
+		{
+			Name:       "baz",
+			SourceAddr: "git::https://example.com/",
+			SourceSet:  true,
+			SourceAddrRange: hcl.Range{
+				Filename: "module-calls.tf",
+				Start:    hcl.Pos{Line: 15, Column: 12, Byte: 193},
+				End:      hcl.Pos{Line: 15, Column: 39, Byte: 220},
+			},
+			DependsOn: []hcl.Traversal{
+				{
+					hcl.TraverseRoot{
+						Name: "module",
+						SrcRange: hcl.Range{
+							Filename: "module-calls.tf",
+							Start:    hcl.Pos{Line: 23, Column: 5, Byte: 295},
+							End:      hcl.Pos{Line: 23, Column: 11, Byte: 301},
+						},
+					},
+					hcl.TraverseAttr{
+						Name: "bar",
+						SrcRange: hcl.Range{
+							Filename: "module-calls.tf",
+							Start:    hcl.Pos{Line: 23, Column: 11, Byte: 301},
+							End:      hcl.Pos{Line: 23, Column: 15, Byte: 305},
+						},
+					},
+				},
+			},
+			Providers: []PassedProviderConfig{
+				{
+					InChild: &ProviderConfigRef{
+						Name: "aws",
+						NameRange: hcl.Range{
+							Filename: "module-calls.tf",
+							Start:    hcl.Pos{Line: 27, Column: 5, Byte: 332},
+							End:      hcl.Pos{Line: 27, Column: 8, Byte: 335},
+						},
+					},
+					InParent: &ProviderConfigRef{
+						Name: "aws",
+						NameRange: hcl.Range{
+							Filename: "module-calls.tf",
+							Start:    hcl.Pos{Line: 27, Column: 11, Byte: 338},
+							End:      hcl.Pos{Line: 27, Column: 14, Byte: 341},
+						},
+						Alias: "foo",
+						AliasRange: &hcl.Range{
+							Filename: "module-calls.tf",
+							Start:    hcl.Pos{Line: 27, Column: 14, Byte: 341},
+							End:      hcl.Pos{Line: 27, Column: 18, Byte: 345},
+						},
+					},
+				},
+			},
+			DeclRange: hcl.Range{
+				Filename: "module-calls.tf",
+				Start:    hcl.Pos{Line: 14, Column: 1, Byte: 167},
+				End:      hcl.Pos{Line: 14, Column: 13, Byte: 179},
+			},
+		},
+	}
+
+	// We'll hide all of the bodies/exprs since we're treating them as opaque
+	// here anyway... the point of this test is to ensure we handle everything
+	// else properly.
+	for _, m := range gotModules {
+		m.Config = nil
+		m.Count = nil
+		m.ForEach = nil
+	}
+
+	for _, problem := range deep.Equal(gotModules, wantModules) {
+		t.Error(problem)
+	}
+}

configs/resource.go

@@ -114,7 +114,7 @@ func decodeResourceBlock(block *hcl.Block) (*Resource, hcl.Diagnostics) {
 
 	if attr, exists := content.Attributes["provider"]; exists {
 		var providerDiags hcl.Diagnostics
-		r.ProviderConfigRef, providerDiags = decodeProviderConfigRef(attr)
+		r.ProviderConfigRef, providerDiags = decodeProviderConfigRef(attr.Expr, "provider")
 		diags = append(diags, providerDiags...)
 	}
 
@@ -290,7 +290,7 @@ func decodeDataBlock(block *hcl.Block) (*Resource, hcl.Diagnostics) {
 
 	if attr, exists := content.Attributes["provider"]; exists {
 		var providerDiags hcl.Diagnostics
-		r.ProviderConfigRef, providerDiags = decodeProviderConfigRef(attr)
+		r.ProviderConfigRef, providerDiags = decodeProviderConfigRef(attr.Expr, "provider")
 		diags = append(diags, providerDiags...)
 	}
 
@@ -324,10 +324,11 @@ type ProviderConfigRef struct {
 	AliasRange *hcl.Range // nil if alias not set
 }
 
-func decodeProviderConfigRef(attr *hcl.Attribute) (*ProviderConfigRef, hcl.Diagnostics) {
+func decodeProviderConfigRef(expr hcl.Expression, argName string) (*ProviderConfigRef, hcl.Diagnostics) {
 	var diags hcl.Diagnostics
 
-	expr, shimDiags := shimTraversalInString(attr.Expr, false)
+	var shimDiags hcl.Diagnostics
+	expr, shimDiags = shimTraversalInString(expr, false)
 	diags = append(diags, shimDiags...)
 
 	traversal, travDiags := hcl.AbsTraversalForExpr(expr)
@@ -345,7 +346,7 @@ func decodeProviderConfigRef(attr *hcl.Attribute) (*ProviderConfigRef, hcl.Diagn
 		// showing that usage, so we'll sniff for that situation here and
 		// produce a specialized error message for it to help users find
 		// the new correct form.
-		if exprIsNativeQuotedString(attr.Expr) {
+		if exprIsNativeQuotedString(expr) {
 			diags = append(diags, &hcl.Diagnostic{
 				Severity: hcl.DiagError,
 				Summary:  "Invalid provider configuration reference",
@@ -358,7 +359,7 @@ func decodeProviderConfigRef(attr *hcl.Attribute) (*ProviderConfigRef, hcl.Diagn
 		diags = append(diags, &hcl.Diagnostic{
 			Severity: hcl.DiagError,
 			Summary:  "Invalid provider configuration reference",
-			Detail:   fmt.Sprintf("The %s argument requires a provider type name, optionally followed by a period and then a configuration alias.", attr.Name),
+			Detail:   fmt.Sprintf("The %s argument requires a provider type name, optionally followed by a period and then a configuration alias.", argName),
 			Subject:  expr.Range().Ptr(),
 		})
 		return nil, diags

configs/test-fixtures/valid-files/module-calls.tf

@@ -22,5 +22,8 @@ module "baz" {
   depends_on = [
     module.bar,
   ]
-}
 
+  providers = {
+    aws = aws.foo
+  }
+}