rpcapi: Populate source location fields in protobuf diagnostics

internal/rpcapi/convert.go

@@ -28,6 +28,33 @@ func diagnosticsToProto(diags tfdiags.Diagnostics) []*terraform1.Diagnostic {
 		protoDiag.Summary = desc.Summary
 		protoDiag.Detail = desc.Detail
 
+		srcRngs := diag.Source()
+		if srcRngs.Subject != nil {
+			protoDiag.Subject = sourceRangeToProto(*srcRngs.Subject)
+		}
+		if srcRngs.Context != nil {
+			protoDiag.Context = sourceRangeToProto(*srcRngs.Context)
+		}
 	}
 	return ret
 }
+
+func sourceRangeToProto(rng tfdiags.SourceRange) *terraform1.SourceRange {
+	return &terraform1.SourceRange{
+		// RPC API operations use source address syntax for "filename" by
+		// convention, because the physical filesystem layout is an
+		// implementation detail.
+		SourceAddr: rng.Filename,
+
+		Start: sourcePosToProto(rng.Start),
+		End:   sourcePosToProto(rng.End),
+	}
+}
+
+func sourcePosToProto(pos tfdiags.SourcePos) *terraform1.SourcePos {
+	return &terraform1.SourcePos{
+		Byte:   int64(pos.Byte),
+		Line:   int64(pos.Line),
+		Column: int64(pos.Column),
+	}
+}

internal/rpcapi/convert_test.go

@@ -0,0 +1,184 @@
+package rpcapi
+
+import (
+	"fmt"
+	"testing"
+
+	"github.com/hashicorp/hcl/v2"
+	"github.com/hashicorp/terraform/internal/rpcapi/terraform1"
+	"github.com/hashicorp/terraform/internal/tfdiags"
+
+	"github.com/google/go-cmp/cmp"
+	"google.golang.org/protobuf/testing/protocmp"
+)
+
+func TestDiagnosticsToProto(t *testing.T) {
+	tests := map[string]struct {
+		Input tfdiags.Diagnostics
+		Want  []*terraform1.Diagnostic
+	}{
+		"nil": {
+			Input: nil,
+			Want:  nil,
+		},
+		"empty": {
+			Input: make(tfdiags.Diagnostics, 0, 5),
+			Want:  nil,
+		},
+		"sourceless": {
+			Input: tfdiags.Diagnostics{
+				tfdiags.Sourceless(
+					tfdiags.Error,
+					"Something annoying",
+					"But I'll get over it.",
+				),
+			},
+			Want: []*terraform1.Diagnostic{
+				{
+					Severity: terraform1.Diagnostic_ERROR,
+					Summary:  "Something annoying",
+					Detail:   "But I'll get over it.",
+				},
+			},
+		},
+		"warning": {
+			Input: tfdiags.Diagnostics{
+				tfdiags.Sourceless(
+					tfdiags.Warning,
+					"I have a very bad feeling about this",
+					"That's no moon; it's a space station.",
+				),
+			},
+			Want: []*terraform1.Diagnostic{
+				{
+					Severity: terraform1.Diagnostic_WARNING,
+					Summary:  "I have a very bad feeling about this",
+					Detail:   "That's no moon; it's a space station.",
+				},
+			},
+		},
+		"with subject": {
+			Input: tfdiags.Diagnostics{}.Append(
+				&hcl.Diagnostic{
+					Severity: hcl.DiagError,
+					Summary:  "Something annoying",
+					Detail:   "But I'll get over it.",
+					Subject: &hcl.Range{
+						Filename: "git::https://example.com/foo.git",
+						Start:    hcl.InitialPos,
+						End: hcl.Pos{
+							Byte:   2,
+							Line:   3,
+							Column: 4,
+						},
+					},
+				},
+			),
+			Want: []*terraform1.Diagnostic{
+				{
+					Severity: terraform1.Diagnostic_ERROR,
+					Summary:  "Something annoying",
+					Detail:   "But I'll get over it.",
+					Subject: &terraform1.SourceRange{
+						SourceAddr: "git::https://example.com/foo.git",
+						Start: &terraform1.SourcePos{
+							Byte:   0,
+							Line:   1,
+							Column: 1,
+						},
+						End: &terraform1.SourcePos{
+							Byte:   2,
+							Line:   3,
+							Column: 4,
+						},
+					},
+				},
+			},
+		},
+		"with subject and context": {
+			Input: tfdiags.Diagnostics{}.Append(
+				&hcl.Diagnostic{
+					Severity: hcl.DiagError,
+					Summary:  "Something annoying",
+					Detail:   "But I'll get over it.",
+					Subject: &hcl.Range{
+						Filename: "git::https://example.com/foo.git",
+						Start:    hcl.InitialPos,
+						End: hcl.Pos{
+							Byte:   2,
+							Line:   3,
+							Column: 4,
+						},
+					},
+					Context: &hcl.Range{
+						Filename: "git::https://example.com/foo.git",
+						Start:    hcl.InitialPos,
+						End: hcl.Pos{
+							Byte:   5,
+							Line:   6,
+							Column: 7,
+						},
+					},
+				},
+			),
+			Want: []*terraform1.Diagnostic{
+				{
+					Severity: terraform1.Diagnostic_ERROR,
+					Summary:  "Something annoying",
+					Detail:   "But I'll get over it.",
+					Subject: &terraform1.SourceRange{
+						SourceAddr: "git::https://example.com/foo.git",
+						Start: &terraform1.SourcePos{
+							Byte:   0,
+							Line:   1,
+							Column: 1,
+						},
+						End: &terraform1.SourcePos{
+							Byte:   2,
+							Line:   3,
+							Column: 4,
+						},
+					},
+					Context: &terraform1.SourceRange{
+						SourceAddr: "git::https://example.com/foo.git",
+						Start: &terraform1.SourcePos{
+							Byte:   0,
+							Line:   1,
+							Column: 1,
+						},
+						End: &terraform1.SourcePos{
+							Byte:   5,
+							Line:   6,
+							Column: 7,
+						},
+					},
+				},
+			},
+		},
+		"with only severity and summary": {
+			// This is the kind of degenerate diagnostic we produce when
+			// we're just naively wrapping a Go error, as tends to arise
+			// in providers that are just passing through their SDK errors.
+			Input: tfdiags.Diagnostics{}.Append(
+				fmt.Errorf("oh no bad"),
+			),
+			Want: []*terraform1.Diagnostic{
+				{
+					Severity: terraform1.Diagnostic_ERROR,
+					Summary:  "oh no bad",
+				},
+			},
+		},
+	}
+
+	for name, test := range tests {
+		t.Run(name, func(t *testing.T) {
+			got := diagnosticsToProto(test.Input)
+			want := test.Want
+
+			if diff := cmp.Diff(want, got, protocmp.Transform()); diff != "" {
+				t.Errorf("wrong result\n%s", diff)
+			}
+		})
+	}
+}