feat: AIP-124 – Ensure resource references are valid.

docs/rules/0124/index.md

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+---
+aip_listing: 124
+permalink: /124/
+redirect_from:
+  - /0124/
+---
+
+# Resource association
+
+{% include linter-aip-listing.md aip=124 %}

docs/rules/0124/valid-reference.md

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+---
+rule:
+  aip: 124
+  name: [core, '0124', valid-reference]
+  summary: Resource patterns should use consistent variable naming.
+permalink: /124/valid-reference
+redirect_from:
+  - /0124/valid-reference
+---
+
+# Valid resource references
+
+This rule enforces that resource reference annotations refer to valid and
+reachable resource types, as described in [AIP-124][].
+
+## Details
+
+This rule scans all fields with `google.api.resource_reference` annotations,
+and complains if the `type` on them refers to a resource with no corresponding
+`google.api.resource` or `google.api.resource_definition`.
+
+The rule scans the file where the field is found and all files imported by that
+file (recursively) as long as they are in the same package.
+
+Certain common resource types are exempt from this rule.
+
+## Examples
+
+**Incorrect** code for this rule:
+
+```proto
+// Incorrect.
+message Book {
+  // Needs a resource annotation; without one, resource references are invalid.
+  string name = 1;
+
+  // ...
+}
+
+message GetBookRequest {
+  string name = 1 [(google.api.resource_reference) = {
+    type: "library.googleapis.com/Book"  // Lint warning; referennce not found.
+  }]
+}
+```
+
+**Correct** code for this rule:
+
+```proto
+// Correct.
+message Book {
+  option (google.api.resource) = {
+    type: "library.googleapis.com/Book"
+    pattern: "publishers/{publisher}/books/{book}"
+  };
+
+  string name = 1;
+
+  // ...
+}
+
+message GetBookRequest {
+  string name = 1 [(google.api.resource_reference) = {
+    type: "library.googleapis.com/Book"
+  }]
+}
+```
+
+## Disabling
+
+If you need to violate this rule, use a leading comment above the field.
+Remember to also include an [aip.dev/not-precedent][] comment explaining why.
+
+```proto
+message Book {
+  string name = 1;
+}
+
+message GetBookRequest {
+  // (-- api-linter: core::0124::valid-reference=disabled
+  //     aip.dev/not-precedent: We need to do this because reasons. --)
+  string name = 1 [(google.api.resource_reference) = {
+    type: "library.googleapis.com/Book"
+  }]
+}
+```
+
+If you need to violate this rule for an entire file, place the comment at the
+top of the file.
+
+[aip-124]: http://aip.dev/124
+[aip.dev/not-precedent]: https://aip.dev/not-precedent
+
+```
+
+```

rules/aip0124/aip0124.go

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+// Copyright 2020 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     https://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// Package aip0124 contains rules defined in https://aip.dev/124.
+package aip0124
+
+import (
+	"github.com/googleapis/api-linter/lint"
+)
+
+// AddRules accepts a register function and registers each of
+// this AIP's rules to it.
+func AddRules(r lint.RuleRegistry) error {
+	return r.Register(
+		124,
+		validReference,
+	)
+}

rules/aip0124/aip0124_test.go

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+// Copyright 2020 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     https://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package aip0124
+
+import (
+	"testing"
+
+	"github.com/googleapis/api-linter/lint"
+)
+
+func TestAddRules(t *testing.T) {
+	if err := AddRules(lint.NewRuleRegistry()); err != nil {
+		t.Errorf("AddRules got an error: %v", err)
+	}
+}

rules/aip0124/valid_reference.go

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+// Copyright 2020 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     https://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package aip0124
+
+import (
+	"fmt"
+
+	"bitbucket.org/creachadair/stringset"
+	"github.com/googleapis/api-linter/lint"
+	"github.com/googleapis/api-linter/locations"
+	"github.com/googleapis/api-linter/rules/internal/utils"
+	"github.com/jhump/protoreflect/desc"
+)
+
+var validReference = &lint.FieldRule{
+	Name: lint.NewRuleName(124, "valid-reference"),
+	OnlyIf: func(f *desc.FieldDescriptor) bool {
+		if ref := utils.GetResourceReference(f); ref != nil {
+			urt := ref.GetType()
+			if urt == "" {
+				urt = ref.GetChildType()
+			}
+			return !stringset.New(
+				// Whitelist the common resource types in GCP.
+				// FIXME: Modularize this.
+				"cloudresourcemanager.googleapis.com/Project",
+				"cloudresourcemanager.googleapis.com/Organization",
+				"cloudresourcemanager.googleapis.com/Folder",
+				"billing.googleapis.com/BillingAccount",
+				"locations.googleapis.com/Location",
+
+				// If no type is declared, ignore this.
+				"",
+			).Contains(urt)
+		}
+		return false
+	},
+	LintField: func(f *desc.FieldDescriptor) []lint.Problem {
+		// Get the type we are checking for.
+		ref := utils.GetResourceReference(f)
+		urt := ref.GetType()
+		if urt == "" {
+			urt = ref.GetChildType()
+		}
+
+		// Iterate over each dependency file and check for a matching resource.
+		for _, file := range getDependencies(f.GetFile(), f.GetFile().GetPackage()) {
+			// Most resources will be messages. If we find a message with a
+			// resource annotation matching our universal resource type, we are done.
+			for _, message := range file.GetMessageTypes() {
+				if res := utils.GetResource(message); res != nil {
+					if res.GetType() == urt {
+						return nil
+					}
+				}
+			}
+
+			// Some resources are defined as file annotations. Check for these too.
+			for _, rd := range utils.GetResourceDefinitions(file) {
+				if rd.GetType() == urt {
+					return nil
+				}
+			}
+		}
+
+		// We could not find a resource with that type. Return a problem.
+		return []lint.Problem{{
+			Message:    fmt.Sprintf("Could not find resource of type %q", urt),
+			Descriptor: f,
+			Location:   locations.FieldResourceReference(f),
+		}}
+	},
+}
+
+// getDependencies returns all dependencies in the same package.
+func getDependencies(file *desc.FileDescriptor, pkg string) map[string]*desc.FileDescriptor {
+	answer := map[string]*desc.FileDescriptor{file.GetName(): file}
+	for _, f := range file.GetDependencies() {
+		if _, found := answer[f.GetName()]; !found && f.GetPackage() == pkg {
+			answer[f.GetName()] = f
+			for name, f2 := range getDependencies(f, pkg) {
+				answer[name] = f2
+			}
+		}
+	}
+	return answer
+}

rules/aip0124/valid_reference_test.go

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+// Copyright 2020 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     https://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package aip0124
+
+import (
+	"testing"
+
+	"github.com/googleapis/api-linter/rules/internal/testutils"
+)
+
+func TestValidReference(t *testing.T) {
+	for _, test := range []struct {
+		name     string
+		Field    string
+		Ref      string
+		problems testutils.Problems
+	}{
+		{"Found", "type", "library.googleapis.com/Book", nil},
+		{"FoundChild", "child_type", "library.googleapis.com/Book", nil},
+		{"NotFound", "type", "library.googleapis.com/Bok", testutils.Problems{{Message: "Could not find"}}},
+		{"NotFoundChild", "child_type", "library.googleapis.com/Bok", testutils.Problems{{Message: "Could not find"}}},
+		{"Ignored", "type", "cloudresourcemanager.googleapis.com/Project", nil},
+	} {
+		t.Run(test.name, func(t *testing.T) {
+			t.Run("SameFileResourceDefinition", func(t *testing.T) {
+				f := testutils.ParseProto3Tmpl(t, `
+					import "google/api/resource.proto";
+					option (google.api.resource_definition) = {
+						type: "library.googleapis.com/Book"
+					};
+					message Foo {
+						string book = 1 [(google.api.resource_reference).{{.Field}} = "{{.Ref}}"];
+						string irrelevant = 2;
+					}
+				`, test)
+				field := f.GetMessageTypes()[0].GetFields()[0]
+				if diff := test.problems.SetDescriptor(field).Diff(validReference.Lint(f)); diff != "" {
+					t.Errorf(diff)
+				}
+			})
+
+			t.Run("SameFileResourceMessage", func(t *testing.T) {
+				f := testutils.ParseProto3Tmpl(t, `
+					import "google/api/resource.proto";
+					message Book {
+						option (google.api.resource) = {
+							type: "library.googleapis.com/Book"
+						};
+					}
+					message Foo {
+						string book = 1 [(google.api.resource_reference).{{.Field}} = "{{.Ref}}"];
+					}
+				`, test)
+				field := f.GetMessageTypes()[1].GetFields()[0]
+				if diff := test.problems.SetDescriptor(field).Diff(validReference.Lint(f)); diff != "" {
+					t.Errorf(diff)
+				}
+			})
+		})
+
+		t.Run("DirectDependency", func(t *testing.T) {
+			files := testutils.ParseProto3Tmpls(t, map[string]string{
+				"dep.proto": `
+					import "google/api/resource.proto";
+					message Book {
+						option (google.api.resource) = {
+							type: "library.googleapis.com/Book"
+						};
+					}
+				`,
+				"leaf.proto": `
+					import "google/api/resource.proto";
+					import "dep.proto";
+					message Foo {
+						string book = 1 [(google.api.resource_reference).{{.Field}} = "{{.Ref}}"];
+					}
+				`,
+			}, test)
+			file := files["leaf.proto"]
+			field := file.GetMessageTypes()[0].GetFields()[0]
+			if diff := test.problems.SetDescriptor(field).Diff(validReference.Lint(file)); diff != "" {
+				t.Errorf(diff)
+			}
+		})
+
+		t.Run("RemoteDependency", func(t *testing.T) {
+			files := testutils.ParseProto3Tmpls(t, map[string]string{
+				"dep.proto": `
+					import "google/api/resource.proto";
+					message Book {
+						option (google.api.resource) = {
+							type: "library.googleapis.com/Book"
+						};
+					}
+				`,
+				"intermediate.proto": `import "dep.proto";`,
+				"leaf.proto": `
+					import "google/api/resource.proto";
+					import "intermediate.proto";
+					message Foo {
+						string book = 1 [(google.api.resource_reference).{{.Field}} = "{{.Ref}}"];
+					}
+				`,
+			}, test)
+			file := files["leaf.proto"]
+			field := file.GetMessageTypes()[0].GetFields()[0]
+			if diff := test.problems.SetDescriptor(field).Diff(validReference.Lint(file)); diff != "" {
+				t.Errorf(diff)
+			}
+		})
+	}
+}