Add protovalidate rules to remaining messages

While protovalidate rules are mainly useful for validating gRPC
_request_ messages, adding validation annotations to _response_ messages
has several advantages. Namely, doing so provides implicit documentation
to API consumers on how the API behaves and what its contract is. It
also ensures we think twice before making a change which isn't
technically breaking to the message wire format but could be breaking to
how clients are using API responses.

Author: lberrymage

accrescent/directory/v1/app_download_info.proto

@@ -8,15 +8,16 @@ package accrescent.directory.v1;
 
 import "accrescent/directory/v1/package_info.proto";
 import "accrescent/directory/v1/split_download_info.proto";
+import "buf/validate/validate.proto";
 
 option java_multiple_files = true;
 option java_package = "app.accrescent.directory.v1";
 
 // App download information for a given app.
 message AppDownloadInfo {
   // Download info for each individual split APK.
-  repeated SplitDownloadInfo split_download_info = 1;
+  repeated SplitDownloadInfo split_download_info = 1 [(buf.validate.field).repeated.min_items = 1];
 
   // Package information for this app.
-  PackageInfo package_info = 2;
+  PackageInfo package_info = 2 [(buf.validate.field).required = true];
 }

accrescent/directory/v1/app_listing.proto

@@ -7,26 +7,27 @@ syntax = "proto3";
 package accrescent.directory.v1;
 
 import "accrescent/directory/v1/image.proto";
+import "buf/validate/validate.proto";
 
 option java_multiple_files = true;
 option java_package = "app.accrescent.directory.v1";
 
 // A localized store listing for a given app.
 message AppListing {
   // The application ID this listing is associated with.
-  optional string app_id = 1;
+  optional string app_id = 1 [(buf.validate.field).required = true];
 
   // The language of this listing's fields as a BCP-47 tag.
-  optional string language = 2;
+  optional string language = 2 [(buf.validate.field).required = true];
 
   // The proper name of the app, possibly including very short descriptive text
   // (e.g. "SecureChat - Secure Texting").
-  optional string name = 3;
+  optional string name = 3 [(buf.validate.field).required = true];
 
   // A short description of the app to be shown in headers and small screen
   // spaces.
-  optional string short_description = 4;
+  optional string short_description = 4 [(buf.validate.field).required = true];
 
   // The app's primary icon, usually the same as the launcher icon.
-  Image icon = 5;
+  Image icon = 5 [(buf.validate.field).required = true];
 }

accrescent/directory/v1/compatibility.proto

@@ -7,12 +7,19 @@ syntax = "proto3";
 package accrescent.directory.v1;
 
 import "accrescent/directory/v1/compatibility_level.proto";
+import "buf/validate/validate.proto";
 
 option java_multiple_files = true;
 option java_package = "app.accrescent.directory.v1";
 
 // Compatibility of an app with a given device specification.
 message Compatibility {
   // The level of compatibility.
-  optional CompatibilityLevel level = 1;
+  optional CompatibilityLevel level = 1 [
+    (buf.validate.field).required = true,
+    (buf.validate.field).enum = {
+      defined_only: true
+      not_in: [0]
+    }
+  ];
 }

accrescent/directory/v1/get_app_download_info_response.proto

@@ -8,6 +8,7 @@ package accrescent.directory.v1;
 
 import "accrescent/directory/v1/app_download_info.proto";
 import "accrescent/directory/v1/compatibility.proto";
+import "buf/validate/validate.proto";
 
 option java_multiple_files = true;
 option java_package = "app.accrescent.directory.v1";
@@ -16,7 +17,7 @@ option java_package = "app.accrescent.directory.v1";
 message GetAppDownloadInfoResponse {
   // Compatibility information between the app and the device attributes
   // specified in the request.
-  Compatibility compatibility = 1;
+  Compatibility compatibility = 1 [(buf.validate.field).required = true];
 
   // The app's download info. This field will be populated if and only if all of
   // the following statements apply:
@@ -29,4 +30,13 @@ message GetAppDownloadInfoResponse {
   // In other words, it will only be populated if there are APKs available for
   // download which are newer than those specified in the request.
   AppDownloadInfo app_download_info = 2;
+
+  option (buf.validate.message).cel = {
+    id: "app_download_info.not_present_if_incompatible"
+    message: "app download info must not be present if the app is incompatible"
+    expression:
+      "this.compatibility.level"
+      "== accrescent.directory.v1.CompatibilityLevel.COMPATIBILITY_LEVEL_COMPATIBLE
+      "|| !has(this.app_download_info)"
+  };
 }

accrescent/directory/v1/get_app_listing_response.proto

@@ -7,12 +7,13 @@ syntax = "proto3";
 package accrescent.directory.v1;
 
 import "accrescent/directory/v1/app_listing.proto";
+import "buf/validate/validate.proto";
 
 option java_multiple_files = true;
 option java_package = "app.accrescent.directory.v1";
 
 // Response to requesting an app listing.
 message GetAppListingResponse {
   // The listing provided by the API.
-  AppListing listing = 1;
+  AppListing listing = 1 [(buf.validate.field).required = true];
 }

accrescent/directory/v1/get_app_package_info_response.proto

@@ -7,12 +7,13 @@ syntax = "proto3";
 package accrescent.directory.v1;
 
 import "accrescent/directory/v1/package_info.proto";
+import "buf/validate/validate.proto";
 
 option java_multiple_files = true;
 option java_package = "app.accrescent.directory.v1";
 
 // Response to requesting an app's package info.
 message GetAppPackageInfoResponse {
   // The package info matching the request parameters.
-  PackageInfo package_info = 1;
+  PackageInfo package_info = 1 [(buf.validate.field).required = true];
 }

accrescent/directory/v1/image.proto

@@ -6,12 +6,17 @@ syntax = "proto3";
 
 package accrescent.directory.v1;
 
+import "buf/validate/validate.proto";
+
 option java_multiple_files = true;
 option java_package = "app.accrescent.directory.v1";
 
 // Graphical image to be displayed in client UI.
 message Image {
   // The URL of the image file which can be retrieved with a simple HTTP GET
   // request.
-  optional string url = 1;
+  optional string url = 1 [
+    (buf.validate.field).required = true,
+    (buf.validate.field).string.uri = true
+  ];
 }

accrescent/directory/v1/list_app_listings_response.proto

@@ -7,14 +7,19 @@ syntax = "proto3";
 package accrescent.directory.v1;
 
 import "accrescent/directory/v1/app_listing.proto";
+import "buf/validate/validate.proto";
 
 option java_multiple_files = true;
 option java_package = "app.accrescent.directory.v1";
 
 // Response to requesting a list of app listings.
 message ListAppListingsResponse {
   // The app listings matching the request parameters.
-  repeated AppListing listings = 1;
+  repeated AppListing listings = 1 [(buf.validate.field).cel = {
+    id: "listings.have_unique_app_ids"
+    message: "listings must have unique app IDs"
+    expression: "this.map(l, l.app_id).unique()"
+  }];
 
   // An opaque token which, if passed to another invocation of ListAppListings,
   // will return the next page of app listings.

accrescent/directory/v1/package_info.proto

@@ -6,14 +6,19 @@ syntax = "proto3";
 
 package accrescent.directory.v1;
 
+import "buf/validate/validate.proto";
+
 option java_multiple_files = true;
 option java_package = "app.accrescent.directory.v1";
 
 // Package information for a given app.
 message PackageInfo {
   // The app's version code.
-  optional uint64 version_code = 1;
+  optional uint64 version_code = 1 [
+    (buf.validate.field).required = true,
+    (buf.validate.field).uint64.gt = 0
+  ];
 
   // The app's human-readable version name.
-  optional string version_name = 2;
+  optional string version_name = 2 [(buf.validate.field).required = true];
 }

accrescent/directory/v1/split_download_info.proto

@@ -6,14 +6,19 @@ syntax = "proto3";
 
 package accrescent.directory.v1;
 
+import "buf/validate/validate.proto";
+
 option java_multiple_files = true;
 option java_package = "app.accrescent.directory.v1";
 
 // Download info for an individual split APK.
 message SplitDownloadInfo {
   // The download size in bytes of this individual split APK.
-  optional uint32 download_size = 1;
+  optional uint32 download_size = 1 [(buf.validate.field).required = true];
 
   // The URL of the APK which can be retrieved with a simple HTTP GET.
-  optional string url = 2;
+  optional string url = 2 [
+    (buf.validate.field).required = true,
+    (buf.validate.field).string.uri = true
+  ];
 }