Add support for proto3 optional scalars

Protobuf 3.15 introduced support for marking scalar fields like
uint32 as optional, and all of our tooling appears to support it
now. This allows us to use simple optional/null checks in our Rust/
TypeScript code, without having to resort to an inner message.

I had to apply a minor patch to protobufjs to get this working with
the json-module output; this has also been submitted upstream:
protobufjs/protobuf.js#1693

I've modified CardStatsResponse as an example of the new syntax.

One thing to note: while the Rust and TypeScript bindings use optional/
null fields, as that is the norm in those languages, Google's Python
bindings are not very Pythonic. Referencing an optional field that is
missing will yield the default value, and a separate HasField() call
is required, eg:

```
>>> from anki.stats_pb2 import CardStatsResponse as R
... msg = R.FromString(b"")
... print(msg.first_review)
... print(msg.HasField("first_review"))
0
False
```

proto/anki/stats.proto

@@ -32,10 +32,10 @@ message CardStatsResponse {
   string deck = 4;
   // Unix timestamps
   int64 added = 5;
-  generic.Int64 first_review = 6;
-  generic.Int64 latest_review = 7;
-  generic.Int64 due_date = 8;
-  generic.Int32 due_position = 9;
+  optional int64 first_review = 6;
+  optional int64 latest_review = 7;
+  optional int64 due_date = 8;
+  optional int32 due_position = 9;
   // days
   uint32 interval = 10;
   // per mill

proto/protobuf.bzl

@@ -33,39 +33,39 @@ def setup_protobuf_binary(name):
         http_archive,
         name = "protoc_bin_macos",
         urls = [
-            "https://github.com/protocolbuffers/protobuf/releases/download/v3.14.0/protoc-3.14.0-osx-x86_64.zip",
+            "https://github.com/protocolbuffers/protobuf/releases/download/v3.19.4/protoc-3.19.4-osx-x86_64.zip",
         ],
-        sha256 = "699ceee7ef0988ecf72bf1c146dee5d9d89351a19d4093d30ebea3c04008bb8c",
+        sha256 = "d8b55cf1e887917dd43c447d77bd5bd213faff1e18ac3a176b35558d86f7ffff",
         build_file_content = """exports_files(["bin/protoc"])""",
     )
 
     maybe(
         http_archive,
         name = "protoc_bin_linux_x86_64",
         urls = [
-            "https://github.com/protocolbuffers/protobuf/releases/download/v3.14.0/protoc-3.14.0-linux-x86_64.zip",
+            "https://github.com/protocolbuffers/protobuf/releases/download/v3.19.4/protoc-3.19.4-linux-x86_64.zip",
         ],
-        sha256 = "a2900100ef9cda17d9c0bbf6a3c3592e809f9842f2d9f0d50e3fba7f3fc864f0",
+        sha256 = "058d29255a08f8661c8096c92961f3676218704cbd516d3916ec468e139cbd87",
         build_file_content = """exports_files(["bin/protoc"])""",
     )
 
     maybe(
         http_archive,
         name = "protoc_bin_linux_arm64",
         urls = [
-            "https://github.com/protocolbuffers/protobuf/releases/download/v3.14.0/protoc-3.14.0-linux-aarch_64.zip",
+            "https://github.com/protocolbuffers/protobuf/releases/download/v3.19.4/protoc-3.19.4-linux-aarch_64.zip",
         ],
-        sha256 = "67db019c10ad0a151373278383e4e9b756dc90c3cea6c1244d5d5bd230af7c1a",
+        sha256 = "95584939e733bdd6ffb8245616b2071f565cd4c28163b6c21c8f936a9ee20861",
         build_file_content = """exports_files(["bin/protoc"])""",
     )
 
     maybe(
         http_archive,
         name = "protoc_bin_windows",
         urls = [
-            "https://github.com/protocolbuffers/protobuf/releases/download/v3.14.0/protoc-3.14.0-win64.zip",
+            "https://github.com/protocolbuffers/protobuf/releases/download/v3.19.4/protoc-3.19.4-win64.zip",
         ],
-        sha256 = "642554ed4dd2dba94e1afddcccdd7d832999cea309299cc5952f13db389894f8",
+        sha256 = "828d2bdfe410e988cfc46462bcabd34ffdda8cc172867989ec647eadc55b03b5",
         build_file_content = """exports_files(["bin/protoc.exe"])""",
     )
 

rslib/src/stats/card.rs

@@ -32,12 +32,8 @@ impl Collection {
             note_id: card.note_id.into(),
             deck: deck.human_name(),
             added: card.id.as_secs().0,
-            first_review: revlog.first().map(|entry| pb::generic::Int64 {
-                val: entry.id.as_secs().0,
-            }),
-            latest_review: revlog.last().map(|entry| pb::generic::Int64 {
-                val: entry.id.as_secs().0,
-            }),
+            first_review: revlog.first().map(|entry| entry.id.as_secs().0),
+            latest_review: revlog.last().map(|entry| entry.id.as_secs().0),
             due_date,
             due_position,
             interval: card.interval,
@@ -52,22 +48,17 @@ impl Collection {
         })
     }
 
-    fn due_date_and_position(
-        &mut self,
-        card: &Card,
-    ) -> Result<(Option<pb::generic::Int64>, Option<pb::generic::Int32>)> {
+    fn due_date_and_position(&mut self, card: &Card) -> Result<(Option<i64>, Option<i32>)> {
         let due = if card.original_due != 0 {
             card.original_due
         } else {
             card.due
         };
         Ok(match card.queue {
-            CardQueue::New => (None, Some(pb::generic::Int32 { val: due })),
+            CardQueue::New => (None, Some(due)),
             CardQueue::Learn => (
-                Some(pb::generic::Int64 {
-                    val: TimestampSecs::now().0,
-                }),
-                card.original_position.map(|u| (u as i32).into()),
+                Some(TimestampSecs::now().0),
+                card.original_position.map(|u| u as i32),
             ),
             CardQueue::Review | CardQueue::DayLearn => (
                 {
@@ -78,10 +69,10 @@ impl Collection {
                         let days_remaining = due - (self.timing_today()?.days_elapsed as i32);
                         let mut due = TimestampSecs::now();
                         due.0 += (days_remaining as i64) * 86_400;
-                        Some(pb::generic::Int64 { val: due.0 })
+                        Some(due.0)
                     }
                 },
-                card.original_position.map(|u| (u as i32).into()),
+                card.original_position.map(|u| u as i32),
             ),
             _ => (None, None),
         })

ts/card-info/CardStats.svelte

@@ -4,7 +4,7 @@ License: GNU AGPL, version 3 or later; http://www.gnu.org/licenses/agpl.html
 -->
 <script lang="ts">
     import * as tr2 from "../lib/ftl";
-    import { Stats, unwrapOptionalNumber } from "../lib/proto";
+    import { Stats } from "../lib/proto";
     import { DAY, timeSpan, Timestamp } from "../lib/time";
 
     export let stats: Stats.CardStatsResponse;
@@ -23,33 +23,29 @@ License: GNU AGPL, version 3 or later; http://www.gnu.org/licenses/agpl.html
 
         statsRows.push({ label: tr2.cardStatsAdded(), value: dateString(stats.added) });
 
-        const firstReview = unwrapOptionalNumber(stats.firstReview);
-        if (firstReview !== undefined) {
+        if (stats.firstReview != null) {
             statsRows.push({
                 label: tr2.cardStatsFirstReview(),
-                value: dateString(firstReview),
+                value: dateString(stats.firstReview),
             });
         }
-        const latestReview = unwrapOptionalNumber(stats.latestReview);
-        if (latestReview !== undefined) {
+        if (stats.latestReview != null) {
             statsRows.push({
                 label: tr2.cardStatsLatestReview(),
-                value: dateString(latestReview),
+                value: dateString(stats.latestReview),
             });
         }
 
-        const dueDate = unwrapOptionalNumber(stats.dueDate);
-        if (dueDate !== undefined) {
+        if (stats.dueDate != null) {
             statsRows.push({
                 label: tr2.statisticsDueDate(),
-                value: dateString(dueDate),
+                value: dateString(stats.dueDate),
             });
         }
-        const duePosition = unwrapOptionalNumber(stats.duePosition);
-        if (duePosition !== undefined) {
+        if (stats.duePosition != null) {
             statsRows.push({
                 label: tr2.cardStatsNewCardPosition(),
-                value: duePosition,
+                value: stats.duePosition,
             });
         }
 

ts/lib/proto.ts

@@ -73,14 +73,3 @@ export const stats = Stats.StatsService.create(serviceCallback as RPCImpl);
 
 export { Tags };
 export const tags = Tags.TagsService.create(serviceCallback as RPCImpl);
-
-export function unwrapOptionalNumber(
-    msg: Generic.IInt64 | Generic.IUInt32 | Generic.IInt32 | null | undefined,
-): number | undefined {
-    if (msg && msg !== null) {
-        if (msg.val !== null) {
-            return msg.val;
-        }
-    }
-    return undefined;
-}

ts/patches/protobufjs+6.11.2.patch

@@ -1,3 +1,16 @@
+diff --git a/node_modules/protobufjs/src/field.js b/node_modules/protobufjs/src/field.js
+index 20c1cd2..3a1395f 100644
+--- a/node_modules/protobufjs/src/field.js
++++ b/node_modules/protobufjs/src/field.js
+@@ -270,6 +270,8 @@ Field.prototype.resolve = function resolve() {
+             this.typeDefault = null;
+         else // instanceof Enum
+             this.typeDefault = this.resolvedType.values[Object.keys(this.resolvedType.values)[0]]; // first defined
++    } else if (this.options && this.options.proto3_optional) {
++        this.typeDefault = null;
+     }
+
+     // use explicitly set default value if present
 diff --git a/node_modules/protobufjs/src/root.js b/node_modules/protobufjs/src/root.js
 index df6f11f..112f9e8 100644
 --- a/node_modules/protobufjs/src/root.js