feat: add feature emit_fields

.circleci/config.yml

@@ -131,6 +131,9 @@ jobs:
       - run:
           name: Cargo test (btree)
           command: cargo test --workspace --features btree
+      - run:
+          name: Cargo test (emit fields)
+          command: cargo test --workspace --features emit-fields
       - cache_save
 
 workflows:

pbjson-build/Cargo.toml

@@ -10,7 +10,6 @@ categories = ["encoding"]
 repository = "https://github.com/influxdata/pbjson"
 
 [dependencies]
-
 heck = "0.4"
 prost = "0.11"
 prost-types = "0.11"

pbjson-build/src/generator/message.rs

@@ -39,12 +39,13 @@ pub fn generate_message<W: Write>(
     writer: &mut W,
     ignore_unknown_fields: bool,
     btree_map_paths: &[String],
+    emit_fields: bool,
 ) -> Result<()> {
     let rust_type = resolver.rust_type(&message.path);
 
     // Generate Serialize
     write_serialize_start(0, &rust_type, writer)?;
-    write_message_serialize(resolver, 2, message, writer)?;
+    write_message_serialize(resolver, 2, message, writer, emit_fields)?;
     write_serialize_end(0, writer)?;
 
     // Generate Deserialize
@@ -62,7 +63,15 @@ pub fn generate_message<W: Write>(
     Ok(())
 }
 
-fn write_field_empty_predicate<W: Write>(member: &Field, writer: &mut W) -> Result<()> {
+fn write_field_empty_predicate<W: Write>(
+    member: &Field,
+    writer: &mut W,
+    emit_fields: bool,
+) -> Result<()> {
+    if emit_fields {
+        return write!(writer, "true");
+    }
+
     match (&member.field_type, &member.field_modifier) {
         (_, FieldModifier::Required) => unreachable!(),
         (_, FieldModifier::Repeated)
@@ -96,11 +105,12 @@ fn write_message_serialize<W: Write>(
     indent: usize,
     message: &Message,
     writer: &mut W,
+    emit_fields: bool,
 ) -> Result<()> {
-    write_struct_serialize_start(indent, message, writer)?;
+    write_struct_serialize_start(indent, message, writer, emit_fields)?;
 
     for field in &message.fields {
-        write_serialize_field(resolver, indent, field, writer)?;
+        write_serialize_field(resolver, indent, field, writer, emit_fields)?;
     }
 
     for one_of in &message.one_ofs {
@@ -114,6 +124,7 @@ fn write_struct_serialize_start<W: Write>(
     indent: usize,
     message: &Message,
     writer: &mut W,
+    emit_fields: bool,
 ) -> Result<()> {
     writeln!(writer, "{}use serde::ser::SerializeStruct;", Indent(indent))?;
 
@@ -134,7 +145,7 @@ fn write_struct_serialize_start<W: Write>(
             continue;
         }
         write!(writer, "{}if ", Indent(indent))?;
-        write_field_empty_predicate(field, writer)?;
+        write_field_empty_predicate(field, writer, emit_fields)?;
         writeln!(writer, " {{")?;
         writeln!(writer, "{}len += 1;", Indent(indent + 1))?;
         writeln!(writer, "{}}}", Indent(indent))?;
@@ -357,6 +368,7 @@ fn write_serialize_field<W: Write>(
     indent: usize,
     field: &Field,
     writer: &mut W,
+    emit_fields: bool,
 ) -> Result<()> {
     let as_ref = format!("&self.{}", field.rust_field_name());
     let variable = Variable {
@@ -386,7 +398,7 @@ fn write_serialize_field<W: Write>(
         }
         FieldModifier::Repeated | FieldModifier::UseDefault => {
             write!(writer, "{}if ", Indent(indent))?;
-            write_field_empty_predicate(field, writer)?;
+            write_field_empty_predicate(field, writer, emit_fields)?;
             writeln!(writer, " {{")?;
             write_serialize_variable(resolver, indent + 1, field, variable, writer)?;
             writeln!(writer, "{}}}", Indent(indent))?;

pbjson-build/src/lib.rs

@@ -105,6 +105,7 @@ pub struct Builder {
     retain_enum_prefix: bool,
     ignore_unknown_fields: bool,
     btree_map_paths: Vec<String>,
+    emit_fields: bool,
 }
 
 impl Builder {
@@ -178,6 +179,12 @@ impl Builder {
         self
     }
 
+    /// Output fields with their default values.
+    pub fn emit_fields(&mut self) -> &mut Self {
+        self.emit_fields = true;
+        self
+    }
+
     /// Generates code for all registered types where `prefixes` contains a prefix of
     /// the fully-qualified path of the type
     pub fn build<S: AsRef<str>>(&mut self, prefixes: &[S]) -> Result<()> {
@@ -261,6 +268,7 @@ impl Builder {
                             writer,
                             self.ignore_unknown_fields,
                             &self.btree_map_paths,
+                            self.emit_fields,
                         )?
                     }
                 }

pbjson-test/Cargo.toml

@@ -15,6 +15,7 @@ serde = { version = "1.0", features = ["derive"] }
 [features]
 ignore-unknown-fields = []
 btree = []
+emit-fields = []
 
 [dev-dependencies]
 chrono = "0.4"

pbjson-test/build.rs

@@ -50,6 +50,10 @@ fn main() -> Result<()> {
         builder.btree_map([".test"]);
     }
 
+    if cfg!(feature = "emit-fields") {
+        builder.emit_fields();
+    }
+
     builder.build(&[".test"])?;
 
     Ok(())

pbjson-test/src/lib.rs

@@ -89,6 +89,14 @@ mod tests {
     }
 
     #[test]
+    #[cfg(feature = "emit-fields")]
+    fn test_emit_fields() {
+        let mut decoded: KitchenSink = serde_json::from_str("{}").unwrap();
+        assert_ne!(serde_json::to_string(&decoded).unwrap().as_str(), "{}");
+    }
+
+    #[test]
+    #[cfg(not(feature = "emit-fields"))]
     fn test_kitchen_sink() {
         let mut decoded: KitchenSink = serde_json::from_str("{}").unwrap();