Remove the zero index from VarZeroVec

CHANGELOG.md

@@ -43,6 +43,7 @@
     - `zerovec`
       - This release has multiple changes that affect the bit representation of various types. Do not update to this release if you wish to retain stable data formats.
         - Change the `VarZeroVecFormat` values shipped by default to use the same index and length width. This breaks data layout for all `VarZeroVec`s. (https://github.com/unicode-org/icu4x/pull/5594)
+        - Change the `VarZeroVec` format to not store a superfluous 0 index at the beginning of the index array. This breaks data layout for all `VarZeroVec`s (https://github.com/unicode-org/icu4x/pull/5601)
         - Optimize `MultiFieldsULE` to not store a length anymore. This breaks data layout for any `#[make_varule]`-using struct with multiple variable-sized fields. (https://github.com/unicode-org/icu4x/pull/5593)
     - `writeable`
 

components/plurals/src/provider.rs

@@ -1073,10 +1073,10 @@ fn test_serde_nonsingleton_roundtrip() {
     assert_eq!(
         postcard_bytes,
         &[
-            14,   // Postcard header
+            12,   // Postcard header
             0x80, // Discriminant
             3, b'a', b'b', b'c', // String of length 3
-            1, 0, 0, 0, // VarZeroVec of length 1
+            1, 0, // VarZeroVec of length 1
             0x10, b'd', b'e', b'f', b'g' // Plural category 1 and string "defg"
         ]
     );

components/plurals/src/rules/runtime/ast.rs

@@ -573,7 +573,7 @@ mod test {
         let vzv = VarZeroVec::<_>::from(relations.as_slice());
         assert_eq!(
             vzv.as_bytes(),
-            &[1, 0, 0, 0, 192, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0]
+            &[1, 0, 192, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0]
         );
     }
 }

provider/blob/benches/auxkey_bench.rs

@@ -279,7 +279,7 @@ fn make_blob_v3() -> Vec<u8> {
     put_payloads::<MarkerD>(&mut exporter);
     exporter.close().unwrap();
     drop(exporter);
-    assert_eq!(blob.len(), 32980);
+    assert_eq!(blob.len(), 32974);
     assert!(blob.len() > 100);
     blob
 }

provider/blob/tests/test_versions.rs

@@ -108,7 +108,6 @@ fn test_format() {
     let mut blob: Vec<u8> = Vec::new();
     let exporter = BlobExporter::new_with_sink(Box::new(&mut blob));
     run_driver(exporter, &HelloWorldProvider);
-    std::fs::write("./tests/data/v3.postcard", blob.as_slice()).unwrap();
     assert_eq!(BLOB_V3, blob.as_slice());
 
     let blob_provider = BlobDataProvider::try_new_from_blob(blob.into_boxed_slice()).unwrap();
@@ -136,7 +135,7 @@ fn test_format_bigger() {
     let hash = hasher.finish();
 
     assert_eq!(
-        hash, 15551798874510060652,
+        hash, 2996389886987900285,
         "V2Bigger format appears to have changed!"
     );
 

provider/data/casemap/fingerprints.csv

@@ -1,2 +1,2 @@
-props/casemap@1, <singleton>, 22513B, 22426B, a4a125633510e06d
-props/casemap_unfold@1, <singleton>, 972B, 928B, b861f4456b3907f
+props/casemap@1, <singleton>, 22511B, 22424B, ea77be8d954ef566
+props/casemap_unfold@1, <singleton>, 968B, 924B, 8871e8e52249b1d5