feat (DAL): client-side support for float4 (#671)

This PR adds client-side support for float4.
Numbers provided by the user are rounded to the nearest float4
representation using `Math.fround()`.
Similarly, when numbers are read from a float4 column in the DB they are
rounded to the nearest float4 representation.
This would not strictly be necessary if all writes happen through the
DAL but because of SQLite's dynamic typing, users can write
larger/smaller numbers to float4 columns in which case we would read
numbers that fall out of range.

clients/typescript/src/cli/migrations/migrate.ts

@@ -349,14 +349,15 @@ function addValidator(ln: string): string {
 
   if (field) {
     const intValidator = '@zod.number.int().gte(-2147483648).lte(2147483647)'
-    const float8Validator = '@zod.custom.use(z.number().or(z.nan()))'
+    const floatValidator = '@zod.custom.use(z.number().or(z.nan()))'
 
     // Map attributes to validators
     const attributeValidatorMapping = new Map([
       ['@db.Uuid', '@zod.string.uuid()'],
       ['@db.SmallInt', '@zod.number.int().gte(-32768).lte(32767)'],
       ['@db.Int', intValidator],
-      ['@db.DoublePrecision', float8Validator],
+      ['@db.DoublePrecision', floatValidator],
+      ['@db.Real', floatValidator],
     ])
     const attribute = field.attributes
       .map((a) => a.type)
@@ -371,9 +372,9 @@ function addValidator(ln: string): string {
         ['Int', intValidator],
         ['Int?', intValidator],
         ['Int[]', intValidator],
-        ['Float', float8Validator],
-        ['Float?', float8Validator],
-        ['Float[]', float8Validator],
+        ['Float', floatValidator],
+        ['Float?', floatValidator],
+        ['Float[]', floatValidator],
       ])
       const typeValidator = typeValidatorMapping.get(field.type)
 

clients/typescript/src/client/conversions/sqlite.ts

@@ -29,6 +29,11 @@ export function toSqlite(v: any, pgType: PgType): any {
     // and deserialise it back to `NaN` when reading from the DB.
     // cf. https://github.com/WiseLibs/better-sqlite3/issues/1088
     return 'NaN'
+  } else if (
+    pgType === PgBasicType.PG_FLOAT4 ||
+    pgType === PgBasicType.PG_REAL
+  ) {
+    return Math.fround(v)
   } else {
     return v
   }
@@ -46,10 +51,18 @@ export function fromSqlite(v: any, pgType: PgType): any {
     return deserialiseBoolean(v)
   } else if (
     v === 'NaN' &&
-    (pgType === PgBasicType.PG_FLOAT8 || pgType === PgBasicType.PG_FLOAT4)
+    (pgType === PgBasicType.PG_FLOAT8 ||
+      pgType === PgBasicType.PG_FLOAT4 ||
+      pgType === PgBasicType.PG_REAL)
   ) {
     // it's a serialised NaN
     return NaN
+  } else if (
+    pgType === PgBasicType.PG_FLOAT4 ||
+    pgType === PgBasicType.PG_REAL
+  ) {
+    // convert to float4 in case someone would have written a bigger value to SQLite directly
+    return Math.fround(v)
   } else {
     return v
   }

clients/typescript/test/client/conversions/input.test.ts

@@ -31,7 +31,7 @@ await tbl.sync()
 function setupDB() {
   db.exec('DROP TABLE IF EXISTS DataTypes')
   db.exec(
-    "CREATE TABLE DataTypes('id' int PRIMARY KEY, 'date' varchar, 'time' varchar, 'timetz' varchar, 'timestamp' varchar, 'timestamptz' varchar, 'bool' int, 'uuid' varchar, 'int2' int2, 'int4' int4, 'float8' real, 'relatedId' int);"
+    "CREATE TABLE DataTypes('id' int PRIMARY KEY, 'date' varchar, 'time' varchar, 'timetz' varchar, 'timestamp' varchar, 'timestamptz' varchar, 'bool' int, 'uuid' varchar, 'int2' int2, 'int4' int4, 'float4' real, 'float8' real, 'relatedId' int);"
   )
 
   db.exec('DROP TABLE IF EXISTS Dummy')
@@ -232,6 +232,7 @@ const dateNulls = {
   bool: null,
   int2: null,
   int4: null,
+  float4: null,
   float8: null,
   uuid: null,
 }

clients/typescript/test/client/conversions/sqlite.test.ts

@@ -30,7 +30,7 @@ await tbl.sync()
 function setupDB() {
   db.exec('DROP TABLE IF EXISTS DataTypes')
   db.exec(
-    "CREATE TABLE DataTypes('id' int PRIMARY KEY, 'date' varchar, 'time' varchar, 'timetz' varchar, 'timestamp' varchar, 'timestamptz' varchar, 'bool' int, 'uuid' varchar, 'int2' int2, 'int4' int4, 'float8' real, 'relatedId' int);"
+    "CREATE TABLE DataTypes('id' int PRIMARY KEY, 'date' varchar, 'time' varchar, 'timetz' varchar, 'timestamp' varchar, 'timestamptz' varchar, 'bool' int, 'uuid' varchar, 'int2' int2, 'int4' int4, 'float4' real, 'float8' real, 'relatedId' int);"
   )
 }
 
@@ -183,31 +183,42 @@ test.serial('floats are converted correctly to SQLite', async (t) => {
     data: [
       {
         id: 1,
+        float4: 1.234,
         float8: 1.234,
       },
       {
         id: 2,
+        float4: NaN,
         float8: NaN,
       },
       {
         id: 3,
+        float4: Infinity,
         float8: +Infinity,
       },
       {
         id: 4,
+        float4: -Infinity,
         float8: -Infinity,
       },
     ],
   })
 
   const rawRes = await electric.db.raw({
-    sql: 'SELECT id, float8 FROM DataTypes ORDER BY id ASC',
+    sql: 'SELECT id, float4, float8 FROM DataTypes ORDER BY id ASC',
     args: [],
   })
   t.deepEqual(rawRes, [
-    { id: 1, float8: 1.234 },
-    { id: 2, float8: 'NaN' },
-    { id: 3, float8: Infinity },
-    { id: 4, float8: -Infinity },
+    // 1.234 cannot be stored exactly in a float4
+    // hence, there is a rounding error, which is observed when we
+    // read the float4 value back into a 64-bit JS number
+    // The value 1.2339999675750732 that we read back
+    // is also what Math.fround(1.234) returns
+    // as being the nearest 32-bit single precision
+    // floating point representation of 1.234
+    { id: 1, float4: 1.2339999675750732, float8: 1.234 },
+    { id: 2, float4: 'NaN', float8: 'NaN' },
+    { id: 3, float4: Infinity, float8: Infinity },
+    { id: 4, float4: -Infinity, float8: -Infinity },
   ])
 })