fix: ensure temporal field propagates to time expression (#8757)

Fixes #7185

Author: marr

examples/compiled/bar_simple_binned_timeunit_special_chars.vg.json

@@ -60,7 +60,7 @@
           "fill": {"value": "#4c78a8"},
           "ariaRoleDescription": {"value": "bar"},
           "description": {
-            "signal": "\"b: \" + (format(datum[\"b\"], \"\")) + \"; a.b: \" + (timeFormat(datum[\"a.b\"], timeUnitSpecifier([\"year\",\"month\",\"date\"], {\"year-month\":\"%b %Y \",\"year-month-date\":\"%b %d, %Y \"})))"
+            "signal": "\"b: \" + (format(datum[\"b\"], \"\")) + \"; a.b: \" + (utcFormat(datum[\"a.b\"], timeUnitSpecifier([\"year\",\"month\",\"date\"], {\"year-month\":\"%b %Y \",\"year-month-date\":\"%b %d, %Y \"})))"
           },
           "x": {"scale": "x", "field": "b_end"},
           "x2": {"scale": "x", "field": "b_start"},

examples/compiled/time_output_utc_timeunit.vg.json

@@ -46,7 +46,7 @@
         "update": {
           "stroke": {"value": "#4c78a8"},
           "description": {
-            "signal": "\"date (year-month-date-hours-minutes): \" + (timeFormat(datum[\"utcyearmonthdatehoursminutes_date\"], timeUnitSpecifier([\"year\",\"month\",\"date\",\"hours\",\"minutes\"], {\"year-month\":\"%b %Y \",\"year-month-date\":\"%b %d, %Y \"}))) + \"; price: \" + (format(datum[\"price\"], \"\"))"
+            "signal": "\"date (year-month-date-hours-minutes): \" + (utcFormat(datum[\"utcyearmonthdatehoursminutes_date\"], timeUnitSpecifier([\"year\",\"month\",\"date\",\"hours\",\"minutes\"], {\"year-month\":\"%b %Y \",\"year-month-date\":\"%b %d, %Y \"}))) + \"; price: \" + (format(datum[\"price\"], \"\"))"
           },
           "x": {"scale": "x", "field": "utcyearmonthdatehoursminutes_date"},
           "y": {"scale": "y", "field": "price"},

examples/compiled/time_parse_binnedutc.vg.json

@@ -40,7 +40,7 @@
           "fill": {"value": "#4c78a8"},
           "ariaRoleDescription": {"value": "bar"},
           "description": {
-            "signal": "\"time: \" + (timeFormat(datum[\"date\"], timeUnitSpecifier([\"year\",\"month\",\"date\",\"hours\"], {\"year-month\":\"%b %Y \",\"year-month-date\":\"%b %d, %Y \"})))"
+            "signal": "\"time: \" + (utcFormat(datum[\"date\"], timeUnitSpecifier([\"year\",\"month\",\"date\",\"hours\"], {\"year-month\":\"%b %Y \",\"year-month-date\":\"%b %d, %Y \"})))"
           },
           "x": {"field": {"group": "width"}},
           "x2": {"value": 0},

examples/compiled/time_parse_utc.vg.json

@@ -45,7 +45,7 @@
           "stroke": {"value": "#4c78a8"},
           "ariaRoleDescription": {"value": "point"},
           "description": {
-            "signal": "\"time: \" + (timeFormat(datum[\"utchours_date\"], timeUnitSpecifier([\"hours\"], {\"year-month\":\"%b %Y \",\"year-month-date\":\"%b %d, %Y \"})))"
+            "signal": "\"time: \" + (utcFormat(datum[\"utchours_date\"], timeUnitSpecifier([\"hours\"], {\"year-month\":\"%b %Y \",\"year-month-date\":\"%b %d, %Y \"})))"
           },
           "x": {"signal": "width", "mult": 0.5},
           "y": {"scale": "y", "field": "utchours_date"}

src/compile/format.ts

@@ -95,14 +95,25 @@ export function formatSignalRef({
     }
   }
 
+  function getTimeDef(def: FieldDef<string> | DatumDef<string>) {
+    if (!isFieldDef(def)) {
+      return {
+        unit: undefined,
+        utc: undefined,
+      };
+    }
+    return normalizeTimeUnit(def.timeUnit) || {};
+  }
+
   if (isFieldOrDatumDefForTimeFormat(fieldOrDatumDef)) {
+    const {unit: timeUnit, utc: isUTCUnit} = getTimeDef(fieldOrDatumDef);
     const signal = timeFormatExpression({
       field,
-      timeUnit: isFieldDef(fieldOrDatumDef) ? normalizeTimeUnit(fieldOrDatumDef.timeUnit)?.unit : undefined,
+      timeUnit,
       format,
       formatType: config.timeFormatType,
       rawTimeFormat: config.timeFormat,
-      isUTCScale: isScaleFieldDef(fieldOrDatumDef) && fieldOrDatumDef.scale?.type === ScaleType.UTC,
+      isUTCScale: isUTCUnit || (isScaleFieldDef(fieldOrDatumDef) && fieldOrDatumDef.scale?.type === ScaleType.UTC),
     });
     return signal ? {signal} : undefined;
   }

test/compile/format.test.ts

@@ -70,6 +70,17 @@ describe('Format', () => {
       expect(expression).toBe(`utcFormat(datum["yearmonth_a"], "%Y")`);
     });
 
+    it('should get the right time expression for utcyearmonth', () => {
+      const fieldDef = {timeUnit: 'utcyearmonth', field: 'a', type: TEMPORAL} as const;
+      const expression = timeFormatExpression({
+        field: vgField(fieldDef, {expr: 'datum'}),
+        timeUnit: 'month',
+        format: '%Y',
+        isUTCScale: true,
+      });
+      expect(expression).toBe(`utcFormat(datum["utcyearmonth_a"], "%Y")`);
+    });
+
     it('should get the right time expression for with a custom timeFormatType', () => {
       const fieldDef = {field: 'a', type: TEMPORAL} as const;
       const expression = timeFormatExpression({
@@ -157,6 +168,19 @@ describe('Format', () => {
   });
 
   describe('formatSignalRef()', () => {
+    it('should derive the correct temporal unit', () => {
+      expect(
+        formatSignalRef({
+          fieldOrDatumDef: {field: 'foo', type: TEMPORAL, timeUnit: 'utcdate'},
+          format: undefined,
+          formatType: undefined,
+          config: {},
+        }),
+      ).toEqual({
+        signal:
+          'utcFormat(utcdate_foo, timeUnitSpecifier(["date"], {"year-month":"%b %Y ","year-month-date":"%b %d, %Y "}))',
+      });
+    });
     it('should format ordinal field defs if format is present', () => {
       expect(
         formatSignalRef({