Fix: Record Merging “Auto-populate” preference applies in reverse

specifyweb/frontend/js_src/lib/components/Merging/__tests__/autoMerge.test.ts

@@ -248,7 +248,7 @@ describe('autoMerge', () => {
         "agentAttachments": [],
         "agentGeographies": [],
         "agentSpecialties": [],
-        "agentType": 1,
+        "agentType": 0,
         "catalogerOf": "/api/specify/CollectionObject?cataloger=2305",
         "collContentContact": null,
         "collTechContact": null,
@@ -257,7 +257,7 @@ describe('autoMerge', () => {
         "date1": null,
         "date1Precision": null,
         "date2": null,
-        "date2Precision": null,
+        "date2Precision": 2,
         "dateOfBirth": null,
         "dateOfBirthPrecision": null,
         "dateOfDeath": null,
@@ -415,7 +415,7 @@ describe('autoMerge', () => {
         "agentAttachments": [],
         "agentGeographies": [],
         "agentSpecialties": [],
-        "agentType": 1,
+        "agentType": 0,
         "catalogerOf": "/api/specify/CollectionObject?cataloger=2305",
         "collContentContact": null,
         "collTechContact": null,
@@ -424,7 +424,7 @@ describe('autoMerge', () => {
         "date1": "2020-01-01",
         "date1Precision": null,
         "date2": null,
-        "date2Precision": null,
+        "date2Precision": 2,
         "dateOfBirth": null,
         "dateOfBirthPrecision": null,
         "dateOfDeath": null,
@@ -582,7 +582,7 @@ describe('autoMerge', () => {
         "agentAttachments": [],
         "agentGeographies": [],
         "agentSpecialties": [],
-        "agentType": 1,
+        "agentType": 0,
         "catalogerOf": "/api/specify/CollectionObject?cataloger=2305",
         "collContentContact": null,
         "collTechContact": null,
@@ -591,7 +591,7 @@ describe('autoMerge', () => {
         "date1": null,
         "date1Precision": null,
         "date2": null,
-        "date2Precision": null,
+        "date2Precision": 2,
         "dateOfBirth": null,
         "dateOfBirthPrecision": null,
         "dateOfDeath": null,
@@ -636,4 +636,37 @@ describe('autoMerge', () => {
       }
     `);
   });
+
+  test('prefers longest string values when auto populating', () => {
+    const merged = autoMerge(
+      tables.Agent,
+      [
+        addMissingFields('Agent', { lastName: '' }),
+        addMissingFields('Agent', { lastName: 'Longer Value' }),
+        addMissingFields('Agent', { lastName: 'Mid' }),
+      ] as unknown as RA<SerializedResource<AnySchema>>,
+      false
+    );
+    expect(merged.lastName).toBe('Longer Value');
+  });
+
+  test('fills dependent precision even if newest record lacks it', () => {
+    const merged = autoMerge(
+      tables.Agent,
+      [
+        addMissingFields('Agent', {
+          timestampModified: '2024-01-01',
+          dateOfDeath: '2023-01-01',
+          dateOfDeathPrecision: null,
+        }),
+        addMissingFields('Agent', {
+          timestampModified: '2023-01-01',
+          dateOfDeath: '2023-01-01',
+          dateOfDeathPrecision: 0,
+        }),
+      ] as unknown as RA<SerializedResource<AnySchema>>,
+      false
+    );
+    expect(merged.dateOfDeathPrecision).toBe(0);
+  });
 });

specifyweb/frontend/js_src/lib/components/Merging/autoMerge.ts

@@ -88,7 +88,16 @@ function mergeField(
     resource[field.name],
   ]);
   const values = parentChildValues.map(([_, child]) => child);
-  const nonFalsyValues = f.unique(values.filter(Boolean));
+  const nonFalsyValues = f.unique(
+    values.filter(
+      (value) =>
+        value !== null &&
+        value !== undefined &&
+        value !== '' &&
+        // Preserve zeros and false, but drop NaN
+        value === value
+    )
+  );
   const firstValue = nonFalsyValues[0] ?? values[0];
   if (field.isRelationship)
     if (field.isDependent())
@@ -150,8 +159,9 @@ function mergeField(
     // Pick the longest value
     return (
       Array.from(nonFalsyValues).sort(
-        sortFunction((string) =>
-          typeof string === 'string' ? string.length : 0
+        sortFunction(
+          (string) => (typeof string === 'string' ? string.length : 0),
+          true
         )
       )[0] ?? firstValue
     );
@@ -213,10 +223,15 @@ function mergeDependentField(
   sourceValue: ReturnType<typeof mergeField>
 ): ReturnType<typeof mergeField> {
   const sourceField = strictDependentFields()[fieldName];
-  const sourceResource = resources.find(
+  const matchingResources = resources.filter(
     (resource) => resource[sourceField] === sourceValue
   );
-  return sourceResource?.[fieldName] ?? null;
+  const preferredResource =
+    matchingResources.find((resource) => {
+      const value = resource[fieldName];
+      return value !== null && value !== undefined;
+    }) ?? matchingResources[0];
+  return preferredResource?.[fieldName] ?? null;
 }
 
 /**

specifyweb/frontend/js_src/lib/components/Merging/index.tsx

@@ -22,6 +22,7 @@ import { icons } from '../Atoms/Icons';
 import { Link } from '../Atoms/Link';
 import { Submit } from '../Atoms/Submit';
 import { LoadingContext } from '../Core/Contexts';
+import { addMissingFields } from '../DataModel/addMissingFields';
 import { runAllFieldChecks } from '../DataModel/businessRules';
 import type { AnySchema, SerializedResource } from '../DataModel/helperTypes';
 import type { SpecifyResource } from '../DataModel/legacyTypes';
@@ -210,31 +211,36 @@ function Merging({
   const clones = sortedResources.slice(1);
 
   const [merged, setMerged] = useAsyncState(
-    React.useCallback(
-      async () =>
-        records === undefined || initialRecords.current === undefined
-          ? undefined
-          : postMergeResource(
-              initialRecords.current,
-              autoMerge(
-                table,
-                initialRecords.current,
-                userPreferences.get(
-                  'recordMerging',
-                  'behavior',
-                  'autoPopulate'
-                ),
-                target.id
-              )
-            ).then(async (merged) => {
-              const mergedResource = deserializeResource(
-                merged as SerializedResource<AnySchema>
-              );
-              if (merged !== undefined) await runAllFieldChecks(mergedResource);
-              return mergedResource;
-            }),
-      [table, records]
-    ),
+    React.useCallback(async () => {
+      if (
+        records === undefined ||
+        initialRecords.current === undefined ||
+        target === undefined
+      )
+        return undefined;
+
+      const shouldAutoPopulate = userPreferences.get(
+        'recordMerging',
+        'behavior',
+        'autoPopulate'
+      );
+
+      const mergedPayload = shouldAutoPopulate
+        ? await postMergeResource(
+            initialRecords.current,
+            autoMerge(table, initialRecords.current, false, target.id)
+          )
+        : addMissingFields(
+            table.name,
+            {} as Partial<SerializedResource<AnySchema>>
+          );
+
+      const mergedResource = deserializeResource(
+        mergedPayload as SerializedResource<AnySchema>
+      );
+      if (mergedPayload !== undefined) await runAllFieldChecks(mergedResource);
+      return mergedResource;
+    }, [table, records, target]),
     true
   );