Support single-Map `@JsonAnySetter` methods by goutamadwant · Pull Request #6075 · FasterXML/jackson-databind

goutamadwant · 2026-07-07T00:57:41Z

Root cause

@JsonAnySetter discovery handled fields, creator parameters, and two-argument setter methods, but explicitly annotated one-argument methods were still treated as regular setters. That meant a method like setOther(Map<String, Object> other) was not recognized as an any-setter target.

Change

This adds support for explicitly annotated single-argument Map any-setter methods. Unknown properties are collected into a map using the existing any-setter key/value deserialization flow, then the annotated method is invoked once with the collected values.

Verification

./mvnw -q -Dtest=tools.jackson.databind.deser.AnySetterTest#testJsonAnySetterOnMapMethod test
./mvnw -q -Dtest=tools.jackson.databind.deser.AnySetterTest test
./mvnw -q -Dtest=tools.jackson.databind.deser.AnySetterTest,tools.jackson.databind.deser.builder.BuilderSimpleTest,tools.jackson.databind.deser.creators.AnySetterForCreator562Test,tools.jackson.databind.introspect.POJOPropertiesCollectorTest test
./mvnw -q test
./mvnw -q -DskipTests animal-sniffer:check
git diff --check

JooHyukKim · 2026-07-07T08:20:59Z

Can you specify issue number on test methods? @goutamadwant See neighboring test cases as example

goutamadwant · 2026-07-08T06:49:15Z

Can you specify issue number on test methods? @goutamadwant See neighboring test cases as example

Thanks @JooHyukKim, updated the new test method names to include 4889, matching the neighboring test cases. Let me know if any suggestions. thanks!

github-actions · 2026-07-10T08:26:43Z

🧪 Code Coverage Report

Metric	Coverage	Change
Instructions	81.70%	📉 -0.010%
Branches	75.19%	📉 -0.040%

Coverage data generated from JaCoCo test results

JooHyukKim

We need JavaDocs as well.
Thanks!

JooHyukKim · 2026-07-12T03:47:03Z

+                if (anyMethod.getParameterCount() == 1) {
+                    Class<?> type = anyMethod.getRawParameterType(0);
+                    if (!Map.class.isAssignableFrom(type)) {
+                        throw new IllegalArgumentException(String.format(


Not sure if we can simply throw error, considering we are doing minor version fix...? 🤔

JooHyukKim · 2026-07-12T03:49:40Z

        throw new UnsupportedOperationException("Cannot call createParameterObject() on " + getClass().getName());
    }

+    public void finish(DeserializationContext ctxt, Object instance) throws JacksonException { }


Method name is generic too much.
Can we do both below?

Change name

Add JavaDoc

I'm talking about all finish methods

github-actions · 2026-07-23T01:15:50Z

🧪 Code Coverage Report

Metric	Coverage	Change
Instructions	81.79%	📈 +0.010%
Branches	75.40%	📈 +0.010%

Coverage data generated from JaCoCo test results

cowtowncoder · 2026-07-23T22:41:38Z

Thank you @goutamadwant ! One more thing we need is CLA, from:

https://github.com/FasterXML/jackson/blob/main/CLA-jackson-2026.pdf

(only needs to be sent once)
which is usually down by printing it, filling & signing, scan/photo, email to cla at fasterxml dot com.

cowtowncoder · 2026-07-23T22:47:10Z

Hmmmmh. This is WAY bigger change than I'd expect. I wonder if there is some refactoring that could be done to simplify implementation?

gitar-bot · 2026-08-09T23:31:02Z

+    public static SettableAnyProperty constructForMapMethod(DeserializationContext ctxt,
+            BeanProperty property,
+            AnnotatedMember setter, JavaType valueType,
+            KeyDeserializer keyDeser,
+            ValueDeserializer<Object> valueDeser, TypeDeserializer typeDeser)
+    {
+        Class<?> mapType = property.getType().getRawClass();
+        if (mapType == Map.class) {
+            mapType = LinkedHashMap.class;
+        }
+        ValueInstantiator vi = JDKValueInstantiators.findStdValueInstantiator(ctxt.getConfig(), mapType);
+        return new MapMethodAnyProperty(property, setter, valueType,
+                keyDeser, valueDeser, typeDeser,
+                vi);
+    }


💡 Edge Case: Map any-setter with non-instantiable concrete Map fails late

constructForMapMethod only remaps the raw Map.class interface to LinkedHashMap; for other non-instantiable declared types (e.g. SortedMap, Map.Entry-less abstract maps, or a concrete type without a default constructor) findStdValueInstantiator returns null and _createMap throws a DatabindException only at deserialization time when the first unknown property arrives. Consider validating instantiability at introspection/construction time (like other constructForMap* helpers already have this same limitation) so misconfiguration surfaces earlier, and/or mapping common interfaces such as SortedMap/NavigableMap to TreeMap.

_{Was this helpful? React with 👍 / 👎}

Would be helpful to verify this case

added a test verifying that an unsupported custom Map type reports the expected DatabindException when an unknown property is encountered.

github-actions · 2026-08-09T23:43:57Z

🧪 Code Coverage Report

Metric	Coverage	Change
Instructions	81.91%	📈 +0.010%
Branches	75.52%	📈 +0.020%

Coverage data generated from JaCoCo test results

goutamadwant · 2026-08-10T00:15:20Z

Thank you @goutamadwant ! One more thing we need is CLA, from:

https://github.com/FasterXML/jackson/blob/main/CLA-jackson-2026.pdf

(only needs to be sent once) which is usually down by printing it, filling & signing, scan/photo, email to cla at fasterxml dot com.

done @cowtowncoder I emailed the pdf to the provided address.

goutamadwant · 2026-08-10T00:24:37Z

Thanks for the review @cowtowncoder @JooHyukKim looked at all the comments and pushed a follow up update as below.

renames the generic completion hooks to finishAnySetter(...) and adds Javadocs
keeps single-argument type validation in BeanDeserializerFactory instead of throwing during bean introspection
simplifies the deferred map storage by removing the composite key class
verifies that only explicitly annotated one-argument methods are treated as any-setters
adds coverage for active views, property-based creators with external type ids, no unknown properties, regular Map setters, and builder deserialization
updates the builder test name to include issue 4889

The no-unknown-properties behavior remains consistent with existing two-argument any-setters. Support for additional Map interfaces was left out because the same limitation exists for Map-field any-setters and would be better handled separately.

let me know if there any other suggestions or comments. thanks!

JooHyukKim

Added a lil more reviews, hope it helps!

JooHyukKim · 2026-08-11T23:13:04Z

+            if (am.getParameterCount() == 1) {
+                JavaType paramType = am.getParameterType(0);
+                if (!paramType.isMapLikeType()) {
+                    return ctxt.reportBadDefinition(beanDescRef.getType(), String.format(


Is it really possible to reach this code path? If so, this would throw error --backward-incompatible

nice point @JooHyukKim only one-argument Map methods are now registered as any-setters. Non-Map methods remain regular setters also has a regression test covering this behavior.

JooHyukKim · 2026-08-11T23:14:51Z

+    public static SettableAnyProperty constructForMapMethod(DeserializationContext ctxt,
+            BeanProperty property,
+            AnnotatedMember setter, JavaType valueType,
+            KeyDeserializer keyDeser,
+            ValueDeserializer<Object> valueDeser, TypeDeserializer typeDeser)
+    {
+        Class<?> mapType = property.getType().getRawClass();
+        if (mapType == Map.class) {
+            mapType = LinkedHashMap.class;
+        }
+        ValueInstantiator vi = JDKValueInstantiators.findStdValueInstantiator(ctxt.getConfig(), mapType);
+        return new MapMethodAnyProperty(property, setter, valueType,
+                keyDeser, valueDeser, typeDeser,
+                vi);
+    }


Would be helpful to verify this case

JooHyukKim · 2026-08-11T23:19:37Z

Just style suggestion so quite subjective but, how about isolate into new _addSetterMethod() method like we have for arg count 0 case?

Done @JooHyukKim one-argument methods now delegate to _addSetterMethod(), which handles Map any-setter classification before regular setter discovery.

gitar-bot · 2026-08-12T06:32:20Z

Code Review 👍 Approved with suggestions 2 resolved / 3 findings

Adds support for single-argument Map @JsonAnySetter methods with comprehensive test coverage. Consider adding early validation in constructForMapMethod to catch non-instantiable concrete map types before runtime execution.

💡 Edge Case: Map any-setter with non-instantiable concrete Map fails late

📄 src/main/java/tools/jackson/databind/deser/SettableAnyProperty.java:94-108 📄 src/main/java/tools/jackson/databind/deser/SettableAnyProperty.java:462-470

constructForMapMethod only remaps the raw Map.class interface to LinkedHashMap; for other non-instantiable declared types (e.g. SortedMap, Map.Entry-less abstract maps, or a concrete type without a default constructor) findStdValueInstantiator returns null and _createMap throws a DatabindException only at deserialization time when the first unknown property arrives. Consider validating instantiability at introspection/construction time (like other constructForMap* helpers already have this same limitation) so misconfiguration surfaces earlier, and/or mapping common interfaces such as SortedMap/NavigableMap to TreeMap.

✅ 2 resolved

✅ Edge Case: Map any-setter may be skipped in view/external-id paths

📄 src/main/java/tools/jackson/databind/deser/bean/BeanDeserializer.java:608-615 📄 src/main/java/tools/jackson/databind/deser/SettableAnyProperty.java:444-458
The new _finishAnySetter(...) flush was added to the vanilla, unwrapped, and standard property-based paths, but it is not obviously present in every terminal return path (e.g. deserializeWithView, and the property-based external-type-id path deserializeUsingPropertyBasedWithExternalTypeId). Because a single-Map @JsonAnySetter method now only collects entries into a context-attribute map during _set and is invoked exclusively from finish(...), any deserialization path that returns the bean without calling _finishAnySetter will silently drop all collected unknown properties and never invoke the annotated method. Please verify each return bean path that can process unknown properties (@JsonView-active beans, external type id) routes through _finishAnySetter, and add tests covering a Map any-setter method combined with @JsonView.

✅ Edge Case: Map any-setter method not invoked when no unknown props

📄 src/main/java/tools/jackson/databind/deser/SettableAnyProperty.java:430-444
For a single-Map @JsonAnySetter method, _set is only called for unknown properties, so when a payload has no unknown properties the context-attribute map is never created and finish(...) returns early without invoking the annotated method. The target field therefore stays at its default (e.g. null) rather than being set to an empty map. This matches the two-argument any-setter behavior, but if callers expect the method to always be invoked (e.g. to initialize an empty map), document the behavior or invoke the setter with an empty map. Consider adding a test asserting the no-unknowns case.

🤖 Prompt for agents

Code Review: Adds support for single-argument Map `@JsonAnySetter` methods with comprehensive test coverage. Consider adding early validation in `constructForMapMethod` to catch non-instantiable concrete map types before runtime execution.

1. 💡 Edge Case: Map any-setter with non-instantiable concrete Map fails late
   Files: src/main/java/tools/jackson/databind/deser/SettableAnyProperty.java:94-108, src/main/java/tools/jackson/databind/deser/SettableAnyProperty.java:462-470

   `constructForMapMethod` only remaps the raw `Map.class` interface to `LinkedHashMap`; for other non-instantiable declared types (e.g. `SortedMap`, `Map.Entry`-less abstract maps, or a concrete type without a default constructor) `findStdValueInstantiator` returns null and `_createMap` throws a `DatabindException` only at deserialization time when the first unknown property arrives. Consider validating instantiability at introspection/construction time (like other constructForMap* helpers already have this same limitation) so misconfiguration surfaces earlier, and/or mapping common interfaces such as `SortedMap`/`NavigableMap` to `TreeMap`.

Options

Auto-apply is off → Gitar will not commit updates to this branch.
Display: compact → Showing less information.

Comment with these commands to change the behavior for this request:

`Auto-apply`	`Compact`
`gitar auto-apply:on`	`gitar display:verbose`

_{Was this helpful? React with 👍 / 👎 | Powered by Gitar — free for open source}

goutamadwant

addressed all the review comments. thanks

goutamadwant mentioned this pull request Jul 7, 2026

Support @JsonAnySetter on setter method (single Map parameter) #4889

Open

Support single-Map @JsonAnySetter methods

41e77d2

goutamadwant force-pushed the fix-anysetter-map-method branch from 75278f1 to 41e77d2 Compare July 8, 2026 06:40

Merge branch '3.x' into fix-anysetter-map-method

a405789

cowtowncoder changed the title ~~Support single-Map @JsonAnySetter methods~~ Support single-Map @JsonAnySetter methods Jul 10, 2026

JooHyukKim reviewed Jul 12, 2026

View reviewed changes

Merge branch '3.x' into fix-anysetter-map-method

c662dcb

cowtowncoder added the cla-needed PR looks good (although may also require code review), but CLA needed from submitter label Jul 23, 2026

Merge branch '3.x' into fix-anysetter-map-method

78a2d19

Merge branch '3.x' into fix-anysetter-map-method

aa6c23e

gitar-bot Bot reviewed Aug 9, 2026

View reviewed changes

Comment thread src/main/java/tools/jackson/databind/deser/bean/BeanDeserializer.java

gitar-bot Bot reviewed Aug 9, 2026

View reviewed changes

Comment thread src/main/java/tools/jackson/databind/deser/SettableAnyProperty.java

gitar-bot Bot reviewed Aug 9, 2026

View reviewed changes

Address review feedback for map any-setters

6c5aad5

JooHyukKim reviewed Aug 11, 2026

View reviewed changes

goutamadwant and others added 2 commits August 11, 2026 23:25

Preserve regular one-argument setter handling

b4ba56a

Merge branch '3.x' into fix-anysetter-map-method

f90883e

goutamadwant commented Aug 12, 2026

View reviewed changes

Uh oh!

Uh oh!

Conversation

goutamadwant commented Jul 7, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Root cause

Change

Verification

Uh oh!

JooHyukKim commented Jul 7, 2026

Uh oh!

goutamadwant commented Jul 8, 2026

Uh oh!

github-actions Bot commented Jul 10, 2026

🧪 Code Coverage Report

Uh oh!

JooHyukKim left a comment

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

github-actions Bot commented Jul 23, 2026

🧪 Code Coverage Report

Uh oh!

cowtowncoder commented Jul 23, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Uh oh!

cowtowncoder commented Jul 23, 2026

Uh oh!

Uh oh!

Uh oh!

gitar-bot Bot Aug 9, 2026

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

github-actions Bot commented Aug 9, 2026

🧪 Code Coverage Report

Uh oh!

goutamadwant commented Aug 10, 2026

Uh oh!

goutamadwant commented Aug 10, 2026

Uh oh!

JooHyukKim left a comment

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

gitar-bot Bot commented Aug 12, 2026

Uh oh!

goutamadwant left a comment

Choose a reason for hiding this comment

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

3 participants

goutamadwant commented Jul 7, 2026 •

edited

Loading

cowtowncoder commented Jul 23, 2026 •

edited

Loading