Json patch, initial pr, structures only by suarezrominajulieta · Pull Request #1525 · WebFuzzing/EvoMaster

suarezrominajulieta · 2026-04-26T21:53:15Z

Summary

Introduces the foundational gene structure and builder needed to model JSON Patch

New files

Gene model (`core/src/main/kotlin/.../search/gene/patch/`)

JsonPatchOperationGene — enum-backed gene representing a single RFC 6902 op (add, remove, replace, move, copy, test)
JsonPatchPathOnlyGene — composite gene for ops that only require a path field (remove)
JsonPatchPathValueGene — composite gene for ops that require path + value (add, replace, test)
JsonPatchFromPathGene — composite gene for ops that require path + from (move, copy)
JsonPatchDocumentGene — top-level gene representing a full JSON Patch document (array of operation objects); handles serialization to JSON and mutation logic

Builder (`core/src/main/kotlin/.../problem/rest/builder/`)

JsonPatchGeneBuilder — constructs a JsonPatchDocumentGene from an OpenAPI schema, mapping PATCH request body fields to the appropriate sub-gene variant

Tests (`core/src/test/kotlin/...`)

Unit tests for each gene class and the builder
GeneSamplerForTests and GeneNumberOfGenesTest updated to include new gene types

What's NOT included yet

Integration with RestActionBuilderV3 (wiring the builder into the main action pipeline)
E2E test against a real PATCH endpoint

Notes

This is a structural PR — all new classes compile and their unit tests pass, but the genes are not yet invoked during actual fuzzing runs.

jgaleotti · 2026-04-27T14:36:16Z

Hi @suarezrominajulieta, first ask for my review and then, when I aprove the PR, I will request @arcuri82 's review.

suarezrominajulieta · 2026-04-27T16:46:05Z

Hi @jgaleotti ! Okey, done :)

jgaleotti · 2026-04-27T17:31:00Z

+ * Provides heuristics that extract valid JSON Pointer paths from a resource schema
+ * and group them by field type to construct type-safe path-value pairs.
+ */
+object JsonPatchGeneBuilder {


Why it is saying that it provides "heuristics"? This class deterministically creates an JsonPathGene from a given schema

jgaleotti · 2026-04-27T17:32:46Z

+            resourceSchema: Gene?
+        ): ArrayGene<ChoiceGene<JsonPatchOperationGene>> {
+
+            val allPaths = JsonPatchGeneBuilder.extractAllPaths(resourceSchema)


what happens if resourceSchema is null?

Can/should we let it do nothing for this pr?

jgaleotti · 2026-04-27T17:33:37Z

+            val choices = mutableListOf<JsonPatchOperationGene>()
+
+            // Operations that only need a path
+            choices.add(JsonPatchPathOnlyGene("remove", pathEnum.copy() as EnumGene<String>))


replace "remove" and other strings with constants

jgaleotti · 2026-04-27T17:45:52Z

+
+            // Operations that need path + value; pairs are grouped by schema field type
+            val pathValueEntries = JsonPatchGeneBuilder.buildPathValueEntries(allPaths)
+            val effectiveEntries: List<PairGene<EnumGene<String>, Gene>> =


what does effectiveEntries mean? Shouldn't this list be called pathValuePairGenes?

jgaleotti · 2026-04-27T17:48:52Z

+    val fromGene: EnumGene<String>,
+    val pathGene: EnumGene<String>,
+    geneName: String = "${operationName}Op"
+) : JsonPatchOperationGene(geneName, operationName, listOf(fromGene, pathGene)) {


check that the operation name is move or copy. Why does it add the "Op" ?

jgaleotti · 2026-04-27T19:07:33Z

+ * Provides heuristics that extract valid JSON Pointer paths from a resource schema
+ * and group them by field type to construct type-safe path-value pairs.
+ */
+object JsonPatchGeneBuilder {


Do not include the schema extraction heuristics in this PR

jgaleotti · 2026-04-27T19:08:50Z

+class JsonPatchPathOnlyGene(
+    operationName: String,
+    val pathGene: EnumGene<String>,
+    geneName: String = "${operationName}Op"


why do we have operationName and geneName?

I'm not sure what I should implement. Could you explain again what we were expecting here?

I created the operationName property, which inherits from the abstract class, to verify and distinguish between a pathfrom that is a move and a pathfrom that is a copy, and to ensure that each is printed correctly.

And then there's the geneName or name, which should be the name of the gene, which can be anything, like "Gene1".

I'm wondering if the child classes should only have operationName and not name, or if we should keep both, but make them exactly the same as those defined by the parent class in the inheritance.

I understood why we have both. Please keep geneName (name) and operationName.

jgaleotti · 2026-04-27T19:11:35Z

+        targetFormat: OutputFormat?,
+        extraCheck: Boolean
+    ): String {
+        val activePair = pathValueChoice.activeGene()


same as previous comments

…nd dependency

…nd tests

suarezrominajulieta · 2026-05-06T03:27:33Z

Hi @jgaleotti ! i added the following as previously talked:

the resourceSchema logic when given, or random if not and it's tests (and value entries with random string or integer genes also).
and the whole json document tests for json and xml printing.

I'd appreciate it if you could review it now, thanks!

jgaleotti · 2026-05-04T19:20:30Z

+ * a ChoiceGene that selects among the six standard operations:
+ *   remove, move, copy, add, replace, test.
+ *
+ * [resourceSchema] is stored for future schema-aware path extraction but is not yet analysed.


update this javadoc

jgaleotti · 2026-05-04T20:16:06Z

+    // --- XML serialization ---
+
+    @Test
+    fun testRemoveOperationXmlFormat() {


Add a test case checking JSON Format for this

jgaleotti · 2026-05-04T20:16:21Z

+    }
+
+    @Test
+    fun testMoveOperationXmlFormat() {


Add a test case checking JSON Format

jgaleotti · 2026-05-11T19:06:37Z

+        extraCheck: Boolean
+    ): String {
+        val inner = operationsArray.getValueAsPrintableString(previousGenes, mode, targetFormat, extraCheck)
+        return if (mode == GeneUtils.EscapeMode.XML) "<patch>$inner</patch>" else inner


Add comment regarding lack of XML convention for JSON Patch documents written in XML

jgaleotti · 2026-05-11T19:08:42Z

+ */
+class JsonPatchDocumentGene private constructor(
+    name: String,
+    val resourceSchema: Gene?,


it seems to me that the resourceSchema does not need to be stored

jgaleotti · 2026-05-11T19:11:22Z

+        extraCheck: Boolean
+    ): String = formatOperation(
+        mode,
+        OpField("from", fromGene.getValueAsRawString()),


shouldn't this be fromGene.getValueAsPrintableString()

jgaleotti · 2026-05-11T19:16:54Z

+        }
+    }
+
+    override fun getValueAsPrintableString(


getValueAsPrintableString should be defined in the superclass JsonPatchOperationGene

jgaleotti · 2026-05-11T19:17:24Z

+    /** A single field in a JSON Patch operation, with its serialized value.
+     *  [quoted] controls whether the value is wrapped in quotes in JSON output
+     *  (true for string fields like path/from; false for typed fields like value). */
+    protected data class OpField(val name: String, val value: String, val quoted: Boolean = true)


I think this class is not actually needed

suarezrominajulieta · 2026-05-17T20:18:48Z

Hi, @jgaleotti i made the changes we last talked about:

Add a comment stating that we are not implementing a convention, because there isn't one, by using patch as the root's nametag.
We can remove the resource schema: receive it, build the template with it, and discard it.
The parent operation should only have getValueAsPrintableString, and the children should not:

I had to keep getValueAsRawString with EnumGene because getValueAsPrintableString in enums, prints with "", i.e: "/example", and it would print an xml like this "/x" instead of /x.

ty!

jgaleotti · 2026-05-19T22:11:26Z

+     */
+    fun buildOperationsArray(
+        resourceSchema: Gene? = null,
+        randomness: Randomness? = null


I don't remember discussing the creation of random paths when no resourceSchema is provided. I am not very confortable having a "nondetermintisc" gene creation.

ok, but what should we do in case there's no schema provided, how do we build the enum genes for the paths?

should we make it non nulleable, and throw an exception if not provided?

Let's try having a schema by default as you used to have (the one with /a, /b, etc).
What do you think?

jgaleotti · 2026-05-19T22:11:59Z

+    // private helpers
+    // ---------------------------------------------------------------------------
+
+    private fun generateRandomPaths(randomness: Randomness): List<String> =


I am not sure about this renadom path creation. I think this builder should be completely deterministic.

jgaleotti · 2026-05-19T22:12:33Z

+    private fun buildFromPaths(
+        paths: List<String>
+    ): ArrayGene<ChoiceGene<JsonPatchOperationGene>> {
+        val pathEnum = EnumGene<String>("path", paths)


use constants instead of strings such as "path", "entry_string", etc.

jgaleotti · 2026-05-19T22:25:30Z

+        targetFormat: OutputFormat?,
+        extraCheck: Boolean
+    ): String {
+        // path/from fields use getValueAsRawString() instead of getValueAsPrintableString() because


I am still not sure about using getValueAsRawString(). As an example, what happens if I have an ObjectGene with an EnumGene?

jgaleotti · 2026-05-19T22:27:17Z

+
+    private fun children(randomness: Randomness = rand): List<JsonPatchOperationGene> =
+        JsonPatchDocumentGeneBuilder.buildOperationsArray(randomness = randomness)
+            .template.getViewOfChildren().map { it as JsonPatchOperationGene }


I do not like builder using randomness.

jgaleotti · 2026-05-19T22:31:38Z

+        val paths = (removeOp.pathGene as EnumGene<*>).values.map { it.toString() }
+        assertTrue(paths.isNotEmpty() && paths.all { it.startsWith("/") })
+    }
+}


Add test cases for the scenario where there are multiple paths with the same value type

jgaleotti · 2026-05-20T15:12:04Z

+        // wrong quotes inside XML tags (<path>"/x"</path>). getValueAsRawString() returns the
+        // bare string (e.g. /x), letting us control quoting per format ourselves.
+        val fields = when (this) {
+            is JsonPatchPathOnlyGene -> {


I think it is possible to have this implementation without referring explicitly to each subclass using the ``children'' fields

jgaleotti · 2026-05-20T17:38:05Z

+        // EnumGene<String>.getValueAsPrintableString() always wraps the value in quotes regardless of
+        // mode or targetFormat. Using it would produce double-quoting in JSON ("path":""/x"") and
+        // wrong quotes inside XML tags (<path>"/x"</path>). getValueAsRawString() returns the
+        // bare string (e.g. /x), letting us control quoting per format ourselves.


This is strange since I am not seeing that this is actually happening when having enumgenes in an objectgene

@Test fun testObjectGeneWithEnumGene() { val name = "com.example.MyDto" val schema = """ "$name": { "type": "object", "properties": { "path": { "type": "string", "enum": ["/some", "/some/path", "/some/other/path"] } }, "required": ["path"] } """.trimIndent() val gene = RestActionBuilderV3.createGeneForDTO(name, schema, name, RestActionBuilderV3.Options()) assertTrue(gene is ObjectGene) val objectGene = gene as ObjectGene val field = objectGene.fields.find { it.name == "path" } assertNotNull(field) assertTrue(ParamUtil.getValueGene(field!!) is EnumGene<*>) val enumGene = ParamUtil.getValueGene(field) as EnumGene<String> assertEquals(3, enumGene.values.size) assertTrue(enumGene.values.containsAll(listOf("/some", "/some/path", "/some/other/path"))) val json = objectGene.getValueAsPrintableString(listOf(), GeneUtils.EscapeMode.JSON, OutputFormat.JAVA_JUNIT_5) assertTrue(json == """{"path":"/some"}""" || json == """{"path":"/some/path"}""" || json == """{"path":"/some/other/path"}""") }

you are rigth, this prints okey for json, adding the "" to the string printed (not double-quoting, that's wrong in my comment/possible implementation) => assertTrue(enumGene.values.containsAll(listOf("/some", "/some/path", "/some/other/path"))) ok.

but for xml, enumGene.getValueAsPrintableString prints the same as json, with the simple quoting, resulting in, for ex.: <operation><op>remove</op><path>"/some/path"</path></operation>, which is not xml correct.

val xmlPrintable = enumGene.getValueAsPrintableString(mode = GeneUtils.EscapeMode.XML) assertEquals("\"/age\"", xmlPrintable)

that's why i used raw, so for json i add the simple quoting and in xml, they don't appear. but maybe we should fix the mode printing in enumgene?

suarezrominajulieta added 4 commits April 26, 2026 18:51

initial pr for json patch, structures only

40ddf46

Merge branch 'master' into feature/jsonPatch

a187e0f

Fixes for geneSamplerForTests

0c1e123

Merge branch 'master' into feature/jsonPatch

eb38089

suarezrominajulieta marked this pull request as ready for review April 27, 2026 11:33

suarezrominajulieta requested review from arcuri82 and jgaleotti April 27, 2026 11:33

suarezrominajulieta removed the request for review from arcuri82 April 27, 2026 16:45

Merge branch 'master' into feature/jsonPatch

e3ef6a7

jgaleotti requested changes Apr 27, 2026

View reviewed changes

suarezrominajulieta added 10 commits April 27, 2026 21:30

Merge branch 'master' into feature/jsonPatch

20dd5e8

Fix path and main test

1a12c92

Merge branch 'master' into feature/jsonPatch

269142e

Fix tests, add print to xml

d2b7cd0

fix for geneRandomizedTest

446891a

Merge branch 'master' into feature/jsonPatch

8746e9e

Fix the print and sampler

9743fc4

Fix strings to constants, fix print, add test and fix builder place a…

8cb61ac

…nd dependency

Fix tests and prints

843d11d

unify print in abstract class

56ec4b3

suarezrominajulieta requested a review from jgaleotti May 4, 2026 02:18

add final test for printing in xml, add resurceSchema aware builder a…

8e4c63d

…nd tests

Merge branch 'master' into feature/jsonPatch

a16199d

jgaleotti requested changes May 11, 2026

View reviewed changes

suarezrominajulieta added 3 commits May 14, 2026 18:00

Merge branch 'master' into feature/jsonPatch

9ba5a2d

Merge branch 'master' into feature/jsonPatch

9745e30

Fixes for resource schema

6fca9df

suarezrominajulieta added 3 commits May 15, 2026 19:24

Fix printing

6019121

Fix for printing

37e06c2

Change builder place, and add some comments

47660f0

suarezrominajulieta requested a review from jgaleotti May 17, 2026 20:10

jgaleotti requested changes May 19, 2026

View reviewed changes

Merge branch 'master' into feature/jsonPatch

e6a536d

jgaleotti reviewed May 20, 2026

View reviewed changes

Merge branch 'master' into feature/jsonPatch

31da8d9

jgaleotti requested changes May 20, 2026

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suarezrominajulieta commented Apr 26, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

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Summary

New files

Gene model (core/src/main/kotlin/.../search/gene/patch/)

Builder (core/src/main/kotlin/.../problem/rest/builder/)

Tests (core/src/test/kotlin/...)

What's NOT included yet

Notes

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jgaleotti commented Apr 27, 2026

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suarezrominajulieta commented Apr 27, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

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suarezrominajulieta commented May 6, 2026

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suarezrominajulieta commented May 17, 2026

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suarezrominajulieta commented Apr 26, 2026 •

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Gene model (`core/src/main/kotlin/.../search/gene/patch/`)

Builder (`core/src/main/kotlin/.../problem/rest/builder/`)

Tests (`core/src/test/kotlin/...`)

suarezrominajulieta commented Apr 27, 2026 •

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