Apply a number of improvements and bugfixes to JsonNode #88194

eiriktsarpalis · 2023-06-29T14:42:13Z

This PR applies a number of improvements and bugfixes to JsonNode following up from #87381.

Avoid potential torn reads on lazy initialization in methods that attempt to access the JsonElement field directly in JsonObject and JsonArray, related to the fixes found in Ensure delayed initialization of JsonArray/JsonObject is thread-safe #77567. Makes adjustments so that code in the two classes is more uniform. Change contained in b02f735.
Simplify the implementation of JsonValue, more specifically this removes the obsolete JsonValueTrimmable/JsonValueNotTrimmable distinction in favor of a common resolver-agnostic implementation. Fixes a number of issues related to the newly added DeepEquals method when comparing JsonValue. Change contained in d9ac996.
Misc opportunistic simplifications, including simplifying the JsonNode serialization implementations.

… code patterns.

ghost · 2023-06-29T14:42:24Z

Tagging subscribers to this area: @dotnet/area-system-text-json, @gregsdennis
See info in area-owners.md if you want to be subscribed.

Issue Details

This PR applies a number of improvements and bugfixes to JsonNode following up from #87381.

Avoid potential torn reads on lazy initialization in methods that attempt to access the JsonElement field directly in JsonObject and JsonArray. Makes adjustments so that code in the two classes is more uniform. Change contained in b02f735.
Simplify the implementation of JsonValue, more specifically this removes the obsolete JsonValueTrimmable/JsonValueNotTrimmable distinction in favor of a common resolver-agnostic implementation. Fixes a number of issues related to the newly added DeepEquals method when comparing JsonValue. Change contained in d9ac996.
Misc opportunistic simplifications, including simplifying the JsonNode serialization implementations.

Author:	eiriktsarpalis
Assignees:	eiriktsarpalis
Labels:	`area-System.Text.Json`
Milestone:	-

src/libraries/System.Text.Json/src/System/Text/Json/Nodes/JsonValueOfTPrimitive.cs

…ValueOfTPrimitive.cs

eiriktsarpalis · 2023-06-29T17:17:54Z

src/libraries/System.Text.Json/src/System/Text/Json/Nodes/JsonArray.IList.cs

@@ -31,12 +31,21 @@ public void Add(JsonNode? item)
        /// </summary>
        public void Clear()
        {
-            for (int i = 0; i < List.Count; i++)
+            List<JsonNode?>? list = _list;


Updates the code so that List is not accidentally initialized here.

eiriktsarpalis · 2023-06-29T17:21:07Z

src/libraries/System.Text.Json/src/System/Text/Json/Nodes/JsonNode.To.cs

@@ -5,22 +5,14 @@ namespace System.Text.Json.Nodes
 {
    public abstract partial class JsonNode
    {
-        // trimming-safe default JsonSerializerOptions instance used by JsonNode methods.
-        private protected static readonly JsonSerializerOptions s_defaultOptions = new();


No longer necessary since the JsonNode.WriteTo implementations no longer compose via intermediate JsonConverter.Write calls that require a JsonSerializerOptions.

eiriktsarpalis · 2023-06-29T17:22:49Z

src/libraries/System.Text.Json/src/System/Text/Json/Nodes/JsonObject.IDictionary.cs

-            InitializeIfRequired();
-            Debug.Assert(_dictionary != null);
-            _dictionary.Add(propertyName, value);
+            Dictionary.Add(propertyName, value);


Replaces initialization code with a Dictionary property that drives initialization, following the style of the JsonArray implementation.

eiriktsarpalis · 2023-06-29T18:32:37Z

src/libraries/System.Text.Json/src/System/Text/Json/Nodes/JsonObject.cs

@@ -220,16 +216,19 @@ internal override void GetPath(List<string> path, JsonNode? child)

        internal void SetItem(string propertyName, JsonNode? value)
        {
-            InitializeIfRequired();
-            Debug.Assert(_dictionary != null);
-            JsonNode? existing = _dictionary.SetValue(propertyName, value, () => value?.AssignParent(this));


Refactored to avoid a delegate allocation in the setter method.

eiriktsarpalis · 2023-06-30T16:55:19Z

src/libraries/System.Text.Json/src/System/Text/Json/Nodes/JsonObject.cs

        {
-            if (_jsonElement.HasValue)
+            GetUnderlyingRepresentation(out JsonPropertyDictionary<JsonNode?>? dictionary, out JsonElement? jsonElement);


Refactored to avoid potential races with the intializer method that clears out the _jsonElement field.

src/libraries/System.Text.Json/src/System/Text/Json/Nodes/JsonArray.IList.cs

src/libraries/System.Text.Json/src/System/Text/Json/Nodes/JsonNode.To.cs

src/libraries/System.Text.Json/src/System/Text/Json/Nodes/JsonObject.IDictionary.cs

Sergio0694 · 2023-07-03T12:09:01Z

Sharing updated binary size numbers from the Store just for tracking:

Version	Package size
8.0.0-preview.6.23316.2	65,121 KB
8.0.0-preview.7.23330.6	65,143 KB

Very small 20 KB regression (I suspect just generally for the new stuff added in #87381, especially I guess those new IEnumerable<T> APIs, given we have MCG generating WinRT wrappers left and right for those), but completely negligible in general. I know we have proper size tracking through unit tests and ASP.NET now, but given .NET Native is different and handles trimming completely different, I figured having more reference points for this can't hurt 😄

eiriktsarpalis · 2023-07-03T14:32:35Z

especially I guess those new IEnumerable APIs

You mean JsonArray.GetValues<T>()? I'd be surprised this would be rooted unless it somehow ends up being invoked somewhere.

Sergio0694 · 2023-07-03T14:57:20Z

Yeah that's the one. I was thinking that might be another case of MCG being overzealous and preemptively rooting all generated CCWs for IEnumerable<T> types it finds in the assembly, just in case they were ever marshalled to the WinRT side. I believe this generation step runs before the IL-level trimming done by ILC, so it'd cause that to be rooted even though the method is never actually called (@jkoritzinsky correct me if I'm wrong 😄). Or, I suppose, that 40 KB could also just be a small difference just due to general code reshuffling with the recent changes somewhere. To be clear — it's not an issue, I was just trying to give a possible explanation for the (very small) binary size regression compared to Preview 6, is all 🙂

EgorBo · 2023-07-06T16:55:17Z

Improvements on arm64:

[Perf] Linux/arm64: 4 Improvements on 7/1/2023 8:07:46 AM perf-autofiling-issues#19588
[Perf] Windows/arm64: 3 Improvements on 7/1/2023 8:07:46 AM perf-autofiling-issues#19584

Sergio0694 · 2023-07-11T14:09:18Z

Some more updated numbers, looks like the latest few PRs did help a little bit again 😄

Version	Package size
8.0.0-preview.7.23330.6	64,771 KB
8.0.0-preview.7.23360.15	64,713 KB

So that's another small (but free) ~60 KB improvement. Note that the baseline with the previous version doesn't match that from #88194 (comment), but that's only because I've rebased the dogfooding branch on top of our main in the meantime. Just consider the relative size delta between different System.Text.Json versions 🙂

eiriktsarpalis added 2 commits June 28, 2023 18:41

Avoid JsonElement torn read in a few JsonArray/JsonDocument and unify…

b02f735

… code patterns.

Simplify and clean up JsonValue implementation -- fix DeepEquality bugs.

d9ac996

eiriktsarpalis requested a review from stephentoub June 29, 2023 14:42

dotnet-issue-labeler bot added the area-System.Text.Json label Jun 29, 2023

ghost assigned eiriktsarpalis Jun 29, 2023

eiriktsarpalis requested review from steveharter, krwq and layomia June 29, 2023 14:42

eiriktsarpalis commented Jun 29, 2023

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src/libraries/System.Text.Json/src/System/Text/Json/Nodes/JsonValueOfTPrimitive.cs Outdated Show resolved Hide resolved

Update src/libraries/System.Text.Json/src/System/Text/Json/Nodes/Json…

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…ValueOfTPrimitive.cs

eiriktsarpalis added this to the 8.0.0 milestone Jun 29, 2023

build-analysis bot mentioned this pull request Jun 29, 2023

windows-x86 release MSBuild_CMake is failing #88172

Closed

eiriktsarpalis commented Jun 29, 2023

View reviewed changes

Avoid delegate allocation in the JsonObject setter.

02376c5

eiriktsarpalis commented Jun 29, 2023

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build-analysis bot mentioned this pull request Jun 29, 2023

Tracking issue for CI build timeouts #76454

Closed

eiriktsarpalis commented Jun 30, 2023

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stephentoub reviewed Jun 30, 2023

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src/libraries/System.Text.Json/src/System/Text/Json/Nodes/JsonArray.IList.cs Show resolved Hide resolved

stephentoub reviewed Jun 30, 2023

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eiriktsarpalis merged commit 1db4357 into dotnet:main Jul 1, 2023
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eiriktsarpalis deleted the cleanup-jsonvalue branch July 1, 2023 08:07

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Apply a number of improvements and bugfixes to JsonNode #88194

Apply a number of improvements and bugfixes to JsonNode #88194

eiriktsarpalis commented Jun 29, 2023 •

edited

ghost commented Jun 29, 2023

eiriktsarpalis Jun 29, 2023

eiriktsarpalis Jun 29, 2023

eiriktsarpalis Jun 29, 2023

eiriktsarpalis Jun 29, 2023 •

edited

eiriktsarpalis Jun 30, 2023

Sergio0694 commented Jul 3, 2023

eiriktsarpalis commented Jul 3, 2023

Sergio0694 commented Jul 3, 2023

EgorBo commented Jul 6, 2023 •

edited

Sergio0694 commented Jul 11, 2023

Apply a number of improvements and bugfixes to JsonNode #88194

Apply a number of improvements and bugfixes to JsonNode #88194

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