Users/tevinstanley/allocatelistsizecorrectly#12027
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SimaTian merged 4 commits intodotnet:mainfrom Feb 13, 2026
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Pull Request Overview
This PR reduces memory allocations by reusing and pre-sizing a single list of strings instead of recreating and dynamically resizing it on each iteration.
- Reuse the same
parameterValueslist across loop iterations, clearing it instead of instantiating a new list each time. - In
GetBatchableValuesFromBuildItemGroupChild, adjustparameterValues.Capacitybased onchild.Metadata.Count + 4to avoid repeated resizing.
Comments suppressed due to low confidence (1)
src/Build/BackEnd/Components/RequestBuilder/IntrinsicTasks/ItemGroupIntrinsicTask.cs:143
- Clearing
parameterValuesoutside of afinallyblock may lead to stale data in case of an exception or a NullReferenceException if the list was never initialized. Consider moving this into afinallyor guarding it with a null check.
parameterValues.Clear();
src/Build/BackEnd/Components/RequestBuilder/IntrinsicTasks/ItemGroupIntrinsicTask.cs
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…mGroupIntrinsicTask.cs Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>
SimaTian
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Feb 13, 2026
Copilot AI
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Feb 17, 2026
Fixes # ### Context On traces we could see about 8 mb of allocations due to add nonempty strings. When taking it look at the code we could see alot of adding to a list which was constantly resizing.  ### Changes Made * Instead of defaulting a list of default size we use context to initialize the size to be something closer to what we would like. So that the capacity only needs to be set once throughout its use. * Also reuse the same list throughout instead of using a new one every time. ### Testing After the changes I took a trace and it shows that this path is has been reduced by 5mb.  ### Notes --------- Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>
JanProvaznik
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Feb 25, 2026
Fixes # ### Context On traces we could see about 8 mb of allocations due to add nonempty strings. When taking it look at the code we could see alot of adding to a list which was constantly resizing.  ### Changes Made * Instead of defaulting a list of default size we use context to initialize the size to be something closer to what we would like. So that the capacity only needs to be set once throughout its use. * Also reuse the same list throughout instead of using a new one every time. ### Testing After the changes I took a trace and it shows that this path is has been reduced by 5mb.  ### Notes --------- Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>
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Fixes #
Context
On traces we could see about 8 mb of allocations due to add nonempty strings. When taking it look at the code we could see alot of adding to a list which was constantly resizing.
Changes Made
Testing
After the changes I took a trace and it shows that this path is has been reduced by 5mb.
Notes