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Make the static constructor of PSVersionInfo run faster for stable PowerShell releases #18210

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Make the static constructor of PSVersionInfo run faster for stable PowerShell releases #18210

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@daxian-dbw daxian-dbw commented Oct 3, 2022

PR Summary

Make the static constructor of PSVersionInfo run faster for stable PowerShell releases.

Major changes are:

  1. Fast parse the pre-defined PowerShell version string, instead of going through SemanticVersion.Parse(string).
    • For stable versions, this can avoid all overhead in constructing the SemanticVersion object.
    • For preview versions, a regex matching is still needed when constructing the SementicVersion object.
  2. Fix $PSVersionTable.GitCommitId to actually use the release tag v7.x.x. The v was missing previously.
  3. Change all legacy versions to use Version instead of SemanticVersion, to avoid the overhead of casting when using them for $PSVersionTable.PSCompatibleVersions.
  4. Simplify the constructor of ConsoleHostRawUserInterface to not use Regex.

PR Context

The change reduces the time to run PSVersionInfo type initializer from about 25ms to 11ms on my dev machine.

PR Checklist

@daxian-dbw daxian-dbw requested a review from anmenaga as a code owner Oct 3, 2022
@daxian-dbw daxian-dbw added CL-General Indicates that a PR should be marked as a general cmdlet change in the Change Log CL-Performance Indicates that a PR should be marked as a performance improvement in the Change Log and removed CL-General Indicates that a PR should be marked as a general cmdlet change in the Change Log labels Oct 3, 2022
daxian-dbw
daxian-dbw commented Oct 3, 2022
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src/System.Management.Automation/engine/PSVersionInfo.cs
rawGitCommitId = mainVersion;
}
string rawGitCommitId = ProductVersion.AsSpan(index).StartsWith(" Commits: ")
? "v" + ProductVersion.Replace(" Commits: ", "-").Replace(" SHA: ", "-g")
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@daxian-dbw daxian-dbw Oct 3, 2022

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No optimization for private builds, intentionally.

src/System.Management.Automation/engine/PSVersionInfo.cs

s_psSemVersion = new SemanticVersion(mainVersion);
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@daxian-dbw daxian-dbw Oct 3, 2022

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Avoid calling SemanticVersion(string), which needs to parse the argument.
The PS version format is pre-defined, so we can greatly simplify the parsing.

daxian-dbw
daxian-dbw commented Oct 3, 2022
View changes
src/Microsoft.PowerShell.ConsoleHost/host/msh/ConsoleHostRawUserInterface.cs
titlePattern = Regex.Escape(titlePattern)
.Replace(@"\{1}", ".*")
.Replace(@"\{0}", Regex.Escape(prefix));
if (!Regex.IsMatch(this.WindowTitle, titlePattern))
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@daxian-dbw daxian-dbw Oct 3, 2022 •
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This is to get rid of using Regex at startup, which is not necessary.

@daxian-dbw daxian-dbw requested review from iSazonov, SeeminglyScience and adityapatwardhan and removed request for anmenaga Oct 3, 2022
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pull-request-quantifier bot commented Oct 3, 2022

This PR has 94 quantified lines of changes. In general, a change size of upto 200 lines is ideal for the best PR experience!

Quantification details 

Label      : Small
Size       : +50 -44
Percentile : 37.6%

Total files changed: 4

Change summary by file extension:
.cs : +48 -39
.resx : +1 -4
.ps1 : +1 -1

Change counts above are quantified counts, based on the PullRequestQuantifier customizations.

Why proper sizing of changes matters

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Reviewers

@iSazonov iSazonov

@SeeminglyScience SeeminglyScience

@adityapatwardhan adityapatwardhan

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