Fix for #6976 -replace operator slowed down after adding scriptblock support #7135
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…riptblock support
iSazonov
reviewed
Jun 22, 2018
| if (rList.Count > 1) | ||
| { | ||
| substitute = rList[1]; | ||
| substitute = PSObject.Base(rList[1]); |
Collaborator
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Could you please add a comment why it is needed? what we break without this?
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Sure, This is actually a pretty fundamental operation in PowerShell. Anywhere you receive something of type object, you have to deal with the case where it might be wrapped in a PSObject. So before you can use it as string or ScriptBlock, you have to get the base object. The PSObject.Base() method encapsulates this operation. If it's passed a PSObject, it returns the core object otherwise it just returns the object.
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|
LGTM. |
lzybkr
approved these changes
Jun 26, 2018
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PR Summary
Fix #6976.
The performance of
-replacewas greatly reduced when scriptblock support was added. This is because of the way the code selected what type of replacement to do. In the old code, the first choice was string. In the modified code, the last choice was string and an earlier clause usedTryConvertTo()to see if the substitution object was (or could be transformed into) aMatchEvaluatorobject. It was this (very expensive) call toTryConvertTo()that was slowing everything down. I added a clause for strings (the most common case) to the beginning of the switch statement so it's fast again. I also added a call toPSObject.Base()to make sure the test for strings is correct.PR Checklist
.h,.cpp,.cs,.ps1and.psm1files have the correct copyright headerWIP:to the beginning of the title and remove the prefix when the PR is ready.[feature]if the change is significant or affects feature tests