- Adds `LanguagePrimitives.IsNullLike()` method to account for `DBNull.Value` and `NullString.Value` so that they can be considered the same as a null value where sensible in PowerShell.
- Updates `-ne` and `-eq` binders to treat `DBNull.Value` and `NullString.Value` as equal to null/AutomationNull.
- Update code paths for comparing objects in LanguagePrimitives to ensure consistency with how the `-eq` and `-ne` binders work when calling LanguagePrimitives methods to do the comparisons.
- Make `LanguagePrimitives.IsNull()` and `LanguagePrimitives.IsNullLike()` public methods.
- Added tests for null behaviours in `NullRepresentatives.Tests.ps1`
- Use IndexOf(char) overload instead of IndexOf(string) to benefit from Ordinal search
- Replace IndexOf with Contains to get more understandable code
- Use StringComparison.Ordinal for ASCII chars
.NET Core changes to return "shortest roundtrippable string" by default for the ToString() method of double and float types. This results in ToString() for double/float values sometimes return a string in 17-digit/9-digit precision format. This PR updated the double/float-to-string conversion in PowerShell to continue using the old precision specifier before the change in .NET Core 3.0.
Consolidation of all Windows PowerShell work ported to PSCore6
* Added ps1 file import restriction. Refactored InvokeLanguageModeTestingSupportCmdlet to HelpersSecurity module
* JEA loop back fix. Debugger running commands in CL mode.
* Support for new AMSI codes. Changed to use AMSI buffer API. Unhandled exception fix.
* Fixes for module bugs while running in ConstrainedLanguage mode
* Untrusted input tracking work
* Configuration keyword bug fix, PSRP protocol version check for reconstruct reconnect, Sharing InitialSessionState in runspace pool.
* Restricted remote session in UMCI, Applocker detection collision, Help command exposing functions, Null reference exception fix.
* Added mitigation for debugger function exposure
Support calling methods with ByRef-like type parameters in PowerShell, as long as the argument specified for the parameter can be implicitly/explicitly converted to the ByRef-like type.
We cannot create an instance of a ByRef-like type in PowerShell, but there are types that can be implicitly or explicitly converted to ByRef-like types, such as `T[] -> Span<T>`, `T[] -> ReadOnlySpan<T>`, `String -> ReadOnlySpan<T>`. `ArraySegment<T> -> Span<T>`, `ArraySegment<T> -> ReadOnlySpan<T>`. With changes in this PR, we can call methods with ByRef-like parameter types by providing the arguments of the types that can be cast to the target ByRef-like type.
**What is enabled?**
1. Invoking methods that have ByRef-like parameters, but the return type is not ByRef-like.
2. Invoking constructors with ByRef-like parameters via `[target-type]::new` syntax, but the `target-type` is not ByRef-like.
3. Accessing indexers that have ByRef-like parameters, but the return type is not ByRef-like.
ByRef-like types are supposed to be used on stack only, so we need to fail gracefully when accessing properties, calling methods, or creating objects related to ByRef-like types.
Before the fix the TryConvertTo() is implemented in terms of Convert(), but with wrapping exception handling. This is costly performance wise. By inlining the implementation of ConvertTo(), and getting access to the FigureConversion output we can determine upfront on at least some occations that a conversion is not available.
Refactor code to make it easier to maintain and a little faster. Changes are as follows:
1. Support finding a matching signature with variance. But make PowerShell prefer exact match over a match with variance.
2. The metadata signatures in `PSMethod<..>` are generated based on the array of method overloads in `MethodCacheEntry.MethodInformationStructures`, in the exact same order. So in `LanguagePrimitive.ConvertViaParseMethod`, when we try to figure out if there is a match using the metadata signatures in `PSMethod<..>`, we can get the index of the matching signature, and the same index should locate the matching method in `MethodCacheEntry.MethodInformationStructures`. Therefore, we don't need to compare signatures again in the actual conversion method, and instead, we can just leverage the index we found when figuring out the conversion in `ConvertViaParseMethod`.
- This gets rid of the reflection call `GetMethod("Invoke")` and the subsequent signature comparisons in the final conversion method.
- Also, when comparing signatures using `PSMethod<..>` in `ConvertViaParseMethod`, we can just use the generic argument types of each `Func<..>` metadata type, instead of calling `GetMethod("Invoke")` and then `GetParameters()`. This makes the code for comparing signatures simpler (the type `SignatureComparator`).
- Move `MatchesPSMethodProjectedType` from `PSMemberInfo.cs` to the type `SignatureComparator` in `LanguagePrimitives.cs`, as it's closely related to the signature comparison. Also, renamed it to `ProjectedTypeMatchesTargetType`.
- These changes make PSMethod-to-Delegate conversion a little faster, but no big improvement, as the true bottleneck probably is in delegate creation(?). Actually, the performance of this conversion is not critical at all at this moment because this feature should rarely be used in any hot script path. So this exercise is mainly for fun.
3. Remove `PSEnum<T>`. We can directly use enum types when constructing the metadata type `Func<..>`.
4. Remove the code that generates metadata signatures for generic method definitions (call `MakeGenericMethod` with fake types like `GenericType0`, `GenericType1`). This is because:
- We don't support convert generic method to delegate today, so may be better not spending time on preparing the metadata signature types for those methods.
- When the day comes that we need to support it, it's better to use generic argument types directly to construct the `Func<..>` metadata types. I left comments in `GetMethodGroupType` method in `PSMemberInfo.cs` to explain why that approach is better.
`GetTypeInfo()` were added when porting PowerShell to early version of .NET Core (prior .NET Core 1.0).
Most properties and methods in `System.Type` were missing at that time. Now the call is not needed anymore and should be removed.
Two small improvements:
1. Avoid unnecessary reflection in `ConvertPSMethodInfoToDelegate`. `PSMethod` already has the `MethodInfo` information with its `adapterData` field.
2. Avoid creating the generic `PSMethod<>` type for `PSMethod` that represents constructors, because constructors cannot be converted to a delegate anyways. In case that the `PSMethod` represents constructors, we use a simple `PSMethod` instance instead.
Also, rename the type `Unit` to `VOID` to make it more readable, since that type represents `typeof(void)`.
Based on standard practices, we need to have a copyright and license notice at the top of each source file. Removed existing copyrights and updated/added copyright notices for .h, .cpp, .cs, .ps1, and .psm1 files.
Updated module manifests for consistency to have Author = "PowerShell" and Company = "Microsoft Corporation". Removed multiple line breaks.
Separate PR coming to update contribution document for new source files: #6140
Manually reviewed each change.
Fix#6073
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