feat(wrapper-generator): emit deltaLink-aware pagination for delta operations

tools/Test-WrapperDelta.ps1

@@ -0,0 +1,153 @@
+<#
+.SYNOPSIS
+Deterministic delta-pagination gate (#3742). Drives a REAL compiled delta cmdlet through a stub
+transport that fabricates a change set - no tenant data is read beyond one /me call.
+
+.DESCRIPTION
+The runtime's session adapter cache is pre-seeded with an adapter whose HttpClient returns a
+scripted change set: two @odata.nextLink pages, then a page carrying @odata.deltaLink. A separate
+scripted response answers a resume request and returns a replacement link. The active
+Connect-MgGraph session is used only as the cache KEY.
+
+Proves, deterministically:
+  1. -All walks the change set to its terminal page and publishes the deltaLink
+  2. without -All: first page only, exactly one warning, no link published
+  3. -DeltaLink resumes from the literal link and publishes the replacement
+  4. the variable is cleared at invocation start, so a run that ends without a terminal page
+     cannot leave a previous run's link readable
+  5. no *DeltaWithToken command exists - the token form is a parameter set, not a command
+
+Requires an active or cached Graph session (any scopes - only /me is requested).
+
+.EXAMPLE
+pwsh -NoProfile -File .\tools\Test-WrapperDelta.ps1
+#>
+param([string]$Configuration = 'Release')
+$ErrorActionPreference = 'Stop'
+$repoRoot = Split-Path $PSScriptRoot -Parent
+$psd1 = Join-Path $repoRoot "src\Files\wrapper\v1.0\bin\$Configuration\netstandard2.0\Microsoft.Graph.Wrapper.Files.psd1"
+if (-not (Test-Path $psd1)) {
+    throw "no built module at $psd1 - run tools\Build-WrapperModule.ps1 -Module Files -Configuration $Configuration first"
+}
+
+$fail = [System.Collections.Generic.List[string]]::new()
+function Assert([bool]$ok, [string]$what) {
+    $tag = if ($ok) { 'PASS' } else { $script:fail.Add($what); 'FAIL' }
+    Write-Host "$tag $what"
+}
+
+$probe = @"
+`$ErrorActionPreference = 'Stop'
+Import-Module Microsoft.Graph.Authentication
+Import-Module '$psd1'
+Connect-MgGraph -NoWelcome
+`$null = Invoke-MgGraphRequest -Method GET -Uri 'https://graph.microsoft.com/v1.0/me'
+
+Add-Type -TypeDefinition @'
+using System.Net;
+using System.Net.Http;
+using System.Text;
+using System.Threading;
+using System.Threading.Tasks;
+public class DeltaStubHandler : HttpMessageHandler
+{
+    public System.Collections.Generic.List<string> Urls = new System.Collections.Generic.List<string>();
+    protected override Task<HttpResponseMessage> SendAsync(HttpRequestMessage request, CancellationToken token)
+    {
+        string url = request.RequestUri.ToString();
+        Urls.Add(url);
+        string body;
+        if (url.Contains("RESUMELINK"))
+            body = "{\"value\":[{\"id\":\"r1\"}],\"@odata.deltaLink\":\"https://graph.microsoft.com/v1.0/drives/d/items/i/delta?`$deltatoken=SECOND\"}";
+        else if (url.Contains("PAGE3"))
+            body = "{\"value\":[{\"id\":\"c1\"}],\"@odata.deltaLink\":\"https://graph.microsoft.com/v1.0/drives/d/items/i/delta?`$deltatoken=FIRST\"}";
+        else if (url.Contains("PAGE2"))
+            body = "{\"value\":[{\"id\":\"b1\"},{\"id\":\"b2\"}],\"@odata.nextLink\":\"https://graph.microsoft.com/v1.0/drives/d/items/i/delta?`$skiptoken=PAGE3\"}";
+        else
+            body = "{\"value\":[{\"id\":\"a1\"},{\"id\":\"a2\"}],\"@odata.nextLink\":\"https://graph.microsoft.com/v1.0/drives/d/items/i/delta?`$skiptoken=PAGE2\"}";
+        var resp = new HttpResponseMessage(HttpStatusCode.OK);
+        resp.Content = new StringContent(body, Encoding.UTF8, "application/json");
+        return Task.FromResult(resp);
+    }
+}
+'@
+
+function Get-LoadedAssembly([string]`$name) {
+    `$a = [System.AppDomain]::CurrentDomain.GetAssemblies() | Where-Object { `$_.GetName().Name -eq `$name } | Select-Object -First 1
+    if (-not `$a) { throw "assembly not loaded: `$name" }
+    `$a
+}
+`$runtimeAsm = Get-LoadedAssembly 'Microsoft.Graph.Wrapper.Runtime'
+`$kiotaHttp = Get-LoadedAssembly 'Microsoft.Kiota.Http.HttpClientLibrary'
+`$kiotaAbs = Get-LoadedAssembly 'Microsoft.Kiota.Abstractions'
+
+`$real = [Microsoft.Graph.PowerShell.Authentication.Helpers.HttpHelpers]::GetGraphHttpClient()
+`$handler = [DeltaStubHandler]::new()
+`$stub = [System.Net.Http.HttpClient]::new(`$handler)
+`$anon = `$kiotaAbs.GetType('Microsoft.Kiota.Abstractions.Authentication.AnonymousAuthenticationProvider').GetConstructor([type[]]@()).Invoke(@())
+`$adapterType = `$kiotaHttp.GetType('Microsoft.Kiota.Http.HttpClientLibrary.HttpClientRequestAdapter')
+`$adapter = `$adapterType.GetConstructors() | Where-Object { `$_.GetParameters().Count -eq 5 } |
+    ForEach-Object { `$_.Invoke(@(`$anon, `$null, `$null, `$stub, `$null)) } | Select-Object -First 1
+if (-not `$adapter) { throw 'no 5-parameter HttpClientRequestAdapter constructor - kiota surface changed' }
+
+`$cache = `$runtimeAsm.GetType('Microsoft.Graph.Wrapper.Runtime.SessionAdapterCache', `$true)
+`$flags = [System.Reflection.BindingFlags]'NonPublic,Static'
+`$cache.GetField('_key', `$flags).SetValue(`$null, `$real)
+`$cache.GetField('_adapter', `$flags).SetValue(`$null, `$adapter)
+
+# --- 1. -All walks to the terminal page and publishes the link ---
+`$handler.Urls.Clear()
+`$dl = 'PRESET-STALE'
+`$w1 = @()
+`$all = @(Get-MgDriveItemDelta -DriveId d -DriveItemId i -All -DeltaLinkVariable dl -WarningVariable w1 -WarningAction SilentlyContinue)
+`$r1 = [pscustomobject]@{ Test='all'; Items=`$all.Count; Requests=`$handler.Urls.Count; Warnings=`$w1.Count; Link="`$dl" }
+
+# --- 2. without -All: one page, one warning, nothing published ---
+`$handler.Urls.Clear()
+`$dl2 = 'PRESET-STALE'
+`$w2 = @()
+`$page1 = @(Get-MgDriveItemDelta -DriveId d -DriveItemId i -DeltaLinkVariable dl2 -WarningVariable w2 -WarningAction SilentlyContinue)
+`$r2 = [pscustomobject]@{ Test='nopage'; Items=`$page1.Count; Requests=`$handler.Urls.Count; Warnings=`$w2.Count; Link="`$dl2" }
+
+# --- 3. resume from a link ---
+`$handler.Urls.Clear()
+`$dl3 = ''
+`$w3 = @()
+`$res = @(Get-MgDriveItemDelta -DeltaLink 'https://graph.microsoft.com/v1.0/drives/d/items/i/delta?RESUMELINK' -DeltaLinkVariable dl3 -WarningVariable w3 -WarningAction SilentlyContinue)
+`$r3 = [pscustomobject]@{ Test='resume'; Items=`$res.Count; Requests=`$handler.Urls.Count; Warnings=`$w3.Count; Link="`$dl3"; FirstUrl=`$handler.Urls[0] }
+
+# --- 5. the token form is not a command ---
+`$tokenCmds = @(Get-Command -Module Microsoft.Graph.Wrapper.Files -Name '*DeltaWithToken*' -ErrorAction SilentlyContinue).Count
+`$r5 = [pscustomobject]@{ Test='notoken'; Count=`$tokenCmds }
+
+@(`$r1, `$r2, `$r3, `$r5) | ConvertTo-Json -Compress
+"@
+$enc = [Convert]::ToBase64String([Text.Encoding]::Unicode.GetBytes($probe))
+$out = & pwsh -NoProfile -NonInteractive -EncodedCommand $enc 2>&1
+$json = $out | Where-Object { $_ -match '^\[' } | Select-Object -Last 1
+if (-not $json) { Assert $false "probe produced no result: $(($out | Select-Object -Last 3) -join ' | ')" }
+else {
+    $r = $json | ConvertFrom-Json
+    $a = $r | Where-Object Test -eq 'all'
+    Assert ($a.Items -eq 5) "-All returned the whole change set across 3 pages (got $($a.Items))"
+    Assert ($a.Requests -eq 3) "-All made exactly 3 requests (got $($a.Requests))"
+    Assert ($a.Warnings -eq 0) "-All emitted no warning (got $($a.Warnings))"
+    Assert ($a.Link -like '*deltatoken=FIRST*') "terminal deltaLink published to the variable (got '$($a.Link)')"
+
+    $n = $r | Where-Object Test -eq 'nopage'
+    Assert ($n.Items -eq 2 -and $n.Requests -eq 1) "without -All: first page only, 1 request (items=$($n.Items) req=$($n.Requests))"
+    Assert ($n.Warnings -eq 1) "exactly one truncation warning (got $($n.Warnings))"
+    Assert ([string]::IsNullOrEmpty($n.Link)) "no terminal page reached: variable cleared, not left stale (got '$($n.Link)')"
+
+    $s = $r | Where-Object Test -eq 'resume'
+    Assert ($s.FirstUrl -like '*RESUMELINK*') "resume issued the literal link supplied (got '$($s.FirstUrl)')"
+    Assert ($s.Items -eq 1 -and $s.Requests -eq 1) "resume returned its page in 1 request (items=$($s.Items) req=$($s.Requests))"
+    Assert ($s.Link -like '*deltatoken=SECOND*') "replacement deltaLink published (got '$($s.Link)')"
+
+    $t = $r | Where-Object Test -eq 'notoken'
+    Assert ($t.Count -eq 0) "no *DeltaWithToken command exists (found $($t.Count))"
+}
+
+''
+if ($fail.Count -eq 0) { 'RESULT: ALL PASS' } else { "RESULT: $($fail.Count) FAILURE(S)" }
+exit $fail.Count

tools/WrapperGenerator.Tests/EmitterTests.cs

@@ -1,4 +1,5 @@
-using System.Collections.Generic;
+using System;
+using System.Collections.Generic;
 using System.Net.Http;
 using WrapperGenerator;
 using Xunit;
@@ -119,6 +120,103 @@ public void DispatcherDeclaresAllOnListSetAndPassesPipelineStopThrough()
         Assert.Contains("catch (Exception ex) when (ex is not PipelineStoppedException)", source);
     }
 
+    // Delta pins (#3742). A change-tracking read is a function by classification but a paged
+    // collection in practice, so it gets its own shape. The contract and its evidence live in
+    // tools/WrapperGenerator/docs/edge-cases/delta-edge-cases.md.
+    private static string EmitDeltaSource(IReadOnlySet<string>? queryParams = null)
+    {
+        var naming = Naming.Resolve(new OperationInfo(HttpMethod.Get, "/users/delta()"));
+        return CmdletEmitter.EmitDelta(naming, new EmitContext("Test.Client"),
+            new CmdletEmitter.CallPlan("GetAsDeltaGetResponseAsync", "DeltaGetResponse", BodyTypeName: null),
+            queryParams ?? new HashSet<string> { "$top", "$filter" });
+    }
+
+    // Initial sync and resume are one command with two parameter sets: the published SDK folds
+    // the token form into the canonical delta command rather than shipping it separately.
+    // -DeltaLink is universal, where a token argument exists on only a few routes.
+    [Fact]
+    public void DeltaEmitsSyncAndResumeParameterSets()
+    {
+        var source = EmitDeltaSource();
+
+        Assert.Contains("DefaultParameterSetName = \"DeltaSync\"", source);
+        Assert.Contains("[Parameter(Mandatory = true, ParameterSetName = \"Resume\")]", source);
+        Assert.Contains("public string DeltaLink { get; set; }", source);
+        Assert.Contains("ParameterSetName == \"Resume\"", source);
+        Assert.Contains(".WithUrl(DeltaLink).GetAsDeltaGetResponseAsync(", source);
+
+        // Query options belong to the initial sync only.
+        Assert.Contains("[Parameter(Mandatory = false, ParameterSetName = \"DeltaSync\")]", source);
+
+        // The token form must never appear as a parameter or a command of its own.
+        Assert.DoesNotContain("Token", source);
+    }
+
+    // Resuming from a link must not demand the path ids the link already carries - the raw-URL
+    // builder discards them anyway. Found by the delta gate: with the ids mandatory in every set,
+    // -DeltaLink failed binding with "missing mandatory parameters".
+    [Fact]
+    public void DeltaScopesPathIdsToTheInitialSyncSet()
+    {
+        var naming = Naming.Resolve(new OperationInfo(HttpMethod.Get, "/users/{user-id}/todo/lists/{todoTaskList-id}/tasks/delta()"));
+        var source = CmdletEmitter.EmitDelta(naming, new EmitContext("Test.Client"),
+            new CmdletEmitter.CallPlan("GetAsDeltaGetResponseAsync", "DeltaGetResponse", BodyTypeName: null),
+            new HashSet<string>());
+
+        Assert.Contains("[Parameter(Mandatory = true, Position = 0, ParameterSetName = \"DeltaSync\")]", source);
+        Assert.DoesNotContain("[Parameter(Mandatory = true, Position = 0)]", source);
+    }
+
+    // The terminal link is published to a caller-named variable, the idiom this SDK already uses
+    // for returning a scalar beside a pipeline, and cleared first so a failed run cannot leave
+    // the previous run's link readable.
+    [Fact]
+    public void DeltaPublishesTerminalLinkAndClearsItFirst()
+    {
+        var source = EmitDeltaSource();
+
+        Assert.Contains("[Alias(\"DLV\")]", source);
+        Assert.Contains("public string? DeltaLinkVariable { get; set; }", source);
+        Assert.Contains("SessionState.PSVariable.Set(DeltaLinkVariable, null);", source);
+        Assert.Contains("SessionState.PSVariable.Set(DeltaLinkVariable, deltaLink);", source);
+
+        // Clearing must precede the request, or a failure leaves a stale link behind.
+        Assert.True(source.IndexOf("SessionState.PSVariable.Set(DeltaLinkVariable, null);", StringComparison.Ordinal)
+            < source.IndexOf("result = ParameterSetName", StringComparison.Ordinal));
+    }
+
+    // Every terminal state is decided explicitly; a response carrying both links is refused
+    // rather than guessed at.
+    [Fact]
+    public void DeltaHandlesEveryTerminalState()
+    {
+        var source = EmitDeltaSource();
+
+        Assert.Contains("if (!string.IsNullOrEmpty(nextLink) && !string.IsNullOrEmpty(deltaLink))", source);
+        Assert.Contains("\"InvalidDeltaResponse\"", source);
+        Assert.Contains("if (string.IsNullOrEmpty(nextLink)) break;", source);
+        Assert.Contains("WriteWarning(\"More results are available. Use -All to return all pages.\");", source);
+        Assert.Contains("if (Stopping) break;", source);
+        Assert.Contains("if (this.IsParameterBound(nameof(Top)) && fetched >= Top) break;", source);
+        Assert.Contains("catch (Exception ex) when (ex is not PipelineStoppedException)", source);
+
+        // Continuation re-applies headers only: the link already carries the query state.
+        var continuation = source[source.IndexOf(".WithUrl(nextLink)", StringComparison.Ordinal)..];
+        Assert.DoesNotContain("QueryParameters", continuation);
+    }
+
+    // Without a declared $top there is no cap to enforce, so no counter is emitted either -
+    // an unused variable would not compile cleanly and would be dead weight in every file.
+    [Fact]
+    public void DeltaWithoutTopEmitsNoCounter()
+    {
+        var source = EmitDeltaSource(new HashSet<string>());
+
+        Assert.Contains("if (Stopping) break;", source);
+        Assert.DoesNotContain("fetched", source);
+        Assert.DoesNotContain("public int Top", source);
+    }
+
     // Control: non-list shapes must not grow paging machinery.
     [Fact]
     public void NonListShapesEmitNoPagingMachinery()