From 4e4f12ba9f64013609d449976616e5c7f38385b0 Mon Sep 17 00:00:00 2001
From: "github-actions[bot]"
 <41898282+github-actions[bot]@users.noreply.github.com>
Date: Mon, 31 Aug 2026 02:19:09 +0000
Subject: [PATCH] Add regression test for #3906: verify square brackets are
 escaped in nupkg entries

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
---
 .../Paket.Tests/Packaging/NupkgWriterSpecs.fs | 39 +++++++++++++++++++
 tests/Paket.Tests/Paket.Tests.fsproj          |  1 +
 2 files changed, 40 insertions(+)
 create mode 100644 tests/Paket.Tests/Packaging/NupkgWriterSpecs.fs

diff --git a/tests/Paket.Tests/Packaging/NupkgWriterSpecs.fs b/tests/Paket.Tests/Packaging/NupkgWriterSpecs.fs
new file mode 100644
index 0000000000..7dc66358dd
--- /dev/null
+++ b/tests/Paket.Tests/Packaging/NupkgWriterSpecs.fs
@@ -0,0 +1,39 @@
+module Paket.NupkgWriter.Test
+
+open System.IO
+open System.IO.Compression
+open Paket
+open FsUnit
+open NUnit.Framework
+
+[<Test>]
+let ``#3906 paket pack escapes square brackets in file names``() =
+    let workingDir = Path.Combine(Path.GetTempPath(), "paket-nupkgwriter-test-" + System.Guid.NewGuid().ToString("N"))
+    let outputDir = Path.Combine(workingDir, "out")
+    let harvestDir = Path.Combine(workingDir, "harvest")
+    Directory.CreateDirectory harvestDir |> ignore
+    Directory.CreateDirectory outputDir |> ignore
+    try
+        let bracketFile = Path.Combine(harvestDir, "file[0].txt")
+        File.WriteAllText(bracketFile, "content")
+
+        let core : CompleteCoreInfo =
+            { Id = "Test.Package"
+              Version = Some (SemVer.Parse "1.0.0")
+              Authors = ["Author"]
+              Description = "Description"
+              Symbols = false }
+
+        let optional =
+            { OptionalPackagingInfo.Empty with
+                Files = ["harvest", "lib/net461"] }
+
+        let outputPath = NupkgWriter.Write core optional workingDir outputDir
+
+        use archive = ZipFile.OpenRead outputPath
+        let entryNames = archive.Entries |> Seq.map (fun e -> e.FullName) |> Seq.toList
+
+        entryNames |> shouldContain "lib/net461/file%5B0%5D.txt"
+        entryNames |> List.contains "lib/net461/file[0].txt" |> shouldEqual false
+    finally
+        if Directory.Exists workingDir then Directory.Delete(workingDir, true)
diff --git a/tests/Paket.Tests/Paket.Tests.fsproj b/tests/Paket.Tests/Paket.Tests.fsproj
index 832e4e2a91..2ec87e8825 100644
--- a/tests/Paket.Tests/Paket.Tests.fsproj
+++ b/tests/Paket.Tests/Paket.Tests.fsproj
@@ -206,6 +206,7 @@
     <Compile Include="InstallModel\InstallNuGetContentsTests.fs" />
     <Compile Include="InstallModel\PaketPropsTests.fs" />
     <Compile Include="Packaging\PackageProcessSpecs.fs" />
+    <Compile Include="Packaging\NupkgWriterSpecs.fs" />
     <Compile Include="Packaging\NuspecWriterSpecs.fs" />
     <Compile Include="Packaging\TemplateFileParsing.fs" />
     <Compile Include="Packaging\RemotePushUrlSpecs.fs" />