From 97478dfe217058a1e0186d74d9630cc4c0112100 Mon Sep 17 00:00:00 2001
From: "github-actions[bot]"
 <41898282+github-actions[bot]@users.noreply.github.com>
Date: Tue, 1 Sep 2026 20:05:04 +0000
Subject: [PATCH] Fix pack crash on Compile Remove-only items (#4222)

paket pack --symbols threw 'Compile entry is in unknown format' when
a project's <Compile Remove="..." /> item had neither Include nor
Update attributes (a valid MSBuild construct used to exclude files
from compilation). GetCompileItems now skips such entries instead of
throwing.

Closes #4222

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
---
 .../PaketConfigFiles/ProjectFile.fs           | 53 +++++++++----------
 tests/Paket.Tests/Paket.Tests.fsproj          |  1 +
 tests/Paket.Tests/ProjectFile/OutputSpecs.fs  |  9 ++++
 .../TestData/CompileRemoveOnly.csprojtest     | 11 ++++
 4 files changed, 47 insertions(+), 27 deletions(-)
 create mode 100644 tests/Paket.Tests/ProjectFile/TestData/CompileRemoveOnly.csprojtest

diff --git a/src/Paket.Core/PaketConfigFiles/ProjectFile.fs b/src/Paket.Core/PaketConfigFiles/ProjectFile.fs
index c7fac7430c..8cac0b5a6e 100644
--- a/src/Paket.Core/PaketConfigFiles/ProjectFile.fs
+++ b/src/Paket.Core/PaketConfigFiles/ProjectFile.fs
@@ -2039,32 +2039,31 @@ type ProjectFile with
 
         let getCompileItem (projectFile, compileNode) =
             let projectFolder = projectFile.FileName |> Path.GetFullPath |> Path.GetDirectoryName
-            let sourceFile =
-                let file =
-                    match compileNode |> getAttribute "Include" with
-                    | Some file -> file
-                    | None ->
-                        match compileNode |> getAttribute "Update" with
-                        | Some file -> file
-                        | None -> failwithf "The Compile entry is in unknown format and doesn't contain a Update or Include attribute."
-
-                file
-                |> normalizePath
-                |> fun relPath -> Path.Combine(projectFolder, relPath)
-
-            let destPath =
-                compileNode
-                |> getDescendants "Link"
-                |> function
-                    | [] -> createRelativePath (projectFolder + string Path.DirectorySeparatorChar) sourceFile
-                    | linkNode :: _ -> linkNode.InnerText
-                |> normalizePath
-                |> Path.GetDirectoryName
-            {
-                SourceFile = sourceFile
-                DestinationPath = destPath
-                BaseDir = projectFolder
-            }
+            match compileNode |> getAttribute "Include" |> Option.orElseWith (fun () -> compileNode |> getAttribute "Update") with
+            | None ->
+                // Entries such as <Compile Remove="..." /> without an Include or Update attribute
+                // don't reference a source file, so they can't produce a compile item. Skip them
+                // instead of failing the whole pack/build (see GitHub issue #4222).
+                None
+            | Some file ->
+                let sourceFile =
+                    file
+                    |> normalizePath
+                    |> fun relPath -> Path.Combine(projectFolder, relPath)
+
+                let destPath =
+                    compileNode
+                    |> getDescendants "Link"
+                    |> function
+                        | [] -> createRelativePath (projectFolder + string Path.DirectorySeparatorChar) sourceFile
+                        | linkNode :: _ -> linkNode.InnerText
+                    |> normalizePath
+                    |> Path.GetDirectoryName
+                Some {
+                    SourceFile = sourceFile
+                    DestinationPath = destPath
+                    BaseDir = projectFolder
+                }
 
         let getRealItems compileItem =
             let sourceFolder = Path.GetDirectoryName(compileItem.SourceFile)
@@ -2080,7 +2079,7 @@ type ProjectFile with
         this.GetProjects includeReferencedProjects cache
         |> this.ProjectsWithoutTemplates
         |> Seq.collect getCompileRefs
-        |> Seq.map getCompileItem
+        |> Seq.choose getCompileItem
         |> Seq.collect getRealItems
 
 
diff --git a/tests/Paket.Tests/Paket.Tests.fsproj b/tests/Paket.Tests/Paket.Tests.fsproj
index 832e4e2a91..a2dd610165 100644
--- a/tests/Paket.Tests/Paket.Tests.fsproj
+++ b/tests/Paket.Tests/Paket.Tests.fsproj
@@ -130,6 +130,7 @@
     <Compile Include="LocalFile\LocalFileSpecs.fs" />
     <Compile Include="Simplifier\BasicScenarioSpecs.fs" />
     <TestAsset Include="ProjectFile\TestData\MicrosoftNetSdkWithTargetFrameworkAndOutputPath.csprojtest" />
+    <TestAsset Include="ProjectFile\TestData\CompileRemoveOnly.csprojtest" />
     <TestAsset Include="ProjectFile\TestData\EmptyFsharpGuid.fsprojtest" />
     <TestAsset Include="ProjectFile\TestData\EmptyVbGuid.vbprojtest" />
     <TestAsset Include="ProjectFile\TestData\EmptyPyGuid.pyprojtest" />
diff --git a/tests/Paket.Tests/ProjectFile/OutputSpecs.fs b/tests/Paket.Tests/ProjectFile/OutputSpecs.fs
index 88b95a32ed..fec37effca 100644
--- a/tests/Paket.Tests/ProjectFile/OutputSpecs.fs
+++ b/tests/Paket.Tests/ProjectFile/OutputSpecs.fs
@@ -176,6 +176,15 @@ let ``should maintain order when updating project file items`` () =
         ]
     CollectionAssert.AreEqual(expected, actual)
 
+[<Test>]
+let ``should not fail on Compile Remove entry without Include or Update attribute`` () =
+    ensureDir ()
+    let projFile = ProjectFile.TryLoad("./ProjectFile/TestData/CompileRemoveOnly.csprojtest").Value
+    let cache = PackProcessCache.empty
+    projFile.GetCompileItems false cache
+    |> Seq.toList
+    |> shouldEqual []
+
 [<Test>]
 let ``should remove missing files that exist in the project`` () = 
     ensureDir ()
diff --git a/tests/Paket.Tests/ProjectFile/TestData/CompileRemoveOnly.csprojtest b/tests/Paket.Tests/ProjectFile/TestData/CompileRemoveOnly.csprojtest
new file mode 100644
index 0000000000..56535c851e
--- /dev/null
+++ b/tests/Paket.Tests/ProjectFile/TestData/CompileRemoveOnly.csprojtest
@@ -0,0 +1,11 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <AssemblyName>TestPaket</AssemblyName>
+    <TargetFramework>netstandard1.4</TargetFramework>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <Compile Remove="Excluded.cs" />
+  </ItemGroup>
+</Project>