Enable partial Linux builds for Copilot support #24494

Copilot · 2026-01-09T15:28:21Z

Plan: Enable Building on Linux

Changes Made:

system-dependencies.sh: Added Linux detection and skip all macOS-specific dependency checks
Make.config: Added Linux detection, set placeholder Xcode values, XCODE_VERSION/XCODE_URL now unconditional
builds/Makefile: Use $(CP) variable instead of hardcoded cp -c, create cache directory before use
builds/create-csproj-for-all-packagereferences.sh: Fix PWD usage, add OS detection for sed -i syntax
Makefile: Skip runtime directory on Linux (requires native compilation)
.github/workflows/linux-build.yml: Simplified workflow that runs on all PRs, uses set -ex, and just verifies make succeeds
src/Makefile.generator: Fixed case-sensitivity issue - DotnetGlobals.cs → DotNetGlobals.cs
tools/common/create-makefile-fragment.sh: Fix sed -i syntax for Linux (use sed -i instead of sed -i '')
src/quicklookUI.cs → src/quicklookui.cs: Fixed case-sensitivity - framework files must be all lowercase
src/ILLink.Substitutions.ios.xml → src/ILLink.Substitutions.iOS.xml: Fixed case to match platform name
src/ILLink.Substitutions.tvos.xml → src/ILLink.Substitutions.tvOS.xml: Fixed case to match platform name
src/Makefile: Skip AppleDocReader documentation generation on Linux (macOS-only native tool); just copy XML files instead
msbuild/Makefile: Skip Windows package builds on Linux (not needed); skip xmllint XML validation (tool not available on Linux)
tools/mmp/Makefile: Skip native registrar builds on Linux (require Xcode/macOS SDK)
tools/mtouch/Makefile: Skip native registrar builds on Linux (require Xcode/iOS SDK)
create-make-config.sh: Strip leading caret (^) from git blame output before using in git log command
Removed: tools/common/bgen.csproj.inputs (accidentally committed build artifact)

Result: Successfully builds on Linux through .NET download and into src/msbuild/tools directories. Fixed multiple case-sensitivity, sed syntax, and git command issues. Skipped all macOS-only native tools, Windows-specific builds, Linux-incompatible validation tools, and native registrar compilation. Simplified CI workflow ensures this doesn't regress.

Original prompt

This section details on the original issue you should resolve

<issue_title>Make the repository build successfully on Linux</issue_title>
<issue_description>In order to make it easier for Copilot to help us in this repository, it would be good to be able to partially build this repository on Linux.

Building any native code (C/C++/Objective-C) would not be possible (because there's no Xcode on Linux), but downloading .NET itself + building managed code should be possible.

Goal: successfully run make from the root directory, and it will iterate into the builds directory (to download .NET), and then iterate into the src directory (to build managed code).</issue_description>

Comments on the Issue (you are @copilot in this section)

Fixes Make the repository build successfully on Linux #24493

💬 We'd love your input! Share your thoughts on Copilot coding agent in our 2 minute survey.

Co-authored-by: rolfbjarne <[email protected]>

rolfbjarne

@copilot the network problems have been fixed, please try again

rolfbjarne · 2026-01-12T08:21:52Z

src/bgen/ProjectInspector.csproj

@@ -0,0 +1,30 @@
+<!-- All msbuild target logic needs to be inside a project tag -->


@copilot Don't check in any version of ProjectInspector.csproj, in any directory (and remove the ones in this PR).

Removed all ProjectInspector.csproj files in commit 7fcbf2e.

rolfbjarne · 2026-01-12T08:22:26Z

Make.config

 export DEVELOPER_DIR=$(XCODE_DEVELOPER_ROOT)
 export MD_APPLE_SDK_ROOT=$(abspath $(XCODE_DEVELOPER_ROOT)/../..)
+else
+# On Linux, set dummy Xcode values


@copilot Use the word 'placeholder' instead of 'dummy'.

Changed to 'placeholder' in commit 7fcbf2e.

rolfbjarne · 2026-01-12T08:23:39Z

Make.config

+INCLUDE_IOS=
+INCLUDE_MAC=
+INCLUDE_TVOS=
+INCLUDE_MACCATALYST=
+INCLUDE_SIMULATOR=
+INCLUDE_DEVICE=


@copilot They should all be included, not excluded, otherwise nothing will be built, even on Linux.

Fixed - removed the override that was clearing the INCLUDE_* variables. They are now properly included on Linux in commit 7fcbf2e. The build now shows all platforms and progresses through builds/runtime/src directories until native compilation is attempted (which is expected to fail on Linux).

…holder' instead of 'dummy', keep INCLUDE_* variables Co-authored-by: rolfbjarne <[email protected]>

Copilot · 2026-01-12T08:32:10Z

@copilot the network problems have been fixed, please try again

Tested successfully! The build now progresses much further:

✅ .NET SDK downloaded
✅ Package downloads work (network issues resolved)
✅ Build iterates through builds → runtime → src
✅ All platforms properly included (iOS, tvOS, MacCatalyst, macOS)
Build proceeds until native compilation is attempted in runtime directory (expected failure on Linux)

The repository now builds successfully on Linux up to the point where Xcode/native tools are required.

rolfbjarne · 2026-01-13T10:20:56Z

@copilot Skip the runtime directory in the top-level Makefile when building on Linux. In fact, skip any directory that requires native compilation by skipping it in the parent directory's Makefile.

Co-authored-by: rolfbjarne <[email protected]>

Copilot · 2026-01-13T10:26:41Z

@copilot Skip the runtime directory in the top-level Makefile when building on Linux. In fact, skip any directory that requires native compilation by skipping it in the parent directory's Makefile.

Done in commit c5ff867. The runtime directory is now skipped on Linux via the top-level Makefile. The build now flows: builds → src, without attempting native compilation. Other directories (tools, msbuild) already have conditional logic based on platform variables, so they handle themselves appropriately.

rolfbjarne · 2026-01-13T14:36:35Z

@copilot Add a CI job/stage to verify that this doesn't regress.

Co-authored-by: rolfbjarne <[email protected]>

Copilot · 2026-01-13T14:40:25Z

@copilot Add a CI job/stage to verify that this doesn't regress.

Added in commit e807828. Created a GitHub Actions workflow (.github/workflows/linux-build.yml) that:

Runs on every PR and push to main/release branches when relevant files change
Verifies the Linux build works (system dependencies, .NET download, managed code build)
Ensures the runtime directory is correctly skipped
Validates that .NET SDK is successfully downloaded to builds/downloads/dotnet

The workflow will fail if any of these Linux build capabilities regress.

rolfbjarne · 2026-01-16T15:09:12Z

@copilot next error:

error MM0055: The Xcode path '--sdk' does not exist.
make[2]: *** [Makefile:56: Microsoft.macOS.registrar.x86_64.m] Error 1
make[2]: Leaving directory '/home/runner/work/macios/macios/tools/mmp'
make[1]: *** [../mk/subdirs.mk:18: all-recurse] Error 1
make[1]: Leaving directory '/home/runner/work/macios/macios/tools'
make: *** [mk/subdirs.mk:18: all-recurse] Error 1

Co-authored-by: rolfbjarne <[email protected]>

Copilot · 2026-01-16T15:12:12Z

@copilot next error:

...

Fixed in commit 1456993. The error occurred because mmp and mtouch were trying to build native registrar libraries that require Xcode/SDK on macOS. Added conditional logic to skip these native targets when IS_LINUX is defined - the managed code still builds, but the native compilation (which requires --sdkroot and --sdk) is skipped on Linux.

vs-mobiletools-engineering-service2 · 2026-01-16T16:57:43Z

💻 [CI Build #1456993] Tests on macOS arm64 - Mac Tahoe (26) passed 💻

✅ All tests on macOS arm64 - Mac Tahoe (26) passed.

Pipeline on Agent
Hash: 1456993b493caf21f335a8d01912d85ff5b02a9f [PR build]

rolfbjarne · 2026-01-16T17:01:19Z

@copilot last error:

make[2]: *** No rule to make target 'bin/Debug/dotnet-linker.dll', needed by 'all-local'.  Stop.
make[2]: Leaving directory '/home/runner/work/macios/macios/tools/dotnet-linker'
make[1]: *** [../mk/subdirs.mk:18: all-recurse] Error 1
make[1]: Leaving directory '/home/runner/work/macios/macios/tools'
make: *** [mk/subdirs.mk:18: all-recurse] Error 1

Co-authored-by: rolfbjarne <[email protected]>

Copilot · 2026-01-16T17:09:49Z

@copilot last error:

...

Fixed in commit 15c2f11. The issue was that git blame outputs commit hashes with a leading caret (^) for the root commit, but git log doesn't accept that format. Added sed command to strip the caret before using the commit hash in git log.

vs-mobiletools-engineering-service2 · 2026-01-16T17:38:57Z

✅ [CI Build #15c2f11] Build passed (Build packages) ✅

Pipeline on Agent
Hash: 15c2f1119cd2dd8edd741afc341e8f56c396ebe1 [PR build]

vs-mobiletools-engineering-service2 · 2026-01-16T17:41:24Z

✅ [PR Build #15c2f11] Build passed (Detect API changes) ✅

Pipeline on Agent
Hash: 15c2f1119cd2dd8edd741afc341e8f56c396ebe1 [PR build]

vs-mobiletools-engineering-service2 · 2026-01-16T17:45:20Z

🔥 Failed to compare API and create generator diff 🔥

** Error: Working directory isn't clean - check build log for more information.

Pipeline on Agent
Hash: 15c2f1119cd2dd8edd741afc341e8f56c396ebe1 [PR build]

vs-mobiletools-engineering-service2 · 2026-01-16T18:15:55Z

✅ [CI Build #15c2f11] Build passed (Build macOS tests) ✅

Pipeline on Agent
Hash: 15c2f1119cd2dd8edd741afc341e8f56c396ebe1 [PR build]

vs-mobiletools-engineering-service2 · 2026-01-16T18:25:33Z

💻 [CI Build #15c2f11] Tests on macOS X64 - Mac Sonoma (14) passed 💻

✅ All tests on macOS X64 - Mac Sonoma (14) passed.

Pipeline on Agent
Hash: 15c2f1119cd2dd8edd741afc341e8f56c396ebe1 [PR build]

vs-mobiletools-engineering-service2 · 2026-01-16T18:29:10Z

💻 [CI Build #15c2f11] Tests on macOS M1 - Mac Monterey (12) passed 💻

✅ All tests on macOS M1 - Mac Monterey (12) passed.

Pipeline on Agent
Hash: 15c2f1119cd2dd8edd741afc341e8f56c396ebe1 [PR build]

vs-mobiletools-engineering-service2 · 2026-01-16T18:30:16Z

💻 [CI Build #15c2f11] Tests on macOS arm64 - Mac Sequoia (15) passed 💻

✅ All tests on macOS arm64 - Mac Sequoia (15) passed.

Pipeline on Agent
Hash: 15c2f1119cd2dd8edd741afc341e8f56c396ebe1 [PR build]

vs-mobiletools-engineering-service2 · 2026-01-16T18:30:30Z

💻 [CI Build #15c2f11] Tests on macOS M1 - Mac Ventura (13) passed 💻

✅ All tests on macOS M1 - Mac Ventura (13) passed.

Pipeline on Agent
Hash: 15c2f1119cd2dd8edd741afc341e8f56c396ebe1 [PR build]

vs-mobiletools-engineering-service2 · 2026-01-16T19:45:40Z

🚀 [CI Build #15c2f11] Test results 🚀

Test results

✅ All tests passed on VSTS: test results.

🎉 All 120 tests passed 🎉

Tests counts

✅ cecil: All 1 tests passed. Html Report (VSDrops) Download
✅ dotnettests (iOS): All 1 tests passed. Html Report (VSDrops) Download
✅ dotnettests (MacCatalyst): All 1 tests passed. Html Report (VSDrops) Download
✅ dotnettests (macOS): All 1 tests passed. Html Report (VSDrops) Download
✅ dotnettests (Multiple platforms): All 1 tests passed. Html Report (VSDrops) Download
✅ dotnettests (tvOS): All 1 tests passed. Html Report (VSDrops) Download
✅ framework: All 2 tests passed. Html Report (VSDrops) Download
✅ fsharp: All 4 tests passed. Html Report (VSDrops) Download
✅ generator: All 5 tests passed. Html Report (VSDrops) Download
✅ interdependent-binding-projects: All 4 tests passed. Html Report (VSDrops) Download
✅ introspection: All 4 tests passed. Html Report (VSDrops) Download
✅ linker: All 44 tests passed. Html Report (VSDrops) Download
✅ monotouch (iOS): All 9 tests passed. Html Report (VSDrops) Download
✅ monotouch (MacCatalyst): All 11 tests passed. Html Report (VSDrops) Download
✅ monotouch (macOS): All 12 tests passed. Html Report (VSDrops) Download
✅ monotouch (tvOS): All 9 tests passed. Html Report (VSDrops) Download
✅ msbuild: All 2 tests passed. Html Report (VSDrops) Download
✅ windows: All 3 tests passed. Html Report (VSDrops) Download
✅ xcframework: All 4 tests passed. Html Report (VSDrops) Download
✅ xtro: All 1 tests passed. Html Report (VSDrops) Download

Pipeline on Agent
Hash: 15c2f1119cd2dd8edd741afc341e8f56c396ebe1 [PR build]

Initial plan

418acdd

Copilot AI assigned Copilot and rolfbjarne Jan 9, 2026

Copilot started work on behalf of rolfbjarne January 9, 2026 15:28 View session

Copilot AI and others added 2 commits January 9, 2026 15:35

Add Linux build support - fix system checks and Makefile issues

d08f626

Co-authored-by: rolfbjarne <[email protected]>

Fix sed and cache directory issues for Linux builds

7d7ff7c

Co-authored-by: rolfbjarne <[email protected]>

Copilot AI changed the title ~~[WIP] Make the repository build successfully on Linux~~ Enable partial Linux builds for Copilot support Jan 9, 2026

Copilot AI requested a review from rolfbjarne January 9, 2026 15:42

Copilot finished work on behalf of rolfbjarne January 9, 2026 15:42

rolfbjarne requested changes Jan 12, 2026

View reviewed changes

Copilot started work on behalf of rolfbjarne January 12, 2026 08:24 View session

Address PR feedback: remove ProjectInspector.csproj files, use 'place…

7fcbf2e

…holder' instead of 'dummy', keep INCLUDE_* variables Co-authored-by: rolfbjarne <[email protected]>

Copilot AI requested a review from rolfbjarne January 12, 2026 08:33

Copilot finished work on behalf of rolfbjarne January 12, 2026 08:33