unit test `TestLLVM_AMDGPUAddrSpace/llvm-22.1.8-support/AMDGPUAddrSpace` failed occasionally

[xushiwei]

error log:

=== RUN   TestLLVM_AMDGPUAddrSpace/llvm-22.1.8-support/AMDGPUAddrSpace
2026/09/28 21:21:42 ============== testSingleFile: package AMDGPUAddrSpace ==============
xgo: downloading github.com/llarhub/libcxx v0.1.1
2026/09/28 21:21:43 ==> modfetch.Get: github.com/llarhub/libcxx v0.1.1
2026/09/28 21:21:43 ==> includeDirs: [/home/runner/work/llcppg/llcppg/tool/_testcpp/llvm-22.1.8-support/include /home/runner/go/pkg/mod/github.com/llarhub/libcxx@v0.1.1/include /usr/lib/llvm-22/lib/clang/22/include /usr/local/include /usr/include/x86_64-linux-gnu /usr/include]
2026/09/28 21:21:43 macro LLVM_SUPPORT_AMDGPUADDRSPACE_H - 1 tokens
2026/09/28 21:21:43 include /../lib/gcc/x86_64-linux-gnu/14/../../../../include/c++/14/cstdint
2026/09/28 21:21:43 [WARN] loadInclude: package not found for /../lib/gcc/x86_64-linux-gnu/14/../../../../include/c++/14/cstdint
2026/09/28 21:21:43 enum LlvmAMDGPUAS_(unnamed enum at /home/runner/work/llcppg/llcppg/tool/_testcpp/llvm-22.1.8-support/include/llvm/Support/AMDGPUAddrSpace.h:28:1) unsigned int anonymous: true scoped: false
2026/09/28 21:21:43 enum LlvmAMDGPU_DWARFAS_(unnamed enum at /home/runner/work/llcppg/llcppg/tool/_testcpp/llvm-22.1.8-support/include/llvm/Support/AMDGPUAddrSpace.h:127:1) unsigned int anonymous: true scoped: false
2026/09/28 21:21:43 namespace LlvmAMDGPU_Impl - ignored
2026/09/28 21:21:43 func LlvmAMDGPU_IsFlatGlobalAddrSpace - bool (unsigned int) - isOp: false deleted: 0
2026/09/28 21:21:43   => param AS - unsigned int
2026/09/28 21:21:43 inline func LlvmAMDGPU_IsFlatGlobalAddrSpace - skipped
2026/09/28 21:21:43 func LlvmAMDGPU_IsExtendedGlobalAddrSpace - bool (unsigned int) - isOp: false deleted: 0
2026/09/28 21:21:43   => param AS - unsigned int
2026/09/28 21:21:43 inline func LlvmAMDGPU_IsExtendedGlobalAddrSpace - skipped
2026/09/28 21:21:43 func LlvmAMDGPU_IsConstantAddressSpace - bool (unsigned int) - isOp: false deleted: 0
2026/09/28 21:21:43   => param AS - unsigned int
2026/09/28 21:21:43 inline func LlvmAMDGPU_IsConstantAddressSpace - skipped
2026/09/28 21:21:43 func LlvmAMDGPU_MapToDWARFAddrSpace - int (unsigned int) - isOp: false deleted: 0
2026/09/28 21:21:43   => param LLVMAddrSpace - unsigned int
2026/09/28 21:21:43 inline func LlvmAMDGPU_MapToDWARFAddrSpace - skipped
2026/09/28 21:21:43 func LlvmAMDGPU_GetNullPointerValue - int64_t (unsigned int) - isOp: false deleted: 0
2026/09/28 21:21:43   => param AS - unsigned int
--- FAIL: TestLLVM_AMDGPUAddrSpace (1.04s)
    --- FAIL: TestLLVM_AMDGPUAddrSpace/llvm-22.1.8-support (1.04s)
        --- FAIL: TestLLVM_AMDGPUAddrSpace/llvm-22.1.8-support/AMDGPUAddrSpace (1.04s)
panic: todo: toType int64_t

goroutine 189 [running]:
github.com/goplus/llcppg/cl.toTypeEx(...)
	type.go:161 +0x9a2
github.com/goplus/llcppg/cl.toFuncResults(...)
	type.go:197 +0x80
github.com/goplus/llcppg/cl.compileFuncOrMethod(...)
	func.go:85 +0x449
github.com/goplus/llcppg/cl.(*pkgCtx).compile(...)
	ctx.go:192 +0x90
github.com/goplus/llcppg/cl.NewPackage(...)
	compile.go:178 +0x76f
github.com/goplus/llcppg/tool_test.testSingleFile(...)
	/home/runner/work/llcppg/llcppg/tool/gen_test.go:121 +0xdc6
github.com/goplus/llcppg/tool_test.testFromDir$1.func1(...)
	/home/runner/work/llcppg/llcppg/tool/gen_test.go:214 +0x3e
testing.tRunner(...)
	/opt/hostedtoolcache/go/1.27.1/x64/src/testing/testing.go:2193 +0x179
testing.(*testState).waitParallel(...)
	/opt/hostedtoolcache/go/1.27.1/x64/src/testing/testing.go:2377 +0x12c
created by testing.(*T).Run in goroutine 188
	/opt/hostedtoolcache/go/1.27.1/x64/src/testing/testing.go:2258 +0x498
FAIL	github.com/goplus/llcppg/tool	2.631s
	github.com/goplus/llcppg/tool/pputil		coverage: 0.0% of statements
	github.com/goplus/llcppg/chore/listth		coverage: 0.0% of statements
	github.com/goplus/llcppg/clang		coverage: 0.0% of statements
	github.com/goplus/llcppg/xtool/env/clang		coverage: 0.0% of statements
	github.com/goplus/llcppg/xtool/env/cstdlib		coverage: 0.0% of statements
	github.com/goplus/llcppg/chore/llcppdump		coverage: 0.0% of statements
	github.com/goplus/llcppg/chore/llgogen		coverage: 0.0% of statements
	github.com/goplus/llcppg/chore/llimport		coverage: 0.0% of statements
	github.com/goplus/llcppg/chore/ppresolve		coverage: 0.0% of statements
	github.com/goplus/llcppg/cl/cltest		coverage: 0.0% of statements
	github.com/goplus/llcppg/cmd/llcppg		coverage: 0.0% of statements
	github.com/goplus/llcppg/xtool/clang/preprocessor		coverage: 0.0% of statements
FAIL

The exception is that the log of modfetch.Get is github.com/llarhub/libcxx v0.1.1, and the correct one is github.com/llarhub/libcxx/c v0.1.1

[xushiwei]

@fennoai Please identify the root cause and fix it. You will likely need to submit a PR to https://github.com/goplus/mod.

[fennoai]

Root cause & fix

Root cause — a non-deterministic bug in github.com/goplus/mod modfetch.Get.

llcppg resolves a dependency's include dir via modfetch.Get(modVer.Path + "/c@" + modVer.Version), i.e. modfetch.Get("github.com/llarhub/libcxx/c@v0.1.1") (tool/gen.go:227). Both github.com/llarhub/libcxx and github.com/llarhub/libcxx/c are separate modules in the same multi-module repo.

When go get github.com/llarhub/libcxx/c@v0.1.1 runs, go downloads the parent module too and prints two lines whose order is non-deterministic:

go: downloading github.com/llarhub/libcxx v0.1.1      # parent
go: downloading github.com/llarhub/libcxx/c v0.1.1    # the requested module

goplus/mod's getResult took the first go: downloading line unconditionally. When the parent line comes first, it returns github.com/llarhub/libcxx — the /c suffix is dropped (exactly the anomalous log you noted). modcache.Path then points at the wrong module root, so clang gets the wrong include dir, int64_t fails to resolve, and cl.toTypeEx hits panic: todo: toType int64_t.

Why it's occasional: whichever go: downloading line prints first wins. I confirmed the ordering flips across repeated clean-cache runs (parent-first on some, child-first on others). If the parent is already cached, only the correct /c line appears and the test passes.

Fix (in goplus/mod): scan all go: downloading lines and select the one whose module path exactly matches the requested module; fall back to the first line otherwise (preserves single-module behavior).

PR

Submitted to goplus/mod: goplus/mod#167

• modfetch/fetch.go — getResult now matches the requested path; Get passes the version-stripped path down.
• modfetch/fetch_test.go — new tests covering both orderings, the fallback, and not-found.

Verified

• go build ./... and go test ./modfetch/ pass in goplus/mod.
• End-to-end: modfetch.Get("github.com/llarhub/libcxx/c@v0.1.1") now returns github.com/llarhub/libcxx/c in both a fresh cache and a parent-already-cached cache.
• Unit tests pass for both the parent-first and child-first orderings.

Not done

• The full TestLLVM_AMDGPUAddrSpace was not run here — this sandbox lacks the LLVM 22 / clang toolchain the CI provides. It was verified at the modfetch.Get layer, which is the exact source of the failure.
• No change is needed in llcppg itself. After PR docs: add the doc of the llpkgstore design #167 merges and goplus/mod is tagged, bump github.com/goplus/mod in llcppg/go.mod to pick up the fix.