Re: [Libguestfs] [libnbd PATCH] golang: Bump minimum Go version to 1.17

Go 1.17 or newer is required to use unsafe.Slice(), which in turn allows us to write a simpler conversion from a C array to a Go object during callbacks. To check if this makes sense, look at https://repology.org/project/go/versions compared to our list in ci/manifest.yml, at the time I made this commit: Alpine 3.15: 1.17.10 AlmaLinux 8: 1.19.10 CentOS Stream 8: 1.20.4 Debian 10: 1.11.6 Debian 11: 1.15.15 (mainline), 1.19.8 (backports) Debian 12: 1.19.8 Fedoar 36: 1.19.8 FreeBSD Ports: 1.20.7 OpenSUSE Leap 15.3: 1.16.3 OpenSUSE Leap 15.4: 1.18.1 Ubuntu 18.04: 1.18.1 We previously required a minimum of 1.13 for module support, which means Debian 10 was already not supporting Go bindings. OpenSUSE Leap 15.3 loses support, but is relatively old these days. All other systems appear unaffected by this bump in requirements, at least if they can be configured to use developer backports. Suggested-by: Nir Soffer <nsoffer(a)redhat.com&gt; Signed-off-by: Eric Blake <eblake(a)redhat.com&gt; --- This replaces https://listman.redhat.com/archives/libguestfs/2023-August/032227.html generator/GoLang.ml | 8 ++++---- README.md | 2 +- golang/configure/go.mod | 4 ++-- golang/configure/test.go | 11 +++++++++++ golang/go.mod | 4 ++-- 5 files changed, 20 insertions(+), 9 deletions(-) diff --git a/generator/GoLang.ml b/generator/GoLang.ml index 73df5254..55ff1b8a 100644 --- a/generator/GoLang.ml +++ b/generator/GoLang.ml @@ -517,10 +517,10 @@ let func copy_uint32_array(entries *C.uint32_t, count C.size_t) []uint32 { ret := make([]uint32, int(count)) - // See https://github.com/golang/go/wiki/cgo#turning-c-arrays-into-go-slices - // TODO: Use unsafe.Slice() when we require Go 1.17. - s := (*[1 << 30]uint32)(unsafe.Pointer(entries))[:count:count]

- copy(ret, s) + s := unsafe.Slice(entries, count) + for i, item := range s { + ret[i] = uint32(item) + } return ret } "; diff --git a/README.md b/README.md index c7166613..8524038e 100644 --- a/README.md +++ b/README.md @@ -105,7 +105,7 @@ ## Building from source * Python >= 3.3 to build the Python 3 bindings and NBD shell (nbdsh). * FUSE 3 to build the nbdfuse program. * Linux >= 6.0 and ublksrv library to build nbdublk program. -* go and cgo, for compiling the golang bindings and tests. +* go and cgo >= 1.17, for compiling the golang bindings and tests. * bash-completion >= 1.99 for tab completion. Optional, only needed to run the test suite: diff --git a/golang/configure/go.mod b/golang/configure/go.mod index ce3e4f39..fcdb28db 100644 --- a/golang/configure/go.mod +++ b/golang/configure/go.mod @@ -1,4 +1,4 @@ module libguestfs.org/configure -// First version of golang with working module support. -go 1.13 +// First version of golang with working module support and unsafe.Slice.

+go 1.17 diff --git a/golang/configure/test.go b/golang/configure/test.go index fe742f2b..a15c9ea3 100644 --- a/golang/configure/test.go +++ b/golang/configure/test.go @@ -25,8 +25,19 @@ import ( "fmt" "runtime" + "unsafe" ) +func check_slice(arr *uint32, cnt int) []uint32 { + /* We require unsafe.Slice(), introduced in 1.17 */ + ret := make([]uint32, cnt) + s := unsafe.Slice(arr, cnt) + for i, item := range s { + ret[i] = uint32(item) + } + return ret +}

+ func main() { fmt.Println(runtime.Version()) diff --git a/golang/go.mod b/golang/go.mod index fc772840..1b72e77d 100644 --- a/golang/go.mod +++ b/golang/go.mod @@ -1,4 +1,4 @@ module libguestfs.org/libnbd -// First version of golang with working module support. -go 1.13 +// First version of golang with working module support and unsafe.Slice. +go 1.17 -- 2.41.0