V4 musl parity: Linux_x86_musl and Linux_arm64_musl (4.0.0)

.github/workflows/syntax.yml

@@ -6,10 +6,10 @@ jobs:
   syntax-check:
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@master
+    - uses: actions/checkout@v6
     - name: Check Markdown links
-      uses: gaurav-nelson/github-action-markdown-link-check@v1
+      uses: gaurav-nelson/github-action-markdown-link-check@3c3b66f1f7d0900e37b71eca45b63ea9eedfce31 # v1.0.17
       with:
         use-verbose-mode: 'yes'
     - name: Run ShellCheck
-      uses: ludeeus/action-shellcheck@master
+      uses: ludeeus/action-shellcheck@00cae500b08a931fb5698e11e79bfbd38e612a38 # v2.0.0

CHANGES.md

@@ -1,4 +1,36 @@
-## 3.3.0
+## 4.0.0
+
+* `V4` gains full musl parity on Linux: new ABIs `Linux_x86_musl` and
+  `Linux_arm64_musl` join `Linux_x86_64_musl`. The `<features.h>` /
+  `__GLIBC__` test now covers the `__i386__` and `__aarch64__` branches of
+  the C header (new macros `DKML_ABI_linux_x86_musl` and
+  `DKML_ABI_linux_arm64_musl`).
+* `V1`-`V3` report the new musl ABIs under their glibc names (`Linux_x86`,
+  `Linux_arm64`), matching the existing `Linux_x86_64_musl` -> `Linux_x86_64`
+  behavior. In `V1`, an x86 musl host gets the pre-existing `Result.error`
+  because `V1` never had `Linux_x86`.
+* BREAKING (relative to the unpublished 3.3.0 git tag): the `V4.t_abi`
+  constructor list stays alphabetical, so the insertions change the ranks of
+  later constructors. Rebuild anything that marshalled `V4.t_abi` values.
+  3.3.0 was tagged but never published to opam; use 4.0.0 instead.
+* `C_conf.load ()` now uses `V4` (was `V3`): on musl hosts the ABI-specific
+  environment variable suffix is now e.g. `DEFAULT_LINUX_X86_64_MUSL` instead
+  of `DEFAULT_LINUX_X86_64`. glibc, Windows, and macOS hosts are unchanged.
+* Versioning policy restored: interface module `V<n>` ships in major version
+  `n` (`V4` <-> 4.0.0, as `V3` <-> 3.0.0 and `V2` <-> 2.0.0).
+* Known gap: the Linux arm32 ABIs (`linux_arm32v6`, `linux_arm32v7`) have no
+  musl variants yet.
+* CI: GitHub Actions re-enabled and every workflow brought onto the
+  repository's curated Actions allowlist (third-party actions SHA-pinned).
+  The `Tests` workflow now also covers musl: a C-header probe on Alpine
+  (musl) and Debian (glibc) across x86_64, x86 and arm64, and the full
+  dune-configurator path on a real musl host, alongside the BSD guests
+  (upgraded `cross-platform-actions`) and the Windows/macOS/Linux matrix on
+  `ocaml/setup-ocaml` (replacing the former DkML MSVC/MSYS2 + manylinux
+  reusable-workflow matrix, whose actions are not allowlisted). `syntax.yml`
+  upgraded to pinned `markdown-link-check` and `action-shellcheck`.
+
+## 3.3.0 (git tag only; never published to opam — superseded by 4.0.0)
 
 * Add `V4` with the new ABI `Linux_x86_64_musl`: a Linux x86_64 host whose C
   compiler targets a non-glibc libc (musl). Detection pulls in `<features.h>`

CONTRIBUTORS.md

@@ -25,7 +25,13 @@ If you would like to add a new ABI, you will need to:
 * Add the ABI introspection test to the C header at [src/config/dkml_compiler_probe.h](src/config/dkml_compiler_probe.h).
 * Create a new versioned module (ex. `module V123`) of the ABI enumeration in
   [src/config/discover.ml](src/config/discover.ml). See how `module V2` extends `module V1` in a backwards-compatible way.
-* Update the `(version xxx)` in [dune-project](dune-project)
+* Extend `adjust_pre_v<n>_abi` in [src/config/discover.ml](src/config/discover.ml)
+  so the older modules degrade the new ABI: to the closest pre-existing ABI if
+  older consumers always saw that value on such hosts (like the musl ABIs), or
+  to `Result.error` if the ABI is genuinely new to them (like the BSDs).
+* Update the `(version xxx)` in [dune-project](dune-project). A new
+  `module V<n>` must ship as major version `n.0.0`: the interface module
+  version matches the opam major version.
 
 Before submitting your PR make sure you have:
 1. Run `dune build`

README.md

@@ -195,9 +195,11 @@ module V4 :
       | Linux_arm32v6
       | Linux_arm32v7
       | Linux_arm64
+      | Linux_arm64_musl
       | Linux_x86
       | Linux_x86_64
       | Linux_x86_64_musl
+      | Linux_x86_musl
       | NetBSD_x86_64
       | OpenBSD_x86_64
       | Windows_arm32
@@ -350,9 +352,24 @@ The header file will be available as the following expressions:
 #   else
 #       define DKML_OS_NAME "Linux"
 #       define DKML_OS_Linux
+        /* musl does not define an identifying macro. Pull in <features.h>
+           (glibc and uclibc define __GLIBC__ there; musl defines nothing)
+           and treat a hosted Linux without __GLIBC__ as musl. */
+#       if defined(__has_include)
+#           if __has_include(<features.h>)
+#               include <features.h>
+#           endif
+#       else
+#           include <features.h>
+#       endif
 #       if __aarch64__
-#           define DKML_ABI "linux_arm64"
-#           define DKML_ABI_linux_arm64
+#           if defined(__GLIBC__)
+#               define DKML_ABI "linux_arm64"
+#               define DKML_ABI_linux_arm64
+#           else
+#               define DKML_ABI "linux_arm64_musl"
+#               define DKML_ABI_linux_arm64_musl
+#           endif /* __GLIBC__ */
 #       elif __arm__
 #           if defined(__ARM_ARCH_6__) || defined(__ARM_ARCH_6J__) || defined(__ARM_ARCH_6K__) || defined(__ARM_ARCH_6Z__) || defined(__ARM_ARCH_6ZK__) || defined(__ARM_ARCH_6T2__)
 #               define DKML_ABI "linux_arm32v6"
@@ -362,16 +379,6 @@ The header file will be available as the following expressions:
 #               define DKML_ABI_linux_arm32v7
 #           endif /* __ARM_ARCH_6__ || ...,  __ARM_ARCH_7__ || ... */
 #       elif __x86_64__
-            /* musl does not define an identifying macro. Pull in <features.h>
-               (glibc and uclibc define __GLIBC__ there; musl defines nothing)
-               and treat a hosted Linux x86_64 without __GLIBC__ as musl. */
-#           if defined(__has_include)
-#               if __has_include(<features.h>)
-#                   include <features.h>
-#               endif
-#           else
-#               include <features.h>
-#           endif
 #           if defined(__GLIBC__)
 #               define DKML_ABI "linux_x86_64"
 #               define DKML_ABI_linux_x86_64
@@ -380,8 +387,13 @@ The header file will be available as the following expressions:
 #               define DKML_ABI_linux_x86_64_musl
 #           endif /* __GLIBC__ */
 #       elif __i386__
-#           define DKML_ABI "linux_x86"
-#           define DKML_ABI_linux_x86
+#           if defined(__GLIBC__)
+#               define DKML_ABI "linux_x86"
+#               define DKML_ABI_linux_x86
+#           else
+#               define DKML_ABI "linux_x86_musl"
+#               define DKML_ABI_linux_x86_musl
+#           endif /* __GLIBC__ */
 #       elif defined(__ppc64__) || defined(__PPC64__)
 #           define DKML_ABI "linux_ppc64"
 #           define DKML_ABI_linux_ppc64

dkml-c-probe.opam

@@ -1,6 +1,6 @@
 # This file is generated by dune, edit dune-project instead
 opam-version: "2.0"
-version: "3.3.0"
+version: "4.0.0"
 synopsis:
   "Cross-compiler friendly ABI and library discovery for OCaml's native C compilers"
 description: """
@@ -32,8 +32,8 @@ build: [
   ["dune" "build" "-p" name "-j" jobs "@doc"] {with-doc}
 ]
 # dkml-c-probe has strong backwards-compatibility.
-# Any 3.x minor version is maintained for the latest patch version.
+# Any 3.x or 4.x minor version is maintained for the latest patch version.
 # Please upgrade if there is a patch version for a minor release;
 # the patch generally means there was an important bug fix.
-# Also the latest version is maintained, in case it gets to 4.x.x.
-x-maintenance-intent: ["latest" "3.(any).(latest)"]
+# Also the latest version is maintained.
+x-maintenance-intent: ["latest" "4.(any).(latest)" "3.(any).(latest)"]

dkml-c-probe.opam.template

@@ -8,8 +8,8 @@ build: [
   ["dune" "build" "-p" name "-j" jobs "@doc"] {with-doc}
 ]
 # dkml-c-probe has strong backwards-compatibility.
-# Any 3.x minor version is maintained for the latest patch version.
+# Any 3.x or 4.x minor version is maintained for the latest patch version.
 # Please upgrade if there is a patch version for a minor release;
 # the patch generally means there was an important bug fix.
-# Also the latest version is maintained, in case it gets to 4.x.x.
-x-maintenance-intent: ["latest" "3.(any).(latest)"]
+# Also the latest version is maintained.
+x-maintenance-intent: ["latest" "4.(any).(latest)" "3.(any).(latest)"]

dune-project

@@ -2,7 +2,7 @@
 
 (name dkml-c-probe)
 
-(version 3.3.0)
+(version 4.0.0)
 
 (using mdx 0.1)
 

src/c_conf.ml

@@ -89,7 +89,7 @@ let load_from_dune_context_name ?(getenv = default_env_getter) ctxname =
   else create_error ()
 
 let load ?(getenv = default_env_getter) () =
-  let abi_name_res = C_abi.V3.get_abi_name () in
+  let abi_name_res = C_abi.V4.get_abi_name () in
   match abi_name_res with
   | Ok abi_name -> load_from_findlib_toolchain ~getenv (Some abi_name)
   | Error msg -> Error msg

src/config/discover.ml

@@ -17,21 +17,6 @@
 open Configurator.V1
 open Flags
 
-type t_abi =
-  | Android_arm64v8a
-  | Android_arm32v7a
-  | Android_x86
-  | Android_x86_64
-  | Darwin_arm64
-  | Darwin_x86_64
-  | Linux_arm64
-  | Linux_arm32v6
-  | Linux_arm32v7
-  | Linux_x86_64
-  | Linux_x86
-  | Windows_x86_64
-  | Windows_x86
-
 type osinfo = {
   ostypename : (string, string) result;
   osname: (string, string) result;
@@ -95,6 +80,8 @@ let get_osinfo t =
         (Result.ok "Unknown_unknown")
     | [ (_, String ("linux_arm64")) ] ->
         (Result.ok "Linux_arm64")
+    | [ (_, String ("linux_arm64_musl")) ] ->
+        (Result.ok "Linux_arm64_musl")
     | [ (_, String ("linux_arm32v6")) ] ->
         (Result.ok "Linux_arm32v6")
     | [ (_, String ("linux_arm32v7")) ] ->
@@ -104,6 +91,8 @@ let get_osinfo t =
     | [ (_, String ("linux_x86_64_musl")) ] ->
         (Result.ok "Linux_x86_64_musl")
     | [ (_, String ("linux_x86")) ] -> (Result.ok "Linux_x86")
+    | [ (_, String ("linux_x86_musl")) ] ->
+        (Result.ok "Linux_x86_musl")
     | [ (_, String "linux_ppc64") ] ->
         (Result.ok "Unknown_unknown")
     | [ (_, String "linux_s390x") ] ->
@@ -144,15 +133,21 @@ let result_to_quoted_string = function
   | Result.Error e -> "Result.error (\"" ^ String.escaped e ^ "\")"
 
 (* Unlike the pre-V2/pre-V3 adjusters which downgrade newer ABIs to
-   Result.error, the musl ABI degrades to plain Linux_x86_64 in V1-V3. A musl
-   host is a Linux x86_64 host, and V1-V3 consumers compiled before musl
-   detection existed always saw Linux_x86_64 on musl (the probe could not tell
-   the difference), so reporting Linux_x86_64 preserves their behavior instead
-   of turning working consumers into runtime errors. *)
+   Result.error, the musl ABIs degrade to their glibc counterparts in V1-V3.
+   A musl host is still the same Linux machine architecture, and V1-V3
+   consumers compiled before musl detection existed always saw the glibc name
+   there (the probe could not tell the difference), so keeping the glibc name
+   preserves their behavior instead of turning working consumers into runtime
+   errors. In V1 the degraded Linux_x86 then hits adjust_pre_v2_abi's
+   Result.error, since V1 never had Linux_x86. *)
 let adjust_pre_v4_abi ~abitypename ~abiname =
   match (abitypename, abiname) with
+  | Result.Ok "Linux_arm64_musl", _ | _, Result.Ok "linux_arm64_musl" ->
+      (Result.ok "Linux_arm64", Result.ok "linux_arm64")
   | Result.Ok "Linux_x86_64_musl", _ | _, Result.Ok "linux_x86_64_musl" ->
       (Result.ok "Linux_x86_64", Result.ok "linux_x86_64")
+  | Result.Ok "Linux_x86_musl", _ | _, Result.Ok "linux_x86_musl" ->
+      (Result.ok "Linux_x86", Result.ok "linux_x86")
   | Result.Ok tn, Result.Ok n -> (Result.ok tn, Result.ok n)
   | Result.Error e, _ | _, Result.Error e -> (Result.error e, Result.error e)
 
@@ -365,8 +360,9 @@ let () =
 
       (* V4.
 
-         Adds Linux_x86_64_musl: a Linux x86_64 host whose C compiler targets
-         a non-glibc libc (musl). V1-V3 report such a host as Linux_x86_64
+         Adds the musl ABIs Linux_arm64_musl, Linux_x86_64_musl and
+         Linux_x86_musl: Linux hosts whose C compiler targets a non-glibc
+         libc (musl). V1-V3 report such hosts under the glibc ABI names
          (see adjust_pre_v4_abi). *)
       let lines =
         lines
@@ -398,9 +394,11 @@ let () =
               | Linux_arm32v6
               | Linux_arm32v7
               | Linux_arm64
+              | Linux_arm64_musl
               | Linux_x86
               | Linux_x86_64
               | Linux_x86_64_musl
+              | Linux_x86_musl
               | NetBSD_x86_64
               | OpenBSD_x86_64
               | Windows_arm32

src/config/dkml_compiler_probe.h

@@ -94,9 +94,24 @@
 #   else
 #       define DKML_OS_NAME "Linux"
 #       define DKML_OS_Linux
+        /* musl does not define an identifying macro. Pull in <features.h>
+           (glibc and uclibc define __GLIBC__ there; musl defines nothing)
+           and treat a hosted Linux without __GLIBC__ as musl. */
+#       if defined(__has_include)
+#           if __has_include(<features.h>)
+#               include <features.h>
+#           endif
+#       else
+#           include <features.h>
+#       endif
 #       if __aarch64__
-#           define DKML_ABI "linux_arm64"
-#           define DKML_ABI_linux_arm64
+#           if defined(__GLIBC__)
+#               define DKML_ABI "linux_arm64"
+#               define DKML_ABI_linux_arm64
+#           else
+#               define DKML_ABI "linux_arm64_musl"
+#               define DKML_ABI_linux_arm64_musl
+#           endif /* __GLIBC__ */
 #       elif __arm__
 #           if defined(__ARM_ARCH_6__) || defined(__ARM_ARCH_6J__) || defined(__ARM_ARCH_6K__) || defined(__ARM_ARCH_6Z__) || defined(__ARM_ARCH_6ZK__) || defined(__ARM_ARCH_6T2__)
 #               define DKML_ABI "linux_arm32v6"
@@ -106,16 +121,6 @@
 #               define DKML_ABI_linux_arm32v7
 #           endif /* __ARM_ARCH_6__ || ...,  __ARM_ARCH_7__ || ... */
 #       elif __x86_64__
-            /* musl does not define an identifying macro. Pull in <features.h>
-               (glibc and uclibc define __GLIBC__ there; musl defines nothing)
-               and treat a hosted Linux x86_64 without __GLIBC__ as musl. */
-#           if defined(__has_include)
-#               if __has_include(<features.h>)
-#                   include <features.h>
-#               endif
-#           else
-#               include <features.h>
-#           endif
 #           if defined(__GLIBC__)
 #               define DKML_ABI "linux_x86_64"
 #               define DKML_ABI_linux_x86_64
@@ -124,8 +129,13 @@
 #               define DKML_ABI_linux_x86_64_musl
 #           endif /* __GLIBC__ */
 #       elif __i386__
-#           define DKML_ABI "linux_x86"
-#           define DKML_ABI_linux_x86
+#           if defined(__GLIBC__)
+#               define DKML_ABI "linux_x86"
+#               define DKML_ABI_linux_x86
+#           else
+#               define DKML_ABI "linux_x86_musl"
+#               define DKML_ABI_linux_x86_musl
+#           endif /* __GLIBC__ */
 #       elif defined(__ppc64__) || defined(__PPC64__)
 #           define DKML_ABI "linux_ppc64"
 #           define DKML_ABI_linux_ppc64