build-sys: Hard require Rust

As something that manages your base operating system, we care
about reliability, predictability, as well as performance and
low-level access to native operating system facilities.  The
C programming language is great for the latter two, but fails
at providing a truly memory-safe environment.  Rust is fairly
unique in providing a language that doesn't carry a runtime,
so we can gradually "oxidize" and convert our C code without
imposing additional overhead.  It's also got a lot of modern
design niceties, like not having a null pointer.

Let's pull the trigger here and hard require Rust.  It's the
programming language I personally want to be primarily writing in for
years to come.

This is also in line with a recent trend of reducing our
experimental/optional matrix.

Closes: #1509
Approved by: jlebon

.papr.yml

@@ -130,8 +130,6 @@ env:
 # since https://github.com/projectatomic/rpm-ostree/pull/875
 tests:
   - docker run --privileged --rm
-    -e CONFIGOPTS=--enable-rust
-    -e CI_PKGS=cargo
     -e RPMOSTREE_COMPOSE_TEST_FILTER
     -e RPMOSTREE_COMPOSE_TEST_USE_REPOS=/etc/yum.repos.d.host
     -v /etc/yum.repos.d:/etc/yum.repos.d.host:ro

Makefile-rpm-ostree.am

@@ -72,9 +72,8 @@ rpm_ostree_CFLAGS = $(AM_CFLAGS) -I$(srcdir)/src/app -I$(srcdir)/src/daemon \
 	-fvisibility=hidden -DPKGLIBDIR=\"$(pkglibdir)\" $(PKGDEP_RPMOSTREE_CFLAGS)
 rpm_ostree_LDADD = $(PKGDEP_RPMOSTREE_LIBS) librpmostreepriv.la librpmostree-1.la librpmostreed.la
 # https://github.com/ostreedev/ostree/commit/1f832597fc83fda6cb8daf48c4495a9e1590774c
-if ENABLE_RUST
+# https://github.com/rust-lang/rust/issues/47714
 rpm_ostree_LDADD += -ldl
-endif
 
 privdatadir=$(pkglibdir)
 privdata_DATA = src/app/rpm-ostree-0-integration.conf
@@ -86,7 +85,6 @@ if BUILDOPT_NEW_NAME
 INSTALL_DATA_HOOKS += install-bin-hook
 endif
 
-if ENABLE_RUST
 librpmostree_rust_path = @abs_top_builddir@/target/@RUST_TARGET_SUBDIR@/librpmostree_rust.a
 # If the target directory exists, use --frozen; we don't
 # want to (by default) touch the Internet during builds here.
@@ -105,6 +103,5 @@ rpm_ostree_SOURCES += rust/include/librpmostree-rust.h
 rpm_ostree_LDADD += $(librpmostree_rust_path)
 rustfmt:
 	rustfmt $(LIBRPMOSTREE_RUST_SRCS)
-endif # ENABLE_RUST
 # Outside the ifdef, otherwise automake complains
 .PHONY: rustfmt

Makefile.am

@@ -71,7 +71,6 @@ TYPELIBS = $(GIRS:.gir=.typelib)
 # but have been adapted to non-recursive Automake, and additionally
 # the "cargo vendor" bits for us live in packaging/Makefile.dist-packaging.
 .PHONY: check-local-cargo clean-local-cargo use-git-not-dist-hook
-if ENABLE_RUST
 if RUST_DEBUG
 CARGO_RELEASE_ARGS=
 else
@@ -95,8 +94,6 @@ use-git-not-dist-hook:
 DIST_HOOKS += use-git-not-dist-hook
 GITIGNOREFILES += target/
 
-endif # end ENABLE_RUST
-
 include libglnx/Makefile-libglnx.am.inc
 noinst_LTLIBRARIES += libglnx.la
 include Makefile-libpriv.am

ci/build.sh

@@ -24,6 +24,7 @@ fi
 pkg_upgrade
 pkg_install_builddeps rpm-ostree
 # Temporary until spec file changes are upstreamed
+pkg_install cargo
 pkg_install_if_os fedora python3-sphinx python3-devel
 # Mostly dependencies for tests
 pkg_install ostree{,-devel,-grub2} createrepo_c /usr/bin/jq PyYAML \

configure.ac

@@ -194,49 +194,40 @@ AS_IF([test x$enable_staged = xyes], [
   AC_DEFINE(BUILDOPT_STAGE_DEPLOYMENTS, 1, [Define if we are staging deployments])
 ])
 
-AC_ARG_ENABLE(rust,
+AC_PATH_PROG([cargo], [cargo])
-              AS_HELP_STRING([--enable-rust],
+AS_IF([test -z "$cargo"], [AC_MSG_ERROR([cargo is required for --enable-rust])])
-                             [Compile Rust features (e.g. compose tree --yaml)]),,
+AC_PATH_PROG([rustc], [rustc])
-              [enable_rust=no; rust_debug_release=no])
+AS_IF([test -z "$rustc"], [AC_MSG_ERROR([rustc is required for --enable-rust])])
 
-AS_IF([test x$enable_rust = xyes], [
+dnl These bits based on gnome:librsvg/configure.ac
-    AC_PATH_PROG([cargo], [cargo])
+dnl By default, we build in public release mode.
-    AS_IF([test -z "$cargo"], [AC_MSG_ERROR([cargo is required for --enable-rust])])
+AC_ARG_ENABLE(rust-debug,
-    AC_PATH_PROG([rustc], [rustc])
+  AC_HELP_STRING([--enable-rust-debug],
-    AS_IF([test -z "$rustc"], [AC_MSG_ERROR([rustc is required for --enable-rust])])
+    [Build Rust code with debugging information [default=no]]),
-    AC_DEFINE(HAVE_RUST, 1, [Define if we are building with Rust])
+    [rust_debug_release=$enableval],
+    [rust_debug_release=release])
 
-   dnl These bits based on gnome:librsvg/configure.ac
+AC_MSG_CHECKING(whether to build in debug mode)
-
+debug_release=no
-   dnl By default, we build in public release mode.
-   AC_ARG_ENABLE(rust-debug,
-      AC_HELP_STRING([--enable-rust-debug],
-       [Build Rust code with debugging information [default=no]]),
-       [rust_debug_release=$enableval],
-       [rust_debug_release=release])
-
-   AC_MSG_CHECKING(whether to build Rust code with debugging information)
-   if test "x$rust_debug_release" = "xyes" ; then
-      rust_debug_release=debug
-      AC_MSG_RESULT(yes)
-   else
-      AC_MSG_RESULT(no)
-   fi
-   RUST_TARGET_SUBDIR=${rust_debug_release}
-   AC_SUBST([RUST_TARGET_SUBDIR])
-])
-AM_CONDITIONAL(RUST_DEBUG, [test "x$rust_debug_release" = "xdebug"])
-AM_CONDITIONAL(ENABLE_RUST, [test x$enable_rust = xyes])
-if test x$enable_rust != xno; then RPM_OSTREE_FEATURES="$RPM_OSTREE_FEATURES rust"; fi
-
-dnl Try to automatically determine cmake type from CFLAGS
 if $(echo $CFLAGS |grep -q -E "(-O0|-Og)"); then
-  cmake_args="-DCMAKE_BUILD_TYPE=Debug"
+  debug_release=yes
-  export cmake_args
-else
-  cmake_args=-DCMAKE_BUILD_TYPE=RelWithDebugInfo
-  export cmake_args
 fi
+AC_MSG_RESULT($debug_release)
+RUST_TARGET_SUBDIR=release
+if test ${debug_release} = yes; then
+  RUST_TARGET_SUBDIR=debug
+fi
+AC_SUBST([RUST_TARGET_SUBDIR])
+AM_CONDITIONAL(RUST_DEBUG, [test "x$rust_debug_release" = "xdebug"])
+dnl Unconditional now.
+RPM_OSTREE_FEATURES="$RPM_OSTREE_FEATURES rust"
+
+dnl And propagate the release/debug type to cmake
+cmake_args=-DCMAKE_BUILD_TYPE=RelWithDebugInfo
+if test ${debug_release} = yes; then
+  cmake_args="-DCMAKE_BUILD_TYPE=Debug"
+fi
+export cmake_args
 
 dnl I picked /usr/libexec/rpm-ostree just because we need an
 dnl arbitrary path - we don't actually install there.
@@ -272,5 +263,5 @@ echo "
     introspection:                           $found_introspection
     bubblewrap:                              $with_bubblewrap
     gtk-doc:                                 $enable_gtk_doc
-    rust:                                    $enable_rust
+    rust:                                    (always enabled now)
 "

src/app/rpmostree-compose-builtin-tree.c

@@ -45,9 +45,7 @@
 #include "rpmostree-passwd-util.h"
 #include "rpmostree-libbuiltin.h"
 #include "rpmostree-rpm-util.h"
-#ifdef HAVE_RUST
 #include "rpmostree-rust.h"
-#endif
 
 #include "libglnx.h"
 
@@ -127,9 +125,7 @@ typedef struct {
   gboolean rojig_spec_in_workdir;
   char *previous_checksum;
 
-#ifdef HAVE_RUST
   RpmOstreeRsTreefile *treefile_rs;
-#endif
   JsonParser *treefile_parser;
   JsonNode *treefile_rootval; /* Unowned */
   JsonObject *treefile; /* Unowned */
@@ -160,9 +156,7 @@ rpm_ostree_tree_compose_context_free (RpmOstreeTreeComposeContext *ctx)
   g_free (ctx->ref);
   g_free (ctx->rojig_spec);
   g_free (ctx->previous_checksum);
-#ifdef HAVE_RUST
   g_clear_pointer (&ctx->treefile_rs, (GDestroyNotify) rpmostree_rs_treefile_free);
-#endif
   g_clear_object (&ctx->treefile_parser);
   g_clear_pointer (&ctx->serialized_treefile, (GDestroyNotify)g_bytes_unref);
   g_free (ctx);
@@ -694,10 +688,6 @@ parse_treefile_to_json (RpmOstreeTreeComposeContext  *self,
   if (g_str_has_suffix (treefile_path, ".yaml") ||
       g_str_has_suffix (treefile_path, ".yml"))
     {
-#ifndef HAVE_RUST
-      return glnx_throw (error, "This version of rpm-ostree was built without "
-                                "rust, and doesn't support YAML treefiles");
-#else
       const char *arch = self ? dnf_context_get_base_arch (rpmostree_context_get_dnf (self->corectx)) : NULL;
       self->treefile_rs = rpmostree_rs_treefile_new (treefile_path, arch,
                                                      self->workdir_tmp.fd,
@@ -712,7 +702,6 @@ parse_treefile_to_json (RpmOstreeTreeComposeContext  *self,
 
       if (!json_parser_load_from_stream (parser, json_s, NULL, error))
         return FALSE;
-#endif
     }
   else
     {
@@ -1003,13 +992,11 @@ rpm_ostree_compose_context_new (const char    *treefile_pathstr,
     return FALSE;
   if (rojig_spec)
     self->rojig_spec = g_build_filename (gs_file_get_path_cached (treefile_dir), rojig_spec, NULL);
-  #ifdef HAVE_RUST
   else if (self->treefile_rs)
     {
       self->rojig_spec = g_strdup (rpmostree_rs_treefile_get_rojig_spec_path (self->treefile_rs));
       self->rojig_spec_in_workdir = TRUE;
     }
-  #endif
 
   *out_context = g_steal_pointer (&self);
   return TRUE;