libutil: make RunningProgram::wait more resilient

this will usually be used either directly (which is always fine) or in
Finally blocks (where it must never throw execptions). make sure that,
exceptions being handled or not, the calling wait() in Finally doesn't
cause crashes due to the Finally no-nested-exceptions-thrown assertion

Change-Id: Ib83a5d9483b1fe83b9a957dcefeefce5d088f06d

releng/docker.xsh

@@ -44,23 +44,8 @@ def upload_docker_images(target: DockerTarget, paths: list[Path]):
 
         for path in paths:
             digest_file = tmp / (path.name + '.digest')
-            tmp_image = tmp / 'tmp-image.tar.gz'
 
-            # insecure-policy: we don't have any signature policy, we are just uploading an image
-            #
-            # Absurd: we copy it into an OCI image first so we can get the hash
-            # we need to upload it untagged, because skopeo has no "don't tag
-            # this" option.
-            # The reason for this is that forgejo's container registry throws
-            # away old versions of tags immediately, so we cannot use a temp
-            # tag, and it *does* reduce confusion to not upload tags that
-            # should not be used.
-            #
-            # Workaround for: https://github.com/containers/skopeo/issues/2354
-            log.info('skopeo copy to temp oci-archive %s', tmp_image)
-            skopeo --insecure-policy copy --format oci --all --digestfile @(digest_file) docker-archive:@(path) oci-archive:@(tmp_image)
-
-            inspection = json.loads($(skopeo inspect oci-archive:@(tmp_image)))
+            inspection = json.loads($(skopeo inspect docker-archive:@(path)))
 
             docker_arch = inspection['Architecture']
             docker_os = inspection['Os']
@@ -68,8 +53,9 @@ def upload_docker_images(target: DockerTarget, paths: list[Path]):
 
             log.info('Pushing image %s for %s to %s', path, docker_arch, target.registry_path)
 
+            # insecure-policy: we don't have any signature policy, we are just uploading an image
+            skopeo --insecure-policy copy --digestfile @(digest_file) --all docker-archive:@(path) f'docker://{target.registry_path}@@unknown-digest@@'
             digest = digest_file.read_text().strip()
-            skopeo --insecure-policy copy --preserve-digests --all oci-archive:@(tmp_image) f'docker://{target.registry_path}@{digest}'
 
             # skopeo doesn't give us the manifest size directly, so we just ask the registry
             metadata = reg.image_info(target.registry_path, digest)

src/libutil/processes.cc

@@ -280,9 +280,14 @@ RunningProgram::~RunningProgram()
 
 void RunningProgram::wait()
 {
-    int status = pid.wait();
-    if (status)
-        throw ExecError(status, "program '%1%' %2%", program, statusToString(status));
+    if (std::uncaught_exceptions() == 0) {
+        int status = pid.wait();
+        if (status)
+            throw ExecError(status, "program '%1%' %2%", program, statusToString(status));
+    } else {
+        pid.kill();
+        debug("killed subprocess %1% during exception handling", program);
+    }
 }
 
 RunningProgram runProgram2(const RunOptions & options)