Fix CentOS Stream 10 checksum file retrieval (follow-up #966)

[chaosoffire]

Problem

While verifying the fixes from my previous PR #966, a specific issue with CentOS Stream 10 was identified.

CentOS Stream 10 builds fail as attempting to fetch sha256sum.txt.asc. Like CentOS Stream 9, Stream 10 uses a single SHA256SUM file.

Error Log:

INFO [2026-01-10T21:31:14+08:00] Downloading source
Error: Error while downloading source: Failed to download "http://mirrors.xtom.com/centos-stream//10-stream/BaseOS/x86_64/iso/sha256sum.txt.asc": Unable to fetch http://mirrors.xtom.com/centos-stream//10-stream/BaseOS/x86_64/iso/sha256sum.txt.asc: resource not found
ERROR [2026-01-10T21:31:17+08:00] Failed running distrobuilder err="Error while downloading source: Failed to download \"http://mirrors.xtom.com/centos-stream//10-stream/BaseOS/x86_64/iso/sha256sum.txt.asc\": Unable to fetch http://mirrors.xtom.com/centos-stream//10-stream/BaseOS/x86_64/iso/sha256sum.txt.asc: resource not found"

Fix

Updated sources/centos-http.go to apply the same checksum file logic used for CentOS Stream 9 to CentOS Stream 10.

Verification

Verified success for CentOS Stream 10. Also verified stability across other recently fixed distributions (VoidLinux, Gentoo, Rocky Linux) to ensure no issues.

Verification Logs

VoidLinux (Only HTTPS) (Verification - Passed)

sudo distrobuilder build-dir lxc-ci/images/voidlinux.yaml ./rootfs-test \
 -o image.architecture=x86_64 \
 -o image.release=current \
 -o source.url=https://mirrors.cicku.me/voidlinux/live/current/
INFO [2026-01-10T21:43:57+08:00] Downloading source
INFO [2026-01-10T21:43:58+08:00] Unpacking image file=/tmp/distrobuilder/voidlinux-current-x86_64/void-x86_64-ROOTFS-20250202.tar.xz

Gentoo OpenRC (Verification - Passed)

sudo distrobuilder build-dir lxc-ci/images/gentoo.yaml ./rootfs-test \
 -o image.architecture=amd64 \
 -o source.variant=openrc \
 -o image.variant=openrc \
 -o source.url=http://mirrors.kernel.org/gentoo/
INFO [2026-01-10T21:47:46+08:00] Downloading source
/tmp/distrobuilder/gentoo--amd64/stage3-amd64-openrc-20260107T201601Z.tar.xz: 100% (7.35MB/s))
gpg: Signature made Thu Jan 8 05:01:06 2026 CST
gpg: using RSA key 534E4209AB49EEE1C19D96162C44695DB9F6043D
gpg: Good signature from "Gentoo Linux Release Engineering (Automated Weekly Release Key) <[email protected]>" [expired]
gpg: Signature notation: manu=2,2.5+1.11,2,2
gpg: Note: This key has expired!
Primary key fingerprint: 13EB BDBE DE7A 1277 5DFD B1BA BB57 2E0E 2D18 2910
Subkey fingerprint: 534E 4209 AB49 EEE1 C19D 9616 2C44 695D B9F6 043D
INFO [2026-01-10T21:48:48+08:00] Unpacking image file=/tmp/distrobuilder/gentoo--amd64/stage3-amd64-openrc-20260107T201601Z.tar.xz

Gentoo Systemd (Verification - Passed)

sudo distrobuilder build-dir lxc-ci/images/gentoo.yaml ./rootfs-test \
 -o image.architecture=amd64 \
 -o source.variant=systemd \
 -o image.variant=systemd \
 -o source.url=http://mirrors.kernel.org/gentoo/
INFO [2026-01-10T21:54:54+08:00] Downloading source
/tmp/distrobuilder/gentoo--amd64/stage3-amd64-systemd-20260107T201601Z.tar.xz: 100% (8.41MB/s))
gpg: Signature made Thu Jan 8 09:21:07 2026 CST
gpg: using RSA key 534E4209AB49EEE1C19D96162C44695DB9F6043D
gpg: Good signature from "Gentoo Linux Release Engineering (Automated Weekly Release Key) <[email protected]>" [expired]
gpg: Signature notation: manu=2,2.5+1.11,2,2
gpg: Note: This key has expired!
Primary key fingerprint: 13EB BDBE DE7A 1277 5DFD B1BA BB57 2E0E 2D18 2910
Subkey fingerprint: 534E 4209 AB49 EEE1 C19D 9616 2C44 695D B9F6 043D
INFO [2026-01-10T21:55:51+08:00] Unpacking image file=/tmp/distrobuilder/gentoo--amd64/stage3-amd64-systemd-20260107T201601Z.tar.xz

CentOS Stream 10 (Verification - Passed)

sudo distrobuilder build-dir lxc-ci/images/centos.yaml ./rootfs-test \
 -o image.architecture=x86_64 \
 -o image.variant=default \
 -o source.variant=boot \
 -o source.url=http://mirrors.xtom.com/centos-stream/
INFO [2026-01-10T21:46:06+08:00] Downloading source
/tmp/distrobuilder/centos-10-stream-x86_64/SHA256SUM: 100% (368B/s)
INFO [2026-01-10T21:46:08+08:00] Unpacking image file=/tmp/distrobuilder/centos-10-stream-x86_64/CentOS-Stream-10-20260105.0-x86_64-boot.iso

CentOS Stream 9 (Verification - Passed)

sudo distrobuilder build-dir lxc-ci/images/centos.yaml ./rootfs-test \
 -o image.architecture=x86_64 \
 -o image.release=9-Stream \
 -o image.variant=default \
 -o source.variant=boot \
 -o source.url=http://mirrors.xtom.com/centos-stream/
INFO [2026-01-10T21:46:38+08:00] Downloading source
/tmp/distrobuilder/centos-9-stream-x86_64/SHA256SUM: 100% (365B/s)
INFO [2026-01-10T21:46:41+08:00] Unpacking image file=/tmp/distrobuilder/centos-9-stream-x86_64/CentOS-Stream-9-20260105.0-x86_64-boot.iso

Rocky Linux 10 (Verification - Passed)

sudo distrobuilder build-dir lxc-ci/images/rockylinux.yaml ./rootfs \
 -o image.architecture=x86_64 \
 -o image.release=10 \
 -o image.variant=default \
 -o source.variant=boot \
 -o source.url=http://mirrors.xtom.com/rocky/
INFO   [2026-01-10T22:15:20+08:00] Downloading source
/tmp/distrobuilder/rockylinux-10-x86_64/CHECKSUM: 100% (938B/s)
gpg: Signature made Sat Nov 22 02:50:42 2025 CST
gpg:                using RSA key FC226859C0860BF0DDB95B085B106C736FEDFC85
gpg: Good signature from "Release Engineering (Rocky Linux 10) <[email protected]>" [unknown]
gpg: WARNING: This key is not certified with a trusted signature!
gpg:          There is no indication that the signature belongs to the owner.
Primary key fingerprint: FC22 6859 C086 0BF0 DDB9  5B08 5B10 6C73 6FED FC85
INFO   [2026-01-10T22:15:21+08:00] Unpacking ISO                                 file=/tmp/distrobuilder/rockylinux-10-x86_64/Rocky-10.1-x86_64-boot.iso
INFO   [2026-01-10T22:15:21+08:00] Unpacking root image                          file=/var/cache/distrobuilder.120117154/temp_76430491/images/install.img

Rocky Linux 9 (Verification - Passed)

sudo distrobuilder build-dir lxc-ci/images/rockylinux.yaml ./rootfs \
 -o image.architecture=x86_64 \
 -o image.release=9 \
 -o image.variant=default \
 -o source.variant=boot \
 -o source.url=https://mirrors.xtom.com/rocky/
INFO   [2026-01-10T22:15:44+08:00] Downloading source
/tmp/distrobuilder/rockylinux-9-x86_64/CHECKSUM: 100% (928B/s)
INFO   [2026-01-10T22:15:46+08:00] Unpacking ISO                                 file=/tmp/distrobuilder/rockylinux-9-x86_64/Rocky-9.7-x86_64-boot.iso

Rocky Linux 8 (Verification - Passed)

sudo distrobuilder build-dir lxc-ci/images/rockylinux.yaml ./rootfs \
 -o image.architecture=x86_64 \
 -o image.release=9 \
 -o image.variant=default \
 -o source.variant=boot \
 -o source.url=https://mirrors.xtom.com/rocky/
INFO   [2026-01-10T22:16:38+08:00] Downloading source
/tmp/distrobuilder/rockylinux-8-x86_64/CHECKSUM: 100% (1.50kB/s)
INFO   [2026-01-10T22:16:39+08:00] Unpacking ISO                                 file=/tmp/distrobuilder/rockylinux-8-x86_64/Rocky-8.10-x86_64-boot.iso