From d50d17657394bcb9459aa1c1c36325fb902ce8d4 Mon Sep 17 00:00:00 2001
From: osr21 <osr21@users.noreply.github.com>
Date: Sat, 8 Aug 2026 19:34:12 +0000
Subject: [PATCH 1/2] fix(arcup): accept checksum files without a trailing
 newline

verify_checksum_file() decided emptiness from the exit status of
`read -r expected_checksum expected_name < "$checksum_path"`. `read`
returns non-zero when it reaches EOF before a newline, even though it has
already populated the variables. A .sha256 whose single line lacks a
trailing newline is valid, but arcup rejected it with
"Checksum file is empty", aborting a correct install.

Decide emptiness from the parsed hash instead of read's exit status.
A genuinely empty file still yields an empty hash and is still rejected.

Adds regression tests covering the no-trailing-newline and empty cases.
---
 arcup/arcup         | 7 ++++++-
 arcup/test_arcup.sh | 9 +++++++++
 2 files changed, 15 insertions(+), 1 deletion(-)

diff --git a/arcup/arcup b/arcup/arcup
index 3590cd36..999bc2b2 100755
--- a/arcup/arcup
+++ b/arcup/arcup
@@ -656,7 +656,12 @@ verify_checksum_file() {
     local archive_name="$3"
     local expected_checksum expected_name actual_checksum
 
-    if ! read -r expected_checksum expected_name < "$checksum_path"; then
+    # `read` returns non-zero when it hits EOF before a newline, even though it
+    # still populates the variables. A checksum file whose single line has no
+    # trailing newline is valid, so decide emptiness from the parsed hash rather
+    # than from read's exit status.
+    read -r expected_checksum expected_name < "$checksum_path" || true
+    if [[ -z "$expected_checksum" ]]; then
         error "Checksum file is empty: $checksum_path"
     fi
 
diff --git a/arcup/test_arcup.sh b/arcup/test_arcup.sh
index 49021191..32f7033d 100755
--- a/arcup/test_arcup.sh
+++ b/arcup/test_arcup.sh
@@ -119,6 +119,15 @@ test_checksum_validation() {
 
     printf '%s  other-asset.tar.gz\n' "$checksum" > "$checksum_file"
     expect_fail "checksum filename mismatch fails" verify_checksum_file "$archive" "$checksum_file" "$archive_name"
+
+    # A checksum file whose only line has no trailing newline is still valid.
+    printf '%s  %s' "$checksum" "$archive_name" > "$checksum_file"
+    verify_checksum_file "$archive" "$checksum_file" "$archive_name"
+    pass "checksum file without trailing newline passes"
+
+    # A genuinely empty checksum file must still be rejected.
+    : > "$checksum_file"
+    expect_fail "empty checksum file fails" verify_checksum_file "$archive" "$checksum_file" "$archive_name"
 }
 
 test_download_error_lists_assets() {

From 01694c42966a1c1142ed8e0203517a24269934e9 Mon Sep 17 00:00:00 2001
From: osr21 <osr21@users.noreply.github.com>
Date: Sun, 9 Aug 2026 18:47:33 +0000
Subject: [PATCH 2/2] test(arcup): cover mismatched checksum without trailing
 newline

---
 arcup/test_arcup.sh | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/arcup/test_arcup.sh b/arcup/test_arcup.sh
index 32f7033d..cb56b648 100755
--- a/arcup/test_arcup.sh
+++ b/arcup/test_arcup.sh
@@ -128,6 +128,11 @@ test_checksum_validation() {
     # A genuinely empty checksum file must still be rejected.
     : > "$checksum_file"
     expect_fail "empty checksum file fails" verify_checksum_file "$archive" "$checksum_file" "$archive_name"
+
+    # A wrong hash without a trailing newline must still fail the comparison,
+    # not slip through the emptiness check.
+    printf '%s  %s' "0000000000000000000000000000000000000000000000000000000000000000" "$archive_name" > "$checksum_file"
+    expect_fail "mismatched checksum without trailing newline fails" verify_checksum_file "$archive" "$checksum_file" "$archive_name"
 }
 
 test_download_error_lists_assets() {