diff --git a/.gitattributes b/.gitattributes
index a1ec394..29276dc 100644
--- a/.gitattributes
+++ b/.gitattributes
@@ -9,4 +9,3 @@
 *.png binary
 
 .github export-ignore
-Tests export-ignore
diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 26c12e9..d9f6037 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -67,6 +67,11 @@ jobs:
       - name: Test signing identity resolution
         run: Scripts/ci/test-signing-identity-resolution.sh
 
+      - name: Test source release archive
+        env:
+          RESIZELINT_VERIFY_FORMULA_CHECKSUM: ${{ matrix.runner == 'macos-26' && '1' || '0' }}
+        run: Scripts/release/test-source-archive.sh
+
       - name: Validate machine contracts
         run: Scripts/ci/validate-machine-contracts.py
 
diff --git a/Formula/resizelint.rb b/Formula/resizelint.rb
index 1d576e4..e968afb 100644
--- a/Formula/resizelint.rb
+++ b/Formula/resizelint.rb
@@ -2,7 +2,7 @@ class Resizelint < Formula
   desc "Static analysis for Swift apps that need to work in every window size"
   homepage "https://github.com/mikonyaa/ResizeLint"
   url "https://github.com/mikonyaa/ResizeLint/releases/download/1.0.0/ResizeLint-1.0.0-source.tar.gz"
-  sha256 "fea82e67b1c23fbfea201d7d326b553d98847bdfed8cf2164053f2e1be33fac1"
+  sha256 "4cea87f9dcc2e418f97cd3b4f5c2ac8d66f817b3a74962d92e8cef4f7328f173"
   license "MIT"
 
   depends_on "swift" => :build
diff --git a/Scripts/release/build-source-archive.sh b/Scripts/release/build-source-archive.sh
index 62d1edf..2bf3ea7 100755
--- a/Scripts/release/build-source-archive.sh
+++ b/Scripts/release/build-source-archive.sh
@@ -22,41 +22,24 @@ temporary_root=$(mktemp -d "${TMPDIR:-/tmp}/resizelint-source.XXXXXX")
 trap 'rm -rf "$temporary_root"' EXIT
 
 prefix="ResizeLint-$version"
-staging="$temporary_root/staging"
-mkdir -p "$staging/$prefix"
-
+uncompressed="$temporary_root/source.tar"
 (
   cd "$repository_root"
-  git checkout-index -a --prefix="$staging/$prefix/"
-)
-
-rm -rf \
-  "$staging/$prefix/.build" \
-  "$staging/$prefix/.github" \
-  "$staging/$prefix/Artifacts" \
-  "$staging/$prefix/Formula"
-
-find "$staging/$prefix" -exec touch -h -t 200001010000 {} +
-listing="$temporary_root/files.txt"
-(
-  cd "$staging"
-  LC_ALL=C find "$prefix" -print | LC_ALL=C sort > "$listing"
+  tree=$(git write-tree)
+  git archive \
+    --format=tar \
+    --mtime="2000-01-01T00:00:00Z" \
+    --prefix="$prefix/" \
+    --output="$uncompressed" \
+    "$tree" \
+    -- \
+    . \
+    ':(exclude).build' \
+    ':(exclude).github' \
+    ':(exclude)Artifacts' \
+    ':(exclude)Formula'
 )
 
-uncompressed="$temporary_root/source.tar"
-tar -cf "$uncompressed" \
-  --format=ustar \
-  --uid 0 \
-  --gid 0 \
-  --uname root \
-  --gname root \
-  --no-acls \
-  --no-fflags \
-  --no-mac-metadata \
-  --no-xattrs \
-  -C "$staging" \
-  -T "$listing"
-
 archive="$destination/ResizeLint-$version-source.tar.gz"
 gzip -9 -n -c "$uncompressed" > "$archive"
 printf '%s\n' "$archive"
diff --git a/Scripts/release/test-source-archive.sh b/Scripts/release/test-source-archive.sh
index e5c98f2..a6ba7fa 100755
--- a/Scripts/release/test-source-archive.sh
+++ b/Scripts/release/test-source-archive.sh
@@ -4,6 +4,7 @@ set -euo pipefail
 
 repository_root=$(cd "$(dirname "${BASH_SOURCE[0]}")/../.." && pwd -P)
 builder="$repository_root/Scripts/release/build-source-archive.sh"
+formula="$repository_root/Formula/resizelint.rb"
 
 if [[ ! -x "$builder" ]]; then
   echo "Source archive builder is missing or not executable: $builder" >&2
@@ -13,8 +14,20 @@ fi
 temporary_root=$(mktemp -d "${TMPDIR:-/tmp}/resizelint-source-test.XXXXXX")
 trap 'rm -rf "$temporary_root"' EXIT
 
-first=$($builder "$temporary_root/first" 1.0.0)
-second=$($builder "$temporary_root/second" 1.0.0)
+fake_bin="$temporary_root/bin"
+mkdir -p "$fake_bin"
+real_tar=$(command -v tar)
+cat > "$fake_bin/tar" <<'EOF'
+#!/usr/bin/env bash
+
+set -euo pipefail
+echo "Source archive builder must not invoke system tar" >&2
+exit 66
+EOF
+chmod 0755 "$fake_bin/tar"
+
+first=$(PATH="$fake_bin:$PATH" "$builder" "$temporary_root/first" 1.0.0)
+second=$(PATH="$fake_bin:$PATH" "$builder" "$temporary_root/second" 1.0.0)
 first_hash=$(shasum -a 256 "$first" | awk '{ print $1 }')
 second_hash=$(shasum -a 256 "$second" | awk '{ print $1 }')
 
@@ -23,8 +36,20 @@ if [[ "$first_hash" != "$second_hash" ]]; then
   exit 1
 fi
 
+if [[ "${RESIZELINT_VERIFY_FORMULA_CHECKSUM:-0}" == "1" ]]; then
+  formula_hash=$(awk '/^[[:space:]]*sha256 / { gsub(/"/, "", $2); print $2; exit }' "$formula")
+  if [[ -z "$formula_hash" ]]; then
+    echo "Homebrew formula does not declare a source archive checksum" >&2
+    exit 1
+  fi
+  if [[ "$formula_hash" != "$first_hash" ]]; then
+    echo "Homebrew formula checksum is $formula_hash; source archive checksum is $first_hash" >&2
+    exit 1
+  fi
+fi
+
 listing="$temporary_root/listing.txt"
-tar -tzf "$first" > "$listing"
+"$real_tar" -tzf "$first" > "$listing"
 grep -q '^ResizeLint-1.0.0/Package.swift$' "$listing"
 grep -q '^ResizeLint-1.0.0/Tests/ResizeLintCoreTests/VersionTests.swift$' "$listing"
 
@@ -33,4 +58,7 @@ if grep -Eq '(^|/)Formula/|(^|/)\.build/|(^|/)\.git/' "$listing"; then
   exit 1
 fi
 
-echo "Source archive self-test passed: $first_hash"
+echo "Source archive reproducibility test passed: $first_hash"
+if [[ "${RESIZELINT_VERIFY_FORMULA_CHECKSUM:-0}" == "1" ]]; then
+  echo "Homebrew formula checksum test passed."
+fi