From df7d8c2f9dad6a847a747a493216249161e763e7 Mon Sep 17 00:00:00 2001
From: James Garbutt <43081j@users.noreply.github.com>
Date: Fri, 20 Mar 2026 21:45:59 +0000
Subject: [PATCH 1/2] fix: don't diff install size with first version

Most initial versions are empty or unfinished, so generally show up as a
large bump in file size to the 2nd version.

This is misleading so we should just skip those.
---
 app/composables/useInstallSizeDiff.ts | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/app/composables/useInstallSizeDiff.ts b/app/composables/useInstallSizeDiff.ts
index d084ba14c3..0dd85206e2 100644
--- a/app/composables/useInstallSizeDiff.ts
+++ b/app/composables/useInstallSizeDiff.ts
@@ -31,7 +31,9 @@ function getComparisonVersion(pkg: SlimPackument, resolvedVersion: string): stri
     .sort((a, b) => compare(a, b))
 
   const currentIdx = stableVersions.indexOf(resolvedVersion)
-  if (currentIdx <= 0) return null
+  // Don't compare the second version against the first as the first
+  // has no baseline so a large size difference is expected
+  if (currentIdx <= 1) return null
 
   return stableVersions[currentIdx - 1]!
 }

From cc4dd6881fbbc8d7d13715fb14de826806c02f32 Mon Sep 17 00:00:00 2001
From: James Garbutt <43081j@users.noreply.github.com>
Date: Sat, 21 Mar 2026 04:17:30 +0000
Subject: [PATCH 2/2] test: fix 'em up

---
 .../composables/use-install-size-diff.spec.ts | 36 ++++++++++++++++---
 1 file changed, 32 insertions(+), 4 deletions(-)

diff --git a/test/nuxt/composables/use-install-size-diff.spec.ts b/test/nuxt/composables/use-install-size-diff.spec.ts
index d464e2e353..100ca89f93 100644
--- a/test/nuxt/composables/use-install-size-diff.spec.ts
+++ b/test/nuxt/composables/use-install-size-diff.spec.ts
@@ -61,8 +61,19 @@ describe('useInstallSizeDiff', () => {
       expect(comparisonVersion.value).toBeNull()
     })
 
+    it('returns null for the second stable version (no baseline for first)', () => {
+      const pkg = createPackage('test', {
+        '1.0.0': '2020-01-01',
+        '1.1.0': '2021-01-01',
+      })
+
+      const { comparisonVersion } = useInstallSizeDiff('test', '1.1.0', pkg, null)
+      expect(comparisonVersion.value).toBeNull()
+    })
+
     it('skips prerelease versions when finding previous stable', () => {
       const pkg = createPackage('test', {
+        '0.9.0': '2019-01-01',
         '1.0.0': '2020-01-01',
         '2.0.0-beta.1': '2021-01-01',
         '2.0.0-beta.2': '2021-06-01',
@@ -117,6 +128,7 @@ describe('useInstallSizeDiff', () => {
 
     it('returns null when both thresholds are not met', async () => {
       const pkg = createPackage('pkg-no-threshold', {
+        '0.9.0': '2019-01-01',
         '1.0.0': '2020-01-01',
         '1.1.0': '2021-01-01',
       })
@@ -140,7 +152,11 @@ describe('useInstallSizeDiff', () => {
     })
 
     it('sets sizeThresholdExceeded when size increased by more than 25%', async () => {
-      const pkg = createPackage('pkg-size-only', { '1.0.0': '2020-01-01', '1.1.0': '2021-01-01' })
+      const pkg = createPackage('pkg-size-only', {
+        '0.9.0': '2019-01-01',
+        '1.0.0': '2020-01-01',
+        '1.1.0': '2021-01-01',
+      })
       const current = createInstallSize('pkg-size-only', {
         version: '1.1.0',
         totalSize: 7000,
@@ -172,7 +188,11 @@ describe('useInstallSizeDiff', () => {
     })
 
     it('sets depThresholdExceeded when more than 5 dependencies were added', async () => {
-      const pkg = createPackage('pkg-deps-only', { '1.0.0': '2020-01-01', '1.1.0': '2021-01-01' })
+      const pkg = createPackage('pkg-deps-only', {
+        '0.9.0': '2019-01-01',
+        '1.0.0': '2020-01-01',
+        '1.1.0': '2021-01-01',
+      })
       const current = createInstallSize('pkg-deps-only', {
         version: '1.1.0',
         totalSize: 5100,
@@ -204,7 +224,11 @@ describe('useInstallSizeDiff', () => {
     })
 
     it('returns correct diff values', async () => {
-      const pkg = createPackage('pkg-both', { '1.0.0': '2020-01-01', '1.1.0': '2021-01-01' })
+      const pkg = createPackage('pkg-both', {
+        '0.9.0': '2019-01-01',
+        '1.0.0': '2020-01-01',
+        '1.1.0': '2021-01-01',
+      })
       const current = createInstallSize('pkg-both', {
         version: '1.1.0',
         totalSize: 10000,
@@ -234,7 +258,11 @@ describe('useInstallSizeDiff', () => {
 
   describe('fetch behavior', () => {
     it('calls the correct API endpoint for the comparison version', async () => {
-      const pkg = createPackage('my-pkg', { '1.0.0': '2020-01-01', '1.1.0': '2021-01-01' })
+      const pkg = createPackage('my-pkg', {
+        '0.9.0': '2019-01-01',
+        '1.0.0': '2020-01-01',
+        '1.1.0': '2021-01-01',
+      })
       const current = createInstallSize('my-pkg', { version: '1.1.0', totalSize: 7000 })
       fetchSpy.mockResolvedValue(createInstallSize('my-pkg', { version: '1.0.0', totalSize: 5000 }))