From 6bef6d89d280b4ffa7c39526d5f49795e5967e56 Mon Sep 17 00:00:00 2001
From: Robert Pocklington <rpocklin@gmail.com>
Date: Fri, 13 Aug 2021 12:12:46 +1000
Subject: [PATCH 1/2] fix: handle loading and parsing errors when loading
 themes

---
 packages/web-runtime/src/helpers/theme.js     | 19 ++++++++++---------
 .../tests/unit/helpers/theme.spec.js          | 16 +++++++++++++---
 2 files changed, 23 insertions(+), 12 deletions(-)

diff --git a/packages/web-runtime/src/helpers/theme.js b/packages/web-runtime/src/helpers/theme.js
index 825e56b9c6d..67e3a4c6bad 100644
--- a/packages/web-runtime/src/helpers/theme.js
+++ b/packages/web-runtime/src/helpers/theme.js
@@ -4,20 +4,21 @@ export const loadTheme = async (location = '') => {
   const defaults = { theme: defaultTheme }
 
   if (location.split('.').pop() !== 'json') {
+    console.error(`Theme '${location}' does not specify a json file, using default theme.`)
     return defaults
   }
 
-  let response
   try {
-    response = await fetch(location)
+    const response = await fetch(location)
+    if (!response.ok) {
+      return defaults
+    }
+    const theme = await response.json()
+    return { theme }
   } catch (e) {
+    console.error(
+      `Failed to load theme '${location}' is not a valid json file, using default theme.`
+    )
     return defaults
   }
-
-  if (!response.ok) {
-    return defaults
-  }
-
-  const theme = await response.json()
-  return { theme }
 }
diff --git a/packages/web-runtime/tests/unit/helpers/theme.spec.js b/packages/web-runtime/tests/unit/helpers/theme.spec.js
index 719fa09b421..36da68a51d6 100644
--- a/packages/web-runtime/tests/unit/helpers/theme.spec.js
+++ b/packages/web-runtime/tests/unit/helpers/theme.spec.js
@@ -4,7 +4,10 @@ import merge from 'lodash-es/merge'
 
 describe('theme loading and error reporting', () => {
   beforeEach(() => {
-    fetch.resetMocks()
+    global.console = { error: jest.fn() }
+  })
+  afterEach(() => {
+    jest.clearAllMocks()
   })
 
   it('should load the default theme if location is empty', async () => {
@@ -12,17 +15,24 @@ describe('theme loading and error reporting', () => {
     expect(theme).toMatchObject(defaultTheme)
   })
 
-  it('should load the default theme if location is not a json file', async () => {
+  it('should load the default theme if location is not a json file extension', async () => {
     const { theme } = await loadTheme('some_location_without_json_file_ending.xml')
     expect(theme).toMatchObject(defaultTheme)
   })
 
-  it('should load the default theme if location errors', async () => {
+  it('should load the default theme if location is not found', async () => {
     fetch.mockResponse(new Error(), { status: 404 })
     const { theme } = await loadTheme('http://www.owncloud.com/unknown.json')
     expect(theme).toMatchObject(defaultTheme)
   })
 
+  it('should load the default theme if location is not a valid json file', async () => {
+    const customTheme = merge({}, defaultTheme, { default: { logo: { login: 'custom.svg' } } })
+    fetch.mockResponse(JSON.stringify(customTheme) + '-invalid')
+    const { theme } = await loadTheme('http://www.owncloud.com/invalid.json')
+    expect(theme).toMatchObject(defaultTheme)
+  })
+
   it('should load the default theme if server errors', async () => {
     fetch.mockReject(new Error())
     const { theme } = await loadTheme('http://www.owncloud.com')

From c7bb70bff75b64d00a7bad3e65b3248ccf2760e0 Mon Sep 17 00:00:00 2001
From: Robert Pocklington <rpocklin@gmail.com>
Date: Fri, 13 Aug 2021 12:54:49 +1000
Subject: [PATCH 2/2] Add changelog item

---
 .../unreleased/bugfix-handle-errors-when-loading-themes      | 5 +++++
 1 file changed, 5 insertions(+)
 create mode 100644 changelog/unreleased/bugfix-handle-errors-when-loading-themes

diff --git a/changelog/unreleased/bugfix-handle-errors-when-loading-themes b/changelog/unreleased/bugfix-handle-errors-when-loading-themes
new file mode 100644
index 00000000000..cb2a2f070e4
--- /dev/null
+++ b/changelog/unreleased/bugfix-handle-errors-when-loading-themes
@@ -0,0 +1,5 @@
+Bugfix: Handle loading and parsing errors when loading themes
+
+Adds graceful error handling of json parse errors when loading custom themes.
+
+https://github.com/owncloud/web/pull/5669