Fix subscribers chart issues

[irfano]

This PR

before	after	description
		adds title to the Subscribers chart card in loading state
		handles empty state of Followers card (wordpress-mobile/WordPress-FluxC-Android#3005). Since all cards in error state now, the screen displays Retry button
		Renames the chart card's title to "Subscriber Growth"
		Add singular-plural "subscribers" label support to the marker view of the subscribers chart.

---

To Test:

1. Log in.
2. Set the airplane mode on your device.
3. Open SUBSCRIBERS from "My Site → Stats".
4. Verify that the Retry button id displayed instead of displaying "No data yet" message on the Subscribers card.
5. Turn off airplane mode.
6. Verify that the Subscribers chart card has a title in the loading state.

---

Regression Notes

1. Potential unintended areas of impact

   • None

2. What I did to test those areas of impact (or what existing automated tests I relied on)

   • N/A

3. What automated tests I added (or what prevented me from doing so)

   • Not an important case for automated tests.

---

PR Submission Checklist:

• I have completed the Regression Notes.
• I have considered adding accessibility improvements for my changes.
• I have considered if this change warrants user-facing release notes and have added them to RELEASE-NOTES.txt if necessary.

---

Testing Checklist (strike-out the not-applying and unnecessary ones):

• WordPress.com sites and self-hosted Jetpack sites.
• Portrait and landscape orientations.
• Light and dark modes.
• Fonts: Larger, smaller and bold text.
• High contrast.
• Talkback.
• Languages with large words or with letters/accents not frequently used in English.
• Right-to-left languages. (Even if translation isn’t complete, formatting should still respect the right-to-left layout)
• Large and small screen sizes. (Tablet and smaller phones)
• Multi-tasking: Split screen and Pop-up view. (Android 10 or higher)

[wpmobilebot]

📲 You can test the changes from this Pull Request in WordPress by scanning the QR code below to install the corresponding build.

	App Name	WordPress
	Flavor	Jalapeno
	Build Type	Debug
	Version	pr20776-e31a090
	Commit	e31a090
	Direct Download	wordpress-prototype-build-pr20776-e31a090.apk

Note: Google Login is not supported on these builds.

[wpmobilebot]

📲 You can test the changes from this Pull Request in Jetpack by scanning the QR code below to install the corresponding build.

	App Name	Jetpack
	Flavor	Jalapeno
	Build Type	Debug
	Version	pr20776-e31a090
	Commit	e31a090
	Direct Download	jetpack-prototype-build-pr20776-e31a090.apk

Note: Google Login is not supported on these builds.

[codecov]

Codecov Report

Attention: Patch coverage is 40.00000% with 3 lines in your changes are missing coverage. Please review.

Project coverage is 40.66%. Comparing base (ce04048) to head (e31a090).
Report is 4 commits behind head on release/24.9.

Files	Patch %	Lines
...sections/subscribers/usecases/SubscribersMapper.kt	0.00%	1 Missing ⚠️
.../ui/stats/refresh/utils/LineChartLabelFormatter.kt	0.00%	1 Missing ⚠️
...ts/refresh/utils/SubscribersChartLabelFormatter.kt	0.00%	1 Missing ⚠️

Additional details and impacted files

@@              Coverage Diff              @@
##           release/24.9   #20776   +/-   ##
=============================================
  Coverage         40.66%   40.66%           
=============================================
  Files              1490     1490           
  Lines             68621    68621           
  Branches          11338    11338           
=============================================
  Hits              27907    27907           
  Misses            38195    38195           
  Partials           2519     2519           

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

[notandyvee]

Code LGTM and everything works great. But one thing I noticed. Two cards have the same title, which is less than ideal. I recommend making it clearer. "Subscribers Chart", "Subscribers List", Etc. Since we are here.

cc @staskus . This could be the same in iOS. Syncing between the two would be helpful. Or we can decide to ignore it. Up to y'all.

[aditi-bhatia]

^ I agree with @notandyvee 's feedback, I thought it was strange at first that both cards have the same title - but then noticed that's how it was in the final designs as well.

In the earlier proposed designs (IqhXWz3Iir7RMb5XH5gGfZ-fi-108_4611), the name of that card was Subscriber Growth:

Maybe we could change it to that, any thoughts?

[staskus]

Thanks, @aditi-bhatia and @notandyvee, great observation. I think calling it Subscriber Growth would be appropriate 👍 I'll update it on iOS as well. cc @irfano

[dangermattic]

	1 Warning
⚠️	This PR is assigned to the milestone 24.9 ❄️. The due date for this milestone has already passed. Please assign it to a milestone with a later deadline or check whether the release for this milestone has already been finished.

Generated by 🚫 Danger

[irfano]

I also updated the title to the "Subscriber Growth" in this PR.

[aditi-bhatia]

Changes look good to me and work as expected 👍 I left a small clarifying comment on the Flux-C PR related to this to get a better understanding before I approve: wordpress-mobile/WordPress-FluxC-Android#3005 (review)

[aditi-bhatia]

Hi @irfano, I spent some time testing again today and there's a crash that I'm seeing from SubscribersChartLabelFormatter.kt. I'm only able to reproduce on one device with airplane mode on + I'm only seeing when testing with a blog with 0 subscribers (I've been using buddyuniversity.wordpress.com for this) :

I haven't debugged it too much yet (I can help with this tomorrow) but this is the value after setting a breakpoint:

[irfano]

I couldn't reproduce your crash, but I did fix another issue related to 0 subscribers case. It was crashing when tapping the line on sites with 0 subscribers. This might be related to the crash you're experiencing. I would appreciate it if you could find a way to reproduce it.

[aditi-bhatia]

Hi @irfano, I can't seem to reproduce the crash I mentioned above which would occur after clicking on My Site -> Stats on airplane mode on a blog with 0 subscribers. Now, I'm seeing a different crash after clicking the chart:

To reproduce:

• Load Stats with data on on a blog with 0 subscribers
• Turn off data and access Stats -> Subscribers again
• Click the blue line on the Subscribers Growth Chart

[irfano]

That's the crash I mentioned and fixed with my latest commit (9c581d3). Can you ensure that you pulled the latest commit?

[aditi-bhatia]

I used a fresh install last time but maybe something went wrong with the versioning since I'm not able to reproduce the crash today. Tested using a fresh install on two devices, lgtm 👍

[irfano]

@oguzkocer, sorry for the delay in making this ready before the code freeze. We should have let you know earlier. Can we include this in release/24.9?

[oguzkocer]

@irfano Sure - but you'll need to wait a couple days for the beta as I just submitted it.

[irfano]

Thank you!

but you'll need to wait a couple days

That's fine! This fixes required but minor issues. So, it won't disrupt the testing process until the next beta is released.

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
No data about Coverage
0.0% Duplication on New Code

See analysis details on SonarCloud

[antonis]

Thank you for including a fix for #20864 in your PR @irfano 🙇
The code changes in e31a090 look good and the app works as expected 🎉