Migrate helloworld to use {usesCleartextTraffic} manifest placeholder

[cortinico]

Summary:
This removes the need to specify 2 Manifests for apps and we can just use the main manifes to toggle if usesCleartextTraffic should be enabled or not.

This will have to be replicated in the template repository.

Changelog:
[Android] [Added] - Add support to specify a single Manifest rather than 2 (main/debug) by using the usesCleartextTraffic manifest placeholder which is autoconfigured by RNGP.

Differential Revision: D78425139

[facebook-github-bot]

This pull request was exported from Phabricator. Differential Revision: D78425139

[facebook-github-bot]

This pull request was exported from Phabricator. Differential Revision: D78425139

[facebook-github-bot]

This pull request was exported from Phabricator. Differential Revision: D78425139

[facebook-github-bot]

This pull request was exported from Phabricator. Differential Revision: D78425139

[facebook-github-bot]

This pull request has been merged in d89acc1.

[Ikthegreat]

@cortinico Hi, thank you for the changes in this PR.

I have a question regarding usesCleartextTraffic handling after upgrading to React Native 0.81.5.

In our project, we maintain a custom dev buildType, which is intended to behave similarly to debug (for debugging) while being closer to release in terms of build configuration. This buildType has been used internally for some time without issues.

After upgrading to RN 0.81.5, we started seeing a manifest merge error when building dev, caused by a missing usesCleartextTraffic placeholder. Upon investigation, we found that react-native-gradle-plugin now explicitly injects usesCleartextTraffic values for the default debug and release buildTypes.

From what I can see, configureBuildTypesForApp in RNGP branches only on debug and release. This made me wonder:
1. For custom buildTypes added by the app (like our dev buildType), what is the recommended way to apply usesCleartextTraffic?
Should this be fully handled at the app level via manifestPlaceholders, or is there an intended extension point we should rely on?
2. I also noticed that a new debugOptimized buildType was introduced around this change.
Since it is not explicitly handled in configureBuildTypesForApp, how is usesCleartextTraffic applied to debugOptimized internally?
3. As a general design question:
It seems that applying usesCleartextTraffic = true only for debug, and false for all other buildTypes (including release-like variants), would be closest to the previous behavior.
Is there a reason why this simpler branching strategy was not adopted?

I’m commenting on this PR because it appears to be the most closely related change in changelog.md, but please let me know if there is a more appropriate issue or PR where this question should be raised instead.

Thanks in advance for your guidance.

[cortinico]

Happy to answer @Ikthegreat

From what I can see, configureBuildTypesForApp in RNGP branches only on debug and release. This made me wonder:

The part you're missing is

react-native/packages/gradle-plugin/react-native-gradle-plugin/src/main/kotlin/com/facebook/react/utils/AgpConfiguratorUtils.kt

Lines 44 to 49 in dba18bb

	maybeCreate("debugOptimized").apply {
	manifestPlaceholders["usesCleartextTraffic"] = "true"
	initWith(debug)
	matchingFallbacks += listOf("release")
	externalNativeBuild { cmake { arguments("-DCMAKE_BUILD_TYPE=Release") } }
	}

Essentially we create debugOptimized with initWith(debug). So that build type will inherit the Manifest from the debug one. This makes is easier for us to maintain as we don't need a new manifest just for debugOptimized.

1. For custom buildTypes added by the app (like our dev buildType), what is the recommended way to apply usesCleartextTraffic?

If your custom build type needs to connect to Metro/React Native DevTools, then you need usesCleartextTraffic. That's beacuse the bundler generally runs on http://localhost:8081 and having HTTPS on localhost is a PITA.

Should this be fully handled at the app level via manifestPlaceholders, or is there an intended extension point we should rely on?

You should be able to use manifestPlaceholders and specify it in the same way as we do inside RNGP

2. I also noticed that a new debugOptimized buildType was introduced around this change.
   Since it is not explicitly handled in configureBuildTypesForApp, how is usesCleartextTraffic applied to debugOptimized internally?

See my above answer related to initWith(debug)

3. As a general design question:
   It seems that applying usesCleartextTraffic = true only for debug, and false for all other buildTypes (including release-like variants), would be closest to the previous behavior.
   Is there a reason why this simpler branching strategy was not adopted?

I believe I already answered this essentially. Let me know if something is still unclear.