From c784ea8b4029c4768f7e4194a4b4ef6980707d88 Mon Sep 17 00:00:00 2001
From: Riccardo Cipolleschi <cipolleschi@meta.com>
Date: Wed, 22 Apr 2026 02:03:38 -0700
Subject: [PATCH] Use Hermes V1 by default (#56476)
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Summary:
The recent introduction of the `IRuntime` JSI interface moved `ScopeState` from `Runtime` to `IRuntime`, changing the C++ ABI (mangled symbol names). The Android build was still consuming a legacy Hermes nightly (`hermes-compiler@nightly`) that was built against the old JSI headers, causing an `UnsatisfiedLinkError` crash at startup:

```
dlopen failed: cannot locate symbol "_ZN8facebook3jsi7Runtime8popScopeEPNS1_10ScopeStateE" referenced by "libhermesvm.so"
```

This PR aligns Android with how iOS already handles Hermes V1:

1. **`scripts/try-set-nightly-hermes-compiler.js`** — The `yarn install` preinstall hook now installs `hermes-compiler@latest-v1` instead of `hermes-compiler@nightly`. This is the same npm dist-tag that iOS uses in `scripts/ios-prebuild/hermes.js`.

2. **`build.gradle.kts`** — When `hermesV1Enabled=true`, the Hermes version from `package.json` is used as-is (no `-SNAPSHOT` suffix), since V1 stable releases are published as regular Maven artifacts, not snapshots.

3. **`version.properties`** — Bumps `HERMES_V1_VERSION_NAME` from `250829098.0.11` to `250829098.0.12` for release builds and iOS podspec.

## Changelog:

[ANDROID] [FIXED] - Use Hermes V1 stable release instead of legacy nightly to fix startup crash caused by JSI ABI mismatch


Test Plan:
- Run `yarn install` from the repo root and verify `hermes-compiler` in `packages/react-native/package.json` is set to the `latest-v1` version (currently `250829098.0.12`)
- Run `yarn android` from `packages/rn-tester` and verify the app launches without crashing
- Verify CI `build_android` job passes

Reviewed By: javache

Differential Revision: D101247487

Pulled By: cipolleschi
---
 build.gradle.kts                                       | 10 +++++++++-
 .../react-native/sdks/hermes-engine/version.properties |  2 +-
 scripts/try-set-nightly-hermes-compiler.js             |  6 +++---
 3 files changed, 13 insertions(+), 5 deletions(-)

diff --git a/build.gradle.kts b/build.gradle.kts
index 65cec5f60c40..0858b5cb2917 100644
--- a/build.gradle.kts
+++ b/build.gradle.kts
@@ -137,7 +137,15 @@ if (project.findProperty("react.internal.useHermesStable")?.toString()?.toBoolea
     )
   }
 
-  hermesSubstitution = "$hermesCompilerVersion-SNAPSHOT" to "Users opted to use hermes nightly"
+  val hermesV1Enabled = project.findProperty("hermesV1Enabled")?.toString()?.toBoolean() ?: true
+  // Hermes V1 stable releases are published without the -SNAPSHOT suffix.
+  // Legacy nightly builds use -SNAPSHOT.
+  val resolvedVersion =
+      if (hermesV1Enabled) hermesCompilerVersion else "$hermesCompilerVersion-SNAPSHOT"
+  val reason =
+      if (hermesV1Enabled) "Users opted to use hermes V1 stable"
+      else "Users opted to use hermes nightly"
+  hermesSubstitution = resolvedVersion to reason
 } else {
   logger.warn(
       """
diff --git a/packages/react-native/sdks/hermes-engine/version.properties b/packages/react-native/sdks/hermes-engine/version.properties
index 4e24a29fd47d..e5d8f2e9a530 100644
--- a/packages/react-native/sdks/hermes-engine/version.properties
+++ b/packages/react-native/sdks/hermes-engine/version.properties
@@ -1,2 +1,2 @@
 HERMES_VERSION_NAME=1000.0.0
-HERMES_V1_VERSION_NAME=250829098.0.11
+HERMES_V1_VERSION_NAME=250829098.0.12
diff --git a/scripts/try-set-nightly-hermes-compiler.js b/scripts/try-set-nightly-hermes-compiler.js
index ef931e4a6b9b..6b3edd0c9415 100644
--- a/scripts/try-set-nightly-hermes-compiler.js
+++ b/scripts/try-set-nightly-hermes-compiler.js
@@ -16,10 +16,10 @@ function main() {
  const hermesCompilerVersion = packageJson.dependencies['hermes-compiler'];
 
  if (hermesCompilerVersion === '0.0.0') {
-   console.log(`Hermes compiler version not set. Updating to the latest nightly release.`);
-   execSync('yarn workspace react-native add hermes-compiler@nightly --exact', { stdio: 'inherit' });
+   console.log(`Hermes compiler version not set. Updating to the latest-v1 release.`);
+   execSync('yarn workspace react-native add hermes-compiler@latest-v1 --exact', { stdio: 'inherit' });
  } else {
-   console.log(`Hermes compiler version set to ${hermesCompilerVersion}. Not setting nightly hermes.`);
+   console.log(`Hermes compiler version set to ${hermesCompilerVersion}. Not setting hermes.`);
  }
 }