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Explicitly enable debugger when building Hermes for Fantom#55202

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Explicitly enable debugger when building Hermes for Fantom#55202
j-piasecki wants to merge 2 commits intofacebook:mainfrom
j-piasecki:export-D90849881

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Summary:
Changelog: [Internal]

After changing Hermes V1 to be the default engine, Fantom tests started failing. This was due to a combination of changes, one of them being the change of default value for HERMES_ENABLE_DEBUGGER. In case of legacy Hermes it was enabled by default, while for Hermes V1 it's disabled by default.

Fantom didn't explicitly set this flag, but the debug build of RN (which Fantom performs) requires it to be enabled. This diff explicitly sets this flag to true for Fantom builds.

Differential Revision: D90849881

@meta-cla meta-cla bot added the CLA Signed This label is managed by the Facebook bot. Authors need to sign the CLA before a PR can be reviewed. label Jan 16, 2026
@facebook-github-bot facebook-github-bot added p: Software Mansion Partner: Software Mansion Partner p: Facebook Partner: Facebook labels Jan 16, 2026
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meta-codesync bot commented Jan 16, 2026

@j-piasecki has exported this pull request. If you are a Meta employee, you can view the originating Diff in D90849881.

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Review automatically exported from Phabricator review in Meta.

Summary:

Changelog: [Internal]

At the moment, Fantom doesn't propagate the Hermes V1 opt-in to the React Native build, which causes the code that should be gated by compile-time flags to be compiled. Since Hermes V1 differs in some cases, the headers there are missing.

This diff adds the opt-in propagation, so the code can be correctly compiled out.

Reviewed By: cortinico

Differential Revision: D90674696
…55202)

Summary:

Changelog: [Internal]

After changing Hermes V1 to be the default engine, Fantom tests started failing. This was due to a combination of changes, one of them being the change of default value for `HERMES_ENABLE_DEBUGGER`. In case of legacy Hermes it was enabled by default, while for Hermes V1 it's disabled by default.

Fantom didn't explicitly set this flag, but the debug build of RN (which Fantom performs) requires it to be enabled. This diff explicitly sets this flag to true for Fantom builds.

Reviewed By: cortinico

Differential Revision: D90849881
@meta-codesync meta-codesync bot closed this in 1c63877 Jan 16, 2026
@facebook-github-bot facebook-github-bot added the Merged This PR has been merged. label Jan 16, 2026
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meta-codesync bot commented Jan 16, 2026

This pull request has been merged in 1c63877.

react-native-bot pushed a commit that referenced this pull request Jan 19, 2026
Summary:
Pull Request resolved: #55202

Changelog: [Internal]

After changing Hermes V1 to be the default engine, Fantom tests started failing. This was due to a combination of changes, one of them being the change of default value for `HERMES_ENABLE_DEBUGGER`. In case of legacy Hermes it was enabled by default, while for Hermes V1 it's disabled by default.

Fantom didn't explicitly set this flag, but the debug build of RN (which Fantom performs) requires it to be enabled. This diff explicitly sets this flag to true for Fantom builds.

Reviewed By: cipolleschi, cortinico

Differential Revision: D90849881

fbshipit-source-id: 17f8393872eacef26f927f50aaf364644d9b94d7
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This pull request was successfully merged by @j-piasecki in ae15c9c

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4 participants