iOS: apply bsdiff patches during package install by ofalvai · Pull Request #48 · bitrise-io/react-native-code-push

ofalvai · 2026-08-28T10:36:55Z

Context

iOS counterpart of #42 and #43. Builds on top of #44 and the rest of the PR stack.

Changes

Call [CodePushBinaryDiffPatcher applyBinaryDiffPatchesFromManifest:] from the main package install flow.
Add config field CodePushEnableDeltaUpdates and handle its different states in combination with the manifest version value.

Decisions

Tests: unlike #53 for Android, the CodePushPackage.m changes can't be unit tested at the moment because of the transitive dependency on React (single CodePush.h import, which we started breaking up in #56, #59 and #58). Adding new E2E test cases is an option, but the test harness would have to be extended with bsdiff patch generation and v2 manifest handling. It would also increase our already bad test run times.

ofalvai · 2026-09-08T11:10:17Z

-                                                            NSArray *deletedFiles = manifestJSON[@"deletedFiles"];
-                                                            for (NSString *deletedFileName in deletedFiles) {
-                                                                NSString *absoluteDeletedFilePath = [newUpdateFolderPath stringByAppendingPathComponent:deletedFileName];
+                                                            if (error) {


Bug: unhandled error from [NSJSONSerialization JSONObjectWithData] :)

Copilot

🟡 Changes recommended

Duplicate Xcode object IDs, a breaking public selector change, and missing install-orchestration coverage must be addressed.

Once you've addressed the issues Copilot identified, you can request another Copilot review.

Pull request overview

Adds opt-in iOS support for applying bsdiff patches during package installation.

Changes:

Parses and validates diff manifests before safely applying binary patches.
Adds the CodePushEnableDeltaUpdates configuration flag.
Updates iOS project wiring and setup documentation.

File summaries

File	Description
`ios/CodePush/CodePushPackage.m`	Integrates manifest validation and binary patch application.
`ios/CodePush/CodePushConfig.m`	Reads the delta-update flag from `Info.plist`.
`ios/CodePush/CodePush.m`	Passes the configuration into package downloads.
`ios/CodePush/CodePush.h`	Exposes the flag and updated download method.
`ios/CodePush.xcodeproj/project.pbxproj`	Adds binary patcher test-target references.
`docs/setup-ios.md`	Documents enabling delta updates.

Review details

Suppressed comments (1)

ios/CodePush.xcodeproj/project.pbxproj:204

This PBXFileReference uses the same object ID as the existing definition at line 207. Duplicate PBX object keys can be collapsed or rejected by Xcode tooling; remove the duplicate definition so the test file has one reference object.

		F42FA68BF21AED765F55E71A /* CodePushBinaryDiffPatcherTests.swift */ = {isa = PBXFileReference; includeInIndex = 1; lastKnownFileType = sourcecode.swift; path = CodePushBinaryDiffPatcherTests.swift; sourceTree = "<group>"; };

Files reviewed: 6/6 changed files
Comments generated: 3
Review effort level: Balanced

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miklosboros · 2026-09-15T09:14:57Z

+{
+    BOOL enableDeltaUpdates = [[CodePushConfig current] enableDeltaUpdates];
+
+    if (diffManifest.version > 2 || diffManifest.version < 1) {


The version and flag validation depend on nothing, but the parsed manifest. They run after the copies have been done. You could split the method and run validations right after manifestFromJSON making rejections happen before the copies are done.

Rejecting an invalid manifest before any of the package copy operations is a way bigger refactor (see below), so I'd rather not include that in this PR. But I agree about splitting the validation code into its own function, so I just did that.

miklosboros

A few minor / nit-level notes on the implementation details, separate from the larger points.

miklosboros · 2026-09-15T09:21:59Z

+@interface CodePushPackage ()
+
+ (BOOL)validateAndApplyDiffManifest:(CodePushDiffManifest *)diffManifest
+                 currentPackageFolder:(NSString *)currentPackageFolderPath
+                       unzippedFolder:(NSString *)unzippedFolderPath
+                      newUpdateFolder:(NSString *)newUpdateFolderPath
+                                error:(NSError **)error;
+
+@end


This extension isn't needed: the definition at line 38 precedes the only call site at line 294, so the compiler already has the declaration by then. Dropping it also removes a second copy of the signature to keep in sync — the parameter alignment has already drifted a space from the definition.

Nice, happy coincidence. Removing it

miklosboros · 2026-09-15T09:22:00Z

+        // The patches folder must not stay in the installed package: it is
+        // not part of the released contents, so it changes the folder hash
+        // and surfaces later as a misleading integrity-check failure.


The invariant this relies on — patch files living under __hcp_patches — isn't actually enforced anywhere. CodePushPatchedFileEntry.patch documents it as "under the reserved patches folder prefix", but resolveWithin(unzippedFolder, entry.patch, …) in the patcher only checks containment, not the prefix.

So a manifest that puts a patch file anywhere else leaves it in the installed package and produces exactly the misleading integrity-check failure this comment is guarding against. verifyFolderHash still catches it, so it fails safe — but validating the prefix in manifestFromJSON: would close the gap properly. Same gap on Android, so this could be a follow-up rather than a blocker.

Fully agree, good find. Because it needs to be fixed on both platforms, here's a follow-up ticket, I'll open a separate PR: https://bitrise.atlassian.net/browse/RA-4925

miklosboros · 2026-09-15T09:22:00Z

+- (BOOL)enableDeltaUpdates
+{
+    return _enableDeltaUpdates;
+}


@property (readonly) BOOL enableDeltaUpdates would autosynthesize both the _enableDeltaUpdates ivar and this getter, so the explicit ivar on line 6 and this method can both go — just assign in init.

Separately: this is the only config value stored outside _configDictionary, which makes it the only one absent from configuration (line 76) — the dictionary CodePush.m:959 hands to JS. Deliberate? publicKey is also setter-less but still lives in the dictionary, and it carries a comment explaining why there's no setter; worth the same one-liner here.

About autosynthesis: thanks, fixed!

Regarding _configDictionary: I didn't want to propage that existing pattern because it reads and writes a NSMutableDictionary, so there isn't any type safety for the values we store inside.

I didn't notice how that dictionary is exposed to the JS side, but in this specific case, I think it's completely okay not to expose this new field: this feature flag can only be defined statically in Info.plist, so I don't see any reason why an app would want to query this at runtime (unlike the other config values, which can be overridden from the JS side)

ofalvai changed the title ~~ios apply patches~~ iOS: apply bsdiff patches during package install Aug 28, 2026

ofalvai mentioned this pull request Aug 28, 2026

iOS: consolidate SHA-256 hashing into a shared utility #47

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ofalvai force-pushed the ios-apply-patches branch from c9f5d13 to 5aefe55 Compare August 28, 2026 14:20

ofalvai force-pushed the ios-apply-patches branch from 5aefe55 to 2a740c0 Compare August 31, 2026 12:10

ofalvai force-pushed the ios-apply-patches branch from 2a740c0 to 316a439 Compare September 3, 2026 10:48

ofalvai force-pushed the ios-apply-patches branch from 316a439 to 221514a Compare September 8, 2026 10:22

ofalvai mentioned this pull request Sep 8, 2026

iOS: bspatch integration #44

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ofalvai force-pushed the ios-apply-patches branch from 221514a to f86f490 Compare September 8, 2026 10:50

ofalvai commented Sep 8, 2026

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ofalvai removed this pull request from stack #41 September 9, 2026 06:38

ofalvai force-pushed the ios-apply-patches branch from f86f490 to 80a906d Compare September 9, 2026 06:47

ofalvai changed the base branch from ios-sha256-refactor to ios-binary-diff-patcher September 9, 2026 06:47

ofalvai added this pull request to stack #57 September 9, 2026 06:47

Copilot AI balanced review requested due to automatic review settings September 9, 2026 15:37

ofalvai force-pushed the ios-apply-patches branch from 80a906d to 813d75f Compare September 9, 2026 15:37

Copilot started reviewing on behalf of ofalvai September 9, 2026 15:38 View session

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Comment thread ios/CodePush.xcodeproj/project.pbxproj Outdated

Comment thread ios/CodePush/CodePush.h Outdated

Comment thread ios/CodePush/CodePushPackage.m

ofalvai mentioned this pull request Sep 14, 2026

iOS: add CodePushDiffManifest for parsing diff manifests #58

Merged

ofalvai mentioned this pull request Sep 14, 2026

iOS: add CodePushBinaryDiffPatcher to apply bsdiff patches #59

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ofalvai force-pushed the ios-apply-patches branch from 813d75f to 92fe5c4 Compare September 14, 2026 14:21

ofalvai force-pushed the ios-apply-patches branch from 92fe5c4 to 2b598e6 Compare September 14, 2026 15:46

ofalvai marked this pull request as ready for review September 14, 2026 15:58

miklosboros requested changes Sep 15, 2026

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miklosboros reviewed Sep 15, 2026

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ofalvai force-pushed the ios-apply-patches branch 2 times, most recently from 0e59454 to 6043a6b Compare September 21, 2026 11:49

ofalvai force-pushed the ios-apply-patches branch 2 times, most recently from 8428205 to 9cb8a25 Compare September 22, 2026 10:59

iOS: apply bsdiff patches during package install

93c37a6

ofalvai force-pushed the ios-apply-patches branch from 9cb8a25 to 93c37a6 Compare September 22, 2026 11:09

miklosboros approved these changes Sep 22, 2026

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ofalvai merged commit 7f4c6af into master Sep 22, 2026
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ofalvai deleted the ios-apply-patches branch September 22, 2026 14:40

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ofalvai commented Aug 28, 2026 •

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ofalvai Sep 22, 2026 •

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