fix(ios): improve ListChannelsDec decoder to handle unexpected response formats#709
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dhruvkej9 wants to merge 1 commit intoCap-go:mainfrom
Open
fix(ios): improve ListChannelsDec decoder to handle unexpected response formats#709dhruvkej9 wants to merge 1 commit intoCap-go:mainfrom
dhruvkej9 wants to merge 1 commit intoCap-go:mainfrom
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…se formats Fixes Cap-go#706 - listChannels() was failing with 'Response could not be decoded because of error: The data couldn't be read because it isn't in the correct format.' The original decoder used singleValueContainer() as primary path, then fell back to a keyed container for error responses. However, if the backend returned a wrapped format ({ "channels": [...] }) or any format not strictly a JSON array, the single value decode would fail, then the keyed container decode would also fail silently, resulting in a confusing decode error being surfaced to the user. Changes: - Handle direct array format (primary: backend returns [] directly) - Handle wrapped object format ({ "channels": [...] }) - Handle error response format ({ "error": "..." }) - Return a descriptive error string instead of throwing when no format matches, preventing the cryptic iOS decode error from propagating to the user
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Actionable comments posted: 1
🤖 Prompt for all review comments with AI agents
Verify each finding against the current code and only fix it if needed.
Inline comments:
In `@ios/Sources/CapacitorUpdaterPlugin/InternalUtils.swift`:
- Around line 94-107: When a keyed container decodes but neither the expected
channels array nor the "error" string is present, set a descriptive fallback
error instead of leaving self.error nil; in the initializer that calls
decoder.container(keyedBy: CodingKeys.self) (the branch handling channels /
error for ChannelInfo), after attempting
keyedContainer.decode([ChannelInfo].self, forKey: .channels) and
keyedContainer.decode(String.self, forKey: .error), detect the case where both
self.channels and self.error are nil and assign a clear message (e.g. "Response
could not be decoded: unexpected keyed payload") to self.error so unsupported
keyed payloads are surfaced to callers.
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ios/Sources/CapacitorUpdaterPlugin/InternalUtils.swift
Comment on lines
+94
to
+107
| if let keyedContainer = try? decoder.container(keyedBy: CodingKeys.self) { | ||
| // Try wrapped channels array format: { "channels": [...] } | ||
| if let channelsArray = try? keyedContainer.decode([ChannelInfo].self, forKey: .channels) { | ||
| self.channels = channelsArray | ||
| self.error = try? keyedContainer.decode(String.self, forKey: .error) | ||
| return | ||
| } | ||
| // Error response format: { "error": "..." } | ||
| self.channels = nil | ||
| self.error = try? keyedContainer.decode(String.self, forKey: .error) | ||
| } else { | ||
| // Handle error response | ||
| let errorContainer = try decoder.container(keyedBy: CodingKeys.self) | ||
| // Could not decode in any known format — return empty/nil gracefully | ||
| self.channels = nil | ||
| self.error = try? errorContainer.decode(String.self, forKey: .error) | ||
| self.error = "Response could not be decoded: unexpected format" |
There was a problem hiding this comment.
Return the descriptive fallback error for unsupported keyed payloads.
On Lines 94-107, an object like { "message": "..." } or { "channels": {} } still decodes to channels == nil and error == nil because every keyed decode is wrapped in try?. At the only use site in ios/Sources/CapacitorUpdaterPlugin/CapgoUpdater.swift:1739-1758, that is treated as a successful decode with no error surfaced, so the original decode failure becomes a silent empty result instead of the intended descriptive message.
Suggested fix
- if let keyedContainer = try? decoder.container(keyedBy: CodingKeys.self) {
- // Try wrapped channels array format: { "channels": [...] }
- if let channelsArray = try? keyedContainer.decode([ChannelInfo].self, forKey: .channels) {
- self.channels = channelsArray
- self.error = try? keyedContainer.decode(String.self, forKey: .error)
- return
- }
- // Error response format: { "error": "..." }
- self.channels = nil
- self.error = try? keyedContainer.decode(String.self, forKey: .error)
+ if let keyedContainer = try? decoder.container(keyedBy: CodingKeys.self) {
+ // Try wrapped channels array format: { "channels": [...] }
+ if let channelsArray = try? keyedContainer.decode([ChannelInfo].self, forKey: .channels) {
+ self.channels = channelsArray
+ self.error = try? keyedContainer.decode(String.self, forKey: .error)
+ return
+ }
+
+ // Error response format: { "error": "..." }
+ if let serverError = try? keyedContainer.decode(String.self, forKey: .error) {
+ self.channels = nil
+ self.error = serverError
+ return
+ }
+
+ self.channels = nil
+ self.error = "Response could not be decoded: unexpected format"
} else {
// Could not decode in any known format — return empty/nil gracefully
self.channels = nil
self.error = "Response could not be decoded: unexpected format"
}🤖 Prompt for AI Agents
Verify each finding against the current code and only fix it if needed.
In `@ios/Sources/CapacitorUpdaterPlugin/InternalUtils.swift` around lines 94 -
107, When a keyed container decodes but neither the expected channels array nor
the "error" string is present, set a descriptive fallback error instead of
leaving self.error nil; in the initializer that calls decoder.container(keyedBy:
CodingKeys.self) (the branch handling channels / error for ChannelInfo), after
attempting keyedContainer.decode([ChannelInfo].self, forKey: .channels) and
keyedContainer.decode(String.self, forKey: .error), detect the case where both
self.channels and self.error are nil and assign a clear message (e.g. "Response
could not be decoded: unexpected keyed payload") to self.error so unsupported
keyed payloads are surfaced to callers.
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Problem
Fixes #706 -
listChannels()was throwing a confusing error on iOS:Root Cause
The original
ListChannelsDeccustom decoder usedsingleValueContainer()as the primary decode path, then fell back to a keyed container for error responses.When the backend returns a response in a format that is not strictly a raw JSON array (e.g. a wrapped object
{ "channels": [...] }or an error object with unexpected keys), the decode chain fails silently at both stages — causing Swift's Codable to surface a cryptic format error instead of a useful message.Fix
Restructured the
init(from:)decoder to handle three distinct response shapes:[...]— primary backend format{ "channels": [...] }— handles potential future/wrapped formats{ "error": "..." }— properly surfaces server errorsAs a safety net, when none of the known formats match, a descriptive error string is returned instead of propagating Swift's cryptic decode error.
Testing
/claim #706
Summary by CodeRabbit
Bug Fixes