GeezerVison

Draft until ios-device-lib is released. CI can't compile this against 0.9.6, because the types for the new stream are missing. After NativeScript/ios-device-lib#88 ships, bump the dependency here and mark this ready.

What is the current behavior?

App logs on devices come from syslog_relay, filtered with fragile regexes. Kernel noise such as wlan0: lines gets through, non-ASCII text is escaped, and there is no way to choose how much native output to show. Long messages are truncated by os_log with <…>.

What is the new behavior?

• Devices stream os_trace_relay and simulators use log stream --style ndjson, both selected by executable name, so logs survive closing and reopening the app with no pid tracking.
• --log sets the scope:
  • default: JS output
  • debug: the whole app process without debug entries, like Xcode
  • trace / all: everything
• Debug builds write "logFormat": 1 to the app's package.json. The runtime then logs each piece of a split message as [ns <id> <index>/<count>] <piece>, and the CLI puts the pieces back together by process and message id. A message prints as soon as its last piece arrives; after 500 ms, missing pieces show as <…lost…>, and the next message is never joined onto an unfinished one. Webpack doesn't touch that file and the key only re-signs, so build caching isn't affected.
• Devices fall back to the syslog relay, with the piece headers removed, if the stream isn't available. Pieces aren't put back together there.
• The unused lib/common/mobile/ios/ios-log-filter.ts is deleted.

print() and stderr capture follow in #6181.

Testing

Run on the first version of this PR, which used invisible chunk markers. Demo app, 11 messages (up to 100 KB, emoji, 800 lines, console.error, objects) compared exactly against the expected text, on both launches of each run. The full four-PR stack with the runtime PRs:

• Release prepare leaves the key out and debug prepare includes it.
• Trailing whitespace at the end of a message is trimmed, as it already was.
• The syslog fallback has only been tested on captured logs, not in a live app.
• --log trace is large: about 11,000–13,000 extra lines per run of the demo app.
• After the switch to logFormat: all unit tests pass, including new ones for lost pieces, interleaved messages and whitespace. On a simulator, captured log stream output from the main thread, two workers and stdout logging at once was rebuilt exactly by this code; see feat(console): split long messages for os_log and report errors as errors ios#530 for the numbers. Not rerun on the iPad.
• Pieces can still be lost under extreme bursts; see feat(console): split long messages for os_log and report errors as errors ios#530.

Part of a stack

Base: #6178. Needs NativeScript/ios-device-lib#88 released, and NativeScript/ios#530 for stitching.