Highlighted line is off by one line on non existing property

[skinsapp]

OS:

• Windows
• MacOS
• Linux

Platform:

• iOS
• Android

SDK:

• @sentry/react-native (>= 1.0.0)
• react-native-sentry (<= 0.43.2)

SDK version: 0.0.0

react-native version: 0.0.0

Are you using Expo?

• Yes
• No

Are you using sentry.io or on-premise?

• sentry.io (SaaS)
• on-premise

If you are using sentry.io, please post a link to your issue so we can take a look:

[Link to issue]

Configuration:

(@sentry/react-native)

const bundleId = Platform.OS === 'ios' ? config.bundleIdIos : config.bundleIdAndroid

const { appVersion, label } = await codePush.getUpdateMetadata()
const release = `${bundleId}@${appVersion}+codepush:${label}` // eg: [email protected]+codepush:v68

Sentry.init({
    dsn: "https://518d6f8ce5f44c12a464be5ff5e614be@o4505131309203456.ingest.sentry.io/4505131310841856",
    tracesSampleRate: .1,
    release,
    dist: label
});

---

I have following issue:

The sourcemap is one line off. In the following screenshot, line 43 should be highlighted, not line 42:

The android version of my app does not have this issue.

Steps to reproduce:

I'm using these scripts to generate the source maps:

{
 "ios:deploy": "npm run appcenter:login && npm run ios:codepush:release && npm run ios:sentry",
 "appcenter:login": "appcenter login --token foobar",
 
 "ios:getNativeVersion": "sed -n '/MARKETING_VERSION/{s/MARKETING_VERSION = //;s/;//;s/^[[:space:]]*//;p;q;}' ./ios/skins.xcodeproj/project.pbxproj",
 "ios:getCodePushVersion": "appcenter codepush deployment list --app foo/bar | sed -n -e 's/^\\(.*\\)\\(Label: \\)\\(v[0-9]*\\) \\(.*\\)$/\\3/p'",

 "ios:codepush:release": "rm -rf sentry && appcenter codepush release-react --extra-bundler-option=--reset-cache --extra-bundler-option=--minify --extra-bundler-option false -m -a foo/bar -d Production --sourcemap-output './sentry/CodePush/main.jsbundle.map' --output-dir './sentry'",

 "ios:sentry": "export SENTRY_PROPERTIES=./ios/sentry.properties; v=$(npm run --silent ios:getNativeVersion) && c=$(npm run --silent ios:getCodePushVersion) && sentry-cli react-native appcenter foo/bar ios './sentry/CodePush' --bundle-id 'com.foo.bar' --version-name $v --dist $c --deployment Production",
}

Actual result:

highlighted line is 42

Expected result:

highlighted line is 43

[kahest]

Hey @the-skins-app, thanks for reporting and the details - we'll investigate. Please let us know if you see something similar in other parts of your code.

[krystofwoldrich]

Hi,
thank you for the message and the details.

It looks like there is a difference between Sentry symbolication and metro-symbolicator which points to the correct line number 43.

Does this happen only with CodePush updates or also with full app releases?

Does this still happen, when you send a new error?

[krystofwoldrich]

I've reproduced the error with our sample app.

https://sentry-sdks.sentry.io/issues/4453310672/events/62307475e6814589bfbc249c5f6e91c0/

Minified stack trace

ReferenceError: Property 'thisVariableDoesNotExist' doesn't exist
  at onPress(app:///index.android.bundle:1:985288)

Sentry

ReferenceError: Property 'thisVariableDoesNotExist' doesn't exist
  at Button.props.onPress(src/Screens/HomeScreen.tsx:81:24)

Metro Symbolicate

 ❯ npx metro-symbolicate index.map < stacktrace.txt
ReferenceError: Property 'thisVariableDoesNotExist' doesn't exist
  at onPress(src/Screens/HomeScreen.tsx:82:Button.props.onPress)

stacktrace.txt

ReferenceError: Property 'thisVariableDoesNotExist' doesn't exist
  at onPress(app:///index.android.bundle:1:985288)

index.map

source-map

const fs = require('fs');
const sourceMap = require('source-map');
var smc = new sourceMap.SourceMapConsumer(fs.readFileSync('./sample-new-architecture/index.map', 'utf8'));
console.log(smc.originalPositionFor({ line: 1, column: 985288 }));

{
  source: 'src/Screens/HomeScreen.tsx',
  line: 82,
  column: 12,
  name: 'thisVariableDoesNotExist'
}

[Swatinem]

The off-by-one seems to be here somewhere:

<Token src/Screens/HomeScreen.tsx:80:23 (0:985283)>
<Token src/Screens/HomeScreen.tsx:81:12 name=thisVariableDoesNotExist (0:985288)>

The first token is the one we find, while the second token is the right one.

We are doing a -1 on both line and column, as the stack traces report those as 1-indexed, whereas the sourcemap tokens themselves contain those as 0-indexed.

So we are internally actually looking for 985287 and find the previous token. I’m just wondering why the other tools are doing the right thing here.

[Swatinem]

Some digging in the past later:

Seems like we have been adjusting columns ever since getsentry/sentry@bc8fa24 / getsentry/sentry#5922
(And adding +1 when the token comes back: getsentry/sentry@6867a45#diff-5649208c3eac2367f8d3130a299d7c3cd3020aa4c1a21f1d4ea57b80de38ef34R600)

When porting that logic to symbolicator, we have cargo-culted that behavior as well:

getsentry/symbolicator@70451dc#diff-d8382530b3ce9204a7a4c01b6ff3bde446870d29db23b45b8236281c5a5eea7cR183-R184
interestingly, backwards adjusting was added later:
getsentry/symbolicator@eb6b197#diff-d8382530b3ce9204a7a4c01b6ff3bde446870d29db23b45b8236281c5a5eea7cR166-R168

Even though other tools agree that columns are 0-based, both in stack traces as well as in the sourcemaps.

https://github.com/mozilla/source-map/blob/master/lib/source-map-consumer.js#L472-L475
https://github.com/tc39/source-map-spec/blob/1ac019b79757d9cea70401fa530a78b6c062feb8/source-map-rev3.md?plain=1#L110

I’m questioning my sanity a bit by now.

[Swatinem]

Okay, @mitsuhiko cleared up the confusion. While the JS/SourceMap ecosystem may agree that columns are 0-based, Sentry itself uses 1-based column in its event payloads and the UI.

So possibly the SDK fails to adjust the column before it sends it over to Sentry?

[skinsapp]

@krystofwoldrich it only occurs with CodePush, not with Native builds. Yes, new errors are still one line off, but I did notice one that happened to be correct a while ago. I'm not sure why.

@Swatinem thank you for looking into this. You seem to be on the scent.

[krystofwoldrich]

@the-skins-app Thank you for the update. We reproduce it even with a native build. It should not make a difference. Do you have the same error where one if from Code Push one line off and one is from Native build and correct?

[krystofwoldrich]

• Line/Column indexing in RN [DevTools] Use line number and column number to match hook facebook/react#21792 (comment)

Differs based on the engine JSC/Hermes.