Fix crash when parsing native stack frames without symbols by BartoszLitwiniuk · Pull Request #278 · backtrace-labs/backtrace-unity

BartoszLitwiniuk · 2026-03-05T21:04:05Z

Summary

Fixes a crash in the native stack trace parser when frames are missing symbol information. Refactors BacktraceRawStackTraceParser for safer parsing and adds unit test coverage.

It's a follow up of changes made in #258 and bug BT-5953.

Changes

Added bounds checks in SetNativeStackTraceInformation to prevent out-of-range access when a native frame lacks symbol data
Extract parsing logic to BacktraceRawStackTraceParser for clearer, more defensive frame parsing
Added debug logging to aid future diagnosis of malformed frames
Added BacktraceRawStackTraceParserTests covering native frame parsing edge cases
Use BacktraceRawStackTraceParser in BacktraceUnhandledException instead of mixing unhandled exception handler with parsing logic

Testing

New unit tests validate safe parsing of native frames, including frames without symbols
Existing tests continue to pass

Add bounds checks in SetNativeStackTraceInformation Add NativeParserTests to validate safe native frame parsing

…ve_stack_frames_fix # Conflicts: # Runtime/Model/BacktraceRawStackTraceParser.cs

…mes_fix # Conflicts: # Runtime/Model/BacktraceRawStackTraceParser.cs # Tests/Runtime/Model/BacktraceRawStackTraceParserTests.cs

melekr · 2026-05-08T14:20:33Z

can you link sample BT reports @BartoszLitwiniuk ?

melekr · 2026-05-08T14:22:11Z

+
+# Platforms
+iOS/
+Mac/


what's the reason here?

# Conflicts: # Tests/Editor.meta # Tests/Tests.meta

melekr · 2026-05-12T20:00:34Z

+                int methodNameEndIndex = frameString.IndexOf(')');
+                int openParentIndex = frameString.LastIndexOf('(', methodNameEndIndex); // we require a '(' that appears before this ')'


This can throw before the invalid-frame check.

If frameString is non-empty and has no ), then methodNameEndIndex is -1,
and LastIndexOf('(', -1) throws ArgumentOutOfRangeException.

That changes behaviour from the previous implementation which preserved frames without )as raw BacktraceStackFrame instances.

With the current code, the catch returns null, and ConvertStackFrames drops the frame entirely.

I suggest something like this :

Suggested change

int methodNameEndIndex = frameString.IndexOf(')');

int openParentIndex = frameString.LastIndexOf('(', methodNameEndIndex); // we require a '(' that appears before this ')'

int methodNameEndIndex = frameString.IndexOf(')');

if (methodNameEndIndex == -1)

{

return new BacktraceStackFrame

{

FunctionName = frame,

InvalidFrame = true

};

}

int openParentIndex = frameString.LastIndexOf('(', methodNameEndIndex);

if (openParentIndex == -1 || openParentIndex > methodNameEndIndex)

{

return new BacktraceStackFrame

{

FunctionName = frame,

InvalidFrame = true

};

}

melekr · 2026-05-12T20:02:34Z

+                Debug.LogError($"Exception while parsing stack frame: '{frame}'. Exception: {e}");
+                return null;


Returning null here causes the frame to be dropped.

I think parser failure should preserve the raw frame, not remove diagnostic data from the report.

Also, logging with Debug.LogError from report construction is risky in this SDK: Unity error logs are reportable, so a parser failure can create a secondary Backtrace report or another capture.

melekr · 2026-05-12T20:03:34Z

+                if (methodNameEndIndex == -1 || openParentIndex == -1 || openParentIndex > methodNameEndIndex)
+                {
+                    // If either index is missing, it's an invalid frame
+                    Debug.LogWarning($"Invalid stack frame format: '{frameString}'.");


I would avoid logging from the parser for the same reason.

melekr · 2026-05-12T20:05:51Z

+                return stackFrame;
+            }
+
+            frameString = frameString.Substring(frameString.IndexOf(' ')).Trim();


This remains unsafe;

If a JIT frame starts with # but does not contain a space, IndexOf(' ') returns -1 and Substring(-1) throws.

With the current wrapper logic, that exception causes the frame to be dropped.

melekr · 2026-05-12T20:06:54Z

+                return stackFrame;
+            }
+
+            frameString = frameString.Substring(frameString.IndexOf(' ')).Trim();


something like :

Suggested change

frameString = frameString.Substring(frameString.IndexOf(' ')).Trim();

int firstSpace = frameString.IndexOf(' ');

if (firstSpace == -1 || firstSpace == frameString.Length - 1)

{

stackFrame.FunctionName = frameString;

return stackFrame;

}

frameString = frameString.Substring(firstSpace + 1).Trim();

melekr · 2026-05-12T20:08:57Z

+
+namespace Backtrace.Unity.Tests.Runtime
+{
+    public class BacktraceRawStackTraceParserTests


needs more coverage especially through ConvertStackFrames and ConvertStackFrames

melekr · 2026-05-12T20:09:26Z

 namespace Backtrace.Unity.Types
 {
-    enum BacktraceStackFrameType
+    public enum BacktraceStackFrameType


Why does this need to become public ?

melekr · 2026-05-12T20:13:40Z

+
+namespace Backtrace.Unity.Tests.Runtime
+{
+    public class BacktraceRawStackTraceParserTests


Let's add an end-to-end serialization test or attach a sample Backtrace report here.

melekr and others added 10 commits October 8, 2025 00:53

Prevent crash when parsing native frames without symbols

b0bcb36

Add bounds checks in SetNativeStackTraceInformation Add NativeParserTests to validate safe native frame parsing

Update workflow unityVersion

a1797ac

Update build.yml

a3ee28a

Update build.yml

236f94d

Merge branch 'master' into bugfix/native_stack_frames_fix

364bdaa

Revert CI/CD changes

252e4ad

Update gitignore

a0e201e

PR fixes

b6fa36a

Refactor parsing frames

4f5f898

Fix formatting

3693d67

BartoszLitwiniuk changed the title ~~Bugfix/native stack frames fix~~ Draft: Bugfix/native stack frames fix Mar 5, 2026

BartoszLitwiniuk marked this pull request as draft March 5, 2026 21:04

Bartosz Litwiniuk added 4 commits March 5, 2026 22:04

Remove empty line

48c16e5

Add one more unit-tests

c4f9558

Merge branch 'master' into bugfix/native_stack_frames_fix

c9d93aa

Merge branch 'master' into bugfix/native_stack_frames_fix

954b4e5

BartoszLitwiniuk changed the base branch from bugfix/native_stack_frames to master April 11, 2026 07:07

BartoszLitwiniuk marked this pull request as ready for review April 15, 2026 10:37

BartoszLitwiniuk marked this pull request as draft April 15, 2026 10:57

Bartosz Litwiniuk added 5 commits April 15, 2026 13:24

Improve tests

ca1e1aa

Improve code quality

ce2d385

Refactor parser

0b2503f

Refactor parser, add debug logs

7ca4908

Add missing import

d7785df

BartoszLitwiniuk marked this pull request as ready for review April 21, 2026 18:02

Bartosz Litwiniuk added 3 commits April 21, 2026 20:09

Remove new lines

41a2bfb

Revert changes and add logger

d8f53ab

Merge branch 'bugfix/native_stack_frames_fix_revert' into bugfix/nati…

bc779f0

…ve_stack_frames_fix # Conflicts: # Runtime/Model/BacktraceRawStackTraceParser.cs

BartoszLitwiniuk changed the title ~~Draft: Bugfix/native stack frames fix~~ Fix crash when parsing native stack frames without symbols Apr 21, 2026

Remove unused imports

f545428

melekr assigned BartoszLitwiniuk Apr 22, 2026

melekr requested review from konraddysput and melekr April 22, 2026 18:34

melekr and others added 4 commits April 24, 2026 11:54

Merge branch 'master' into bugfix/native_stack_frames_fix

27e206e

Update README.md

d1467c7

Apply changes with parser for native stackframes

4f4cb18

Temporary fix for test.yml

37113e0

melekr approved these changes May 6, 2026

View reviewed changes

Bartosz Litwiniuk added 5 commits May 6, 2026 22:57

Fix unit tests

95b60bb

Fix native frames parsing

eb794f9

Revert changes

843bf5b

Revert changes

bb9ab09

Merge branch 'fix-parsing-native-frames' into bugfix/native_stack_fra…

e1c027f

…mes_fix # Conflicts: # Runtime/Model/BacktraceRawStackTraceParser.cs # Tests/Runtime/Model/BacktraceRawStackTraceParserTests.cs

melekr self-requested a review May 8, 2026 14:18

melekr reviewed May 8, 2026

View reviewed changes

melekr self-requested a review May 8, 2026 14:22

Bartosz Litwiniuk and others added 7 commits May 11, 2026 20:04

Revert breaking changes

e8f07f8

Revert change

2d5455b

Revert changes

bd52133

Fix parsing library

6d1a33e

Revert .gitignore changes

b2a7ba7

Merge branch 'master' into bugfix/native_stack_frames_fix

1db8608

# Conflicts: # Tests/Editor.meta # Tests/Tests.meta

Revert README.md changes

65de110

melekr requested changes May 12, 2026

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Fix crash when parsing native stack frames without symbols#278

Fix crash when parsing native stack frames without symbols#278
BartoszLitwiniuk wants to merge 39 commits into
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bugfix/native_stack_frames_fix

BartoszLitwiniuk commented Mar 5, 2026 •

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		int methodNameEndIndex = frameString.IndexOf(')');
		int openParentIndex = frameString.LastIndexOf('(', methodNameEndIndex); // we require a '(' that appears before this ')'

-                int methodNameEndIndex = frameString.IndexOf(')');
-                int openParentIndex = frameString.LastIndexOf('(', methodNameEndIndex); // we require a '(' that appears before this ')'
+int methodNameEndIndex = frameString.IndexOf(')');
+if (methodNameEndIndex == -1)
+{
+    return new BacktraceStackFrame
+    {
+        FunctionName = frame,
+        InvalidFrame = true
+    };
+}
+int openParentIndex = frameString.LastIndexOf('(', methodNameEndIndex);
+if (openParentIndex == -1 || openParentIndex > methodNameEndIndex)
+{
+    return new BacktraceStackFrame
+    {
+        FunctionName = frame,
+        InvalidFrame = true
+    };
+}

		Debug.LogError($"Exception while parsing stack frame: '{frame}'. Exception: {e}");
		return null;

-            frameString = frameString.Substring(frameString.IndexOf(' ')).Trim();
+            int firstSpace = frameString.IndexOf(' ');
+if (firstSpace == -1 || firstSpace == frameString.Length - 1)
+{
+    stackFrame.FunctionName = frameString;
+    return stackFrame;
+}
+frameString = frameString.Substring(firstSpace + 1).Trim();

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BartoszLitwiniuk commented Mar 5, 2026 •

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