Production Bugs

Example of an Implementation defined core constant expression whose evaluation has runtime undefined behavior

by

Summary The C++ standard defines a core constant expression as an expression that can be evaluated at compile-time, but with some exceptions. One such exception is when an expression satisfies the constraints of a core constant expression but has runtime-undefined behavior. This article explores an example of such an implementation-defined core constant expression. Root Cause … Read more

Variadic parameter and additional default value not compiling

by

Summary This postmortem analyzes a C++ template bug where a variadic parameter pack becomes unusable because a defaulted trailing parameter (std::source_location) prevents correct overload resolution. The result is a confusing compile‑time error when calling _LOG() with multiple arguments. Root Cause The root cause is the placement of the default parameter after a variadic pack: A … Read more

How can I force align audio with it’s corresponding text inorder to get timestamps?

by

Summary Forced alignment is a critical process for synchronizing audio with text transcripts, enabling precise timestamp generation. When working with less-supported languages like Yiddish, common tools like the Montreal Forced Aligner (MFA) fall short. The ctc-forced-aligner is a viable alternative but can suffer from drift issues, where alignment accuracy degrades over time. This postmortem explores … Read more

My neural network for MNIST digit recognition learns for one epoch and then stops learning

by

Summary This incident describes a neural network that stops learning after the first epoch, with accuracy stuck at ~9.8%, which is effectively random guessing on MNIST. The core issue stems from using MSE with tanh, incorrect gradient flow, and weight‑update logic that silently zeroes out updates. Root Cause The failure to learn is caused by … Read more

Schedule Notification is not properly working in flutter

by

Summary Scheduling notifications in Flutter apps, especially for frequent alerts like medicine reminders, is challenging due to package limitations and background processing constraints. Both awesome_notifications and flutter_local_notifications fail to handle more than ~20 scheduled notifications, and Isar database does not function in background mode, preventing reliable notification scheduling. Root Cause Package Limitations: Both notification packages … Read more

How can I get Unicode output from robocopy in a PowerShell script?

by

Summary Robocopy’s output encoding is fixed as UTF-16LE, which causes issues when redirected or piped in PowerShell scripts. Attempting to change console encoding or using Set-Content with UTF-8 results in gibberish output due to encoding mismatch. Root Cause Robocopy outputs in UTF-16LE regardless of system settings. PowerShell’s default encoding for redirection (>) and pipes (|) … Read more

Container initiated authentication

by

Summary A misconfigured container‑initiated authentication flow caused users to authenticate successfully but remain stuck on the login page instead of being redirected to the originally requested protected resource. The authentication mechanism completed, but the application failed to hand control back to the container so it could perform the redirect. Root Cause The login flow never … Read more

How to convert a BigInt to string to be able to use it in CRUD operations

by

Summary Converting BigInt values to strings is essential when preparing data for CRUD operations, as many databases and APIs do not natively support BigInt. The provided function recursively traverses an object, converting all BigInt values to strings using JSON.stringify and a custom replacer function. Root Cause BigInt values are not universally supported in serialization formats … Read more

Using a repeated block of code as function in xsl

by

Summary This postmortem analyzes a repetitive‑code issue in an XSLT 1.0 stylesheet where the same logic block was duplicated across multiple xsl:if conditions. The lack of functional abstraction led to brittle, hard‑to‑maintain templates. The fix involved extracting the repeated logic into a named template and invoking it with parameters. Root Cause The root cause was … Read more