Production Bugs

AliExpress Dropshipping API – Persistent “IncompleteSignature” Error on Token Exchange (Node.js/TypeScript)

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Summary The AliExpress Dropshipping API integration in a NestJS application consistently failed with an IncompleteSignature error during token exchange. The issue stemmed from incorrect signature generation due to misinterpretation of the AliExpress signature algorithm and missing URL encoding for specific parameters. Root Cause Incorrect Signature Construction: The signature string included parameter keys and values without … Read more

How do i setup a database in ASP.net(MVC)

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Summary Setting up a database in an ASP.NET MVC application involves configuring Entity Framework, installing necessary NuGet packages, and setting up a connection string. A recent issue occurred when a junior developer failed to properly configure the database context, leading to runtime errors and application crashes. Root Cause The root cause was: Missing NuGet packages … Read more

TBB interaction in python binding

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Summary This incident involved a double‑free crash triggered when importing a Python module backed by a C++ library that embeds oneTBB, but only when NumPy is imported first. The failure was caused by two independent TBB runtimes being loaded into the same Python process, each attempting to manage and free overlapping internal resources. Root Cause … Read more

LangChain.js createHistoryAwareRetriever with Ollama embeddings throws invalid input type error

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Summary A type mismatch inside LangChain.js caused createHistoryAwareRetriever to fail when paired with OllamaEmbeddings. The retriever expected a string input, but the history‑aware wrapper produced a message array, triggering an “invalid input type” error. Root Cause The failure stems from incompatible input/output expectations between: ChatOllama, which emits AIMessage / HumanMessage objects createHistoryAwareRetriever, which expects the … Read more

Jetty 12 API changes: How to replace HttpInput.Interceptor and HttpOutput.Interceptor

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Summary This postmortem analyzes the Jetty 12 API removal of HttpInput.Interceptor and HttpOutput.Interceptor, why these hooks disappeared, what breaks during migration, and how senior engineers replace this functionality using Jetty 12’s new Handler/Filter pipeline and Content.Source / Content.Sink abstractions. Root Cause The failure occurs because Jetty 12 removed the legacy Servlet‑container–centric interception APIs (HttpInput.Interceptor, HttpOutput.Interceptor) … Read more

Excel SetFocus on Barcode Textbox -Not working

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Summary The issue involves an Excel VBA userform where Textbox1 fails to regain focus and highlight the barcode after the first scan, especially when the same barcode is scanned consecutively. The AfterUpdate event in Textbox2 does not fire, preventing the focus from returning to Textbox1. Root Cause Event Handling Conflict: The AfterUpdate event in Textbox2 … Read more

I am trying to exclude a file that has -PK in its name in the code below. Auto print from email. File name always is a pdf and has -PK in its name

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Summary An Outlook VBA script intended to auto-print email attachments failed to exclude files containing -PK in their names. The issue arose because the script lacked a filename validation check, causing all matching file types (e.g., .pdf) to be printed regardless of their name. Root Cause The script did not include logic to filter filenames … Read more

Selecting a row with alternatives in R

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Summary Issue: Duplicated lab results for subjects with both hb and hb_urg entries in the dataset. Goal: Retain only hb_urg for subjects with both results, while keeping single entries as-is. Root Cause Duplicate entries for subjects with both hb and hb_urg lab results. Lack of filtering logic to prioritize hb_urg over hb when both exist. … Read more

Appsync Graphql Subscription problem with IAM Authentication

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Summary The issue at hand is an Appsync GraphQL Subscription problem with IAM Authentication. The connection to Appsync is established correctly, but when attempting to subscribe, an error occurs due to a mismatch in the request signature. This is a critical issue as it prevents the application from receiving real-time updates. Root Cause The root … Read more