tlmgr on Debian can fail with “cannot setup TLPDB” when the TeX Live user tree is not initialized, blocking package and configuration management.

Callback definitions can silently replace each other in ResourceController, unlike ActiveRecord’s queued hooks, so trait-based behavior may disappear.

Pass nested form data to a plain model reader such as home_page, without a real association. Works for singular references, with manual record construction and no deletion support.

Missing xelatex causes RTeX::Document::ExecutableNotFoundError during tests; installing texlive-xetex on Ubuntu 14.04 provides the binary.

Character formatting in LibreOffice can trigger unwanted style changes across the whole document. Disabling AutoUpdate on the affected style keeps direct formatting local.

Textarea cursors and selections do not reliably bring the view to the target position. Focusing a shortened value can force the browser to scroll there.

FreeBSD Ports may try to upgrade ruby-iconv even though it is ignored for Ruby 2.0 and newer; setting RUBY_VER=1.9 makes the port match the installed Ruby version.

Precompiled CSS breaks relative image and font URLs when asset paths change; bower-rails can rewrite url(...) references into ERB asset helpers before deployment.

NaN is difficult to compare in JavaScript because it never equals itself. Object.is() works in ES6; ES5 needs a number type check plus isNaN().

AngularJS directives for click-to-edit interfaces and editable grids, enabling in-place editing with support for complex forms.

Use one(...) for handlers that should fire a single time; it accepts the same arguments as on(...) and removes itself after the first event.

Rails asset management becomes easier with bower-rails, using a Bowerfile and rake tasks to install, list, update, and rewrite vendored front-end packages.

Circular references make JSON.stringify fail with TypeError; a custom serializer or safe stringifier is needed to inspect or export object graphs.

none returns an empty ActiveRecord::Relation for default objects and other cases where no records should match, with a fallback initializer for older Rails versions.

Sass-generated stylesheets can surface Encoding::CompatibilityError after a Rails and Ruby upgrade, often from stale cache files or mismatched UTF-8 and ASCII-8BIT encodings.

ActiveRecord::Base.connection.indexes(:table_name) returns the database indexes defined for an ActiveRecord table, useful for checking schema performance and uniqueness constraints.

CoffeeScript classes can initialize instance properties directly from an attribute hash, similar to ActiveRecord-style mass assignment. constructor: ({ @name, @email }) -> binds fields automatically.

Rails 4 controller specs can send raw JSON in a member action request by passing the JSON body before the route parameters.

Native file inputs can accept several uploads at once with multiple, but server parsing usually needs array-style names and custom Rails adaptation.

Useful AngularJS filters for fuzzy string search and formatting values such as percentages.

Store multiple labels in one field and query records by any or all of them with PostgreSQL array operators and a GIN index in Rails 4.

Iterating with a position counter helps rank or label items from any enumerable, including find_each and map, by chaining with_index to the enumerator.

Alternative form objects for Rails may fit better than model-based validation and could become part of Rails 5.