There are innumerable ways to trip up during diagnosis, but there are a few that crop up repeatedly. In this section, we’ll look at some hard-won lessons from the trenches.
If the changes you’re making have no effect, you’re not changing what you think you are.
If the changes you’re making don’t seem to be having an effect, you’re not changing what you think you are. Perhaps you’re editing a file in one source tree but compiling a different one? Or you’re compiling the right file but running the wrong executable? Or the code that you’re editing is disabled by the preprocessor? Or your browser is pointing at the production server instead of the development server? Or….
This pitfall is so common, ...