ui: extract the low level part of 'write' in a dedicated function We are about to add some extra logic related to color. That logic will need to access the low level layer of ui doing the actual write to a stream. (eg: 'win32print'). We extract this logic into a private method for this purpose.

color: add multiple messages input support to 'win32print' All other function doing writes support any number of input message. For simplicity, we make 'win32print' able to do the same.

color: clarify name of an argument of 'win32print' In the current code, the function called to write happens to the 'orig' version of the method calling 'win32print' (obtained with a 'super' call). However, the variable could have a better name. That will be useful when we'll stop having inheritance in play.

color: move the 'colorlabel' call to the core 'ui' class This bring us closer to supporting color in core natively. Core already have a 'label' method that was a no-op. We update its to call the new 'colorlabel' function. Behavior is unchanged when colormode = None.

color: move the 'colorlabel' function in the core module The extract code is relocated in core.

color: extract the label code into its own function We extract the logic into a function. This will allow us to move the logic into the core 'color' module and later call it directly from core.

color: inline the 'showlabel' method This function is quite simple and only have one call site… located a handful of line under the definition. We inline the function for the sake of simplicity. One of the motivation to do that now is that it reduce the amount of new method we will have to add to the core 'ui' class for color support.

color: move '_colormode' to the core 'ui' class Having all 'ui' objects aware of 'color' allows us to update the core code to handle color. The mode will stay 'None' in the default case so that will not introduce any changes.

hgweb: explictly pass basectx in webutil.diffs There's only one case where `basectx` parameter is None (over two usages), so it's probably not worth handling the special case as it makes code-reading harder. Along the way, use ctx.p1() instead of checking for ctx.parents() being empty which should not occur.

serve: mark --stdio and --cmdserver as "(ADVANCED)" flags This will hide them from the default --help output.

help: hide command line options marked as "advanced" Previously, we have keywords like "(DEPRECATED)" and "(EXPERIMENTAL)" to hide command line options in non-verbose help output. However, sometimes an option is neither deprecated nor experimental. It's well-tested and working, but just not designed to average users. This patch adds a keyword "(ADVANCED)" to fit in such use cases. Thanks rom1dep for the suggestion of the word "advanced".

pager: do not try to run an empty pager command If pagercmd is explicitly set to '', the pager process would exit silently and the output would be lost. We'd better disable the pager in such case.