bundle2: add debug output for part generation The part generation process was lacking a ui object and could not produce debug output. It seems valuable to have some debug output on this part too, especially now that we are planning to be able to hide it in the default --debug output.

bundle2: handle new line in 'indebug' function Now that we have a prefix, it make sense to assume all output will be on a single line.

bundle2: prefix all unbundling debug message with 'bundle2-input:' This make the origin of the message more explicit.

bundle2: introduce a specific function for debug messages while unbundling The bundling process is very verbose, we would like to be able to hide such output behind a configuration flag and have it more explicitly referencing bundle2. The first step is to gather all these messages in a dedicated function.

bundle2: add an informative comment to the capability dict It is fairly easy to get confused by capabilities "missing" from this dict. We make it clear the dict is not the whole story.

merge with stable

bundle2: handle new line in 'outdebug' function Now that we have a prefix, it make sense to assume all output will be on a single line.

bundle2: prefix all bundling debug messages with 'bundle2-ouput:' This makes the origin of the message more explicit.

bundle2: introduce a specific function for bundling debug message The bundling process is very verbose, we would like to be able to hide such output behind a configuration flag and have it more explicitly referencing bundle2. The first step is to gather all these messages in a dedicated function. The same gathering will be later do for debug message issue by unbundling.

parsers: simplify the code computing the phases We recently simplified the code computing the heads of a repo. This patch uses the same simplification for phase computation. We use index_get_parents instead of replicating its code.