divert-and-modify - use dpkg-divert to stash and modify files

Overview

The divert-and-modify library uses dpkg-divert to replace files owned by other packages and modify them in predetermined ways. This allows software packages to "patch" other tools and libraries.

Configuration file format

The only format that the divert-and-modify library understands so far is a series of TOML files in the following layout:

[format.version]
major = 0
minor = 1

[[divmod.changes]]
name = "fix-something"
path = "/path/to/file/to/change"
handler.mode = "regex-sub"
handler.regex_sub.pattern = "regular expression to match"
handler.regex_sub.subst = "replacement string possibly including backreferences"

Supported modification handlers

regex-sub - substitute regular expressions within single lines

The regex-sub handler examines the file line by line and applies a regular expression substitution to each line in order. The regular expression is in the format understood by the Python re module. The substitution may contain backreferences, both in the \1 and \g<name> format.

To do

Detect leftover diversions that are not longer listed in any existing configuration file and remove them.

Break the configuration file search out into a separate overdrop-style library.