19.8 VCS To ChangeLog

Gnulib provides the ‘vcs-to-changelog’ module to generate an output similar to the GNU ChangeLog format from metadata of source control software such as git. Here’s an example of using ‘vcs-to-changelog’:

build-aux/vcs-to-changelog.py <from_ref> <to_ref>

where <from_ref> and <to_ref> refer to the range of commits to generate the output.

VCS To ChangeLog currently recognises changes in C source code and can traverse commits in git. Additional source frontends and source control backends may be added to the module. ‘vcs-to-changelog’ takes the following optional arguments:

• -d: Run the parser debugger, used for debugging ‘vcs-to-changelog’
• -q filename: Load filename as the quirks file for the project.

The quirks file is a python module that must minimally implement a get_project_quirks function that returns an object of type ProjectQuirks or its subclass. The subclass may override the following members of ProjectQuirks:

• repo: Specify the project repo source control. The default value is git.
• IGNORE_LIST: A list of files to ignore in the changesets, either because they are not needed (such as the ChangeLog) or because they are not parseable. For example, the GNU C Library has a header file that is only assembly code, which breaks the C parser.
• MACRO_QUIRKS: A list of dictionary entries with indexes as orig and sub where orig is a Python regular expression pattern to match and sub is the substitution. These substitutions are used to work around C/C++ macros that are known to break parsing of C programs.
• C_MACROS: This is a list of C preprocessor macro definitions that are extensively used and are known to break parsing due to some characteristic, mainly the lack of a semicolon at the end.