[PATCH] formatting: apply clang-format using the format-source extension

[Augie Fackler]

> On Jan 14, 2019, at 05:49, Boris Feld <boris.feld at octobus.net> wrote:
> 
> # HG changeset patch
> # User Boris Feld <boris.feld at octobus.net>
> # Date 1547462137 -3600
> #      Mon Jan 14 11:35:37 2019 +0100
> # Node ID 1b6f196b7e094278f9956a479e10e02cd1108a12
> # Parent  8d0d695fc7910665452b81052d1bbc55b3829b14
> # EXP-Topic format-source
> # Available At https://bitbucket.org/octobus/mercurial-devel/
> #              hg pull https://bitbucket.org/octobus/mercurial-devel/ -r 1b6f196b7e09
> formatting: apply clang-format using the format-source extension
> 
> This applies formatting on the source code, similar to what `make format-c`
> does.
> 
> (This catch a lack of formatting in one of our file).
> 
> Using the format source extension means this transformation is tracked in the
> history and can be reused during merges. This smooth the consequence of
> formatting changes between branches (and for in-progress works).
> 
> 
> In theory, the initial formatting is done through format-source. However,
> doing it after the fact is still beneficial as it will track the configuration
> changes.
> 
> We have two main motivations to do this. First, we want to have format-source
> used and testing in a wider range of real-world use case. This will help the
> extension to mature before we submit it for upstream inclusion.

Do you have a plan for how to integrate format-source with fix?

Also, how does `format-source` cope with different versions of clang-format being installed? Our tests, as an example, have to check the major version of the tool before applying it, because older versions do some things differently. When I asked the clang-format devs about this their only advice was to either do version checks or check in the clang-format binary your developers should use...


> Second, we got
> impacted by formatting change during the 4.9 cycle, having format-source
> enabled will help us in the future.
> 
> This formatting has been performed with format-source version 3.3.
> 
> We also plan to use format-source for rust formatting (and python formatting
> once a tool has been picked).
> 
> diff --git a/.hg-format-source b/.hg-format-source
> new file mode 100644
> --- /dev/null
> +++ b/.hg-format-source
> @@ -0,0 +1,1 @@
> +{"configpaths": [".clang-format", "contrib/clang-format-ignorelist"], "pattern": "set:(**.c or **.cc or **.h) and not \"listfile:contrib/clang-format-ignorelist\"", "tool": "clang-format"}
> diff --git a/mercurial/cext/revlog.c b/mercurial/cext/revlog.c
> --- a/mercurial/cext/revlog.c
> +++ b/mercurial/cext/revlog.c
> @@ -995,8 +995,8 @@ static inline int index_baserev(indexObj
> 	if (result < -1) {
> 		PyErr_Format(
> 		    PyExc_ValueError,
> -		    "corrupted revlog, revision base out of range: %d, %d",
> -		    rev, result);
> +		    "corrupted revlog, revision base out of range: %d, %d", rev,
> +		    result);
> 		return -2;
> 	}
> 	return result;