diff: make --stat respect ui.relative-paths

It would have been easy to make all diffs respect ui.relative-paths,
but we don't want that since it makes the diff invalid. Perhaps it
makes sense to do that with --noprefix since the point of that is to
make paths that are easy to copy&paste, and the diff is already
invalid anyway. But this patch just makes the --stat version respect
the config option. The --stat view is not even close to a valid diff,
so I think it makes sense to show the paths in more human-friendly
form.

Differential Revision: https://phab.mercurial-scm.org/D5896

mercurial/logcmdutil.py

@@ -99,6 +99,9 b' def diffordiffstat(ui, repo, diffopts, n'
         width = 80
         if not ui.plain():
             width = ui.termwidth() - graphwidth
+        # If an explicit --root was given, don't respect ui.relative-paths
+        if not relroot:
+            pathfn = compose(scmutil.getuipathfn(repo), pathfn)
 
     chunks = ctx2.diff(ctx1, match, changes, opts=diffopts, pathfn=pathfn,
                        copysourcematch=copysourcematch,

tests/test-diffstat.t

@@ -146,10 +146,21 b' diffstat within directories:'
   $ hg diff --stat .
    dir1/new |  1 +
    1 files changed, 1 insertions(+), 0 deletions(-)
+  $ hg diff --stat . --config ui.relative-paths=yes
+   new |  1 +
+   1 files changed, 1 insertions(+), 0 deletions(-)
   $ hg diff --stat --root .
    new |  1 +
    1 files changed, 1 insertions(+), 0 deletions(-)
 
+  $ hg diff --stat --root . --config ui.relative-paths=yes
+   new |  1 +
+   1 files changed, 1 insertions(+), 0 deletions(-)
+--root trumps ui.relative-paths
+  $ hg diff --stat --root .. --config ui.relative-paths=yes
+   new         |  1 +
+   ../dir2/new |  1 +
+   2 files changed, 2 insertions(+), 0 deletions(-)
   $ hg diff --stat --root ../dir1 ../dir2
   warning: ../dir2 not inside relative root .