incoming: kill the `repo._subtoppath =` hack

incoming: kill the `repo._subtoppath =` hack

We do the same as for `hg outgoing`, instead of relying on implicit passing
value by monkey punching them onto the repo object, we pass equivalent
information by argument to the proper function.

This is way cleaner.

Differential Revision: https://phab.mercurial-scm.org/D10416

--- a/mercurial/commands.py	Wed Apr 14 17:29:27 2021 +0200
+++ b/mercurial/commands.py	Wed Apr 14 17:41:02 2021 +0200
@@ -4351,11 +4351,7 @@
             finally:
                 other.close()
 
-    repo._subtoppath = ui.expandpath(source)
-    try:
-        return hg.incoming(ui, repo, source, opts)
-    finally:
-        del repo._subtoppath
+    return hg.incoming(ui, repo, source, opts)
 
 
 @command(

--- a/mercurial/hg.py	Wed Apr 14 17:29:27 2021 +0200
+++ b/mercurial/hg.py	Wed Apr 14 17:41:02 2021 +0200
@@ -1255,7 +1255,14 @@
 
 
 def _incoming(
-    displaychlist, subreporecurse, ui, repo, source, opts, buffered=False
+    displaychlist,
+    subreporecurse,
+    ui,
+    repo,
+    source,
+    opts,
+    buffered=False,
+    subpath=None,
 ):
     """
     Helper for incoming / gincoming.
@@ -1270,6 +1277,14 @@
         msg %= len(srcs)
         raise error.Abort(msg)
     source, branches = srcs[0]
+    if subpath is not None:
+        subpath = urlutil.url(subpath)
+        if subpath.isabs():
+            source = bytes(subpath)
+        else:
+            p = urlutil.url(source)
+            p.path = os.path.normpath(b'%s/%s' % (p.path, subpath))
+            source = bytes(p)
     other = peer(repo, opts, source)
     cleanupfn = other.close
     try:
@@ -1297,7 +1312,7 @@
     return 0  # exit code is zero since we found incoming changes
 
 
-def incoming(ui, repo, source, opts):
+def incoming(ui, repo, source, opts, subpath=None):
     def subreporecurse():
         ret = 1
         if opts.get(b'subrepos'):
@@ -1321,7 +1336,9 @@
             count += 1
             displayer.show(other[n])
 
-    return _incoming(display, subreporecurse, ui, repo, source, opts)
+    return _incoming(
+        display, subreporecurse, ui, repo, source, opts, subpath=subpath
+    )
 
 
 def _outgoing(ui, repo, dests, opts, subpath=None):

--- a/mercurial/subrepo.py	Wed Apr 14 17:29:27 2021 +0200
+++ b/mercurial/subrepo.py	Wed Apr 14 17:41:02 2021 +0200
@@ -882,7 +882,8 @@
             opts = copy.copy(opts)
             opts.pop(b'rev', None)
             opts.pop(b'branch', None)
-        return hg.incoming(ui, self._repo, _abssource(self._repo, False), opts)
+        subpath = subrepoutil.repo_rel_or_abs_source(self._repo)
+        return hg.incoming(ui, self._repo, source, opts, subpath=subpath)
 
     @annotatesubrepoerror
     def files(self):