histedit: rename variables so they have "ctx" in them

It is convention for context instances to end with "ctx." Until
we have type annotations, this makes auditing much, much easier.

Differential Revision: https://phab.mercurial-scm.org/D2425

hgext/histedit.py

@@ -567,7 +567,7 b' def applychanges(ui, repo, ctx, opts):'
             repo.ui.setconfig('ui', 'forcemerge', '', 'histedit')
     return stats
 
-def collapse(repo, first, last, commitopts, skipprompt=False):
+def collapse(repo, firstctx, lastctx, commitopts, skipprompt=False):
     """collapse the set of revisions from first to last as new one.
 
     Expected commit options are:
@@ -577,14 +577,14 b' def collapse(repo, first, last, commitop'
     Commit message is edited in all cases.
 
     This function works in memory."""
-    ctxs = list(repo.set('%d::%d', first, last))
+    ctxs = list(repo.set('%d::%d', firstctx, lastctx))
     if not ctxs:
         return None
     for c in ctxs:
         if not c.mutable():
             raise error.ParseError(
                 _("cannot fold into public change %s") % node.short(c.node()))
-    base = first.parents()[0]
+    base = firstctx.parents()[0]
 
     # commit a new version of the old changeset, including the update
     # collect all files which might be affected
@@ -593,15 +593,15 b' def collapse(repo, first, last, commitop'
         files.update(ctx.files())
 
     # Recompute copies (avoid recording a -> b -> a)
-    copied = copies.pathcopies(base, last)
+    copied = copies.pathcopies(base, lastctx)
 
     # prune files which were reverted by the updates
-    files = [f for f in files if not cmdutil.samefile(f, last, base)]
+    files = [f for f in files if not cmdutil.samefile(f, lastctx, base)]
     # commit version of these files as defined by head
-    headmf = last.manifest()
+    headmf = lastctx.manifest()
     def filectxfn(repo, ctx, path):
         if path in headmf:
-            fctx = last[path]
+            fctx = lastctx[path]
             flags = fctx.flags()
             mctx = context.memfilectx(repo, ctx,
                                       fctx.path(), fctx.data(),
@@ -614,12 +614,12 b' def collapse(repo, first, last, commitop'
     if commitopts.get('message'):
         message = commitopts['message']
     else:
-        message = first.description()
+        message = firstctx.description()
     user = commitopts.get('user')
     date = commitopts.get('date')
     extra = commitopts.get('extra')
 
-    parents = (first.p1().node(), first.p2().node())
+    parents = (firstctx.p1().node(), firstctx.p2().node())
     editor = None
     if not skipprompt:
         editor = cmdutil.getcommiteditor(edit=True, editform='histedit.fold')