grep: adds allfiles mode

Adds an allfiles flag that lets you grep on all files in the revision
and not just the one that were modified in that changeset.
This would work on a single revision and get all the files that were
there in that revision. So it's like grepping on a previous state.
Using this with wdir() :: `hg grep -r "wdir()" --allfiles` is what the
default behavior is desired for grep.

Support for multiple revisions to be added later.

Differential Revision: https://phab.mercurial-scm.org/D3728

mercurial/cmdutil.py

@@ -1881,10 +1881,13 b' def walkchangerevs(repo, match, opts, pr'
     yielding each context, the iterator will first call the prepare
     function on each context in the window in forward order.'''
 
+    allfiles = opts.get('allfiles')
     follow = opts.get('follow') or opts.get('follow_first')
     revs = _walkrevs(repo, opts)
     if not revs:
         return []
+    if allfiles and len(revs) > 1:
+        raise error.Abort(_("multiple revisions not supported with --allfiles"))
     wanted = set()
     slowpath = match.anypats() or (not match.always() and opts.get('removed'))
     fncache = {}
@@ -1990,7 +1993,11 b' def walkchangerevs(repo, match, opts, pr'
                 ctx = change(rev)
                 if not fns:
                     def fns_generator():
-                        for f in ctx.files():
+                        if allfiles:
+                            fiter = iter(ctx)
+                        else:
+                            fiter = ctx.files()
+                        for f in fiter:
                             if match(f):
                                 yield f
                     fns = fns_generator()

mercurial/commands.py

@@ -2403,6 +2403,8 b' def _stopgraft(ui, repo, graftstate):'
     ('n', 'line-number', None, _('print matching line numbers')),
     ('r', 'rev', [],
      _('only search files changed within revision range'), _('REV')),
+    ('', 'allfiles', False,
+     _('include all files in the changeset while grepping (EXPERIMENTAL)')),
     ('u', 'user', None, _('list the author (long with -v)')),
     ('d', 'date', None, _('list the date (short with -q)')),
     ] + formatteropts + walkopts,

tests/test-completion.t

@@ -313,7 +313,7 b' Show all commands + options'
   debugwireproto: localssh, peer, noreadstderr, nologhandshake, ssh, remotecmd, insecure
   files: rev, print0, include, exclude, template, subrepos
   graft: rev, continue, stop, edit, log, force, currentdate, currentuser, date, user, tool, dry-run
-  grep: print0, all, text, follow, ignore-case, files-with-matches, line-number, rev, user, date, template, include, exclude
+  grep: print0, all, text, follow, ignore-case, files-with-matches, line-number, rev, allfiles, user, date, template, include, exclude
   heads: rev, topo, active, closed, style, template
   help: extension, command, keyword, system
   identify: rev, num, id, branch, tags, bookmarks, ssh, remotecmd, insecure, template

tests/test-grep.t

@@ -372,6 +372,23 b' revisions printed, just their order.'
 
   $ cd ..
 
+Test for showing working of allfiles flag
+
+  $ hg init sng
+  $ cd sng
+  $ echo "unmod" >> um
+  $ hg ci -A -m "adds unmod to um"
+  adding um
+  $ echo "something else" >> new
+  $ hg ci -A -m "second commit"
+  adding new
+  $ hg grep -r "." "unmod"
+  [1]
+  $ hg grep -r "." "unmod" --allfiles
+  um:1:unmod
+
+  $ cd ..
+
 Fix_Wdir(): test that passing wdir() t -r flag does greps on the
 files modified in the working directory