log: fix log -f slow path to actually follow history

The revset created when -f was used with a slow path (for patterns and
directories) did not actually contain any logic to enforce follow. Instead it
was depending on the passed in subset to already be limited (which was limited
to :. but not ::.). This fixes it by adding a '& ::.' to any -f log revset.

hg log -f <file> is still broken, in that it can return results that aren't
actually ancestors of the current file, but fixing that has major perf
implications, so we'll deal with it later.

mercurial/cmdutil.py

@@ -1745,6 +1745,9 b' def _makelogrevset(repo, pats, opts, rev'
             else:
                 slowpath = False
 
+    fpats = ('_patsfollow', '_patsfollowfirst')
+    fnopats = (('_ancestors', '_fancestors'),
+               ('_descendants', '_fdescendants'))
     if slowpath:
         # See walkchangerevs() slow path.
         #
@@ -1763,11 +1766,10 b' def _makelogrevset(repo, pats, opts, rev'
             matchargs.append('x:' + p)
         matchargs = ','.join(('%r' % p) for p in matchargs)
         opts['_matchfiles'] = matchargs
+        if follow:
+            opts[fnopats[0][followfirst]] = '.'
     else:
         if follow:
-            fpats = ('_patsfollow', '_patsfollowfirst')
-            fnopats = (('_ancestors', '_fancestors'),
-                       ('_descendants', '_fdescendants'))
             if pats:
                 # follow() revset interprets its file argument as a
                 # manifest entry, so use match.files(), not pats.

tests/test-glog.t

@@ -1658,13 +1658,17 b' Test --follow on a directory'
   $ testlog -f dir
   []
   (group
-    (func
-      ('symbol', '_matchfiles')
-      (list
+    (and
+      (func
+        ('symbol', '_matchfiles')
         (list
-          ('string', 'r:')
-          ('string', 'd:relpath'))
-        ('string', 'p:dir'))))
+          (list
+            ('string', 'r:')
+            ('string', 'd:relpath'))
+          ('string', 'p:dir')))
+      (func
+        ('symbol', 'ancestors')
+        ('symbol', '.'))))
   $ hg up -q tip
 
 Test --follow on file not in parent revision
@@ -1679,13 +1683,17 b' Test --follow and patterns'
   $ testlog -f 'glob:*'
   []
   (group
-    (func
-      ('symbol', '_matchfiles')
-      (list
+    (and
+      (func
+        ('symbol', '_matchfiles')
         (list
-          ('string', 'r:')
-          ('string', 'd:relpath'))
-        ('string', 'p:glob:*'))))
+          (list
+            ('string', 'r:')
+            ('string', 'd:relpath'))
+          ('string', 'p:glob:*')))
+      (func
+        ('symbol', 'ancestors')
+        ('symbol', '.'))))
 
 Test --follow on a single rename
 
@@ -1852,13 +1860,17 b' Test --removed'
   $ testlog --removed --follow a
   []
   (group
-    (func
-      ('symbol', '_matchfiles')
-      (list
+    (and
+      (func
+        ('symbol', '_matchfiles')
         (list
-          ('string', 'r:')
-          ('string', 'd:relpath'))
-        ('string', 'p:a'))))
+          (list
+            ('string', 'r:')
+            ('string', 'd:relpath'))
+          ('string', 'p:a')))
+      (func
+        ('symbol', 'ancestors')
+        ('symbol', '.'))))
 
 Test --patch and --stat with --follow and --follow-first
 

tests/test-log.t

@@ -1543,3 +1543,24 b' issue3772: hg log -r :null showing revis'
   
 
   $ cd ..
+
+hg log -f dir across branches
+
+  $ hg init acrossbranches
+  $ cd acrossbranches
+  $ mkdir d
+  $ echo a > d/a && hg ci -Aqm a
+  $ echo b > d/a && hg ci -Aqm b
+  $ hg up -q 0
+  $ echo b > d/a && hg ci -Aqm c
+  $ hg log -f d -T '{desc}' -G
+  @  c
+  |
+  o  a
+  
+  $ hg log -f d/a -T '{desc}' -G
+  o  b
+  |
+  o  a
+  
+  $ cd ..