--- a/mercurial/cmdutil.py	Fri Oct 06 14:45:17 2017 +0200
+++ b/mercurial/cmdutil.py	Tue Oct 17 21:15:31 2017 +0200
@@ -26,12 +26,14 @@
     changelog,
     copies,
     crecord as crecordmod,
+    dagop,
     dirstateguard,
     encoding,
     error,
     formatter,
     graphmod,
     match as matchmod,
+    mdiff,
     obsolete,
     patch,
     pathutil,
@@ -2585,6 +2587,87 @@
 
     return revs, expr, filematcher
 
+def _parselinerangelogopt(repo, opts):
+    """Parse --line-range log option and return a list of tuples (filename,
+    (fromline, toline)).
+    """
+    linerangebyfname = []
+    for pat in opts.get('line_range', []):
+        try:
+            pat, linerange = pat.rsplit(',', 1)
+        except ValueError:
+            raise error.Abort(_('malformatted line-range pattern %s') % pat)
+        try:
+            fromline, toline = map(int, linerange.split('-'))
+        except ValueError:
+            raise error.Abort(_("invalid line range for %s") % pat)
+        msg = _("line range pattern '%s' must match exactly one file") % pat
+        fname = scmutil.parsefollowlinespattern(repo, None, pat, msg)
+        linerangebyfname.append(
+            (fname, util.processlinerange(fromline, toline)))
+    return linerangebyfname
+
+def getloglinerangerevs(repo, userrevs, opts):
+    """Return (revs, filematcher, hunksfilter).
+
+    "revs" are revisions obtained by processing "line-range" log options and
+    walking block ancestors of each specified file/line-range.
+
+    "filematcher(rev) -> match" is a factory function returning a match object
+    for a given revision for file patterns specified in --line-range option.
+    If neither --stat nor --patch options are passed, "filematcher" is None.
+
+    "hunksfilter(rev) -> filterfn(fctx, hunks)" is a factory function
+    returning a hunks filtering function.
+    If neither --stat nor --patch options are passed, "filterhunks" is None.
+    """
+    wctx = repo[None]
+
+    # Two-levels map of "rev -> file ctx -> [line range]".
+    linerangesbyrev = {}
+    for fname, (fromline, toline) in _parselinerangelogopt(repo, opts):
+        fctx = wctx.filectx(fname)
+        for fctx, linerange in dagop.blockancestors(fctx, fromline, toline):
+            rev = fctx.introrev()
+            if rev not in userrevs:
+                continue
+            linerangesbyrev.setdefault(
+                rev, {}).setdefault(
+                    fctx.path(), []).append(linerange)
+
+    filematcher = None
+    hunksfilter = None
+    if opts.get('patch') or opts.get('stat'):
+
+        def nofilterhunksfn(fctx, hunks):
+            return hunks
+
+        def hunksfilter(rev):
+            fctxlineranges = linerangesbyrev.get(rev)
+            if fctxlineranges is None:
+                return nofilterhunksfn
+
+            def filterfn(fctx, hunks):
+                lineranges = fctxlineranges.get(fctx.path())
+                if lineranges is not None:
+                    for hr, lines in hunks:
+                        if any(mdiff.hunkinrange(hr[2:], lr)
+                               for lr in lineranges):
+                            yield hr, lines
+                else:
+                    for hunk in hunks:
+                        yield hunk
+
+            return filterfn
+
+        def filematcher(rev):
+            files = list(linerangesbyrev.get(rev, []))
+            return scmutil.matchfiles(repo, files)
+
+    revs = sorted(linerangesbyrev, reverse=True)
+
+    return revs, filematcher, hunksfilter
+
 def _graphnodeformatter(ui, displayer):
     spec = ui.config('ui', 'graphnodetemplate')
     if not spec:

--- a/mercurial/commands.py	Fri Oct 06 14:45:17 2017 +0200
+++ b/mercurial/commands.py	Tue Oct 17 21:15:31 2017 +0200
@@ -3234,6 +3234,9 @@
     ('k', 'keyword', [],
      _('do case-insensitive search for a given text'), _('TEXT')),
     ('r', 'rev', [], _('show the specified revision or revset'), _('REV')),
+    ('L', 'line-range', [],
+     _('follow line range of specified file (EXPERIMENTAL)'),
+     _('FILE,RANGE')),
     ('', 'removed', None, _('include revisions where files were removed')),
     ('m', 'only-merges', None, _('show only merges (DEPRECATED)')),
     ('u', 'user', [], _('revisions committed by user'), _('USER')),
@@ -3275,6 +3278,14 @@
     Paths in the DAG are represented with '|', '/' and so forth. ':' in place
     of a '|' indicates one or more revisions in a path are omitted.
 
+    .. container:: verbose
+
+       Use -L/--line-range FILE,M-N options to follow the history of lines
+       from M to N in FILE. With -p/--patch only diff hunks affecting
+       specified line range will be shown. This option requires --follow;
+       it can be specified multiple times. Currently, this option is not
+       compatible with --graph. This option is experimental.
+
     .. note::
 
        :hg:`log --patch` may generate unexpected diff output for merge
@@ -3290,6 +3301,14 @@
 
     .. container:: verbose
 
+       .. note::
+
+          The history resulting from -L/--line-range options depends on diff
+          options; for instance if white-spaces are ignored, respective changes
+          with only white-spaces in specified line range will not be listed.
+
+    .. container:: verbose
+
       Some examples:
 
       - changesets with full descriptions and file lists::
@@ -3336,6 +3355,15 @@
 
           hg log -r "last(tagged())::" --template "{desc|firstline}\\n"
 
+      - changesets touching lines 13 to 23 for file.c::
+
+          hg log -L file.c,13-23
+
+      - changesets touching lines 13 to 23 for file.c and lines 2 to 6 of
+        main.c with patch::
+
+          hg log -L file.c,13-23 -L main.c,2-6 -p
+
     See :hg:`help dates` for a list of formats valid for -d/--date.
 
     See :hg:`help revisions` for more about specifying and ordering
@@ -3350,14 +3378,38 @@
 
     """
     opts = pycompat.byteskwargs(opts)
+    linerange = opts.get('line_range')
+
+    if linerange and not opts.get('follow'):
+        raise error.Abort(_('--line-range requires --follow'))
+
     if opts.get('follow') and opts.get('rev'):
         opts['rev'] = [revsetlang.formatspec('reverse(::%lr)', opts.get('rev'))]
         del opts['follow']
 
     if opts.get('graph'):
+        if linerange:
+            raise error.Abort(_('graph not supported with line range patterns'))
         return cmdutil.graphlog(ui, repo, pats, opts)
 
     revs, expr, filematcher = cmdutil.getlogrevs(repo, pats, opts)
+    hunksfilter = None
+
+    if linerange:
+        revs, lrfilematcher, hunksfilter = cmdutil.getloglinerangerevs(
+            repo, revs, opts)
+
+        if filematcher is not None and lrfilematcher is not None:
+            basefilematcher = filematcher
+
+            def filematcher(rev):
+                files = (basefilematcher(rev).files()
+                         + lrfilematcher(rev).files())
+                return scmutil.matchfiles(repo, files)
+
+        elif filematcher is None:
+            filematcher = lrfilematcher
+
     limit = cmdutil.loglimit(opts)
     count = 0
 
@@ -3385,7 +3437,12 @@
             revmatchfn = filematcher(ctx.rev())
         else:
             revmatchfn = None
-        displayer.show(ctx, copies=copies, matchfn=revmatchfn)
+        if hunksfilter:
+            revhunksfilter = hunksfilter(rev)
+        else:
+            revhunksfilter = None
+        displayer.show(ctx, copies=copies, matchfn=revmatchfn,
+                       hunksfilterfn=revhunksfilter)
         if displayer.flush(ctx):
             count += 1
 

--- a/tests/test-completion.t	Fri Oct 06 14:45:17 2017 +0200
+++ b/tests/test-completion.t	Tue Oct 17 21:15:31 2017 +0200
@@ -225,7 +225,7 @@
   export: output, switch-parent, rev, text, git, binary, nodates
   forget: include, exclude
   init: ssh, remotecmd, insecure
-  log: follow, follow-first, date, copies, keyword, rev, removed, only-merges, user, only-branch, branch, prune, patch, git, limit, no-merges, stat, graph, style, template, include, exclude
+  log: follow, follow-first, date, copies, keyword, rev, line-range, removed, only-merges, user, only-branch, branch, prune, patch, git, limit, no-merges, stat, graph, style, template, include, exclude
   merge: force, rev, preview, tool
   pull: update, force, rev, bookmark, branch, ssh, remotecmd, insecure
   push: force, rev, bookmark, branch, new-branch, pushvars, ssh, remotecmd, insecure

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/tests/test-log-linerange.t	Tue Oct 17 21:15:31 2017 +0200
@@ -0,0 +1,869 @@
+  $ cat >> $HGRCPATH << EOF
+  > [diff]
+  > git = true
+  > EOF
+
+  $ hg init
+  $ cat > foo << EOF
+  > 0
+  > 1
+  > 2
+  > 3
+  > 4
+  > EOF
+  $ hg ci -Am init
+  adding foo
+  $ cat > foo << EOF
+  > 0
+  > 0
+  > 0
+  > 0
+  > 1
+  > 2
+  > 3
+  > 4
+  > EOF
+  $ hg ci -m 'more 0'
+  $ sed 's/2/2+/' foo > foo.new
+  $ mv foo.new foo
+  $ cat > bar << EOF
+  > a
+  > b
+  > c
+  > d
+  > e
+  > EOF
+  $ hg add bar
+  $ hg ci -Am "2 -> 2+; added bar"
+  $ cat >> foo << EOF
+  > 5
+  > 6
+  > 7
+  > 8
+  > 9
+  > 10
+  > 11
+  > EOF
+  $ hg ci -m "to 11"
+
+Add some changes with two diff hunks
+
+  $ sed 's/^1$/ 1/' foo > foo.new
+  $ mv foo.new foo
+  $ sed 's/^11$/11+/' foo > foo.new
+  $ mv foo.new foo
+  $ hg ci -m '11 -> 11+; leading space before "1"'
+(make sure there are two hunks in "foo")
+  $ hg diff -c .
+  diff --git a/foo b/foo
+  --- a/foo
+  +++ b/foo
+  @@ -2,7 +2,7 @@
+   0
+   0
+   0
+  -1
+  + 1
+   2+
+   3
+   4
+  @@ -12,4 +12,4 @@
+   8
+   9
+   10
+  -11
+  +11+
+  $ sed 's/3/3+/' foo > foo.new
+  $ mv foo.new foo
+  $ sed 's/^11+$/11-/' foo > foo.new
+  $ mv foo.new foo
+  $ sed 's/a/a+/' bar > bar.new
+  $ mv bar.new bar
+  $ hg ci -m 'foo: 3 -> 3+ and 11+ -> 11-; bar: a -> a+'
+(make sure there are two hunks in "foo")
+  $ hg diff -c . foo
+  diff --git a/foo b/foo
+  --- a/foo
+  +++ b/foo
+  @@ -4,7 +4,7 @@
+   0
+    1
+   2+
+  -3
+  +3+
+   4
+   5
+   6
+  @@ -12,4 +12,4 @@
+   8
+   9
+   10
+  -11+
+  +11-
+
+  $ hg log -f -L foo,5-7 -p
+  changeset:   5:cfdf972b3971
+  tag:         tip
+  user:        test
+  date:        Thu Jan 01 00:00:00 1970 +0000
+  summary:     foo: 3 -> 3+ and 11+ -> 11-; bar: a -> a+
+  
+  diff --git a/foo b/foo
+  --- a/foo
+  +++ b/foo
+  @@ -4,7 +4,7 @@
+   0
+    1
+   2+
+  -3
+  +3+
+   4
+   5
+   6
+  
+  changeset:   4:eaec41c1a0c9
+  user:        test
+  date:        Thu Jan 01 00:00:00 1970 +0000
+  summary:     11 -> 11+; leading space before "1"
+  
+  diff --git a/foo b/foo
+  --- a/foo
+  +++ b/foo
+  @@ -2,7 +2,7 @@
+   0
+   0
+   0
+  -1
+  + 1
+   2+
+   3
+   4
+  
+  changeset:   2:63a884426fd0
+  user:        test
+  date:        Thu Jan 01 00:00:00 1970 +0000
+  summary:     2 -> 2+; added bar
+  
+  diff --git a/foo b/foo
+  --- a/foo
+  +++ b/foo
+  @@ -3,6 +3,6 @@
+   0
+   0
+   1
+  -2
+  +2+
+   3
+   4
+  
+  changeset:   0:5ae1f82b9a00
+  user:        test
+  date:        Thu Jan 01 00:00:00 1970 +0000
+  summary:     init
+  
+  diff --git a/foo b/foo
+  new file mode 100644
+  --- /dev/null
+  +++ b/foo
+  @@ -0,0 +1,5 @@
+  +0
+  +1
+  +2
+  +3
+  +4
+  
+
+With --template.
+
+  $ hg log -f -L foo,5-7 -T '{rev}:{node|short} {desc|firstline}\n'
+  5:cfdf972b3971 foo: 3 -> 3+ and 11+ -> 11-; bar: a -> a+
+  4:eaec41c1a0c9 11 -> 11+; leading space before "1"
+  2:63a884426fd0 2 -> 2+; added bar
+  0:5ae1f82b9a00 init
+  $ hg log -f -L foo,5-7 -T json
+  [
+   {
+    "rev": 5,
+    "node": "cfdf972b3971a2a59638bf9583c0debbffee5404",
+    "branch": "default",
+    "phase": "draft",
+    "user": "test",
+    "date": [0, 0],
+    "desc": "foo: 3 -> 3+ and 11+ -> 11-; bar: a -> a+",
+    "bookmarks": [],
+    "tags": ["tip"],
+    "parents": ["eaec41c1a0c9ad0a5e999611d0149d171beffb8c"]
+   },
+   {
+    "rev": 4,
+    "node": "eaec41c1a0c9ad0a5e999611d0149d171beffb8c",
+    "branch": "default",
+    "phase": "draft",
+    "user": "test",
+    "date": [0, 0],
+    "desc": "11 -> 11+; leading space before \"1\"",
+    "bookmarks": [],
+    "tags": [],
+    "parents": ["730a61fbaecf426c17c2c66bc42d195b5d5b0ba8"]
+   },
+   {
+    "rev": 2,
+    "node": "63a884426fd0b277fcd55895bbb2f230434576eb",
+    "branch": "default",
+    "phase": "draft",
+    "user": "test",
+    "date": [0, 0],
+    "desc": "2 -> 2+; added bar",
+    "bookmarks": [],
+    "tags": [],
+    "parents": ["29a1e7c6b80024f63f310a2d71de979e9d2996d7"]
+   },
+   {
+    "rev": 0,
+    "node": "5ae1f82b9a000ff1e0967d0dac1c58b9d796e1b4",
+    "branch": "default",
+    "phase": "draft",
+    "user": "test",
+    "date": [0, 0],
+    "desc": "init",
+    "bookmarks": [],
+    "tags": [],
+    "parents": ["0000000000000000000000000000000000000000"]
+   }
+  ]
+
+With some white-space diff option, respective revisions are skipped.
+
+  $ hg log -f -L foo,5-7 -p --config diff.ignorews=true
+  changeset:   5:cfdf972b3971
+  tag:         tip
+  user:        test
+  date:        Thu Jan 01 00:00:00 1970 +0000
+  summary:     foo: 3 -> 3+ and 11+ -> 11-; bar: a -> a+
+  
+  diff --git a/foo b/foo
+  --- a/foo
+  +++ b/foo
+  @@ -4,7 +4,7 @@
+   0
+    1
+   2+
+  -3
+  +3+
+   4
+   5
+   6
+  
+  changeset:   2:63a884426fd0
+  user:        test
+  date:        Thu Jan 01 00:00:00 1970 +0000
+  summary:     2 -> 2+; added bar
+  
+  diff --git a/foo b/foo
+  --- a/foo
+  +++ b/foo
+  @@ -3,6 +3,6 @@
+   0
+   0
+   1
+  -2
+  +2+
+   3
+   4
+  
+  changeset:   0:5ae1f82b9a00
+  user:        test
+  date:        Thu Jan 01 00:00:00 1970 +0000
+  summary:     init
+  
+  diff --git a/foo b/foo
+  new file mode 100644
+  --- /dev/null
+  +++ b/foo
+  @@ -0,0 +1,5 @@
+  +0
+  +1
+  +2
+  +3
+  +4
+  
+
+Regular file patterns are allowed with -L and their diff shows all lines.
+
+  $ hg log -f -L foo,5-7 -p bar
+  changeset:   5:cfdf972b3971
+  tag:         tip
+  user:        test
+  date:        Thu Jan 01 00:00:00 1970 +0000
+  summary:     foo: 3 -> 3+ and 11+ -> 11-; bar: a -> a+
+  
+  diff --git a/bar b/bar
+  --- a/bar
+  +++ b/bar
+  @@ -1,4 +1,4 @@
+  -a
+  +a+
+   b
+   c
+   d
+  diff --git a/foo b/foo
+  --- a/foo
+  +++ b/foo
+  @@ -4,7 +4,7 @@
+   0
+    1
+   2+
+  -3
+  +3+
+   4
+   5
+   6
+  
+  changeset:   2:63a884426fd0
+  user:        test
+  date:        Thu Jan 01 00:00:00 1970 +0000
+  summary:     2 -> 2+; added bar
+  
+  diff --git a/bar b/bar
+  new file mode 100644
+  --- /dev/null
+  +++ b/bar
+  @@ -0,0 +1,5 @@
+  +a
+  +b
+  +c
+  +d
+  +e
+  diff --git a/foo b/foo
+  --- a/foo
+  +++ b/foo
+  @@ -3,6 +3,6 @@
+   0
+   0
+   1
+  -2
+  +2+
+   3
+   4
+  
+
+Option --rev acts as a restriction.
+
+  $ hg log -f -L foo,5-7 -p -r 'desc(2)'
+  changeset:   2:63a884426fd0
+  user:        test
+  date:        Thu Jan 01 00:00:00 1970 +0000
+  summary:     2 -> 2+; added bar
+  
+  diff --git a/foo b/foo
+  --- a/foo
+  +++ b/foo
+  @@ -3,6 +3,6 @@
+   0
+   0
+   1
+  -2
+  +2+
+   3
+   4
+  
+  changeset:   0:5ae1f82b9a00
+  user:        test
+  date:        Thu Jan 01 00:00:00 1970 +0000
+  summary:     init
+  
+  diff --git a/foo b/foo
+  new file mode 100644
+  --- /dev/null
+  +++ b/foo
+  @@ -0,0 +1,5 @@
+  +0
+  +1
+  +2
+  +3
+  +4
+  
+
+With several -L patterns, changes touching any files in their respective line
+range are show.
+
+  $ hg log -f -L foo,5-7 -L bar,1-2 -p
+  changeset:   5:cfdf972b3971
+  tag:         tip
+  user:        test
+  date:        Thu Jan 01 00:00:00 1970 +0000
+  summary:     foo: 3 -> 3+ and 11+ -> 11-; bar: a -> a+
+  
+  diff --git a/bar b/bar
+  --- a/bar
+  +++ b/bar
+  @@ -1,4 +1,4 @@
+  -a
+  +a+
+   b
+   c
+   d
+  diff --git a/foo b/foo
+  --- a/foo
+  +++ b/foo
+  @@ -4,7 +4,7 @@
+   0
+    1
+   2+
+  -3
+  +3+
+   4
+   5
+   6
+  
+  changeset:   4:eaec41c1a0c9
+  user:        test
+  date:        Thu Jan 01 00:00:00 1970 +0000
+  summary:     11 -> 11+; leading space before "1"
+  
+  diff --git a/foo b/foo
+  --- a/foo
+  +++ b/foo
+  @@ -2,7 +2,7 @@
+   0
+   0
+   0
+  -1
+  + 1
+   2+
+   3
+   4
+  
+  changeset:   2:63a884426fd0
+  user:        test
+  date:        Thu Jan 01 00:00:00 1970 +0000
+  summary:     2 -> 2+; added bar
+  
+  diff --git a/bar b/bar
+  new file mode 100644
+  --- /dev/null
+  +++ b/bar
+  @@ -0,0 +1,5 @@
+  +a
+  +b
+  +c
+  +d
+  +e
+  diff --git a/foo b/foo
+  --- a/foo
+  +++ b/foo
+  @@ -3,6 +3,6 @@
+   0
+   0
+   1
+  -2
+  +2+
+   3
+   4
+  
+  changeset:   0:5ae1f82b9a00
+  user:        test
+  date:        Thu Jan 01 00:00:00 1970 +0000
+  summary:     init
+  
+  diff --git a/foo b/foo
+  new file mode 100644
+  --- /dev/null
+  +++ b/foo
+  @@ -0,0 +1,5 @@
+  +0
+  +1
+  +2
+  +3
+  +4
+  
+
+Multiple -L options with the same file yields changes touching any of
+specified line ranges.
+
+  $ hg log -f -L foo,5-7 -L foo,14-15 -p
+  changeset:   5:cfdf972b3971
+  tag:         tip
+  user:        test
+  date:        Thu Jan 01 00:00:00 1970 +0000
+  summary:     foo: 3 -> 3+ and 11+ -> 11-; bar: a -> a+
+  
+  diff --git a/foo b/foo
+  --- a/foo
+  +++ b/foo
+  @@ -4,7 +4,7 @@
+   0
+    1
+   2+
+  -3
+  +3+
+   4
+   5
+   6
+  @@ -12,4 +12,4 @@
+   8
+   9
+   10
+  -11+
+  +11-
+  
+  changeset:   4:eaec41c1a0c9
+  user:        test
+  date:        Thu Jan 01 00:00:00 1970 +0000
+  summary:     11 -> 11+; leading space before "1"
+  
+  diff --git a/foo b/foo
+  --- a/foo
+  +++ b/foo
+  @@ -2,7 +2,7 @@
+   0
+   0
+   0
+  -1
+  + 1
+   2+
+   3
+   4
+  @@ -12,4 +12,4 @@
+   8
+   9
+   10
+  -11
+  +11+
+  
+  changeset:   3:730a61fbaecf
+  user:        test
+  date:        Thu Jan 01 00:00:00 1970 +0000
+  summary:     to 11
+  
+  diff --git a/foo b/foo
+  --- a/foo
+  +++ b/foo
+  @@ -6,3 +6,10 @@
+   2+
+   3
+   4
+  +5
+  +6
+  +7
+  +8
+  +9
+  +10
+  +11
+  
+  changeset:   2:63a884426fd0
+  user:        test
+  date:        Thu Jan 01 00:00:00 1970 +0000
+  summary:     2 -> 2+; added bar
+  
+  diff --git a/foo b/foo
+  --- a/foo
+  +++ b/foo
+  @@ -3,6 +3,6 @@
+   0
+   0
+   1
+  -2
+  +2+
+   3
+   4
+  
+  changeset:   0:5ae1f82b9a00
+  user:        test
+  date:        Thu Jan 01 00:00:00 1970 +0000
+  summary:     init
+  
+  diff --git a/foo b/foo
+  new file mode 100644
+  --- /dev/null
+  +++ b/foo
+  @@ -0,0 +1,5 @@
+  +0
+  +1
+  +2
+  +3
+  +4
+  
+
+A file with a comma in its name.
+
+  $ cat > ba,z << EOF
+  > q
+  > w
+  > e
+  > r
+  > t
+  > y
+  > EOF
+  $ hg ci -Am 'querty'
+  adding ba,z
+  $ cat >> ba,z << EOF
+  > u
+  > i
+  > o
+  > p
+  > EOF
+  $ hg ci -m 'more keys'
+  $ cat > ba,z << EOF
+  > a
+  > z
+  > e
+  > r
+  > t
+  > y
+  > u
+  > i
+  > o
+  > p
+  > EOF
+  $ hg ci -m 'azerty'
+  $ hg log -f -L ba,z,1-2 -p
+  changeset:   8:52373265138b
+  tag:         tip
+  user:        test
+  date:        Thu Jan 01 00:00:00 1970 +0000
+  summary:     azerty
+  
+  diff --git a/ba,z b/ba,z
+  --- a/ba,z
+  +++ b/ba,z
+  @@ -1,5 +1,5 @@
+  -q
+  -w
+  +a
+  +z
+   e
+   r
+   t
+  
+  changeset:   6:96ba8850f316
+  user:        test
+  date:        Thu Jan 01 00:00:00 1970 +0000
+  summary:     querty
+  
+  diff --git a/ba,z b/ba,z
+  new file mode 100644
+  --- /dev/null
+  +++ b/ba,z
+  @@ -0,0 +1,6 @@
+  +q
+  +w
+  +e
+  +r
+  +t
+  +y
+  
+
+Exact prefix kinds work in -L options.
+
+  $ mkdir dir
+  $ cd dir
+  $ hg log -f -L path:foo,5-7 -p
+  changeset:   5:cfdf972b3971
+  user:        test
+  date:        Thu Jan 01 00:00:00 1970 +0000
+  summary:     foo: 3 -> 3+ and 11+ -> 11-; bar: a -> a+
+  
+  diff --git a/foo b/foo
+  --- a/foo
+  +++ b/foo
+  @@ -4,7 +4,7 @@
+   0
+    1
+   2+
+  -3
+  +3+
+   4
+   5
+   6
+  
+  changeset:   4:eaec41c1a0c9
+  user:        test
+  date:        Thu Jan 01 00:00:00 1970 +0000
+  summary:     11 -> 11+; leading space before "1"
+  
+  diff --git a/foo b/foo
+  --- a/foo
+  +++ b/foo
+  @@ -2,7 +2,7 @@
+   0
+   0
+   0
+  -1
+  + 1
+   2+
+   3
+   4
+  
+  changeset:   2:63a884426fd0
+  user:        test
+  date:        Thu Jan 01 00:00:00 1970 +0000
+  summary:     2 -> 2+; added bar
+  
+  diff --git a/foo b/foo
+  --- a/foo
+  +++ b/foo
+  @@ -3,6 +3,6 @@
+   0
+   0
+   1
+  -2
+  +2+
+   3
+   4
+  
+  changeset:   0:5ae1f82b9a00
+  user:        test
+  date:        Thu Jan 01 00:00:00 1970 +0000
+  summary:     init
+  
+  diff --git a/foo b/foo
+  new file mode 100644
+  --- /dev/null
+  +++ b/foo
+  @@ -0,0 +1,5 @@
+  +0
+  +1
+  +2
+  +3
+  +4
+  
+
+Renames are followed.
+
+  $ hg mv ../foo baz
+  $ sed 's/1/1+/' baz > baz.new
+  $ mv baz.new baz
+  $ hg ci -m 'foo -> dir/baz; 1-1+'
+  $ hg diff -c .
+  diff --git a/foo b/dir/baz
+  rename from foo
+  rename to dir/baz
+  --- a/foo
+  +++ b/dir/baz
+  @@ -2,7 +2,7 @@
+   0
+   0
+   0
+  - 1
+  + 1+
+   2+
+   3+
+   4
+  @@ -11,5 +11,5 @@
+   7
+   8
+   9
+  -10
+  -11-
+  +1+0
+  +1+1-
+  $ hg log -f -L relpath:baz,5-7 -p
+  changeset:   9:6af29c3a778f
+  tag:         tip
+  user:        test
+  date:        Thu Jan 01 00:00:00 1970 +0000
+  summary:     foo -> dir/baz; 1-1+
+  
+  diff --git a/foo b/dir/baz
+  copy from foo
+  copy to dir/baz
+  --- a/foo
+  +++ b/dir/baz
+  @@ -2,7 +2,7 @@
+   0
+   0
+   0
+  - 1
+  + 1+
+   2+
+   3+
+   4
+  
+  changeset:   5:cfdf972b3971
+  user:        test
+  date:        Thu Jan 01 00:00:00 1970 +0000
+  summary:     foo: 3 -> 3+ and 11+ -> 11-; bar: a -> a+
+  
+  diff --git a/foo b/foo
+  --- a/foo
+  +++ b/foo
+  @@ -4,7 +4,7 @@
+   0
+    1
+   2+
+  -3
+  +3+
+   4
+   5
+   6
+  
+  changeset:   4:eaec41c1a0c9
+  user:        test
+  date:        Thu Jan 01 00:00:00 1970 +0000
+  summary:     11 -> 11+; leading space before "1"
+  
+  diff --git a/foo b/foo
+  --- a/foo
+  +++ b/foo
+  @@ -2,7 +2,7 @@
+   0
+   0
+   0
+  -1
+  + 1
+   2+
+   3
+   4
+  
+  changeset:   2:63a884426fd0
+  user:        test
+  date:        Thu Jan 01 00:00:00 1970 +0000
+  summary:     2 -> 2+; added bar
+  
+  diff --git a/foo b/foo
+  --- a/foo
+  +++ b/foo
+  @@ -3,6 +3,6 @@
+   0
+   0
+   1
+  -2
+  +2+
+   3
+   4
+  
+  changeset:   0:5ae1f82b9a00
+  user:        test
+  date:        Thu Jan 01 00:00:00 1970 +0000
+  summary:     init
+  
+  diff --git a/foo b/foo
+  new file mode 100644
+  --- /dev/null
+  +++ b/foo
+  @@ -0,0 +1,5 @@
+  +0
+  +1
+  +2
+  +3
+  +4
+  
+Option --follow is required.
+
+  $ hg log -L foo,5-7
+  abort: --line-range requires --follow
+  [255]
+
+Non-exact pattern kinds are not allowed.
+
+  $ cd ..
+  $ hg log -f -L glob:*a*,1-2
+  hg: parse error: line range pattern 'glob:*a*' must match exactly one file
+  [255]
+
+Graph log does work yet.
+
+  $ hg log -f -L dir/baz,5-7 --graph
+  abort: graph not supported with line range patterns
+  [255]