--- a/mercurial/templatekw.py	Fri May 31 09:25:51 2019 -0700
+++ b/mercurial/templatekw.py	Thu Apr 18 13:35:02 2019 -0700
@@ -290,11 +290,6 @@
             statmap.update((f, char) for f in files)
     return revcache['filestatusmap']  # {path: statchar}
 
-def _showfilesbystat(context, mapping, name, index):
-    stat = _getfilestatus(context, mapping)
-    files = stat[index]
-    return templateutil.compatfileslist(context, mapping, name, files)
-
 @templatekeyword('file_copies',
                  requires={'repo', 'ctx', 'cache', 'revcache'})
 def showfilecopies(context, mapping):
@@ -332,17 +327,23 @@
 @templatekeyword('file_adds', requires={'ctx', 'revcache'})
 def showfileadds(context, mapping):
     """List of strings. Files added by this changeset."""
-    return _showfilesbystat(context, mapping, 'file_add', 1)
+    ctx = context.resource(mapping, 'ctx')
+    return templateutil.compatfileslist(context, mapping, 'file_add',
+                                        ctx.filesadded())
 
 @templatekeyword('file_dels', requires={'ctx', 'revcache'})
 def showfiledels(context, mapping):
     """List of strings. Files removed by this changeset."""
-    return _showfilesbystat(context, mapping, 'file_del', 2)
+    ctx = context.resource(mapping, 'ctx')
+    return templateutil.compatfileslist(context, mapping, 'file_del',
+                                        ctx.filesremoved())
 
 @templatekeyword('file_mods', requires={'ctx', 'revcache'})
 def showfilemods(context, mapping):
     """List of strings. Files modified by this changeset."""
-    return _showfilesbystat(context, mapping, 'file_mod', 0)
+    ctx = context.resource(mapping, 'ctx')
+    return templateutil.compatfileslist(context, mapping, 'file_mod',
+                                        ctx.filesmodified())
 
 @templatekeyword('files', requires={'ctx'})
 def showfiles(context, mapping):

--- a/relnotes/next	Fri May 31 09:25:51 2019 -0700
+++ b/relnotes/next	Thu Apr 18 13:35:02 2019 -0700
@@ -15,6 +15,10 @@
 
 == Bug Fixes  ==
 
+ * issue4292: "hg log and {files} {file_adds} {file_mods} {file_dels}
+   in template show wrong files on merged revision". See details in
+   "Backwards Compatibility Changes".
+
 
 == Backwards Compatibility Changes ==
 
@@ -31,6 +35,16 @@
    previously replace files *in* the configured directory by
    subdirectories.
 
+* Template keyword `{file_mods}`, `{file_adds}`, and `{file_dels}`
+   have changed behavior on merge commits. They used to be relative to
+   the first parent, but they now consider both parents. `{file_adds}`
+   shows files that exists in the commit but did not exist in either
+   parent. `{file_dels}` shows files that do not exist in the commit
+   but existed in either parent. `{file_mods}` show the remaining
+   files from `{files}` that were not in the other two
+   sets.
+
+
 == Internal API Changes ==
 
  * Matchers are no longer iterable. Use `match.files()` instead.

--- a/tests/test-convert-bzr-merges.t	Fri May 31 09:25:51 2019 -0700
+++ b/tests/test-convert-bzr-merges.t	Thu Apr 18 13:35:02 2019 -0700
@@ -59,7 +59,7 @@
   $ glog -R source-hg
   o    5@source "(octopus merge fixup)" files+: [], files-: [], files: [renamed]
   |\
-  | o    4@source "Merged branches" files+: [file-branch1 file-branch2 renamed], files-: [rename_me], files: [file]
+  | o    4@source "Merged branches" files+: [file-branch2 renamed], files-: [rename_me], files: []
   | |\
   o---+  3@source-branch2 "Added brach2 file" files+: [file-branch2 renamed], files-: [rename_me], files: []
    / /
@@ -154,7 +154,7 @@
   $ glog -R hg2hg
   @    5@source "(octopus merge fixup)" files+: [], files-: [], files: []
   |\
-  | o    4@source "Merged branches" files+: [file-branch1 file-branch2 renamed], files-: [rename_me], files: [file]
+  | o    4@source "Merged branches" files+: [file-branch2 renamed], files-: [rename_me], files: []
   | |\
   o---+  3@source-branch2 "Added brach2 file" files+: [file-branch2 renamed], files-: [rename_me], files: []
    / /

--- a/tests/test-convert-bzr.t	Fri May 31 09:25:51 2019 -0700
+++ b/tests/test-convert-bzr.t	Thu Apr 18 13:35:02 2019 -0700
@@ -147,7 +147,7 @@
   1 Editing b
   0 Merged improve branch
   $ glog -R source-hg
-  o    3@source "Merged improve branch" files+: [], files-: [], files: [b]
+  o    3@source "Merged improve branch" files+: [], files-: [], files: []
   |\
   | o  2@source-improve "Editing b" files+: [], files-: [], files: [b]
   | |

--- a/tests/test-template-keywords.t	Fri May 31 09:25:51 2019 -0700
+++ b/tests/test-template-keywords.t	Thu Apr 18 13:35:02 2019 -0700
@@ -809,9 +809,9 @@
   $ hg log -l1 -T '{files}\n'
   a fourth
   $ hg log -l1 -T '{file_mods}\n'
-  third
+  
   $ hg log -l1 -T '{file_adds}\n'
-  b fifth
+  
   $ hg log -l1 -T '{file_dels}\n'
   a fourth