From 198d07e90570e92fc6ae1eea7723f2d203953d0d Mon Sep 17 00:00:00 2001
From: Axel Kohlmeyer <akohlmey@gmail.com>
Date: Thu, 14 Apr 2022 11:06:35 -0400
Subject: [PATCH] print warning when fix property/atom is issues before reading
 a restart

---
 doc/src/fix_property_atom.rst | 16 +++++++++-------
 src/read_restart.cpp          |  4 ++++
 2 files changed, 13 insertions(+), 7 deletions(-)

diff --git a/doc/src/fix_property_atom.rst b/doc/src/fix_property_atom.rst
index cc92c18655..09286cca38 100644
--- a/doc/src/fix_property_atom.rst
+++ b/doc/src/fix_property_atom.rst
@@ -304,13 +304,15 @@ uninterrupted fashion.
 .. warning::
 
    When reading data from a restart file, this fix command has to be
-   specified **exactly** the same was in the input script that created
-   the restart file. LAMMPS will only check whether a fix is of the
-   same style and has the same fix ID and in case of a match will then
-   try to initialize the fix with the data stored in the binary
-   restart file.  If the names and associated date types in the new
-   fix property/atom command do not match the old one exactly, data
-   can be corrupted or LAMMPS may crash.
+   specified **after** the *read_restart* command and **exactly** the
+   same was in the input script that created the restart file.  LAMMPS
+   will only check whether a fix is of the same style and has the same
+   fix ID and in case of a match will then try to initialize the fix
+   with the data stored in the binary restart file.  If the names and
+   associated date types in the new fix property/atom command do not
+   match the old one exactly, data can be corrupted or LAMMPS may crash.
+   If the fix is specified **before** the *read_restart* command its
+   data will not be restored.
 
 None of the :doc:`fix_modify <fix_modify>` options are relevant to
 this fix.  No global or per-atom quantities are stored by this fix for
diff --git a/src/read_restart.cpp b/src/read_restart.cpp
index dea062ed87..645f0c1d6d 100644
--- a/src/read_restart.cpp
+++ b/src/read_restart.cpp
@@ -118,6 +118,10 @@ void ReadRestart::command(int narg, char **arg)
   format_revision();
   check_eof_magic();
 
+  if ((comm->me == 0) && (modify->get_fix_by_style("property/atom").size() > 0))
+    error->warning(FLERR, "Fix property/atom command must be specified after read_restart "
+                   "to restore its data.");
+
   // read header info which creates simulation box
 
   header();