From 21f3f51ea2a719c9e57bdaf31c34b385c0c4efd4 Mon Sep 17 00:00:00 2001
From: Axel Kohlmeyer <akohlmey@gmail.com>
Date: Fri, 2 Aug 2019 10:13:52 -0400
Subject: [PATCH] better error messages on accessing invalid IDs in variable
 expressions

---
 src/variable.cpp | 65 +++++++++++++++++++++++++++++++++---------------
 1 file changed, 45 insertions(+), 20 deletions(-)

diff --git a/src/variable.cpp b/src/variable.cpp
index 3fffa11d5e..1093ce9066 100644
--- a/src/variable.cpp
+++ b/src/variable.cpp
@@ -18,6 +18,7 @@
 #include <cstring>
 #include <cctype>
 #include <unistd.h>
+#include <string>
 #include "universe.h"
 #include "atom.h"
 #include "update.h"
@@ -1302,8 +1303,12 @@ double Variable::evaluate(char *str, Tree **tree, int ivar)
         if (word[0] == 'C') lowercase = 0;
 
         int icompute = modify->find_compute(word+2);
-        if (icompute < 0)
-          print_var_error(FLERR,"Invalid compute ID in variable formula",ivar);
+        if (icompute < 0) {
+          std::string mesg = "Invalid compute ID '";
+          mesg += (word+2);
+          mesg += "' in variable formula";
+          print_var_error(FLERR,mesg.c_str(),ivar);
+        }
         Compute *compute = modify->compute[icompute];
 
         // parse zero or one or two trailing brackets
@@ -1604,9 +1609,10 @@ double Variable::evaluate(char *str, Tree **tree, int ivar)
 
         int ifix = modify->find_fix(word+2);
         if (ifix < 0) {
-          char msg[128];
-          snprintf(msg,128,"Invalid fix ID '%s' in variable formula",word+2);
-          print_var_error(FLERR,msg,ivar);
+          std::string mesg = "Invalid fix ID '";
+          mesg += (word+2);
+          mesg += "' in variable formula";
+          print_var_error(FLERR,mesg.c_str(),ivar);
         }
         Fix *fix = modify->fix[ifix];
 
@@ -3792,8 +3798,12 @@ int Variable::group_function(char *word, char *contents, Tree **tree,
   // group to operate on
 
   int igroup = group->find(args[0]);
-  if (igroup == -1)
-    print_var_error(FLERR,"Group ID in variable formula does not exist",ivar);
+  if (igroup == -1) {
+    std::string mesg = "Group ID '";
+    mesg += args[0];
+    mesg += "' in variable formula does not exist";
+    print_var_error(FLERR,mesg.c_str(),ivar);
+  }
 
   // match word to group function
 
@@ -4001,8 +4011,12 @@ int Variable::group_function(char *word, char *contents, Tree **tree,
 int Variable::region_function(char *id, int ivar)
 {
   int iregion = domain->find_region(id);
-  if (iregion == -1)
-    print_var_error(FLERR,"Region ID in variable formula does not exist",ivar);
+  if (iregion == -1) {
+    std::string mesg = "Region ID '";
+    mesg += id;
+    mesg += "' in variable formula does not exist";
+    print_var_error(FLERR,mesg.c_str(),ivar);
+  }
 
   // init region in case sub-regions have been deleted
 
@@ -4080,9 +4094,10 @@ int Variable::special_function(char *word, char *contents, Tree **tree,
 
       int icompute = modify->find_compute(&args[0][2]);
       if (icompute < 0) {
-        char msg[128];
-        snprintf(msg,128,"Invalid compute ID '%s' in variable formula",word+2);
-        print_var_error(FLERR,msg,ivar);
+        std::string mesg = "Invalid compute ID '";
+        mesg += (args[0]+2);
+        mesg += "' in variable formula";
+        print_var_error(FLERR,mesg.c_str(),ivar);
       }
       compute = modify->compute[icompute];
       if (index == 0 && compute->vector_flag) {
@@ -4123,13 +4138,20 @@ int Variable::special_function(char *word, char *contents, Tree **tree,
       } else index = 0;
 
       int ifix = modify->find_fix(&args[0][2]);
-      if (ifix < 0)
-        print_var_error(FLERR,"Invalid fix ID in variable formula",ivar);
+      if (ifix < 0) {
+        std::string mesg = "Invalid fix ID '";
+        mesg += (args[0]+2);
+        mesg += "' in variable formula";
+        print_var_error(FLERR,mesg.c_str(),ivar);
+      }
       fix = modify->fix[ifix];
       if (index == 0 && fix->vector_flag) {
-        if (update->whichflag > 0 && update->ntimestep % fix->global_freq)
-          print_var_error(FLERR,"Fix in variable not computed at "
-                          "compatible time",ivar);
+        if (update->whichflag > 0 && update->ntimestep % fix->global_freq) {
+          std::string mesg = "Fix with ID '";
+          mesg += (args[0]+2);
+          mesg += "' in variable formula not computed at compatible time";
+          print_var_error(FLERR,mesg.c_str(),ivar);
+        }
         nvec = fix->size_vector;
         nstride = 1;
       } else if (index && fix->array_flag) {
@@ -4336,9 +4358,12 @@ int Variable::special_function(char *word, char *contents, Tree **tree,
       print_var_error(FLERR,"Invalid special function in variable formula",ivar);
 
     int ivar = find(args[0]);
-    if (ivar < 0)
-      print_var_error(FLERR,"Variable ID in "
-                      "variable formula does not exist",ivar);
+    if (ivar < 0) {
+      std::string mesg = "Variable ID '";
+      mesg += args[0];
+      mesg += "' in variable formula does not exist";
+      print_var_error(FLERR,mesg.c_str(),ivar);
+    }
 
     // SCALARFILE has single current value, read next one
     // save value in tree or on argstack