Merge branch 'kb/maint-diff-ws-check' into maint

* kb/maint-diff-ws-check:
  diff: handle lines containing only whitespace and tabs better
  test-lib: extend test_decode_color to handle more color codes

diff --cc t/test-lib.sh
index 25f8bf95cdc7624c80ca57affb7eae799e0090c0,49527a675b15c05344e101de98b1d3335b9c983f..c6afebb00d02808f2a990347c8b0479d825cce5b
--- 1/t/test-lib.sh
--- 2/t/test-lib.sh
+++ b/t/test-lib.sh
@@@ -238,20 -238,49 +238,53 @@@ test_set_editor () 
  }
  
  test_decode_color () {
-       sed     -e 's/.\[1m/<WHITE>/g' \
-               -e 's/.\[31m/<RED>/g' \
-               -e 's/.\[32m/<GREEN>/g' \
-               -e 's/.\[33m/<YELLOW>/g' \
-               -e 's/.\[34m/<BLUE>/g' \
-               -e 's/.\[35m/<MAGENTA>/g' \
-               -e 's/.\[36m/<CYAN>/g' \
-               -e 's/.\[m/<RESET>/g'
+       awk '
+               function name(n) {
+                       if (n == 0) return "RESET";
+                       if (n == 1) return "BOLD";
+                       if (n == 30) return "BLACK";
+                       if (n == 31) return "RED";
+                       if (n == 32) return "GREEN";
+                       if (n == 33) return "YELLOW";
+                       if (n == 34) return "BLUE";
+                       if (n == 35) return "MAGENTA";
+                       if (n == 36) return "CYAN";
+                       if (n == 37) return "WHITE";
+                       if (n == 40) return "BLACK";
+                       if (n == 41) return "BRED";
+                       if (n == 42) return "BGREEN";
+                       if (n == 43) return "BYELLOW";
+                       if (n == 44) return "BBLUE";
+                       if (n == 45) return "BMAGENTA";
+                       if (n == 46) return "BCYAN";
+                       if (n == 47) return "BWHITE";
+               }
+               {
+                       while (match($0, /\x1b\[[0-9;]*m/) != 0) {
+                               printf "%s<", substr($0, 1, RSTART-1);
+                               codes = substr($0, RSTART+2, RLENGTH-3);
+                               if (length(codes) == 0)
+                                       printf "%s", name(0)
+                               else {
+                                       n = split(codes, ary, ";");
+                                       sep = "";
+                                       for (i = 1; i <= n; i++) {
+                                               printf "%s%s", sep, name(ary[i]);
+                                               sep = ";"
+                                       }
+                               }
+                               printf ">";
+                               $0 = substr($0, RSTART + RLENGTH, length($0) - RSTART - RLENGTH + 1);
+                       }
+                       print
+               }
+       '
  }
  
 +nul_to_q () {
 +      perl -pe 'y/\000/Q/'
 +}
 +
  q_to_nul () {
        perl -pe 'y/Q/\000/'
  }