Simultaneously, both Harry and Sally have a crisis of conscience and realize that their code has no comments at all.

Harry:

lottery harry$ vv diff
=== ================
===   Modified: File @/src/pb.c
--- @/src/pb.c  3cdd8958d3467042fd5791f3c16951f3cfdacc5c
+++ @/src/pb.c  2011/05/31 16:53:00.000 +0000
@@ -47,6 +47,7 @@
         return -1;
     }
 
+    // lottery ball numbers are always shown sorted
     qsort(white_balls, 5, sizeof(int), my_sort_func);
 
     return 0;

lottery harry$ vv commit -m "comments"

    revision:  21:cb3675aada7836e63ec88fc5a6eeb9f80a00f656
      branch:  master
         who:  harry
        when:  2011/05/31 11:53:32.590 -0500
     comment:  comments
      parent:  20:68f12175bcda2296298f6b0f30da326341976356

lottery harry$ vv push
Pushing to http://server.futilisoft.com:8080/repos/lottery:
Pushing... Done.                                                               

And Sally:

lottery sally$ vv diff
=== ================
===   Modified: File @/src/pb.c
--- @/src/pb.c  7d927466a22e24d4adc5542f6bf0a4797aa06801
+++ @/src/pb.c  2011/05/31 16:54:57.000 +0000
@@ -35,7 +35,7 @@
 {
     int balls[6];
     int count_balls = 0;
-    int favorite = 0;
+    int favorite = 0;  // this should be a bool
 
     for (int i=1; i<argc; i++)
     {
@@ -69,10 +69,13 @@
         goto usage_error;
     }
 
+    // the power ball is always the last one given
     int power_ball = balls[5];
 
     int result = calculate_result(balls, power_ball);
 
+    // calculate result can return -1 if the ball numbers
+    // are out of range
     if (result < 0)
     {
         goto usage_error;

lottery sally$ vv commit -m "comments"

    revision:  21:69f50e32759eef176403ca0c019fb1af73145fb9
      branch:  no_boys_allowed
         who:  sally
        when:  2011/05/31 11:55:40.174 -0500
     comment:  comments
      parent:  18:37939b07309af8232c44048ca0a1633c982b7506

lottery sally$ vv push
Pushing to http://server.futilisoft.com:8080/repos/lottery:
Pushing... Done.                                                               

Harry decides to try again to merge the changes from Sally’s branch.

lottery harry$ vv heads

    revision:  22:69f50e32759eef176403ca0c019fb1af73145fb9
      branch:  no_boys_allowed
         who:  sally
        when:  2011/05/31 11:55:40.174 -0500
     comment:  comments
      parent:  18:37939b07309af8232c44048ca0a1633c982b7506

    revision:  21:cb3675aada7836e63ec88fc5a6eeb9f80a00f656
      branch:  master
         who:  harry
        when:  2011/05/31 11:53:32.590 -0500
     comment:  comments
      parent:  20:68f12175bcda2296298f6b0f30da326341976356

lottery harry$ vv merge -r 69f50e32759eef176403ca0c019fb1af73145fb9
1 updated, 0 deleted, 0 added, 1 merged, 0 unresolved

No problems with the merge. Let’s review the changes.

lottery harry$ vv diff
=== ================
===   Modified: File @/src/pb.c
--- @/src/pb.c  ec840f5b96e6f64ab9efaf0b37975ceafa6bfe81
+++ @/src/pb.c  2011/05/31 16:57:07.000 +0000
@@ -57,7 +57,7 @@
 {
     int balls[6];
     int count_balls = 0;
-    int favorite = 0;
+    int favorite = 0;  // this should be a bool
 
     for (int i=1; i<argc; i++)
     {
@@ -91,10 +91,13 @@
         goto usage_error;
     }
 
+    // the power ball is always the last one given
     int power_ball = balls[5];
 
     int result = calculate_result(balls, power_ball);
 
+    // calculate result can return -1 if the ball numbers
+    // are out of range
     if (result < 0)
     {
         goto usage_error;

Harry checks to see if everything compiles, and commits the merge.

lottery harry$ make
gcc -std=c99 -Wall -Wextra -Werror pb.c -o pb

lottery harry$ vv commit -m "merge changes from sally"

    revision:  23:31d8497141637a90feeb38f16ac9ff9454673e3d
      branch:  master
         who:  harry
        when:  2011/05/31 11:57:55.503 -0500
     comment:  merge changes from sally
      parent:  22:69f50e32759eef176403ca0c019fb1af73145fb9
      parent:  21:cb3675aada7836e63ec88fc5a6eeb9f80a00f656

lottery harry$ vv push
Pushing to http://server.futilisoft.com:8080/repos/lottery:
Pushing... Done.