Re: [PATCH 0/3] Teach Git about the patience diff algorithm

[Clemens Buchacher <drizzd@aon.at>]

On Thu, Jan 01, 2009 at 05:56:13PM -0800, Linus Torvalds wrote:
> See above - I really don't think this has anything to do with "patience vs 
> non-patience". It's more akin to the things we do for our merge conflict 
> markers: if we have two merge conflicts next to each other, with just a 
> couple of lines in between, we coalesce the merge conflicts into one 
> larger one instead.

But patience diff does more than that. Take a look at "git diff" and "git
diff --patience" output below (taken from [1]). You can see that patience
diff produces two separate hunks, one removing a function and one adding a
function. Merging consecutive diff fragments would have produced one big
hunk instead.

*** git diff ****************************** git diff --patience **********
 #include <stdio.h>                   | #include <stdio.h>
                                      |
+int fib(int n)                       |-// Frobs foo heartily
+{                                    |-int frobnitz(int foo)
+    if(n > 2)                        |+int fib(int n)
+    {                                | {
+        return fib(n-1) + fib(n-2);  |-    int i;
+    }                                |-    for(i = 0; i < 10; i++)
+    return 1;                        |+    if(n > 2)
+}                                    |     {
+                                     |-        printf("Your answer is: ");
 // Frobs foo heartily                |-        printf("%d\n", foo);
 int frobnitz(int foo)                |+        return fib(n-1) + fib(n-2);
 {                                    |     }
     int i;                           |+    return 1;
     for(i = 0; i < 10; i++)          | }
     {                                |
-        printf("Your answer is: ");  |-int fact(int n)
         printf("%d\n", foo);         |+// Frobs foo heartily
     }                                |+int frobnitz(int foo)
 }                                    | {
                                      |-    if(n > 1)
-int fact(int n)                      |+    int i;
-{                                    |+    for(i = 0; i < 10; i++)
-    if(n > 1)                        |     {
-    {                                |-        return fact(n-1) * n;
-        return fact(n-1) * n;        |+        printf("%d\n", foo);
-    }                                |     }
-    return 1;                        |-    return 1;
-}                                    | }
-                                     |
 int main(int argc, char **argv)      | int main(int argc, char **argv)
 {                                    | {
-    frobnitz(fact(10));              |-    frobnitz(fact(10));
+    frobnitz(fib(10));               |+    frobnitz(fib(10));
 }                                    | }

[1] http://alfedenzo.livejournal.com/170301.html