merge(third_party/git): Merge squashed git subtree at v2.23.0

Merge commit '1b593e1ea4' as 'third_party/git'

third_party/git/t/lib-diff-alternative.sh

@@ -0,0 +1,170 @@
+# Helpers shared by the test scripts for diff algorithms (patience,
+# histogram, etc).
+
+test_diff_frobnitz() {
+	cat >file1 <<\EOF
+#include <stdio.h>
+
+// Frobs foo heartily
+int frobnitz(int foo)
+{
+    int i;
+    for(i = 0; i < 10; i++)
+    {
+        printf("Your answer is: ");
+        printf("%d\n", foo);
+    }
+}
+
+int fact(int n)
+{
+    if(n > 1)
+    {
+        return fact(n-1) * n;
+    }
+    return 1;
+}
+
+int main(int argc, char **argv)
+{
+    frobnitz(fact(10));
+}
+EOF
+
+	cat >file2 <<\EOF
+#include <stdio.h>
+
+int fib(int n)
+{
+    if(n > 2)
+    {
+        return fib(n-1) + fib(n-2);
+    }
+    return 1;
+}
+
+// Frobs foo heartily
+int frobnitz(int foo)
+{
+    int i;
+    for(i = 0; i < 10; i++)
+    {
+        printf("%d\n", foo);
+    }
+}
+
+int main(int argc, char **argv)
+{
+    frobnitz(fib(10));
+}
+EOF
+
+	file1=$(git rev-parse --short $(git hash-object file1))
+	file2=$(git rev-parse --short $(git hash-object file2))
+	cat >expect <<EOF
+diff --git a/file1 b/file2
+index $file1..$file2 100644
+--- a/file1
++++ b/file2
+@@ -1,26 +1,25 @@
+ #include <stdio.h>
+ 
++int fib(int n)
++{
++    if(n > 2)
++    {
++        return fib(n-1) + fib(n-2);
++    }
++    return 1;
++}
++
+ // Frobs foo heartily
+ int frobnitz(int foo)
+ {
+     int i;
+     for(i = 0; i < 10; i++)
+     {
+-        printf("Your answer is: ");
+         printf("%d\n", foo);
+     }
+ }
+ 
+-int fact(int n)
+-{
+-    if(n > 1)
+-    {
+-        return fact(n-1) * n;
+-    }
+-    return 1;
+-}
+-
+ int main(int argc, char **argv)
+ {
+-    frobnitz(fact(10));
++    frobnitz(fib(10));
+ }
+EOF
+
+	STRATEGY=$1
+
+	test_expect_success "$STRATEGY diff" '
+		test_must_fail git diff --no-index "--$STRATEGY" file1 file2 > output &&
+		test_cmp expect output
+	'
+
+	test_expect_success "$STRATEGY diff output is valid" '
+		mv file2 expect &&
+		git apply < output &&
+		test_cmp expect file2
+	'
+}
+
+test_diff_unique() {
+	cat >uniq1 <<\EOF
+1
+2
+3
+4
+5
+6
+EOF
+
+	cat >uniq2 <<\EOF
+a
+b
+c
+d
+e
+f
+EOF
+
+	uniq1=$(git rev-parse --short $(git hash-object uniq1))
+	uniq2=$(git rev-parse --short $(git hash-object uniq2))
+	cat >expect <<EOF
+diff --git a/uniq1 b/uniq2
+index $uniq1..$uniq2 100644
+--- a/uniq1
++++ b/uniq2
+@@ -1,6 +1,6 @@
+-1
+-2
+-3
+-4
+-5
+-6
++a
++b
++c
++d
++e
++f
+EOF
+
+	STRATEGY=$1
+
+	test_expect_success 'completely different files' '
+		test_must_fail git diff --no-index "--$STRATEGY" uniq1 uniq2 > output &&
+		test_cmp expect output
+	'
+}
+