Don't do non-fastforward updates in fast-import.

diff --git a/fast-import.c b/fast-import.c
index ee4777fdafcbedc24997155581e55c339b40981e..df84e4d87d3d7c151bd0cdda29b22519e7043c8a 100644 (file)
--- a/fast-import.c
+++ b/fast-import.c
@@ -121,6 +121,7 @@ Format of STDIN stream:
 #include "object.h"
 #include "blob.h"
 #include "tree.h"
+#include "commit.h"
 #include "delta.h"
 #include "pack.h"
 #include "refs.h"
@@ -247,6 +248,7 @@ typedef enum {
 /* Configured limits on output */
 static unsigned long max_depth = 10;
 static unsigned long max_packsize = (1LL << 32) - 1;
+static int force_update;
 
 /* Stats and misc. counters */
 static uintmax_t alloc_count;
@@ -257,6 +259,7 @@ static uintmax_t delta_count_by_type[1 << TYPE_BITS];
 static unsigned long object_count;
 static unsigned long branch_count;
 static unsigned long branch_load_count;
+static int failure;
 
 /* Memory pools */
 static size_t mem_pool_alloc = 2*1024*1024 - sizeof(struct mem_pool);
@@ -1278,19 +1281,48 @@ static int tree_content_remove(struct tree_entry *root, const char *p)
        return 1;
 }
 
-static void dump_branches(void)
+static int update_branch(struct branch *b)
 {
        static const char *msg = "fast-import";
+       struct ref_lock *lock;
+       unsigned char old_sha1[20];
+
+       if (read_ref(b->name, old_sha1))
+               hashclr(old_sha1);
+       lock = lock_any_ref_for_update(b->name, old_sha1);
+       if (!lock)
+               return error("Unable to lock %s", b->name);
+       if (!force_update && !is_null_sha1(old_sha1)) {
+               struct commit *old_cmit, *new_cmit;
+
+               old_cmit = lookup_commit_reference_gently(old_sha1, 0);
+               new_cmit = lookup_commit_reference_gently(b->sha1, 0);
+               if (!old_cmit || !new_cmit) {
+                       unlock_ref(lock);
+                       return error("Branch %s is missing commits.", b->name);
+               }
+
+               if (!in_merge_bases(old_cmit, new_cmit)) {
+                       unlock_ref(lock);
+                       warn("Not updating %s"
+                               " (new tip %s does not contain %s)",
+                               b->name, sha1_to_hex(b->sha1), sha1_to_hex(old_sha1));
+                       return -1;
+               }
+       }
+       if (write_ref_sha1(lock, b->sha1, msg) < 0)
+               return error("Unable to update %s", b->name);
+       return 0;
+}
+
+static void dump_branches(void)
+{
        unsigned int i;
        struct branch *b;
-       struct ref_lock *lock;
 
        for (i = 0; i < branch_table_sz; i++) {
-               for (b = branch_table[i]; b; b = b->table_next_branch) {
-                       lock = lock_any_ref_for_update(b->name, NULL);
-                       if (!lock || write_ref_sha1(lock, b->sha1, msg) < 0)
-                               die("Can't write %s", b->name);
-               }
+               for (b = branch_table[i]; b; b = b->table_next_branch)
+                       failure |= update_branch(b);
        }
 }
 
@@ -1299,13 +1331,13 @@ static void dump_tags(void)
        static const char *msg = "fast-import";
        struct tag *t;
        struct ref_lock *lock;
-       char path[PATH_MAX];
+       char ref_name[PATH_MAX];
 
        for (t = first_tag; t; t = t->next_tag) {
-               sprintf(path, "refs/tags/%s", t->name);
-               lock = lock_any_ref_for_update(path, NULL);
+               sprintf(ref_name, "tags/%s", t->name);
+               lock = lock_ref_sha1(ref_name, NULL);
                if (!lock || write_ref_sha1(lock, t->sha1, msg) < 0)
-                       die("Can't write %s", path);
+                       failure |= error("Unable to update %s", ref_name);
        }
 }
 
@@ -1936,6 +1968,8 @@ int main(int argc, const char **argv)
                        max_active_branches = strtoul(a + 18, NULL, 0);
                else if (!strncmp(a, "--export-marks=", 15))
                        mark_file = a + 15;
+               else if (!strcmp(a, "--force"))
+                       force_update = 1;
                else
                        die("unknown option %s", a);
        }
@@ -2001,5 +2035,5 @@ int main(int argc, const char **argv)
        fprintf(stderr, "---------------------------------------------------------------------\n");
        fprintf(stderr, "\n");
 
-       return 0;
+       return failure ? 1 : 0;
 }