commit-graph: fix segfault on e.g. "git status"

diff --git a/match-trees.c b/match-trees.c
index 2b6d31ef9d35d9422e7ef90792651dcb7a2f9189..ddc4d398456363cede9f3f5d4fa602efb402b5bd 100644 (file)
--- a/match-trees.c
+++ b/match-trees.c
@@ -3,7 +3,7 @@
 #include "tree-walk.h"
 #include "object-store.h"
 
-static int score_missing(unsigned mode, const char *path)
+static int score_missing(unsigned mode)
 {
        int score;
 
@@ -16,7 +16,7 @@ static int score_missing(unsigned mode, const char *path)
        return score;
 }
 
-static int score_differs(unsigned mode1, unsigned mode2, const char *path)
+static int score_differs(unsigned mode1, unsigned mode2)
 {
        int score;
 
@@ -29,7 +29,7 @@ static int score_differs(unsigned mode1, unsigned mode2, const char *path)
        return score;
 }
 
-static int score_matches(unsigned mode1, unsigned mode2, const char *path)
+static int score_matches(unsigned mode1, unsigned mode2)
 {
        int score;
 
@@ -98,24 +98,22 @@ static int score_trees(const struct object_id *hash1, const struct object_id *ha
 
                if (cmp < 0) {
                        /* path1 does not appear in two */
-                       score += score_missing(one.entry.mode, one.entry.path);
+                       score += score_missing(one.entry.mode);
                        update_tree_entry(&one);
                } else if (cmp > 0) {
                        /* path2 does not appear in one */
-                       score += score_missing(two.entry.mode, two.entry.path);
+                       score += score_missing(two.entry.mode);
                        update_tree_entry(&two);
                } else {
                        /* path appears in both */
-                       if (!oideq(one.entry.oid, two.entry.oid)) {
+                       if (!oideq(&one.entry.oid, &two.entry.oid)) {
                                /* they are different */
                                score += score_differs(one.entry.mode,
-                                                      two.entry.mode,
-                                                      one.entry.path);
+                                                      two.entry.mode);
                        } else {
                                /* same subtree or blob */
                                score += score_matches(one.entry.mode,
-                                                      two.entry.mode,
-                                                      one.entry.path);
+                                                      two.entry.mode);
                        }
                        update_tree_entry(&one);
                        update_tree_entry(&two);
@@ -179,7 +177,7 @@ static int splice_tree(const struct object_id *oid1, const char *prefix,
        char *buf;
        unsigned long sz;
        struct tree_desc desc;
-       struct object_id *rewrite_here;
+       unsigned char *rewrite_here;
        const struct object_id *rewrite_with;
        struct object_id subtree;
        enum object_type type;
@@ -199,15 +197,26 @@ static int splice_tree(const struct object_id *oid1, const char *prefix,
        while (desc.size) {
                const char *name;
                unsigned mode;
-               const struct object_id *oid;
 
-               oid = tree_entry_extract(&desc, &name, &mode);
+               tree_entry_extract(&desc, &name, &mode);
                if (strlen(name) == toplen &&
                    !memcmp(name, prefix, toplen)) {
                        if (!S_ISDIR(mode))
                                die("entry %s in tree %s is not a tree", name,
                                    oid_to_hex(oid1));
-                       rewrite_here = (struct object_id *)oid;
+
+                       /*
+                        * We cast here for two reasons:
+                        *
+                        *   - to flip the "char *" (for the path) to "unsigned
+                        *     char *" (for the hash stored after it)
+                        *
+                        *   - to discard the "const"; this is OK because we
+                        *     know it points into our non-const "buf"
+                        */
+                       rewrite_here = (unsigned char *)(desc.entry.path +
+                                                        strlen(desc.entry.path) +
+                                                        1);
                        break;
                }
                update_tree_entry(&desc);
@@ -216,14 +225,16 @@ static int splice_tree(const struct object_id *oid1, const char *prefix,
                die("entry %.*s not found in tree %s", toplen, prefix,
                    oid_to_hex(oid1));
        if (*subpath) {
-               status = splice_tree(rewrite_here, subpath, oid2, &subtree);
+               struct object_id tree_oid;
+               hashcpy(tree_oid.hash, rewrite_here);
+               status = splice_tree(&tree_oid, subpath, oid2, &subtree);
                if (status)
                        return status;
                rewrite_with = &subtree;
        } else {
                rewrite_with = oid2;
        }
-       oidcpy(rewrite_here, rewrite_with);
+       hashcpy(rewrite_here, rewrite_with->hash);
        status = write_object_file(buf, sz, tree_type, result);
        free(buf);
        return status;