[PATCH] Be careful with symlinks when detecting renames and copies.

Earlier round was not treating symbolic links carefully enough,
and would have produced diff output that renamed/copied then
edited the contents of a symbolic link, which made no practical
sense.  Change it to detect only pure renames.

Signed-off-by: Junio C Hamano <junkio@cox.net>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

diff --git a/diffcore-rename.c b/diffcore-rename.c
index 794e5cc..52f09d2 100644 (file)
--- a/diffcore-rename.c
+++ b/diffcore-rename.c
@@ -20,7 +20,7 @@ static void diff_rename_pool_add(struct diff_rename_pool *pool,
                                 struct diff_filespec *s)
 {
        if (S_ISDIR(s->mode))
-               return;  /* rename/copy patch for tree does not make sense. */
+               return;  /* no trees, please */
 
        if (pool->alloc <= pool->nr) {
                pool->alloc = alloc_nr(pool->alloc);
@@ -71,6 +71,13 @@ static int estimate_similarity(struct diff_filespec *src,
        unsigned long delta_size, base_size;
        int score;
 
+       /* We deal only with regular files.  Symlink renames are handled
+        * only when they are exact matches --- in other words, no edits
+        * after renaming.
+        */
+       if (!S_ISREG(src->mode) || !S_ISREG(dst->mode))
+               return 0;
+
        delta_size = ((src->size < dst->size) ?
                      (dst->size - src->size) : (src->size - dst->size));
        base_size = ((src->size < dst->size) ? src->size : dst->size);
@@ -268,7 +275,7 @@ void diffcore_rename(int detect_rename, int minimum_score)
                struct diff_filepair *p = q->queue[i];
                if (!DIFF_FILE_VALID(p->one))
                        if (!DIFF_FILE_VALID(p->two))
-                               continue; /* ignore nonsense */
+                               continue; /* unmerged */
                        else
                                diff_rename_pool_add(&created, p->two);
                else if (!DIFF_FILE_VALID(p->two))
@@ -360,12 +367,9 @@ void diffcore_rename(int detect_rename, int minimum_score)
        for (i = 0; i < q->nr; i++) {
                struct diff_filepair *dp, *p = q->queue[i];
                if (!DIFF_FILE_VALID(p->one)) {
-                       if (DIFF_FILE_VALID(p->two)) {
-                               /* creation */
-                               dp = diff_queue(&outq, p->one, p->two);
-                               dp->xfrm_work = 4;
-                       }
-                       /* otherwise it is a nonsense; just ignore it */
+                       /* creation or unmerged entries */
+                       dp = diff_queue(&outq, p->one, p->two);
+                       dp->xfrm_work = 4;
                }
                else if (!DIFF_FILE_VALID(p->two)) {
                        /* deletion */
@@ -394,7 +398,7 @@ void diffcore_rename(int detect_rename, int minimum_score)
        for (i = 0; i < outq.nr; i++) {
                struct diff_filepair *p = outq.queue[i];
                if (!DIFF_FILE_VALID(p->one)) {
-                       /* created */
+                       /* created or unmerged */
                        if (p->two->xfrm_flags & RENAME_DST_MATCHED)
                                ; /* rename/copy created it already */
                        else
@@ -443,7 +447,7 @@ void diffcore_rename(int detect_rename, int minimum_score)
                else
                        /* otherwise it is a modified (or stayed) entry */
                        diff_queue(q, p->one, p->two);
-               free(p);
+               diff_free_filepair(p);
        }
 
        free(outq.queue);

diff --git a/t/t4004-diff-rename-symlink.sh b/t/t4004-diff-rename-symlink.sh
new file mode 100644 (file)
index 0000000..31fdc50
--- /dev/null
+++ b/t/t4004-diff-rename-symlink.sh
@@ -0,0 +1,66 @@
+#!/bin/sh
+#
+# Copyright (c) 2005 Junio C Hamano
+#
+
+test_description='More rename detection tests.
+
+The rename detection logic should be able to detect pure rename or
+copy of symbolic links, but should not produce rename/copy followed
+by an edit for them.
+'
+. ./test-lib.sh
+
+test_expect_success \
+    'prepare reference tree' \
+    'echo xyzzy | tr -d '\\\\'012 >yomin &&
+     ln -s xyzzy frotz &&
+    git-update-cache --add frotz yomin &&
+    tree=$(git-write-tree) &&
+    echo $tree'
+
+test_expect_success \
+    'prepare work tree' \
+    'mv frotz rezrov &&
+     rm -f yomin &&
+     ln -s xyzzy nitfol &&
+     ln -s xzzzy bozbar &&
+    git-update-cache --add --remove frotz rezrov nitfol bozbar yomin'
+
+# tree has frotz pointing at xyzzy, and yomin that contains xyzzy to
+# confuse things.  work tree has rezrov (xyzzy) nitfol (xyzzy) and
+# bozbar (xzzzy).
+# rezrov and nitfol are rename/copy of frotz and bozbar should be
+# a new creation.
+
+GIT_DIFF_OPTS=--unified=0 git-diff-cache -M -p $tree >current
+cat >expected <<\EOF
+diff --git a/frotz b/nitfol
+similarity index 100%
+copy from frotz
+copy to nitfol
+diff --git a/frotz b/rezrov
+similarity index 100%
+rename old frotz
+rename new rezrov
+diff --git a/yomin b/yomin
+deleted file mode 100644
+--- a/yomin
++++ /dev/null
+@@ -1 +0,0 @@
+-xyzzy
+\ No newline at end of file
+diff --git a/bozbar b/bozbar
+new file mode 120000
+--- /dev/null
++++ b/bozbar
+@@ -0,0 +1 @@
++xzzzy
+\ No newline at end of file
+EOF
+
+test_expect_success \
+    'validate diff output' \
+    'diff -u current expected'
+
+test_done