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authorDavid Aguilar <davvid@gmail.com>2017-03-15 09:31:30 (GMT)
committerJunio C Hamano <gitster@pobox.com>2017-03-15 19:08:10 (GMT)
commit18ec800512eb0634a0bf5e86b36ed156fbee73f3 (patch)
treeffd9ab32ead843561af695169904b0493a060897 /builtin
parent98fde5e47b684c7be28e5c0c2a80354cf088d41d (diff)
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difftool: handle modified symlinks in dir-diff mode
Detect the null object ID for symlinks in dir-diff so that difftool can detect when symlinks are modified in the worktree. Previously, a null symlink object ID would crash difftool. Handle null object IDs as unknown content that must be read from the worktree. Helped-by: Johannes Schindelin <johannes.schindelin@gmx.de> Signed-off-by: David Aguilar <davvid@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
Diffstat (limited to 'builtin')
-rw-r--r--builtin/difftool.c51
1 files changed, 46 insertions, 5 deletions
diff --git a/builtin/difftool.c b/builtin/difftool.c
index d13350c..25e54ad 100644
--- a/builtin/difftool.c
+++ b/builtin/difftool.c
@@ -254,6 +254,49 @@ static int ensure_leading_directories(char *path)
}
}
+/*
+ * Unconditional writing of a plain regular file is what
+ * "git difftool --dir-diff" wants to do for symlinks. We are preparing two
+ * temporary directories to be fed to a Git-unaware tool that knows how to
+ * show a diff of two directories (e.g. "diff -r A B").
+ *
+ * Because the tool is Git-unaware, if a symbolic link appears in either of
+ * these temporary directories, it will try to dereference and show the
+ * difference of the target of the symbolic link, which is not what we want,
+ * as the goal of the dir-diff mode is to produce an output that is logically
+ * equivalent to what "git diff" produces.
+ *
+ * Most importantly, we want to get textual comparison of the result of the
+ * readlink(2). get_symlink() provides that---it returns the contents of
+ * the symlink that gets written to a regular file to force the external tool
+ * to compare the readlink(2) result as text, even on a filesystem that is
+ * capable of doing a symbolic link.
+ */
+static char *get_symlink(const struct object_id *oid, const char *path)
+{
+ char *data;
+ if (is_null_oid(oid)) {
+ /* The symlink is unknown to Git so read from the filesystem */
+ struct strbuf link = STRBUF_INIT;
+ if (has_symlinks) {
+ if (strbuf_readlink(&link, path, strlen(path)))
+ die(_("could not read symlink %s"), path);
+ } else if (strbuf_read_file(&link, path, 128))
+ die(_("could not read symlink file %s"), path);
+
+ data = strbuf_detach(&link, NULL);
+ } else {
+ enum object_type type;
+ unsigned long size;
+ data = read_sha1_file(oid->hash, &type, &size);
+ if (!data)
+ die(_("could not read object %s for symlink %s"),
+ oid_to_hex(oid), path);
+ }
+
+ return data;
+}
+
static int run_dir_diff(const char *extcmd, int symlinks, const char *prefix,
int argc, const char **argv)
{
@@ -270,8 +313,6 @@ static int run_dir_diff(const char *extcmd, int symlinks, const char *prefix,
struct hashmap working_tree_dups, submodules, symlinks2;
struct hashmap_iter iter;
struct pair_entry *entry;
- enum object_type type;
- unsigned long size;
struct index_state wtindex;
struct checkout lstate, rstate;
int rc, flags = RUN_GIT_CMD, err = 0;
@@ -377,13 +418,13 @@ static int run_dir_diff(const char *extcmd, int symlinks, const char *prefix,
}
if (S_ISLNK(lmode)) {
- char *content = read_sha1_file(loid.hash, &type, &size);
+ char *content = get_symlink(&loid, src_path);
add_left_or_right(&symlinks2, src_path, content, 0);
free(content);
}
if (S_ISLNK(rmode)) {
- char *content = read_sha1_file(roid.hash, &type, &size);
+ char *content = get_symlink(&roid, dst_path);
add_left_or_right(&symlinks2, dst_path, content, 1);
free(content);
}
@@ -397,7 +438,7 @@ static int run_dir_diff(const char *extcmd, int symlinks, const char *prefix,
return error("could not write '%s'", src_path);
}
- if (rmode) {
+ if (rmode && !S_ISLNK(rmode)) {
struct working_tree_entry *entry;
/* Avoid duplicate working_tree entries */