I accidentally tried to use "git diff" when I wasn't within a git
repository, only to be confused by getting a usage message with no
particular error output.
This patch tries to provide better explanations to the user when the diff
cannot be done.
Signed-off-by: Anthony Foiani <anthony.foiani@xxxxxxxxx>
---
diff-no-index.c | 122 ++++++++++++++++++++++++++++++++++++++++++------------
1 files changed, 95 insertions(+), 27 deletions(-)
diff --git a/diff-no-index.c b/diff-no-index.c
index 3a36144..3172788 100644
--- a/diff-no-index.c
+++ b/diff-no-index.c
@@ -149,21 +149,56 @@ static int queue_diff(struct diff_options *o,
}
}
-static int path_outside_repo(const char *path)
+/**
+ * path_in_repo() - Determine whether @path is within a git directory/repo.
+ * @path: pathspec to test
+ *
+ * Returns true if @path is equal to, or lies within, the git tree
+ * returned by get_git_work_tree.
+ */
+static int path_in_repo(const char *path)
{
- const char *work_tree;
- size_t len;
+ const char *tree;
+ const char *abs_path;
+ const char *abs_tree;
+ char norm_path[PATH_MAX+1];
+ char norm_tree[PATH_MAX+1];
+ size_t tree_len;
+ size_t path_len;
+
+ /* Paranoia. */
+ if (!path)
+ return 0;
- if (!is_absolute_path(path))
+ /* If there's no tree, then there's no repo to be in. */
+ tree = get_git_work_tree();
+ if (!tree)
return 0;
- work_tree = get_git_work_tree();
- if (!work_tree)
- return 1;
- len = strlen(work_tree);
- if (strncmp(path, work_tree, len) ||
- (path[len] != '\0' && path[len] != '/'))
- return 1;
- return 0;
+
+ /* Get the full paths and normalize them.. */
+ abs_path = real_path(path);
+ if (normalize_path_copy(norm_path, abs_path))
+ die("could not normalize path '%s'", abs_path);
+ abs_tree = real_path(tree);
+ if (normalize_path_copy(norm_tree, abs_tree))
+ die("could not normalize tree '%s'", abs_tree);
+
+ /* See if the work tree is a prefix *directory* of the given path. */
+ path_len = strlen(norm_path);
+ tree_len = strlen(norm_tree);
+
+ if (path_len < tree_len)
+ return 0; /* Can't be a subdir if it's shorter. */
+
+ if (strncmp(norm_path, norm_tree, tree_len))
+ return 0; /* Nor if the first 'tree_len' bytes don't match. */
+
+ if (norm_path[tree_len] == '\0')
+ return 1; /* The path and tree are the same. */
+ if (norm_path[tree_len] == '/')
+ return 1; /* The path is a subdir of the tree. */
+
+ return 0; /* Nope. */
}
void diff_no_index(struct rev_info *revs,
@@ -186,22 +221,55 @@ void diff_no_index(struct rev_info *revs,
break;
}
- if (!no_index && !nongit) {
- /*
- * Inside a git repository, without --no-index. Only
- * when a path outside the repository is given,
- * e.g. "git diff /var/tmp/[12]", or "git diff
- * Makefile /var/tmp/Makefile", allow it to be used as
- * a colourful "diff" replacement.
- */
- if ((argc != i + 2) ||
- (!path_outside_repo(argv[i]) &&
- !path_outside_repo(argv[i+1])))
- return;
+ /* How many pathspecs were given on the command line? */
+ const int n_paths = (argc - i);
+
+ /* If --no-index wasn't specified explicitly, check to see if
+ * we need to force it. */
+ if (!no_index) {
+
+ /* The first pathspec is the "left hand side" */
+ const char *lhs = (n_paths >= 1) ? argv[i] : NULL;
+ const int lhs_in_repo = lhs && path_in_repo(lhs);
+
+ /* And the second is the "right hand side" */
+ const char *rhs = (n_paths >= 2) ? argv[i+1] : NULL;
+ const int rhs_in_repo = rhs && path_in_repo(rhs);
+
+ int force_no_index = 0;
+
+ if (nongit) {
+ warning("'git diff' outside a repo, forcing --no-index");
+ force_no_index = 1;
+ }
+ else {
+ if (lhs_in_repo || rhs_in_repo)
+ return; /* Normal git diff, let core handle it. */
+
+ const int lhs_untracked = (lhs && !lhs_in_repo);
+ const int rhs_untracked = (rhs && !rhs_in_repo);
+
+ if (lhs_untracked && rhs_untracked)
+ warning("neither '%s' nor '%s' are tracked,"
+ " forcing --no-index", lhs, rhs );
+ else if (lhs_untracked)
+ warning("'%s' is not tracked,"
+ " forcing --no-index", lhs );
+ else if (rhs_untracked)
+ warning("'%s' is not tracked,"
+ " forcing --no-index", rhs );
+
+ force_no_index = lhs_untracked || rhs_untracked;
+ }
+
+ if (!force_no_index) /* Impossible? */
+ die("--no-index not set and not forced");
+ }
+
+ if (n_paths != 2) {
+ warning("no-index mode requires exactly two pathspecs");
+ usage("git diff --no-index <path> <path>");
}
- if (argc != i + 2)
- usagef("git diff %s <path> <path>",
- no_index ? "--no-index" : "[--no-index]");
diff_setup(&revs->diffopt);
for (i = 1; i < argc - 2; ) {
--
1.7.4.4
--
To unsubscribe from this list: send the line "unsubscribe git" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html