Merge branch 'da/difftool'

Code clean-up in "git difftool".

* da/difftool:
  difftool: add a missing space to the run_dir_diff() comments
  difftool: remove an unnecessary call to strbuf_release()
  difftool: refactor dir-diff to write files using helper functions
  difftool: create a tmpdir path without repeated slashes

2 files changed, 60 insertions, 51 deletions

diff --git a/builtin/difftool.c b/builtin/difftool.c
index 210da03908..4931c10845 100644
--- a/builtin/difftool.c
+++ b/builtin/difftool.c
@@ -252,16 +252,6 @@ static void changed_files(struct hashmap *result, const char *index_path,
 	strbuf_release(&buf);
 }
 
-static NORETURN void exit_cleanup(const char *tmpdir, int exit_code)
-{
-	struct strbuf buf = STRBUF_INIT;
-	strbuf_addstr(&buf, tmpdir);
-	remove_dir_recursively(&buf, 0);
-	if (exit_code)
-		warning(_("failed: %d"), exit_code);
-	exit(exit_code);
-}
-
 static int ensure_leading_directories(char *path)
 {
 	switch (safe_create_leading_directories(path)) {
@@ -330,19 +320,44 @@ static int checkout_path(unsigned mode, struct object_id *oid,
 	return ret;
 }
 
+static void write_file_in_directory(struct strbuf *dir, size_t dir_len,
+			const char *path, const char *content)
+{
+	add_path(dir, dir_len, path);
+	ensure_leading_directories(dir->buf);
+	unlink(dir->buf);
+	write_file(dir->buf, "%s", content);
+}
+
+/* Write the file contents for the left and right sides of the difftool
+ * dir-diff representation for submodules and symlinks. Symlinks and submodules
+ * are written as regular text files so that external diff tools can diff them
+ * as text files, resulting in behavior that is analogous to to what "git diff"
+ * displays for symlink and submodule diffs.
+ */
+static void write_standin_files(struct pair_entry *entry,
+			struct strbuf *ldir, size_t ldir_len,
+			struct strbuf *rdir, size_t rdir_len)
+{
+	if (*entry->left)
+		write_file_in_directory(ldir, ldir_len, entry->path, entry->left);
+	if (*entry->right)
+		write_file_in_directory(rdir, rdir_len, entry->path, entry->right);
+}
+
 static int run_dir_diff(const char *extcmd, int symlinks, const char *prefix,
 			struct child_process *child)
 {
-	char tmpdir[PATH_MAX];
 	struct strbuf info = STRBUF_INIT, lpath = STRBUF_INIT;
 	struct strbuf rpath = STRBUF_INIT, buf = STRBUF_INIT;
 	struct strbuf ldir = STRBUF_INIT, rdir = STRBUF_INIT;
 	struct strbuf wtdir = STRBUF_INIT;
-	char *lbase_dir, *rbase_dir;
+	struct strbuf tmpdir = STRBUF_INIT;
+	char *lbase_dir = NULL, *rbase_dir = NULL;
 	size_t ldir_len, rdir_len, wtdir_len;
 	const char *workdir, *tmp;
 	int ret = 0, i;
-	FILE *fp;
+	FILE *fp = NULL;
 	struct hashmap working_tree_dups = HASHMAP_INIT(working_tree_entry_cmp,
 							NULL);
 	struct hashmap submodules = HASHMAP_INIT(pair_cmp, NULL);
@@ -351,7 +366,7 @@ static int run_dir_diff(const char *extcmd, int symlinks, const char *prefix,
 	struct pair_entry *entry;
 	struct index_state wtindex;
 	struct checkout lstate, rstate;
-	int rc, flags = RUN_GIT_CMD, err = 0;
+	int flags = RUN_GIT_CMD, err = 0;
 	const char *helper_argv[] = { "difftool--helper", NULL, NULL, NULL };
 	struct hashmap wt_modified, tmp_modified;
 	int indices_loaded = 0;
@@ -360,11 +375,15 @@ static int run_dir_diff(const char *extcmd, int symlinks, const char *prefix,
 
 	/* Setup temp directories */
 	tmp = getenv("TMPDIR");
-	xsnprintf(tmpdir, sizeof(tmpdir), "%s/git-difftool.XXXXXX", tmp ? tmp : "/tmp");
-	if (!mkdtemp(tmpdir))
-		return error("could not create '%s'", tmpdir);
-	strbuf_addf(&ldir, "%s/left/", tmpdir);
-	strbuf_addf(&rdir, "%s/right/", tmpdir);
+	strbuf_add_absolute_path(&tmpdir, tmp ? tmp : "/tmp");
+	strbuf_trim_trailing_dir_sep(&tmpdir);
+	strbuf_addstr(&tmpdir, "/git-difftool.XXXXXX");
+	if (!mkdtemp(tmpdir.buf)) {
+		ret = error("could not create '%s'", tmpdir.buf);
+		goto finish;
+	}
+	strbuf_addf(&ldir, "%s/left/", tmpdir.buf);
+	strbuf_addf(&rdir, "%s/right/", tmpdir.buf);
 	strbuf_addstr(&wtdir, workdir);
 	if (!wtdir.len || !is_dir_sep(wtdir.buf[wtdir.len - 1]))
 		strbuf_addch(&wtdir, '/');
@@ -535,40 +554,19 @@ static int run_dir_diff(const char *extcmd, int symlinks, const char *prefix,
 	 */
 	hashmap_for_each_entry(&submodules, &iter, entry,
 				entry /* member name */) {
-		if (*entry->left) {
-			add_path(&ldir, ldir_len, entry->path);
-			ensure_leading_directories(ldir.buf);
-			write_file(ldir.buf, "%s", entry->left);
-		}
-		if (*entry->right) {
-			add_path(&rdir, rdir_len, entry->path);
-			ensure_leading_directories(rdir.buf);
-			write_file(rdir.buf, "%s", entry->right);
-		}
+		write_standin_files(entry, &ldir, ldir_len, &rdir, rdir_len);
 	}
 
 	/*
-	 * Symbolic links require special treatment.The standard "git diff"
+	 * Symbolic links require special treatment. The standard "git diff"
 	 * shows only the link itself, not the contents of the link target.
 	 * This loop replicates that behavior.
 	 */
 	hashmap_for_each_entry(&symlinks2, &iter, entry,
 				entry /* member name */) {
-		if (*entry->left) {
-			add_path(&ldir, ldir_len, entry->path);
-			ensure_leading_directories(ldir.buf);
-			unlink(ldir.buf);
-			write_file(ldir.buf, "%s", entry->left);
-		}
-		if (*entry->right) {
-			add_path(&rdir, rdir_len, entry->path);
-			ensure_leading_directories(rdir.buf);
-			unlink(rdir.buf);
-			write_file(rdir.buf, "%s", entry->right);
-		}
-	}
 
-	strbuf_release(&buf);
+		write_standin_files(entry, &ldir, ldir_len, &rdir, rdir_len);
+	}
 
 	strbuf_setlen(&ldir, ldir_len);
 	helper_argv[1] = ldir.buf;
@@ -580,7 +578,7 @@ static int run_dir_diff(const char *extcmd, int symlinks, const char *prefix,
 		flags = 0;
 	} else
 		setenv("GIT_DIFFTOOL_DIRDIFF", "true", 1);
-	rc = run_command_v_opt(helper_argv, flags);
+	ret = run_command_v_opt(helper_argv, flags);
 
 	/* TODO: audit for interaction with sparse-index. */
 	ensure_full_index(&wtindex);
@@ -614,7 +612,7 @@ static int run_dir_diff(const char *extcmd, int symlinks, const char *prefix,
 		if (!indices_loaded) {
 			struct lock_file lock = LOCK_INIT;
 			strbuf_reset(&buf);
-			strbuf_addf(&buf, "%s/wtindex", tmpdir);
+			strbuf_addf(&buf, "%s/wtindex", tmpdir.buf);
 			if (hold_lock_file_for_update(&lock, buf.buf, 0) < 0 ||
 			    write_locked_index(&wtindex, &lock, COMMIT_LOCK)) {
 				ret = error("could not write %s", buf.buf);
@@ -644,11 +642,14 @@ static int run_dir_diff(const char *extcmd, int symlinks, const char *prefix,
 	}
 
 	if (err) {
-		warning(_("temporary files exist in '%s'."), tmpdir);
+		warning(_("temporary files exist in '%s'."), tmpdir.buf);
 		warning(_("you may want to cleanup or recover these."));
-		exit(1);
-	} else
-		exit_cleanup(tmpdir, rc);
+		ret = 1;
+	} else {
+		remove_dir_recursively(&tmpdir, 0);
+		if (ret)
+			warning(_("failed: %d"), ret);
+	}
 
 finish:
 	if (fp)
@@ -660,8 +661,9 @@ finish:
 	strbuf_release(&rdir);
 	strbuf_release(&wtdir);
 	strbuf_release(&buf);
+	strbuf_release(&tmpdir);
 
-	return ret;
+	return (ret < 0) ? 1 : ret;
 }
 
 static int run_file_diff(int prompt, const char *prefix,
diff --git a/t/t7800-difftool.sh b/t/t7800-difftool.sh
index 528e0dabf0..096456292c 100755
--- a/t/t7800-difftool.sh
+++ b/t/t7800-difftool.sh
@@ -453,6 +453,13 @@ run_dir_diff_test 'difftool --dir-diff' '
 	grep "^file$" output
 '
 
+run_dir_diff_test 'difftool --dir-diff avoids repeated slashes in TMPDIR' '
+	TMPDIR="${TMPDIR:-/tmp}////" \
+		git difftool --dir-diff $symlinks --extcmd echo branch >output &&
+	grep -v // output >actual &&
+	test_line_count = 1 actual
+'
+
 run_dir_diff_test 'difftool --dir-diff ignores --prompt' '
 	git difftool --dir-diff $symlinks --prompt --extcmd ls branch >output &&
 	grep "^sub$" output &&