[PATCH v6 1/5] difftool: create a tmpdir path without repeated slashes

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5 messages, 1 author, 2021-09-30 · open the first message on its own page

[PATCH v6 1/5] difftool: create a tmpdir path without repeated slashes

From: David Aguilar <hidden>
Date: 2021-09-30 17:01:55

The paths generated by difftool are passed to user-facing diff tools.
Using paths with repeated slashes in them is a cosmetic blemish that
is exposed to users and can be avoided.

Use a strbuf to create the buffer used for the dir-diff tmpdir.
Strip trailing slashes from the value read from TMPDIR to avoid
repeated slashes in the generated paths.

Adjust the error handling to avoid leaking strbufs.

Signed-off-by: David Aguilar <redacted>
---
This patch is a resend based off of "next" so that this series can be
tracked together.

This patch is unchanged since the v5 was submitted, but there are
new related patches that proceed it.

 builtin/difftool.c  | 48 ++++++++++++++++++++++-----------------------
 t/t7800-difftool.sh |  7 +++++++
 2 files changed, 30 insertions(+), 25 deletions(-)
diff --git a/builtin/difftool.c b/builtin/difftool.c
index 210da03908..9d2dfd3361 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)) {
@@ -333,16 +323,16 @@ static int checkout_path(unsigned mode, struct object_id *oid,
 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 +341,7 @@ 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 +350,15 @@ 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, '/');
@@ -580,7 +574,7 @@ 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 +608,7 @@ 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 +638,14 @@ 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)
@@ -660,6 +657,7 @@ static int run_dir_diff(const char *extcmd, int symlinks, const char *prefix,
 	strbuf_release(&rdir);
 	strbuf_release(&wtdir);
 	strbuf_release(&buf);
+	strbuf_release(&tmpdir);
 
 	return ret;
 }
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 &&
-- 
2.33.0.887.g8db6ae3373

[PATCH v6 2/5] difftool: add a missing space to the run_dir_diff() comments

From: David Aguilar <hidden>
Date: 2021-09-30 17:01:56

Signed-off-by: David Aguilar <redacted>
---
Trivial tweak. Unchanged but resubmitted for ease of application.

 builtin/difftool.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/builtin/difftool.c b/builtin/difftool.c
index 9d2dfd3361..fdaaa86bff 100644
--- a/builtin/difftool.c
+++ b/builtin/difftool.c
@@ -542,7 +542,7 @@ static int run_dir_diff(const char *extcmd, int symlinks, const char *prefix,
 	}
 
 	/*
-	 * 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.
 	 */
-- 
2.33.0.887.g8db6ae3373

[PATCH v6 3/5] difftool: avoid returning -1 to cmd_main() from run_dir_diff()

From: David Aguilar <hidden>
Date: 2021-09-30 17:01:56

difftool was forwarding the -1 result from error() to cmd_main(), which
is implementation-defined since it is outside of the 0-255 range
specified by POSIX for program exit codes.

Stop assigning the result of error() to `ret`. Assign a value of 1
whenever internal errors are detected instead.

Signed-off-by: David Aguilar <redacted>
---
This patch addresses the note from Ævar about returning -1 to cmd_main().

 builtin/difftool.c | 22 +++++++++++++---------
 1 file changed, 13 insertions(+), 9 deletions(-)
diff --git a/builtin/difftool.c b/builtin/difftool.c
index fdaaa86bff..e419bd3cd1 100644
--- a/builtin/difftool.c
+++ b/builtin/difftool.c
@@ -447,7 +447,8 @@ static int run_dir_diff(const char *extcmd, int symlinks, const char *prefix,
 
 		if (lmode && status != 'C') {
 			if (checkout_path(lmode, &loid, src_path, &lstate)) {
-				ret = error("could not write '%s'", src_path);
+				ret = 1;
+				error("could not write '%s'", src_path);
 				goto finish;
 			}
 		}
@@ -468,8 +469,8 @@ static int run_dir_diff(const char *extcmd, int symlinks, const char *prefix,
 			if (!use_wt_file(workdir, dst_path, &roid)) {
 				if (checkout_path(rmode, &roid, dst_path,
 						  &rstate)) {
-					ret = error("could not write '%s'",
-						    dst_path);
+					ret = 1;
+					error("could not write '%s'", dst_path);
 					goto finish;
 				}
 			} else if (!is_null_oid(&roid)) {
@@ -487,15 +488,16 @@ static int run_dir_diff(const char *extcmd, int symlinks, const char *prefix,
 
 				add_path(&rdir, rdir_len, dst_path);
 				if (ensure_leading_directories(rdir.buf)) {
-					ret = error("could not create "
-						    "directory for '%s'",
-						    dst_path);
+					ret = 1;
+					error("could not create directory for '%s'",
+						dst_path);
 					goto finish;
 				}
 				add_path(&wtdir, wtdir_len, dst_path);
 				if (symlinks) {
 					if (symlink(wtdir.buf, rdir.buf)) {
-						ret = error_errno("could not symlink '%s' to '%s'", wtdir.buf, rdir.buf);
+						ret = 1;
+						error_errno("could not symlink '%s' to '%s'", wtdir.buf, rdir.buf);
 						goto finish;
 					}
 				} else {
@@ -504,7 +506,8 @@ static int run_dir_diff(const char *extcmd, int symlinks, const char *prefix,
 						st.st_mode = 0644;
 					if (copy_file(rdir.buf, wtdir.buf,
 						      st.st_mode)) {
-						ret = error("could not copy '%s' to '%s'", wtdir.buf, rdir.buf);
+						ret = 1;
+						error("could not copy '%s' to '%s'", wtdir.buf, rdir.buf);
 						goto finish;
 					}
 				}
@@ -515,7 +518,8 @@ static int run_dir_diff(const char *extcmd, int symlinks, const char *prefix,
 	fclose(fp);
 	fp = NULL;
 	if (finish_command(child)) {
-		ret = error("error occurred running diff --raw");
+		ret = 1;
+		error("error occurred running diff --raw");
 		goto finish;
 	}
 
-- 
2.33.0.887.g8db6ae3373

[PATCH v6 4/5] difftool: refactor dir-diff to write files using a helper function

From: David Aguilar <hidden>
Date: 2021-09-30 17:01:57

Add a write_entry() helper function to handle the unlinking and writing
of the dir-diff submodule and symlink stand-in files.

Use write_entry() inside of the hashmap loops to eliminate duplicate
code and to safeguard the submodules hashmap loop against the
symlink-chasing behavior that 5bafb3576a (difftool: fix symlink-file
writing in dir-diff mode, 2021-09-22) addressed.

The submodules loop should not strictly require the unlink() call that
this is introducing to them, but it does not necessarily hurt them
either beyond the cost of the extra unlink().

Signed-off-by: David Aguilar <redacted>
---
This is cleanup refactoring that Junio suggested when
5bafb3576a (difftool: fix symlink-file writing in dir-diff mode, 2021-09-22)
touched this area of the code.

 builtin/difftool.c | 38 ++++++++++++++++----------------------
 1 file changed, 16 insertions(+), 22 deletions(-)
diff --git a/builtin/difftool.c b/builtin/difftool.c
index e419bd3cd1..bbb8b399c2 100644
--- a/builtin/difftool.c
+++ b/builtin/difftool.c
@@ -320,6 +320,17 @@ static int checkout_path(unsigned mode, struct object_id *oid,
 	return ret;
 }
 
+static void write_entry(const char *path, const char *content,
+			struct strbuf *buf, size_t len)
+{
+	if (!*content)
+		return;
+	add_path(buf, len, path);
+	ensure_leading_directories(buf->buf);
+	unlink(buf->buf);
+	write_file(buf->buf, "%s", content);
+}
+
 static int run_dir_diff(const char *extcmd, int symlinks, const char *prefix,
 			struct child_process *child)
 {
@@ -533,16 +544,8 @@ 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_entry(entry->path, entry->left, &ldir, ldir_len);
+		write_entry(entry->path, entry->right, &rdir, rdir_len);
 	}
 
 	/*
@@ -552,18 +555,9 @@ static int run_dir_diff(const char *extcmd, int symlinks, const char *prefix,
 	 */
 	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);
-		}
+
+		write_entry(entry->path, entry->left, &ldir, ldir_len);
+		write_entry(entry->path, entry->right, &rdir, rdir_len);
 	}
 
 	strbuf_release(&buf);
-- 
2.33.0.887.g8db6ae3373

[PATCH v6 5/5] difftool: remove an unnecessary call to strbuf_release()

From: David Aguilar <hidden>
Date: 2021-09-30 17:02:00

The `buf` strbuf is reused again later in the same function, so there
is no benefit to calling strbuf_release(). The subsequent usage is
already using strbuf_reset() to reset the buffer, so releasing it
early is only going to lead to a wasteful reallocation.

Remove the early call to strbuf_release(). The same strbuf is already
cleaned up in the "finish:" section so nothing is leaked, either.

Signed-off-by: David Aguilar <redacted>
---
This is a small cleanup that I noticed while working on the new patches.
There are no previous versions of this patch.

 builtin/difftool.c | 2 --
 1 file changed, 2 deletions(-)
diff --git a/builtin/difftool.c b/builtin/difftool.c
index bbb8b399c2..859ccc6db3 100644
--- a/builtin/difftool.c
+++ b/builtin/difftool.c
@@ -560,8 +560,6 @@ static int run_dir_diff(const char *extcmd, int symlinks, const char *prefix,
 		write_entry(entry->path, entry->right, &rdir, rdir_len);
 	}
 
-	strbuf_release(&buf);
-
 	strbuf_setlen(&ldir, ldir_len);
 	helper_argv[1] = ldir.buf;
 	strbuf_setlen(&rdir, rdir_len);
-- 
2.33.0.887.g8db6ae3373
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