[WIP] [do not merge] Merge Trace2 part v2 into 2.20.1

Makefile

@@ -756,6 +756,7 @@ TEST_BUILTINS_OBJS += test-string-list.o
 TEST_BUILTINS_OBJS += test-submodule-config.o
 TEST_BUILTINS_OBJS += test-submodule-nested-repo-config.o
 TEST_BUILTINS_OBJS += test-subprocess.o
+TEST_BUILTINS_OBJS += test-trace2.o
 TEST_BUILTINS_OBJS += test-urlmatch-normalization.o
 TEST_BUILTINS_OBJS += test-wildmatch.o
 TEST_BUILTINS_OBJS += test-windows-named-pipe.o
@@ -1009,6 +1010,7 @@ LIB_OBJS += trace2/tr2_tgt_event.o
 LIB_OBJS += trace2/tr2_tgt_normal.o
 LIB_OBJS += trace2/tr2_tgt_perf.o
 LIB_OBJS += trace2/tr2_tls.o
+LIB_OBJS += trace2/tr2_verb.o
 LIB_OBJS += trailer.o
 LIB_OBJS += transport.o
 LIB_OBJS += transport-helper.o

builtin/am.c

@@ -468,6 +468,7 @@ static int run_post_rewrite_hook(const struct am_state *state)
 
 	cp.in = xopen(am_path(state, "rewritten"), O_RDONLY);
 	cp.stdout_to_stderr = 1;
+	cp.trace2_hook_name = "post-rewrite";
 
 	ret = run_command(&cp);
 

builtin/checkout.c

@@ -258,6 +258,8 @@ static int checkout_paths(const struct checkout_opts *opts,
 	int errs = 0;
 	struct lock_file lock_file = LOCK_INIT;
 
+	trace2_cmd_subverb(opts->patch_mode ? "patch" : "path");
+
 	if (opts->track != BRANCH_TRACK_UNSPECIFIED)
 		die(_("'%s' cannot be used with updating paths"), "--track");
 
@@ -930,6 +932,9 @@ static int switch_branches(const struct checkout_opts *opts,
 	void *path_to_free;
 	struct object_id rev;
 	int flag, writeout_error = 0;
+
+	trace2_cmd_subverb("branch");
+
 	memset(&old_branch_info, 0, sizeof(old_branch_info));
 	old_branch_info.path = path_to_free = resolve_refdup("HEAD", 0, &rev, &flag);
 	if (old_branch_info.path)
@@ -1159,6 +1164,8 @@ static int switch_unborn_to_new_branch(const struct checkout_opts *opts)
 	int status;
 	struct strbuf branch_ref = STRBUF_INIT;
 
+	trace2_cmd_subverb("unborn");
+
 	if (!opts->new_branch)
 		die(_("You are on a branch yet to be born"));
 	strbuf_addf(&branch_ref, "refs/heads/%s", opts->new_branch);

builtin/commit.c

@@ -145,6 +145,7 @@ static int opt_parse_porcelain(const struct option *opt, const char *arg, int un
 static int do_serialize = 0;
 static char *serialize_path = NULL;
 
+static int reject_implicit = 0;
 static int do_implicit_deserialize = 0;
 static int do_explicit_deserialize = 0;
 static char *deserialize_path = NULL;
@@ -202,7 +203,7 @@ static int opt_parse_deserialize(const struct option *opt, const char *arg, int
 		if (arg) /* override config or stdin */
 			deserialize_path = xstrdup(arg);
 		if (deserialize_path && *deserialize_path
-		    && (access(deserialize_path, R_OK) != 0))
+		    && (wt_status_deserialize_access(deserialize_path, R_OK) != 0))
 			die("cannot find serialization file '%s'",
 			    deserialize_path);
 
@@ -1396,6 +1397,8 @@ static int git_status_config(const char *k, const char *v, void *cb)
 		if (v && *v && access(v, R_OK) == 0) {
 			do_implicit_deserialize = 1;
 			deserialize_path = xstrdup(v);
+		} else {
+			reject_implicit = 1;
 		}
 		return 0;
 	}
@@ -1552,6 +1555,17 @@ int cmd_status(int argc, const char **argv, const char *prefix)
 			   (do_implicit_deserialize || do_explicit_deserialize));
 	if (try_deserialize)
 		goto skip_init;
+	/*
+	 * If we implicitly received a status cache pathname from the config
+	 * and the file does not exist, we silently reject it and do the normal
+	 * status "collect".  Fake up some trace2 messages to reflect this and
+	 * assist post-processors know this case is different.
+	 */
+	if (!do_serialize && reject_implicit) {
+		trace2_cmd_subverb("implicit-deserialize");
+		trace2_data_string("status", the_repository, "deserialize/reject",
+				   "status-cache/access");
+	}
 
 	enable_fscache(0);
 	if (status_format != STATUS_FORMAT_PORCELAIN &&
@@ -1595,6 +1609,7 @@ int cmd_status(int argc, const char **argv, const char *prefix)
 		if (s.relative_paths)
 			s.prefix = prefix;
 
+		trace2_cmd_subverb("deserialize");
 		result = wt_status_deserialize(&s, deserialize_path, dw);
 		if (result == DESERIALIZE_OK)
 			return 0;
@@ -1612,6 +1627,7 @@ int cmd_status(int argc, const char **argv, const char *prefix)
 			fd = -1;
 	}
 
+	trace2_cmd_subverb("collect");
 	wt_status_collect(&s);
 
 	if (0 <= fd)
@@ -1626,6 +1642,7 @@ int cmd_status(int argc, const char **argv, const char *prefix)
 		if (fd_serialize < 0)
 			die_errno(_("could not serialize to '%s'"),
 				  serialize_path);
+		trace2_cmd_subverb("serialize");
 		wt_status_serialize_v1(fd_serialize, &s);
 		close(fd_serialize);
 	}

builtin/rebase.c

@@ -1009,6 +1009,16 @@ int cmd_rebase(int argc, const char **argv, const char *prefix)
 		ACTION_EDIT_TODO,
 		ACTION_SHOW_CURRENT_PATCH,
 	} action = NO_ACTION;
+	static const char *action_names[] = {
+		N_("undefined"),
+		N_("continue"),
+		N_("skip"),
+		N_("abort"),
+		N_("quit"),
+		N_("edit_todo"),
+		N_("show_current_patch"),
+		NULL
+	};
 	const char *gpg_sign = NULL;
 	struct string_list exec = STRING_LIST_INIT_NODUP;
 	const char *rebase_merges = NULL;
@@ -1195,6 +1205,15 @@ int cmd_rebase(int argc, const char **argv, const char *prefix)
 		die(_("The --edit-todo action can only be used during "
 		      "interactive rebase."));
 
+	if (trace2_is_enabled()) {
+		if (is_interactive(&options))
+			trace2_cmd_subverb("interactive");
+		else if (exec.nr)
+			trace2_cmd_subverb("interactive-exec");
+		else
+			trace2_cmd_subverb(action_names[action]);
+	}
+
 	switch (action) {
 	case ACTION_CONTINUE: {
 		struct object_id head;

builtin/receive-pack.c

@@ -694,6 +694,8 @@ static int run_and_feed_hook(const char *hook_name, feed_fn feed,
 	proc.argv = argv;
 	proc.in = -1;
 	proc.stdout_to_stderr = 1;
+	proc.trace2_hook_name = hook_name;
+
 	if (feed_state->push_options) {
 		int i;
 		for (i = 0; i < feed_state->push_options->nr; i++)
@@ -807,6 +809,7 @@ static int run_update_hook(struct command *cmd)
 	proc.stdout_to_stderr = 1;
 	proc.err = use_sideband ? -1 : 0;
 	proc.argv = argv;
+	proc.trace2_hook_name = "update";
 
 	code = start_command(&proc);
 	if (code)
@@ -1190,6 +1193,7 @@ static void run_update_post_hook(struct command *commands)
 	proc.no_stdin = 1;
 	proc.stdout_to_stderr = 1;
 	proc.err = use_sideband ? -1 : 0;
+	proc.trace2_hook_name = "post-update";
 
 	if (!start_command(&proc)) {
 		if (use_sideband)

builtin/reset.c

@@ -419,6 +419,7 @@ int cmd_reset(int argc, const char **argv, const char *prefix)
 	if (patch_mode) {
 		if (reset_type != NONE)
 			die(_("--patch is incompatible with --{hard,mixed,soft}"));
+		trace2_cmd_subverb("patch-interactive");
 		return run_add_interactive(rev, "--patch=reset", &pathspec);
 	}
 
@@ -435,6 +436,13 @@ int cmd_reset(int argc, const char **argv, const char *prefix)
 	if (reset_type == NONE)
 		reset_type = MIXED; /* by default */
 
+	if (read_from_stdin)
+		trace2_cmd_subverb("path-stdin");
+	else if (pathspec.nr)
+		trace2_cmd_subverb("path");
+	else
+		trace2_cmd_subverb(reset_type_names[reset_type]);
+
 	if (reset_type != SOFT && (reset_type != MIXED || get_git_work_tree()))
 		setup_work_tree();
 

builtin/worktree.c

@@ -401,6 +401,7 @@ static int add_worktree(const char *path, const char *refname,
 			cp.dir = path;
 			cp.env = env;
 			cp.argv = NULL;
+			cp.trace2_hook_name = "post-checkout";
 			argv_array_pushl(&cp.args, absolute_path(hook),
 					 oid_to_hex(&null_oid),
 					 oid_to_hex(&commit->object.oid),

common-main.c

@@ -25,6 +25,8 @@ static void restore_sigpipe_to_default(void)
 
 int main(int argc, const char **argv)
 {
+	int result;
+
 	/*
 	 * Always open file descriptors 0/1/2 to avoid clobbering files
 	 * in die().  It also avoids messing up when the pipes are dup'ed
@@ -33,7 +35,9 @@ int main(int argc, const char **argv)
 	sanitize_stdfds();
 	restore_sigpipe_to_default();
 
-	trace2_initialize(argv);
+	trace2_initialize();
+	trace2_cmd_start(argv);
+	trace2_collect_process_info();
 
 	git_resolve_executable_dir(argv[0]);
 
@@ -43,5 +47,9 @@ int main(int argc, const char **argv)
 
 	attr_start();
 
-	return cmd_main(argc, argv);
+	result = cmd_main(argc, argv);
+
+	trace2_cmd_exit(result);
+
+	return result;
 }

compat/mingw.c

@@ -1945,6 +1945,7 @@ static int try_shell_exec(const char *cmd, char *const *argv)
 		return 0;
 	prog = path_lookup(interpr, 1);
 	if (prog) {
+		int exec_id;
 		int argc = 0;
 #ifndef _MSC_VER
 		const
@@ -1954,14 +1955,16 @@ static int try_shell_exec(const char *cmd, char *const *argv)
 		ALLOC_ARRAY(argv2, argc + 1);
 		argv2[0] = (char *)cmd;	/* full path to the script file */
 		memcpy(&argv2[1], &argv[1], sizeof(*argv) * argc);
+		exec_id = trace2_exec(prog, argv2);
 		pid = mingw_spawnv(prog, argv2, interpr);
 		if (pid >= 0) {
 			int status;
 			if (waitpid(pid, &status, 0) < 0)
 				status = 255;
-			trace2_exec_result(status);
+			trace2_exec_result(exec_id, status);
 			exit(status);
 		}
+		trace2_exec_result(exec_id, -1);
 		pid = 1;	/* indicate that we tried but failed */
 		free(prog);
 		free(argv2);
@@ -1974,13 +1977,17 @@ int mingw_execv(const char *cmd, char *const *argv)
 	/* check if git_command is a shell script */
 	if (!try_shell_exec(cmd, argv)) {
 		int pid, status;
+		int exec_id;
 
+		exec_id = trace2_exec(cmd, (const char **)argv);
 		pid = mingw_spawnv(cmd, (const char **)argv, NULL);
-		if (pid < 0)
+		if (pid < 0) {
+			trace2_exec_result(exec_id, -1);
 			return -1;
+		}
 		if (waitpid(pid, &status, 0) < 0)
 			status = 255;
-		trace2_exec_result(status);
+		trace2_exec_result(exec_id, status);
 		exit(status);
 	}
 	return -1;

compat/win32/ancestry.c

@@ -0,0 +1,102 @@
+#include "../../cache.h"
+#include "../../json-writer.h"
+#include <Psapi.h>
+#include <tlHelp32.h>
+
+/*
+ * Find the process data for the given PID in the given snapshot
+ * and update the PROCESSENTRY32 data.
+ */
+static int find_pid(DWORD pid, HANDLE hSnapshot, PROCESSENTRY32 *pe32)
+{
+	pe32->dwSize = sizeof(PROCESSENTRY32);
+
+	if (Process32First(hSnapshot, pe32)) {
+		do {
+			if (pe32->th32ProcessID == pid)
+				return 1;
+		} while (Process32Next(hSnapshot, pe32));
+	}
+	return 0;
+}
+
+/*
+ * Accumulate JSON array:
+ *     [
+ *         exe-name-parent,
+ *         exe-name-grand-parent,
+ *         ...
+ *     ]
+ *
+ * Note: we only report the filename of the process executable; the
+ *       only way to get its full pathname is to use OpenProcess()
+ *       and GetModuleFileNameEx() or QueryfullProcessImageName()
+ *       and that seems rather expensive (on top of the cost of
+ *       getting the snapshot).
+ */
+static void get_processes(struct json_writer *jw, HANDLE hSnapshot)
+{
+	PROCESSENTRY32 pe32;
+	DWORD pid;
+
+	pid = GetCurrentProcessId();
+
+	/* We only want parent processes, so skip self. */
+	if (!find_pid(pid, hSnapshot, &pe32))
+		return;
+	pid = pe32.th32ParentProcessID;
+
+	while (find_pid(pid, hSnapshot, &pe32)) {
+
+		jw_array_string(jw, pe32.szExeFile);
+
+		pid = pe32.th32ParentProcessID;
+	}
+}
+
+/*
+ * Emit JSON data for the current and parent processes.  Individual
+ * trace2 targets can decide how to actually print it.
+ */
+static void get_ancestry(void)
+{
+	HANDLE hSnapshot = CreateToolhelp32Snapshot(TH32CS_SNAPPROCESS, 0);
+
+	if (hSnapshot != INVALID_HANDLE_VALUE) {
+		struct json_writer jw = JSON_WRITER_INIT;
+
+		jw_array_begin(&jw, 0);
+		get_processes(&jw, hSnapshot);
+		jw_end(&jw);
+
+		trace2_data_json("process", the_repository,
+				 "windows/ancestry", &jw);
+
+		jw_release(&jw);
+		CloseHandle(hSnapshot);
+	}
+}
+
+/*
+ * Is a debugger attached to the current process?
+ *
+ * This will catch debug runs (where the debugger started the process).
+ * This is the normal case.  Since this code is called during our startup,
+ * it will not report instances where a debugger is attached dynamically
+ * to a running git process, but that is relatively rare.
+ */
+static void get_is_being_debugged(void)
+{
+	if (IsDebuggerPresent())
+		trace2_data_intmax("process", the_repository,
+			   "windows/debugger_present", 1);
+}
+
+void trace2_collect_process_info(void)
+{
+	if (!trace2_is_enabled())
+		return;
+
+	get_is_being_debugged();
+	get_ancestry();
+}