Merge branch 'nd/trace-with-env'

The tracing machinery learned to report tweaking of environment
variables as well.

* nd/trace-with-env:
  run-command.c: print new cwd in trace_run_command()
  run-command.c: print env vars in trace_run_command()
  run-command.c: print program 'git' when tracing git_cmd mode
  run-command.c: introduce trace_run_command()
  trace.c: move strbuf_release() out of print_trace_line()
  trace: avoid unnecessary quoting
  sq_quote_argv: drop maxlen parameter

builtin/am.c

@@ -1061,7 +1061,7 @@ static void am_setup(struct am_state *state, enum patch_format patch_format,
 	}
 	write_state_text(state, "scissors", str);
 
-	sq_quote_argv(&sb, state->git_apply_opts.argv, 0);
+	sq_quote_argv(&sb, state->git_apply_opts.argv);
 	write_state_text(state, "apply-opt", sb.buf);
 
 	if (state->rebasing)

builtin/rev-parse.c

@@ -516,7 +516,7 @@ static int cmd_parseopt(int argc, const char **argv, const char *prefix)
 			PARSE_OPT_SHELL_EVAL);
 
 	strbuf_addstr(&parsed, " --");
-	sq_quote_argv(&parsed, argv, 0);
+	sq_quote_argv(&parsed, argv);
 	puts(parsed.buf);
 	return 0;
 }
@@ -526,7 +526,7 @@ static int cmd_sq_quote(int argc, const char **argv)
 	struct strbuf buf = STRBUF_INIT;
 
 	if (argc)
-		sq_quote_argv(&buf, argv, 0);
+		sq_quote_argv(&buf, argv);
 	printf("%s\n", buf.buf);
 	strbuf_release(&buf);
 

quote.c

@@ -43,6 +43,22 @@ void sq_quote_buf(struct strbuf *dst, const char *src)
 	free(to_free);
 }
 
+void sq_quote_buf_pretty(struct strbuf *dst, const char *src)
+{
+	static const char ok_punct[] = "+,-./:=@_^";
+	const char *p;
+
+	for (p = src; *p; p++) {
+		if (!isalpha(*p) && !isdigit(*p) && !strchr(ok_punct, *p)) {
+			sq_quote_buf(dst, src);
+			return;
+		}
+	}
+
+	/* if we get here, we did not need quoting */
+	strbuf_addstr(dst, src);
+}
+
 void sq_quotef(struct strbuf *dst, const char *fmt, ...)
 {
 	struct strbuf src = STRBUF_INIT;
@@ -56,7 +72,7 @@ void sq_quotef(struct strbuf *dst, const char *fmt, ...)
 	strbuf_release(&src);
 }
 
-void sq_quote_argv(struct strbuf *dst, const char** argv, size_t maxlen)
+void sq_quote_argv(struct strbuf *dst, const char **argv)
 {
 	int i;
 
@@ -65,8 +81,16 @@ void sq_quote_argv(struct strbuf *dst, const char** argv, size_t maxlen)
 	for (i = 0; argv[i]; ++i) {
 		strbuf_addch(dst, ' ');
 		sq_quote_buf(dst, argv[i]);
-		if (maxlen && dst->len > maxlen)
-			die("Too many or long arguments");
+	}
+}
+
+void sq_quote_argv_pretty(struct strbuf *dst, const char **argv)
+{
+	int i;
+
+	for (i = 0; argv[i]; i++) {
+		strbuf_addch(dst, ' ');
+		sq_quote_buf_pretty(dst, argv[i]);
 	}
 }
 

quote.h

@@ -30,9 +30,17 @@ struct strbuf;
  */
 
 extern void sq_quote_buf(struct strbuf *, const char *src);
-extern void sq_quote_argv(struct strbuf *, const char **argv, size_t maxlen);
+extern void sq_quote_argv(struct strbuf *, const char **argv);
 extern void sq_quotef(struct strbuf *, const char *fmt, ...);
 
+/*
+ * These match their non-pretty variants, except that they avoid
+ * quoting when there are no exotic characters. These should only be used for
+ * human-readable output, as sq_dequote() is not smart enough to dequote it.
+ */
+void sq_quote_buf_pretty(struct strbuf *, const char *src);
+void sq_quote_argv_pretty(struct strbuf *, const char **argv);
+
 /* This unwraps what sq_quote() produces in place, but returns
  * NULL if the input does not look like what sq_quote would have
  * produced.

run-command.c

@@ -6,6 +6,7 @@
 #include "thread-utils.h"
 #include "strbuf.h"
 #include "string-list.h"
+#include "quote.h"
 
 void child_process_init(struct child_process *child)
 {
@@ -556,6 +557,90 @@ static int wait_or_whine(pid_t pid, const char *argv0, int in_signal)
 	return code;
 }
 
+static void trace_add_env(struct strbuf *dst, const char *const *deltaenv)
+{
+	struct string_list envs = STRING_LIST_INIT_DUP;
+	const char *const *e;
+	int i;
+	int printed_unset = 0;
+
+	/* Last one wins, see run-command.c:prep_childenv() for context */
+	for (e = deltaenv; e && *e; e++) {
+		struct strbuf key = STRBUF_INIT;
+		char *equals = strchr(*e, '=');
+
+		if (equals) {
+			strbuf_add(&key, *e, equals - *e);
+			string_list_insert(&envs, key.buf)->util = equals + 1;
+		} else {
+			string_list_insert(&envs, *e)->util = NULL;
+		}
+		strbuf_release(&key);
+	}
+
+	/* "unset X Y...;" */
+	for (i = 0; i < envs.nr; i++) {
+		const char *var = envs.items[i].string;
+		const char *val = envs.items[i].util;
+
+		if (val || !getenv(var))
+			continue;
+
+		if (!printed_unset) {
+			strbuf_addstr(dst, " unset");
+			printed_unset = 1;
+		}
+		strbuf_addf(dst, " %s", var);
+	}
+	if (printed_unset)
+		strbuf_addch(dst, ';');
+
+	/* ... followed by "A=B C=D ..." */
+	for (i = 0; i < envs.nr; i++) {
+		const char *var = envs.items[i].string;
+		const char *val = envs.items[i].util;
+		const char *oldval;
+
+		if (!val)
+			continue;
+
+		oldval = getenv(var);
+		if (oldval && !strcmp(val, oldval))
+			continue;
+
+		strbuf_addf(dst, " %s=", var);
+		sq_quote_buf_pretty(dst, val);
+	}
+	string_list_clear(&envs, 0);
+}
+
+static void trace_run_command(const struct child_process *cp)
+{
+	struct strbuf buf = STRBUF_INIT;
+
+	if (!trace_want(&trace_default_key))
+		return;
+
+	strbuf_addf(&buf, "trace: run_command:");
+	if (cp->dir) {
+		strbuf_addstr(&buf, " cd ");
+		sq_quote_buf_pretty(&buf, cp->dir);
+		strbuf_addch(&buf, ';');
+	}
+	/*
+	 * The caller is responsible for initializing cp->env from
+	 * cp->env_array if needed. We only check one place.
+	 */
+	if (cp->env)
+		trace_add_env(&buf, cp->env);
+	if (cp->git_cmd)
+		strbuf_addstr(&buf, " git");
+	sq_quote_argv_pretty(&buf, cp->argv);
+
+	trace_printf("%s", buf.buf);
+	strbuf_release(&buf);
+}
+
 int start_command(struct child_process *cmd)
 {
 	int need_in, need_out, need_err;
@@ -624,7 +709,8 @@ fail_pipe:
 		cmd->err = fderr[0];
 	}
 
-	trace_argv_printf(cmd->argv, "trace: run_command:");
+	trace_run_command(cmd);
+
 	fflush(NULL);
 
 #ifndef GIT_WINDOWS_NATIVE

t/helper/test-run-command.c

@@ -54,6 +54,15 @@ int cmd_main(int argc, const char **argv)
 	struct child_process proc = CHILD_PROCESS_INIT;
 	int jobs;
 
+	if (argc < 3)
+		return 1;
+	while (!strcmp(argv[1], "env")) {
+		if (!argv[2])
+			die("env specifier without a value");
+		argv_array_push(&proc.env_array, argv[2]);
+		argv += 2;
+		argc -= 2;
+	}
 	if (argc < 3)
 		return 1;
 	proc.argv = (const char **)argv + 2;

t/t0061-run-command.sh

@@ -141,4 +141,41 @@ test_expect_success 'run_command outputs ' '
 	test_cmp expect actual
 '
 
+test_trace () {
+	expect="$1"
+	shift
+	GIT_TRACE=1 test-run-command "$@" run-command true 2>&1 >/dev/null | \
+		sed 's/.* run_command: //' >actual &&
+	echo "$expect true" >expect &&
+	test_cmp expect actual
+}
+
+test_expect_success 'GIT_TRACE with environment variables' '
+	test_trace "abc=1 def=2" env abc=1 env def=2 &&
+	test_trace "abc=2" env abc env abc=1 env abc=2 &&
+	test_trace "abc=2" env abc env abc=2 &&
+	(
+		abc=1 && export abc &&
+		test_trace "def=1" env abc=1 env def=1
+	) &&
+	(
+		abc=1 && export abc &&
+		test_trace "def=1" env abc env abc=1 env def=1
+	) &&
+	test_trace "def=1" env non-exist env def=1 &&
+	test_trace "abc=2" env abc=1 env abc env abc=2 &&
+	(
+		abc=1 def=2 && export abc def &&
+		test_trace "unset abc def;" env abc env def
+	) &&
+	(
+		abc=1 def=2 && export abc def &&
+		test_trace "unset def; abc=3" env abc env def env abc=3
+	) &&
+	(
+		abc=1 && export abc &&
+		test_trace "unset abc;" env abc=2 env abc
+	)
+'
+
 test_done

trace.c

@@ -131,7 +131,6 @@ static void print_trace_line(struct trace_key *key, struct strbuf *buf)
 {
 	strbuf_complete_line(buf);
 	trace_write(key, buf->buf, buf->len);
-	strbuf_release(buf);
 }
 
 static void trace_vprintf_fl(const char *file, int line, struct trace_key *key,
@@ -144,6 +143,7 @@ static void trace_vprintf_fl(const char *file, int line, struct trace_key *key,
 
 	strbuf_vaddf(&buf, format, ap);
 	print_trace_line(key, &buf);
+	strbuf_release(&buf);
 }
 
 static void trace_argv_vprintf_fl(const char *file, int line,
@@ -157,8 +157,9 @@ static void trace_argv_vprintf_fl(const char *file, int line,
 
 	strbuf_vaddf(&buf, format, ap);
 
-	sq_quote_argv(&buf, argv, 0);
+	sq_quote_argv_pretty(&buf, argv);
 	print_trace_line(&trace_default_key, &buf);
+	strbuf_release(&buf);
 }
 
 void trace_strbuf_fl(const char *file, int line, struct trace_key *key,
@@ -171,6 +172,7 @@ void trace_strbuf_fl(const char *file, int line, struct trace_key *key,
 
 	strbuf_addbuf(&buf, data);
 	print_trace_line(key, &buf);
+	strbuf_release(&buf);
 }
 
 static void trace_performance_vprintf_fl(const char *file, int line,
@@ -190,6 +192,7 @@ static void trace_performance_vprintf_fl(const char *file, int line,
 	}
 
 	print_trace_line(&trace_perf_key, &buf);
+	strbuf_release(&buf);
 }
 
 #ifndef HAVE_VARIADIC_MACROS
@@ -426,6 +429,6 @@ void trace_command_performance(const char **argv)
 		atexit(print_command_performance_atexit);
 
 	strbuf_reset(&command_line);
-	sq_quote_argv(&command_line, argv, 0);
+	sq_quote_argv_pretty(&command_line, argv);
 	command_start_time = getnanotime();
 }