trailer: add new .cmd config option

The `trailer.<token>.command` configuration variable
specifies a command (run via the shell, so it does not have
to be a single name or path to the command, but can be a
shell script), and the first occurrence of substring $ARG is
replaced with the value given to the `interpret-trailer`
command for the token in a '--trailer <token>=<value>' argument.

This has three downsides:

* The use of $ARG in the mechanism misleads the users that
the value is passed in the shell variable, and tempt them
to use $ARG more than once, but that would not work, as
the second and subsequent $ARG are not replaced.

* Because $ARG is textually replaced without regard to the
shell language syntax, even '$ARG' (inside a single-quote
pair), which a user would expect to stay intact, would be
replaced, and worse, if the value had an unmatched single
quote (imagine a name like "O'Connor", substituted into
NAME='$ARG' to make it NAME='O'Connor'), it would result in
a broken command that is not syntactically correct (or
worse).

* The first occurrence of substring `$ARG` will be replaced
with the empty string, in the command when the command is
first called to add a trailer with the specified <token>.
This is a bad design, the nature of automatic execution
causes it to add a trailer that we don't expect.

Introduce a new `trailer.<token>.cmd` configuration that
takes higher precedence to deprecate and eventually remove
`trailer.<token>.command`, which passes the value as an
argument to the command.  Instead of "$ARG", users can
refer to the value as positional argument, $1, in their
scripts. At the same time, in order to allow
`git interpret-trailers` to better simulate the behavior
of `git command -s`, 'trailer.<token>.cmd' will not
automatically execute.

Helped-by: Junio C Hamano <gitster@pobox.com>
Helped-by: Christian Couder <christian.couder@gmail.com>
Signed-off-by: ZheNing Hu <adlternative@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/Documentation/git-interpret-trailers.txt b/Documentation/git-interpret-trailers.txt
index 6f2a7a13046491026e95e05420e52be4838f9d56..956a01d184f78832ea8ac8d1874ae1cc568dccaa 100644 (file)
--- a/Documentation/git-interpret-trailers.txt
+++ b/Documentation/git-interpret-trailers.txt
@@ -232,6 +232,20 @@ trailer.<token>.ifmissing::
        that option for trailers with the specified <token>.
 
 trailer.<token>.command::
+       This option behaves in the same way as 'trailer.<token>.cmd', except
+       that it doesn't pass anything as argument to the specified command.
+       Instead the first occurrence of substring $ARG is replaced by the
+       value that would be passed as argument.
++
+The 'trailer.<token>.command' option has been deprecated in favor of
+'trailer.<token>.cmd' due to the fact that $ARG in the user's command is
+only replaced once and that the original way of replacing $ARG is not safe.
++
+When both 'trailer.<token>.cmd' and 'trailer.<token>.command' are given
+for the same <token>, 'trailer.<token>.cmd' is used and
+'trailer.<token>.command' is ignored.
+
+trailer.<token>.cmd::
        This option can be used to specify a shell command that will be called:
        once to automatically add a trailer with the specified <token>, and then
        each time a '--trailer <token>=<value>' argument to modify the <value> of
@@ -247,15 +261,9 @@ leading and trailing whitespace trimmed off.
 If some '--trailer <token>=<value>' arguments are also passed
 on the command line, the command is called again once for each
 of these arguments with the same <token>. And the <value> part
-of these arguments, if any, will be used to replace the first
-occurrence of substring `$ARG` in the command. This way the
-command can produce a <value> computed from the <value> passed
-in the '--trailer <token>=<value>' argument.
-+
-For consistency, the first occurrence of substring `$ARG` is
-also replaced, this time with the empty string, in the command
-when the command is first called to add a trailer with the
-specified <token>.
+of these arguments, if any, will be passed to the command as its
+first argument. This way the command can produce a <value> computed
+from the <value> passed in the '--trailer <token>=<value>' argument.
 
 EXAMPLES
 --------
@@ -338,6 +346,55 @@ subject
 Fix #42
 ------------
 
+* Configure a 'help' trailer with a cmd use a script `glog-find-author`
+  which search specified author identity from git log in git repository
+  and show how it works:
++
+------------
+$ cat ~/bin/glog-find-author
+#!/bin/sh
+test -n "$1" && git log --author="$1" --pretty="%an <%ae>" -1 || true
+$ git config trailer.help.key "Helped-by: "
+$ git config trailer.help.ifExists "addIfDifferentNeighbor"
+$ git config trailer.help.cmd "~/bin/glog-find-author"
+$ git interpret-trailers --trailer="help:Junio" --trailer="help:Couder" <<EOF
+> subject
+>
+> message
+>
+> EOF
+subject
+
+message
+
+Helped-by: Junio C Hamano <gitster@pobox.com>
+Helped-by: Christian Couder <christian.couder@gmail.com>
+------------
+
+* Configure a 'ref' trailer with a cmd use a script `glog-grep`
+  to grep last relevant commit from git log in the git repository
+  and show how it works:
++
+------------
+$ cat ~/bin/glog-grep
+#!/bin/sh
+test -n "$1" && git log --grep "$1" --pretty=reference -1 || true
+$ git config trailer.ref.key "Reference-to: "
+$ git config trailer.ref.ifExists "replace"
+$ git config trailer.ref.cmd "~/bin/glog-grep"
+$ git interpret-trailers --trailer="ref:Add copyright notices." <<EOF
+> subject
+>
+> message
+>
+> EOF
+subject
+
+message
+
+Reference-to: 8bc9a0c769 (Add copyright notices., 2005-04-07)
+------------
+
 * Configure a 'see' trailer with a command to show the subject of a
   commit that is related, and show how it works:
 +

diff --git a/t/t7513-interpret-trailers.sh b/t/t7513-interpret-trailers.sh
index 6602790b5f4c4aace1b101189258b647109ccdb0..04885d0a5e5c2697409395698af15b48002cabe2 100755 (executable)
--- a/t/t7513-interpret-trailers.sh
+++ b/t/t7513-interpret-trailers.sh
@@ -51,6 +51,69 @@ test_expect_success 'setup' '
        EOF
 '
 
+test_expect_success 'with cmd' '
+       test_when_finished "git config --remove-section trailer.bug" &&
+       git config trailer.bug.key "Bug-maker: " &&
+       git config trailer.bug.ifExists "add" &&
+       git config trailer.bug.cmd "echo \"maybe is\"" &&
+       cat >expected2 <<-EOF &&
+
+       Bug-maker: maybe is him
+       Bug-maker: maybe is me
+       EOF
+       git interpret-trailers --trailer "bug: him" --trailer "bug:me" \
+               >actual2 &&
+       test_cmp expected2 actual2
+'
+
+test_expect_success 'with cmd and $1' '
+       test_when_finished "git config --remove-section trailer.bug" &&
+       git config trailer.bug.key "Bug-maker: " &&
+       git config trailer.bug.ifExists "add" &&
+       git config trailer.bug.cmd "echo \"\$1\" is" &&
+       cat >expected2 <<-EOF &&
+
+       Bug-maker: him is him
+       Bug-maker: me is me
+       EOF
+       git interpret-trailers --trailer "bug: him" --trailer "bug:me" \
+               >actual2 &&
+       test_cmp expected2 actual2
+'
+
+test_expect_success 'with cmd and $1 with sh -c' '
+       test_when_finished "git config --remove-section trailer.bug" &&
+       git config trailer.bug.key "Bug-maker: " &&
+       git config trailer.bug.ifExists "replace" &&
+       git config trailer.bug.cmd "sh -c \"echo who is \"\$1\"\"" &&
+       cat >expected2 <<-EOF &&
+
+       Bug-maker: who is me
+       EOF
+       git interpret-trailers --trailer "bug: him" --trailer "bug:me" \
+               >actual2 &&
+       test_cmp expected2 actual2
+'
+
+test_expect_success 'with cmd and $1 with shell script' '
+       test_when_finished "git config --remove-section trailer.bug" &&
+       git config trailer.bug.key "Bug-maker: " &&
+       git config trailer.bug.ifExists "replace" &&
+       git config trailer.bug.cmd "./echoscript" &&
+       cat >expected2 <<-EOF &&
+
+       Bug-maker: who is me
+       EOF
+       cat >echoscript <<-EOF &&
+       #!/bin/sh
+       echo who is "\$1"
+       EOF
+       chmod +x echoscript &&
+       git interpret-trailers --trailer "bug: him" --trailer "bug:me" \
+               >actual2 &&
+       test_cmp expected2 actual2
+'
+
 test_expect_success 'without config' '
        sed -e "s/ Z\$/ /" >expected <<-\EOF &&
 
@@ -1274,6 +1337,27 @@ test_expect_success 'setup a commit' '
        git commit -m "Add file a.txt"
 '
 
+test_expect_success 'cmd takes precedence over command' '
+       test_when_finished "git config --unset trailer.fix.cmd" &&
+       git config trailer.fix.ifExists "replace" &&
+       git config trailer.fix.cmd "test -n \"\$1\" && git log -1 --oneline --format=\"%h (%aN)\" \
+       --abbrev-commit --abbrev=14 \"\$1\" || true" &&
+       git config trailer.fix.command "git log -1 --oneline --format=\"%h (%s)\" \
+               --abbrev-commit --abbrev=14 \$ARG" &&
+       FIXED=$(git log -1 --oneline --format="%h (%aN)" --abbrev-commit --abbrev=14 HEAD) &&
+       cat complex_message_body >expected2 &&
+       sed -e "s/ Z\$/ /" >>expected2 <<-EOF &&
+               Fixes: $FIXED
+               Acked-by= Z
+               Reviewed-by:
+               Signed-off-by: Z
+               Signed-off-by: A U Thor <author@example.com>
+       EOF
+       git interpret-trailers --trailer "review:" --trailer "fix=HEAD" \
+               <complex_message >actual2 &&
+       test_cmp expected2 actual2
+'
+
 test_expect_success 'with command using $ARG' '
        git config trailer.fix.ifExists "replace" &&
        git config trailer.fix.command "git log -1 --oneline --format=\"%h (%s)\" --abbrev-commit --abbrev=14 \$ARG" &&

diff --git a/trailer.c b/trailer.c
index be4e9726421cc81d049e5eec2c557ac896965f7f..7c7cb61a945c7ba2634685d6d49e3ad7ac23204a 100644 (file)
--- a/trailer.c
+++ b/trailer.c
@@ -14,6 +14,7 @@ struct conf_info {
        char *name;
        char *key;
        char *command;
+       char *cmd;
        enum trailer_where where;
        enum trailer_if_exists if_exists;
        enum trailer_if_missing if_missing;
@@ -127,6 +128,7 @@ static void free_arg_item(struct arg_item *item)
        free(item->conf.name);
        free(item->conf.key);
        free(item->conf.command);
+       free(item->conf.cmd);
        free(item->token);
        free(item->value);
        free(item);
@@ -216,18 +218,24 @@ static int check_if_different(struct trailer_item *in_tok,
        return 1;
 }
 
-static char *apply_command(const char *command, const char *arg)
+static char *apply_command(struct conf_info *conf, const char *arg)
 {
        struct strbuf cmd = STRBUF_INIT;
        struct strbuf buf = STRBUF_INIT;
        struct child_process cp = CHILD_PROCESS_INIT;
        char *result;
 
-       strbuf_addstr(&cmd, command);
-       if (arg)
-               strbuf_replace(&cmd, TRAILER_ARG_STRING, arg);
-
-       strvec_push(&cp.args, cmd.buf);
+       if (conf->cmd) {
+               strbuf_addstr(&cmd, conf->cmd);
+               strvec_push(&cp.args, cmd.buf);
+               if (arg)
+                       strvec_push(&cp.args, arg);
+       } else if (conf->command) {
+               strbuf_addstr(&cmd, conf->command);
+               if (arg)
+                       strbuf_replace(&cmd, TRAILER_ARG_STRING, arg);
+               strvec_push(&cp.args, cmd.buf);
+       }
        cp.env = local_repo_env;
        cp.no_stdin = 1;
        cp.use_shell = 1;
@@ -247,7 +255,7 @@ static char *apply_command(const char *command, const char *arg)
 
 static void apply_item_command(struct trailer_item *in_tok, struct arg_item *arg_tok)
 {
-       if (arg_tok->conf.command) {
+       if (arg_tok->conf.command || arg_tok->conf.cmd) {
                const char *arg;
                if (arg_tok->value && arg_tok->value[0]) {
                        arg = arg_tok->value;
@@ -257,7 +265,7 @@ static void apply_item_command(struct trailer_item *in_tok, struct arg_item *arg
                        else
                                arg = xstrdup("");
                }
-               arg_tok->value = apply_command(arg_tok->conf.command, arg);
+               arg_tok->value = apply_command(&arg_tok->conf, arg);
                free((char *)arg);
        }
 }
@@ -430,6 +438,7 @@ static void duplicate_conf(struct conf_info *dst, const struct conf_info *src)
        dst->name = xstrdup_or_null(src->name);
        dst->key = xstrdup_or_null(src->key);
        dst->command = xstrdup_or_null(src->command);
+       dst->cmd = xstrdup_or_null(src->cmd);
 }
 
 static struct arg_item *get_conf_item(const char *name)
@@ -454,8 +463,8 @@ static struct arg_item *get_conf_item(const char *name)
        return item;
 }
 
-enum trailer_info_type { TRAILER_KEY, TRAILER_COMMAND, TRAILER_WHERE,
-                        TRAILER_IF_EXISTS, TRAILER_IF_MISSING };
+enum trailer_info_type { TRAILER_KEY, TRAILER_COMMAND, TRAILER_CMD,
+                       TRAILER_WHERE, TRAILER_IF_EXISTS, TRAILER_IF_MISSING };
 
 static struct {
        const char *name;
@@ -463,6 +472,7 @@ static struct {
 } trailer_config_items[] = {
        { "key", TRAILER_KEY },
        { "command", TRAILER_COMMAND },
+       { "cmd", TRAILER_CMD },
        { "where", TRAILER_WHERE },
        { "ifexists", TRAILER_IF_EXISTS },
        { "ifmissing", TRAILER_IF_MISSING }
@@ -542,6 +552,11 @@ static int git_trailer_config(const char *conf_key, const char *value, void *cb)
                        warning(_("more than one %s"), conf_key);
                conf->command = xstrdup(value);
                break;
+       case TRAILER_CMD:
+               if (conf->cmd)
+                       warning(_("more than one %s"), conf_key);
+               conf->cmd = xstrdup(value);
+               break;
        case TRAILER_WHERE:
                if (trailer_set_where(&conf->where, value))
                        warning(_("unknown value '%s' for key '%s'"), value, conf_key);