Re: [PATCH v2 1/1] quote: handle null and empty strings in sq_quote_buf_pretty()

Garima Singh [off-list ref] writes:

quoted

diff --git a/quote.c b/quote.c
index 7f2aa6faa4..6d0f8a22a9 100644
--- a/quote.c
+++ b/quote.c

@@ -48,6 +48,18 @@ void sq_quote_buf_pretty(struct strbuf *dst, const char *src)
        static const char ok_punct[] = "+,-./:=@_^";
        const char *p;

+       /* In case of null tokens, warn the user of the BUG in their call. */
+       if (!src)
+               BUG("BUG can't append a NULL token to the buffer");

I thought that the BUG() macro already says "BUG" upfront, no?

Dereferencing to see if we have an empty string below will
immediately give us segfault, so I would omit this check if I were
writing this code, though.

quoted

+       /* In case of empty tokens, add a '' to ensure they
+        * don't get inadvertently dropped.
+        */

Our multi-line comments have the opening slash-asterisk and the
closing asterisk-slash on their own lines.

But more importantly, "In case of empty tokens, add a ''" in this
comment has zero information contents---you can read that from the
code.  Why we do that is what we cannot express in the code, and
deserves a comment.

	/* avoid losing a zero-length string by giving nothing */

or something like that, perhaps?

quoted

+       if (!*src) {
+               strbuf_addstr(dst, "''");
+               return;
+       }
+
        for (p = src; *p; p++) {
                if (!isalpha(*p) && !isdigit(*p) && !strchr(ok_punct, *p)) {
                        sq_quote_buf(dst, src);

diff --git a/t/t0014-alias.sh b/t/t0014-alias.sh
index a070e645d7..9c176c7cbb 100755
--- a/t/t0014-alias.sh
+++ b/t/t0014-alias.sh

@@ -37,4 +37,12 @@ test_expect_success 'looping aliases - internal execution' '
 #      test_i18ngrep "^fatal: alias loop detected: expansion of" output
 #'

+test_expect_success 'run-command parses empty args properly, using sq_quote_buf_pretty' '
+       cat >expect <<-EOF &&
+       fatal: cannot change to '\''alias.foo=frotz foo '\'''\'' bar'\'': No such file or directory
+       EOF
+       test_expect_code 128 git -C "alias.foo=frotz foo '\'''\'' bar" foo 2>actual &&
+       test_cmp expect actual
+'

I think it was my mistake, but we do not ahe to use "alias" for
something like this, perhaps like:

    # 'git frotz' will fail with "no such command", but we are
    # not interested in its exit status.  We just want to see
    # how sq_quote_argv_pretty() shows arguments in the trace.
    GIT_TRACE=1 git frotz a "" b " " c 2>&1 |
    sed -ne "/run_command:/s/.*trace: run_command: //p" >actual &&
    echo "git-frotz a '' b ' ' c" >expect &&
    test_cmp expect actual

quoted

+
 test_done
--
gitgitgadget