Re: [PATCH v2] unit-tests: do show relative file paths on non-Windows, too

[Johannes Schindelin <Johannes.Schindelin@gmx.de>]

Hi Junio,

On Sun, 11 Feb 2024, Junio C Hamano wrote:

> diff --git a/t/unit-tests/test-lib.c b/t/unit-tests/test-lib.c
> index 7bf9dfdb95..66d6980ffb 100644
> --- a/t/unit-tests/test-lib.c
> +++ b/t/unit-tests/test-lib.c
> @@ -21,12 +21,11 @@ static struct {
>  	.result = RESULT_NONE,
>  };
>
> -#ifndef _MSC_VER
> -#define make_relative(location) location
> -#else
>  /*
>   * Visual C interpolates the absolute Windows path for `__FILE__`,
>   * but we want to see relative paths, as verified by t0080.
> + * There are other compilers that do the same, and are not for
> + * Windows.
>   */
>  #include "dir.h"
>
> @@ -34,32 +33,66 @@ static const char *make_relative(const char *location)
>  {
>  	static char prefix[] = __FILE__, buf[PATH_MAX], *p;
>  	static size_t prefix_len;
> +	static int need_bs_to_fs = -1;
>
> -	if (!prefix_len) {
> +	/* one-time preparation */
> +	if (need_bs_to_fs < 0) {
>  		size_t len = strlen(prefix);
> -		const char *needle = "\\t\\unit-tests\\test-lib.c";
> +		char needle[] = "t\\unit-tests\\test-lib.c";
>  		size_t needle_len = strlen(needle);
>
> -		if (len < needle_len || strcmp(needle, prefix + len - needle_len))
> -			die("unexpected suffix of '%s'", prefix);
> +		if (len < needle_len)
> +			die("unexpected prefix '%s'", prefix);
> +
> +		/*
> +		 * The path could be relative (t/unit-tests/test-lib.c)
> +		 * or full (/home/user/git/t/unit-tests/test-lib.c).
> +		 * Check the slash between "t" and "unit-tests".
> +		 */
> +		prefix_len = len - needle_len;
> +		if (prefix[prefix_len + 1] == '/') {
> +			/* Oh, we're not Windows */
> +			for (size_t i = 0; i < needle_len; i++)
> +				if (needle[i] == '\\')
> +					needle[i] = '/';

This looks very similar to the `convert_slashes()` function that is
defined in `compat/mingw.h`. It might be a good opportunity to rename that
function and move it to `git-compat-util.h`, then use it here and once
more below at the end of `make_relative()`.

That's just a nit, though. The patch looks good to me.

Thanks,
Johannes

> +			need_bs_to_fs = 0;
> +		} else {
> +			need_bs_to_fs = 1;
> +		}
>
> -		/* let it end in a directory separator */
> -		prefix_len = len - needle_len + 1;
> +		/*
> +		 * prefix_len == 0 if the compiler gives paths relative
> +		 * to the root of the working tree.  Otherwise, we want
> +		 * to see that we did find the needle[] at a directory
> +		 * boundary.  Again we rely on that needle[] begins with
> +		 * "t" followed by the directory separator.
> +		 */
> +		if (fspathcmp(needle, prefix + prefix_len) ||
> +		    (prefix_len && prefix[prefix_len - 1] != needle[1]))
> +			die("unexpected suffix of '%s'", prefix);
>  	}
>
> -	/* Does it not start with the expected prefix? */
> -	if (fspathncmp(location, prefix, prefix_len))
> +	/*
> +	 * Does it not start with the expected prefix?
> +	 * Return it as-is without making it worse.
> +	 */
> +	if (prefix_len && fspathncmp(location, prefix, prefix_len))
>  		return location;
>
> -	strlcpy(buf, location + prefix_len, sizeof(buf));
> +	/*
> +	 * If we do not need to munge directory separator, we can return
> +	 * the substring at the tail of the location.
> +	 */
> +	if (!need_bs_to_fs)
> +		return location + prefix_len;
> +
>  	/* convert backslashes to forward slashes */
> +	strlcpy(buf, location + prefix_len, sizeof(buf));
>  	for (p = buf; *p; p++)
>  		if (*p == '\\')
>  			*p = '/';
> -
>  	return buf;
>  }
> -#endif
>
>  static void msg_with_prefix(const char *prefix, const char *format, va_list ap)
>  {
> --
> 2.44.0-rc0
>
>
>