thodg/libgit2/src/refspec.c

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• Hash : 85addddf
  Author :
  Date : 2016-08-04T13:45:28
  

  refspec: do not set empty rhs for fetch refspecs According to git-fetch(1), "[t]he colon can be omitted when <dst> is empty." So according to git, the refspec "refs/heads/master" is the same as the refspec "refs/heads/master:" when fetching changes. When trying to fetch from a remote with a trailing colon with libgit2, though, the fetch actually fails while it works when the trailing colon is left out. So obviously, libgit2 does _not_ treat these two refspec formats the same for fetches. The problem results from parsing refspecs, where the resulting refspec has its destination set to an empty string in the case of a trailing colon and to a `NULL` pointer in the case of no trailing colon. When passing this to our DWIM machinery, the empty string gets translated to "refs/heads/", which is simply wrong. Fix the problem by having the parsing machinery treat both cases the same for fetch refspecs.

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• src/refspec.c

• /*
   * Copyright (C) the libgit2 contributors. All rights reserved.
   *
   * This file is part of libgit2, distributed under the GNU GPL v2 with
   * a Linking Exception. For full terms see the included COPYING file.
   */
  
  #include "git2/errors.h"
  
  #include "common.h"
  #include "refspec.h"
  #include "util.h"
  #include "posix.h"
  #include "refs.h"
  #include "vector.h"
  
  int git_refspec__parse(git_refspec *refspec, const char *input, bool is_fetch)
  {
  	// Ported from https://github.com/git/git/blob/f06d47e7e0d9db709ee204ed13a8a7486149f494/remote.c#L518-636
  
  	size_t llen;
  	int is_glob = 0;
  	const char *lhs, *rhs;
  	int flags;
  
  	assert(refspec && input);
  
  	memset(refspec, 0x0, sizeof(git_refspec));
  	refspec->push = !is_fetch;
  
  	lhs = input;
  	if (*lhs == '+') {
  		refspec->force = 1;
  		lhs++;
  	}
  
  	rhs = strrchr(lhs, ':');
  
  	/*
  	 * Before going on, special case ":" (or "+:") as a refspec
  	 * for matching refs.
  	 */
  	if (!is_fetch && rhs == lhs && rhs[1] == '\0') {
  		refspec->matching = 1;
  		refspec->string = git__strdup(input);
  		GITERR_CHECK_ALLOC(refspec->string);
  		refspec->src = git__strdup("");
  		GITERR_CHECK_ALLOC(refspec->src);
  		refspec->dst = git__strdup("");
  		GITERR_CHECK_ALLOC(refspec->dst);
  		return 0;
  	}
  
  	if (rhs) {
  		size_t rlen = strlen(++rhs);
  		if (rlen || !is_fetch) {
  			is_glob = (1 <= rlen && strchr(rhs, '*'));
  			refspec->dst = git__strndup(rhs, rlen);
  		}
  	}
  
  	llen = (rhs ? (size_t)(rhs - lhs - 1) : strlen(lhs));
  	if (1 <= llen && memchr(lhs, '*', llen)) {
  		if ((rhs && !is_glob) || (!rhs && is_fetch))
  			goto invalid;
  		is_glob = 1;
  	} else if (rhs && is_glob)
  		goto invalid;
  
  	refspec->pattern = is_glob;
  	refspec->src = git__strndup(lhs, llen);
  	flags = GIT_REF_FORMAT_ALLOW_ONELEVEL | GIT_REF_FORMAT_REFSPEC_SHORTHAND
  		| (is_glob ? GIT_REF_FORMAT_REFSPEC_PATTERN : 0);
  
  	if (is_fetch) {
  		/*
  			* LHS
  			* - empty is allowed; it means HEAD.
  			* - otherwise it must be a valid looking ref.
  			*/
  		if (!*refspec->src)
  			; /* empty is ok */
  		else if (!git_reference__is_valid_name(refspec->src, flags))
  			goto invalid;
  		/*
  			* RHS
  			* - missing is ok, and is same as empty.
  			* - empty is ok; it means not to store.
  			* - otherwise it must be a valid looking ref.
  			*/
  		if (!refspec->dst)
  			; /* ok */
  		else if (!*refspec->dst)
  			; /* ok */
  		else if (!git_reference__is_valid_name(refspec->dst, flags))
  			goto invalid;
  	} else {
  		/*
  			* LHS
  			* - empty is allowed; it means delete.
  			* - when wildcarded, it must be a valid looking ref.
  			* - otherwise, it must be an extended SHA-1, but
  			*   there is no existing way to validate this.
  			*/
  		if (!*refspec->src)
  			; /* empty is ok */
  		else if (is_glob) {
  			if (!git_reference__is_valid_name(refspec->src, flags))
  				goto invalid;
  		}
  		else {
  			; /* anything goes, for now */
  		}
  		/*
  			* RHS
  			* - missing is allowed, but LHS then must be a
  			*   valid looking ref.
  			* - empty is not allowed.
  			* - otherwise it must be a valid looking ref.
  			*/
  		if (!refspec->dst) {
  			if (!git_reference__is_valid_name(refspec->src, flags))
  				goto invalid;
  		} else if (!*refspec->dst) {
  			goto invalid;
  		} else {
  			if (!git_reference__is_valid_name(refspec->dst, flags))
  				goto invalid;
  		}
  
  		/* if the RHS is empty, then it's a copy of the LHS */
  		if (!refspec->dst) {
  			refspec->dst = git__strdup(refspec->src);
  			GITERR_CHECK_ALLOC(refspec->dst);
  		}
  	}
  
  	refspec->string = git__strdup(input);
  	GITERR_CHECK_ALLOC(refspec->string);
  
  	return 0;
  
   invalid:
          giterr_set(
                  GITERR_INVALID,
                  "'%s' is not a valid refspec.", input);
          git_refspec__free(refspec);
  	return -1;
  }
  
  void git_refspec__free(git_refspec *refspec)
  {
  	if (refspec == NULL)
  		return;
  
  	git__free(refspec->src);
  	git__free(refspec->dst);
  	git__free(refspec->string);
  
  	memset(refspec, 0x0, sizeof(git_refspec));
  }
  
  const char *git_refspec_src(const git_refspec *refspec)
  {
  	return refspec == NULL ? NULL : refspec->src;
  }
  
  const char *git_refspec_dst(const git_refspec *refspec)
  {
  	return refspec == NULL ? NULL : refspec->dst;
  }
  
  const char *git_refspec_string(const git_refspec *refspec)
  {
  	return refspec == NULL ? NULL : refspec->string;
  }
  
  int git_refspec_force(const git_refspec *refspec)
  {
  	assert(refspec);
  
  	return refspec->force;
  }
  
  int git_refspec_src_matches(const git_refspec *refspec, const char *refname)
  {
  	if (refspec == NULL || refspec->src == NULL)
  		return false;
  
  	return (p_fnmatch(refspec->src, refname, 0) == 0);
  }
  
  int git_refspec_dst_matches(const git_refspec *refspec, const char *refname)
  {
  	if (refspec == NULL || refspec->dst == NULL)
  		return false;
  
  	return (p_fnmatch(refspec->dst, refname, 0) == 0);
  }
  
  static int refspec_transform(
  	git_buf *out, const char *from, const char *to, const char *name)
  {
  	const char *from_star, *to_star;
  	const char *name_slash, *from_slash;
  	size_t replacement_len, star_offset;
  
  	git_buf_sanitize(out);
  	git_buf_clear(out);
  
  	/*
  	 * There are two parts to each side of a refspec, the bit
  	 * before the star and the bit after it. The star can be in
  	 * the middle of the pattern, so we need to look at each bit
  	 * individually.
  	 */
  	from_star = strchr(from, '*');
  	to_star = strchr(to, '*');
  
  	assert(from_star && to_star);
  
  	/* star offset, both in 'from' and in 'name' */
  	star_offset = from_star - from;
  
  	/* the first half is copied over */
  	git_buf_put(out, to, to_star - to);
  
  	/* then we copy over the replacement, from the star's offset to the next slash in 'name' */
  	name_slash = strchr(name + star_offset, '/');
  	if (!name_slash)
  		name_slash = strrchr(name, '\0');
  
  	/* if there is no slash after the star in 'from', we want to copy everything over */
  	from_slash = strchr(from + star_offset, '/');
  	if (!from_slash)
  		name_slash = strrchr(name, '\0');
  
  	replacement_len = (name_slash - name) - star_offset;
  	git_buf_put(out, name + star_offset, replacement_len);
  
  	return git_buf_puts(out, to_star + 1);
  }
  
  int git_refspec_transform(git_buf *out, const git_refspec *spec, const char *name)
  {
  	assert(out && spec && name);
  	git_buf_sanitize(out);
  
  	if (!git_refspec_src_matches(spec, name)) {
  		giterr_set(GITERR_INVALID, "ref '%s' doesn't match the source", name);
  		return -1;
  	}
  
  	if (!spec->pattern)
  		return git_buf_puts(out, spec->dst);
  
  	return refspec_transform(out, spec->src, spec->dst, name);
  }
  
  int git_refspec_rtransform(git_buf *out, const git_refspec *spec, const char *name)
  {
  	assert(out && spec && name);
  	git_buf_sanitize(out);
  
  	if (!git_refspec_dst_matches(spec, name)) {
  		giterr_set(GITERR_INVALID, "ref '%s' doesn't match the destination", name);
  		return -1;
  	}
  
  	if (!spec->pattern)
  		return git_buf_puts(out, spec->src);
  
  	return refspec_transform(out, spec->dst, spec->src, name);
  }
  
  int git_refspec__serialize(git_buf *out, const git_refspec *refspec)
  {
  	if (refspec->force)
  		git_buf_putc(out, '+');
  
  	git_buf_printf(out, "%s:%s",
  		refspec->src != NULL ? refspec->src : "",
  		refspec->dst != NULL ? refspec->dst : "");
  
  	return git_buf_oom(out) == false;
  }
  
  int git_refspec_is_wildcard(const git_refspec *spec)
  {
  	assert(spec && spec->src);
  
  	return (spec->src[strlen(spec->src) - 1] == '*');
  }
  
  git_direction git_refspec_direction(const git_refspec *spec)
  {
  	assert(spec);
  
  	return spec->push;
  }
  
  int git_refspec__dwim_one(git_vector *out, git_refspec *spec, git_vector *refs)
  {
  	git_buf buf = GIT_BUF_INIT;
  	size_t j, pos;
  	git_remote_head key;
  
  	const char* formatters[] = {
  		GIT_REFS_DIR "%s",
  		GIT_REFS_TAGS_DIR "%s",
  		GIT_REFS_HEADS_DIR "%s",
  		NULL
  	};
  
  	git_refspec *cur = git__calloc(1, sizeof(git_refspec));
  	GITERR_CHECK_ALLOC(cur);
  
  	cur->force = spec->force;
  	cur->push = spec->push;
  	cur->pattern = spec->pattern;
  	cur->matching = spec->matching;
  	cur->string = git__strdup(spec->string);
  
  	/* shorthand on the lhs */
  	if (git__prefixcmp(spec->src, GIT_REFS_DIR)) {
  		for (j = 0; formatters[j]; j++) {
  			git_buf_clear(&buf);
  			git_buf_printf(&buf, formatters[j], spec->src);
  			GITERR_CHECK_ALLOC_BUF(&buf);
  
  			key.name = (char *) git_buf_cstr(&buf);
  			if (!git_vector_search(&pos, refs, &key)) {
  				/* we found something to match the shorthand, set src to that */
  				cur->src = git_buf_detach(&buf);
  			}
  		}
  	}
  
  	/* No shorthands found, copy over the name */
  	if (cur->src == NULL && spec->src != NULL) {
  		cur->src = git__strdup(spec->src);
  		GITERR_CHECK_ALLOC(cur->src);
  	}
  
  	if (spec->dst && git__prefixcmp(spec->dst, GIT_REFS_DIR)) {
  		/* if it starts with "remotes" then we just prepend "refs/" */
  		if (!git__prefixcmp(spec->dst, "remotes/")) {
  			git_buf_puts(&buf, GIT_REFS_DIR);
  		} else {
  			git_buf_puts(&buf, GIT_REFS_HEADS_DIR);
  		}
  
  		git_buf_puts(&buf, spec->dst);
  		GITERR_CHECK_ALLOC_BUF(&buf);
  
  		cur->dst = git_buf_detach(&buf);
  	}
  
  	git_buf_free(&buf);
  
  	if (cur->dst == NULL && spec->dst != NULL) {
  		cur->dst = git__strdup(spec->dst);
  		GITERR_CHECK_ALLOC(cur->dst);
  	}
  
  	return git_vector_insert(out, cur);
  }
  

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