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Re: Friendly refspecs

From
Jeff King <peff@peff.net>
Date
Apr 23, 2008, 09:16 UTC
Message-ID
<20080423091606.GC11935@sigill.intra.peff.net>
In-Reply-To
<7v1w4xuni1.fsf@gitster.siamese.dyndns.org>
On Tue, Apr 22, 2008 at 10:52:06PM -0700, Junio C Hamano wrote:
> Historically we did not favor one way or another for the general purpose
> syntax.  I think Jeff's proposed heuristics to favor branch if a branch
> tip is pushed and tag if a tag is pushed makes sense.
OK, here is a cleaned up patch with tests.

-- >8 -- push: allow unqualified dest refspecs to DWIM

Previously, a push like:
  git push remote src:dst
would go through the following steps:
  1. check for an unambiguous 'dst' on the remote; if it
     exists, then push to that ref
  2. otherwise, check if 'dst' begins with 'refs/'; if it
     does, create a new ref
  3. otherwise, complain because we don't know where in the
     refs hierarchy to put 'dst'

However, in some cases, we can guess about the ref type of 'dst' based on the ref type of 'src'. Specifically, before complaining we now check:

  2.5. if 'src' resolves to a ref starting with refs/heads
       or refs/tags, then prepend that to 'dst'

So now this creates a new branch on the remote, whereas it previously failed with an error message:

  git push master:newbranch

Note that, by design, we limit this DWIM behavior only to source refs which resolve exactly (including symrefs which resolve to existing refs). We still complain on a partial destination refspec if the source is a raw sha1, or a ref expression such as 'master~10'.

Signed-off-by: Jeff King <peff@peff.net>
---
 remote.c              |   32 +++++++++++++++++++++++++++++---
 t/t5516-fetch-push.sh |   40 ++++++++++++++++++++++++++++++++++++++++
 2 files changed, 69 insertions(+), 3 deletions(-)
diff --git a/remote.c b/remote.c
index 06ad156..2d9af40 100644
--- a/remote.c
+++ b/remote.c
@@ -812,6 +812,26 @@ static struct ref *make_linked_ref(const char *name, struct ref ***tail)
 	return ret;
 }
 
+static char *guess_ref(const char *name, struct ref *peer)
+{
+	struct strbuf buf = STRBUF_INIT;
+	unsigned char sha1[20];
+
+	const char *r = resolve_ref(peer->name, sha1, 1, NULL);
+	if (!r)
+		return NULL;
+
+	if (!prefixcmp(r, "refs/heads/"))
+		strbuf_addstr(&buf, "refs/heads/");
+	else if (!prefixcmp(r, "refs/tags/"))
+		strbuf_addstr(&buf, "refs/tags/");
+	else
+		return NULL;
+
+	strbuf_addstr(&buf, name);
+	return strbuf_detach(&buf, NULL);
+}
+
 static int match_explicit(struct ref *src, struct ref *dst,
 			  struct ref ***dst_tail,
 			  struct refspec *rs,
@@ -820,6 +840,7 @@ static int match_explicit(struct ref *src, struct ref *dst,
 	struct ref *matched_src, *matched_dst;
 
 	const char *dst_value = rs->dst;
+	char *dst_guess;
 
 	if (rs->pattern)
 		return errs;
@@ -866,10 +887,15 @@ static int match_explicit(struct ref *src, struct ref *dst,
 	case 0:
 		if (!memcmp(dst_value, "refs/", 5))
 			matched_dst = make_linked_ref(dst_value, dst_tail);
+		else if((dst_guess = guess_ref(dst_value, matched_src)))
+			matched_dst = make_linked_ref(dst_guess, dst_tail);
 		else
-			error("dst refspec %s does not match any "
-			      "existing ref on the remote and does "
-			      "not start with refs/.", dst_value);
+			error("unable to push to unqualified destination: %s\n"
+			      "The destination refspec neither matches an "
+			      "existing ref on the remote nor\n"
+			      "begins with refs/, and we are unable to "
+			      "guess a prefix based on the source ref.",
+			      dst_value);
 		break;
 	default:
 		matched_dst = NULL;
diff --git a/t/t5516-fetch-push.sh b/t/t5516-fetch-push.sh
index f93a100..0a757d5 100755
--- a/t/t5516-fetch-push.sh
+++ b/t/t5516-fetch-push.sh
@@ -273,6 +273,37 @@ test_expect_success 'push with colon-less refspec (4)' '
 
 '
 
+test_expect_success 'push head with non-existant, incomplete dest' '
+
+	mk_test &&
+	git push testrepo master:branch &&
+	check_push_result $the_commit heads/branch
+
+'
+
+test_expect_success 'push tag with non-existant, incomplete dest' '
+
+	mk_test &&
+	git tag -f v1.0 &&
+	git push testrepo v1.0:tag &&
+	check_push_result $the_commit tags/tag
+
+'
+
+test_expect_success 'push sha1 with non-existant, incomplete dest' '
+
+	mk_test &&
+	test_must_fail git push testrepo `git rev-parse master`:foo
+
+'
+
+test_expect_success 'push ref expression with non-existant, incomplete dest' '
+
+	mk_test &&
+	test_must_fail git push testrepo master^:branch
+
+'
+
 test_expect_success 'push with HEAD' '
 
 	mk_test heads/master &&
@@ -311,6 +342,15 @@ test_expect_success 'push with +HEAD' '
 
 '
 
+test_expect_success 'push HEAD with non-existant, incomplete dest' '
+
+	mk_test &&
+	git checkout master &&
+	git push testrepo HEAD:branch &&
+	check_push_result $the_commit heads/branch
+
+'
+
 test_expect_success 'push with config remote.*.push = HEAD' '
 
 	mk_test heads/local &&
-- 
1.5.5.1.69.g9c889.dirty
Previous: Andreas EricssonNext: Jeff King
Message 44 of 86 in “git annoyances”
  1. Ingo MolnarApr 9, 2008
  2. Björn SteinbrinkApr 9, 2008
  3. Jeff KingApr 9, 2008
  4. git-remote: show all remotes with "git remote show"Jeff King, Apr 9, 2008
  5. Johannes SchindelinApr 9, 2008
  6. Junio C HamanoApr 10, 2008
  7. Ingo MolnarApr 9, 2008
  8. Ingo MolnarApr 10, 2008
  9. Avery PennarunApr 9, 2008
  10. Karl HasselströmApr 10, 2008
  11. Avery PennarunApr 10, 2008
  12. Karl HasselströmApr 11, 2008
  13. Friendly refspecs (Was: Re: git annoyances)Teemu Likonen, Apr 9, 2008
  14. Avery PennarunApr 9, 2008
  15. Jeff KingApr 9, 2008
  16. Teemu LikonenApr 9, 2008
  17. Jeff KingApr 9, 2008
  18. Jeff KingApr 10, 2008
  19. Jeff KingApr 10, 2008
  20. Junio C HamanoApr 10, 2008
  21. Jeff KingApr 10, 2008
  22. Teemu LikonenApr 13, 2008
  23. Add examples section to 'git fetch' manualTeemu Likonen, Apr 13, 2008
  24. Junio C HamanoApr 13, 2008
  25. Matt GrahamApr 13, 2008
  26. Teemu LikonenApr 13, 2008
  27. Junio C HamanoApr 14, 2008
  28. Jeff KingApr 16, 2008
  29. Jeff KingApr 16, 2008
  30. Junio C HamanoApr 16, 2008
  31. Jeff KingApr 16, 2008
  32. Daniel BarkalowApr 16, 2008
  33. Junio C HamanoApr 16, 2008
  34. Jeff KingApr 22, 2008
  35. Junio C HamanoApr 22, 2008
  36. Daniel BarkalowApr 22, 2008
  37. Jeff KingApr 22, 2008
  38. Jeff KingApr 22, 2008
  39. Junio C HamanoApr 22, 2008
  40. Jeff KingApr 22, 2008
  41. Teemu LikonenApr 23, 2008
  42. Junio C HamanoApr 23, 2008
  43. Andreas EricssonApr 23, 2008
  44. Jeff KingApr 23, 2008
  45. Jeff KingApr 23, 2008
  46. Teemu LikonenApr 23, 2008
  47. Junio C HamanoApr 9, 2008
  48. Teemu LikonenApr 10, 2008
  49. Santiago GalaApr 12, 2008
  50. Daniel BarkalowApr 9, 2008
  51. Ingo MolnarApr 9, 2008
  52. Daniel BarkalowApr 10, 2008
  53. Junio C HamanoApr 9, 2008
  54. Jon LoeligerApr 9, 2008
  55. Nicolas PitreApr 9, 2008
  56. Jeff KingApr 9, 2008
  57. André Goddard RosaApr 9, 2008
  58. Govind SalinasApr 10, 2008
  59. Jean-Christian de RivazApr 10, 2008
  60. Sverre RabbelierApr 10, 2008
  61. git-bisect annoyancesIngo Molnar, Apr 10, 2008
  62. Christian CouderApr 11, 2008
  63. Ingo MolnarApr 11, 2008
  64. Christian CouderApr 12, 2008
  65. Junio C HamanoApr 11, 2008
  66. When a remote is added but not fetched, tell the user.Gabriel, Apr 10, 2008
  67. Johannes SchindelinApr 11, 2008
  68. GabrielApr 11, 2008
  69. Default to fetching a remote after adding it.Gabriel, Apr 11, 2008
  70. Stephen SinclairApr 11, 2008
  71. Johannes SchindelinApr 12, 2008
  72. GabrielApr 12, 2008
  73. Johannes SchindelinApr 12, 2008
  74. Teemu LikonenApr 11, 2008
  75. Junio C HamanoApr 11, 2008
  76. Sverre RabbelierApr 11, 2008
  77. Junio C HamanoApr 11, 2008
  78. Sverre RabbelierApr 11, 2008
  79. Miles BaderApr 15, 2008
  80. Default to fetching a remote after adding it.Gabriel, Apr 11, 2008
  81. Wincent ColaiutaApr 11, 2008
  82. GabrielApr 11, 2008
  83. Luciano RochaApr 11, 2008
  84. Wincent ColaiutaApr 11, 2008
  85. Jeff KingApr 10, 2008
  86. Sverre RabbelierApr 10, 2008

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