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[PATCH v2 07/11] fast-export: ensure we export requested refs

From
Elijah Newren <newren@gmail.com>
Date
Nov 14, 2018, 00:25 UTC
Message-ID
<20181114002600.29233-8-newren@gmail.com>
In-Reply-To
<20181114002600.29233-1-newren@gmail.com>

If file paths are specified to fast-export and a ref points to a commit that does not touch any of the relevant paths, then that ref would sometimes fail to be exported. (This depends on whether any ancestors of the commit which do touch the relevant paths would be exported with that same ref name or a different ref name.) To avoid this problem, put *all* specified refs into extra_refs to start, and then as we export each commit, remove the refname used in the 'commit $REFNAME' directive from extra_refs. Then, in handle_tags_and_duplicates() we know which refs actually do need a manual reset directive in order to be included.

This means that we do need some special handling for excluded refs; e.g.
if someone runs
   git fast-export ^master master
then they've asked for master to be exported, but they have also asked
for the commit which master points to and all of its history to be
excluded.  That logically means ref deletion.  Previously, such refs
were just silently omitted from being exported despite having been
explicitly requested for export.
Signed-off-by: Elijah Newren <newren@gmail.com>
---
 builtin/fast-export.c  | 54 ++++++++++++++++++++++++++++++++----------
 t/t9350-fast-export.sh | 16 ++++++++++---
 2 files changed, 55 insertions(+), 15 deletions(-)
diff --git a/builtin/fast-export.c b/builtin/fast-export.c
index 2eafe351ea..2fef00436b 100644
--- a/builtin/fast-export.c
+++ b/builtin/fast-export.c
@@ -38,6 +38,7 @@ static int use_done_feature;
 static int no_data;
 static int full_tree;
 static struct string_list extra_refs = STRING_LIST_INIT_NODUP;
+static struct string_list tag_refs = STRING_LIST_INIT_NODUP;
 static struct refspec refspecs = REFSPEC_INIT_FETCH;
 static int anonymize;
 static struct revision_sources revision_sources;
@@ -611,6 +612,13 @@ static void handle_commit(struct commit *commit, struct rev_info *rev,
 			export_blob(&diff_queued_diff.queue[i]->two->oid);
 
 	refname = *revision_sources_at(&revision_sources, commit);
+	/*
+	 * FIXME: string_list_remove() below for each ref is overall
+	 * O(N^2).  Compared to a history walk and diffing trees, this is
+	 * just lost in the noise in practice.  However, theoretically a
+	 * repo may have enough refs for this to become slow.
+	 */
+	string_list_remove(&extra_refs, refname, 0);
 	if (anonymize) {
 		refname = anonymize_refname(refname);
 		anonymize_ident_line(&committer, &committer_end);
@@ -814,7 +822,7 @@ static struct commit *get_commit(struct rev_cmdline_entry *e, char *full_name)
 		/* handle nested tags */
 		while (tag && tag->object.type == OBJ_TAG) {
 			parse_object(the_repository, &tag->object.oid);
-			string_list_append(&extra_refs, full_name)->util = tag;
+			string_list_append(&tag_refs, full_name)->util = tag;
 			tag = (struct tag *)tag->tagged;
 		}
 		if (!tag)
@@ -873,25 +881,30 @@ static void get_tags_and_duplicates(struct rev_cmdline_info *info)
 		}
 
 		/*
-		 * This ref will not be updated through a commit, lets make
-		 * sure it gets properly updated eventually.
+		 * Make sure this ref gets properly updated eventually, whether
+		 * through a commit or manually at the end.
 		 */
-		if (*revision_sources_at(&revision_sources, commit) ||
-		    commit->object.flags & SHOWN)
+		if (e->item->type != OBJ_TAG)
 			string_list_append(&extra_refs, full_name)->util = commit;
+
 		if (!*revision_sources_at(&revision_sources, commit))
 			*revision_sources_at(&revision_sources, commit) = full_name;
 	}
+
+	string_list_sort(&extra_refs);
+	string_list_remove_duplicates(&extra_refs, 0);
 }
 
-static void handle_tags_and_duplicates(void)
+static void handle_tags_and_duplicates(struct string_list *extras)
 {
 	struct commit *commit;
 	int i;
 
-	for (i = extra_refs.nr - 1; i >= 0; i--) {
-		const char *name = extra_refs.items[i].string;
-		struct object *object = extra_refs.items[i].util;
+	for (i = extras->nr - 1; i >= 0; i--) {
+		const char *name = extras->items[i].string;
+		struct object *object = extras->items[i].util;
+		int mark;
+
 		switch (object->type) {
 		case OBJ_TAG:
 			handle_tag(name, (struct tag *)object);
@@ -912,8 +925,24 @@ static void handle_tags_and_duplicates(void)
 				       name, sha1_to_hex(null_sha1));
 				continue;
 			}
-			printf("reset %s\nfrom :%d\n\n", name,
-			       get_object_mark(&commit->object));
+
+			mark = get_object_mark(&commit->object);
+			if (!mark) {
+				/*
+				 * Getting here means we have a commit which
+				 * was excluded by a negative refspec (e.g.
+				 * fast-export ^master master).  If the user
+				 * wants the branch exported but every commit
+				 * in its history to be deleted, that sounds
+				 * like a ref deletion to me.
+				 */
+				printf("reset %s\nfrom %s\n\n",
+				       name, sha1_to_hex(null_sha1));
+				continue;
+			}
+
+			printf("reset %s\nfrom :%d\n\n", name, mark
+			       );
 			show_progress();
 			break;
 		}
@@ -1101,7 +1130,8 @@ int cmd_fast_export(int argc, const char **argv, const char *prefix)
 		}
 	}
 
-	handle_tags_and_duplicates();
+	handle_tags_and_duplicates(&extra_refs);
+	handle_tags_and_duplicates(&tag_refs);
 	handle_deletes();
 
 	if (export_filename && lastimportid != last_idnum)
diff --git a/t/t9350-fast-export.sh b/t/t9350-fast-export.sh
index 299120ba70..50c2fceef4 100755
--- a/t/t9350-fast-export.sh
+++ b/t/t9350-fast-export.sh
@@ -544,10 +544,20 @@ test_expect_success 'use refspec' '
 	test_cmp expected actual
 '
 
-test_expect_success 'delete refspec' '
+test_expect_success 'delete ref because entire history excluded' '
 	git branch to-delete &&
-	git fast-export --refspec :refs/heads/to-delete to-delete ^to-delete > actual &&
-	cat > expected <<-EOF &&
+	git fast-export to-delete ^to-delete >actual &&
+	cat >expected <<-EOF &&
+	reset refs/heads/to-delete
+	from 0000000000000000000000000000000000000000
+
+	EOF
+	test_cmp expected actual
+'
+
+test_expect_success 'delete refspec' '
+	git fast-export --refspec :refs/heads/to-delete >actual &&
+	cat >expected <<-EOF &&
 	reset refs/heads/to-delete
 	from 0000000000000000000000000000000000000000
 
-- 
2.19.1.1063.g2b8e4a4f82.dirty
Previous: Elijah NewrenNext: Elijah Newren
Message 59 of 90 in “Import/Export as a fast way to purge files from Git?”
  1. Lars SchneiderSep 23, 2018
  2. Eric SunshineSep 23, 2018
  3. Lars SchneiderSep 23, 2018
  4. brian m. carlsonSep 23, 2018
  5. Jeff KingSep 23, 2018
  6. Elijah NewrenSep 24, 2018
  7. Lars SchneiderOct 31, 2018
  8. Elijah NewrenNov 1, 2018
  9. 00/10 fast export and import fixes and featuresElijah Newren, Nov 11, 2018
  10. 01/10 git-fast-import.txt: fix documentation for --quiet optionElijah Newren, Nov 11, 2018
  11. Jeff KingNov 11, 2018
  12. 02/10 git-fast-export.txt: clarify misleading documentation about rev-list argsElijah Newren, Nov 11, 2018
  13. Jeff KingNov 11, 2018
  14. Elijah NewrenNov 11, 2018
  15. Elijah NewrenNov 13, 2018
  16. Jonathan NiederNov 13, 2018
  17. Elijah NewrenNov 14, 2018
  18. 03/10 fast-export: use value from correct enumElijah Newren, Nov 11, 2018
  19. Jeff KingNov 11, 2018
  20. Ævar Arnfjörð BjarmasonNov 11, 2018
  21. Ævar Arnfjörð BjarmasonNov 12, 2018
  22. Jeff KingNov 12, 2018
  23. 04/10 fast-export: avoid dying when filtering by paths and old tags existElijah Newren, Nov 11, 2018
  24. Jeff KingNov 11, 2018
  25. Elijah NewrenNov 11, 2018
  26. Jeff KingNov 12, 2018
  27. brian m. carlsonNov 12, 2018
  28. Jeff KingNov 13, 2018
  29. 05/10 fast-export: move commit rewriting logic into a function for reuseElijah Newren, Nov 11, 2018
  30. Jeff KingNov 11, 2018
  31. 06/10 fast-export: when using paths, avoid corrupt stream with non-existent markElijah Newren, Nov 11, 2018
  32. Jeff KingNov 11, 2018
  33. Elijah NewrenNov 11, 2018
  34. Jeff KingNov 12, 2018
  35. Elijah NewrenNov 12, 2018
  36. 07/10 fast-export: ensure we export requested refsElijah Newren, Nov 11, 2018
  37. Jeff KingNov 11, 2018
  38. Elijah NewrenNov 11, 2018
  39. 08/10 fast-export: add --reference-excluded-parents optionElijah Newren, Nov 11, 2018
  40. Jeff KingNov 11, 2018
  41. 09/10 fast-export: add a --show-original-ids option to show original namesElijah Newren, Nov 11, 2018
  42. Jeff KingNov 11, 2018
  43. Elijah NewrenNov 11, 2018
  44. Jeff KingNov 12, 2018
  45. Elijah NewrenNov 12, 2018
  46. Jeff KingNov 12, 2018
  47. 10/10 fast-export: add --always-show-modify-after-renameElijah Newren, Nov 11, 2018
  48. Jeff KingNov 11, 2018
  49. Elijah NewrenNov 11, 2018
  50. Jeff KingNov 12, 2018
  51. Elijah NewrenNov 12, 2018
  52. Jeff KingNov 13, 2018
  53. Elijah NewrenNov 13, 2018
  54. Jeff KingNov 14, 2018
  55. Jeff KingNov 11, 2018
  56. Elijah NewrenNov 11, 2018
  57. Jeff KingNov 12, 2018
  58. 00/11 fast export and import fixes and featuresElijah Newren, Nov 14, 2018
  59. 07/11 fast-export: ensure we export requested refsElijah Newren, Nov 14, 2018
  60. 11/11 fast-export: add --always-show-modify-after-renameElijah Newren, Nov 14, 2018
  61. 01/11 git-fast-import.txt: fix documentation for --quiet optionElijah Newren, Nov 14, 2018
  62. 10/11 fast-export: add a --show-original-ids option to show original namesElijah Newren, Nov 14, 2018
  63. 05/11 fast-export: move commit rewriting logic into a function for reuseElijah Newren, Nov 14, 2018
  64. 09/11 fast-import: remove unmaintained duplicate documentationElijah Newren, Nov 14, 2018
  65. 04/11 fast-export: avoid dying when filtering by paths and old tags existElijah Newren, Nov 14, 2018
  66. SZEDER GáborNov 14, 2018
  67. Elijah NewrenNov 14, 2018
  68. 06/11 fast-export: when using paths, avoid corrupt stream with non-existent markElijah Newren, Nov 14, 2018
  69. 08/11 fast-export: add --reference-excluded-parents optionElijah Newren, Nov 14, 2018
  70. SZEDER GáborNov 14, 2018
  71. Elijah NewrenNov 14, 2018
  72. 03/11 fast-export: use value from correct enumElijah Newren, Nov 14, 2018
  73. 02/11 git-fast-export.txt: clarify misleading documentation about rev-list argsElijah Newren, Nov 14, 2018
  74. Jeff KingNov 14, 2018
  75. 00/11 fast export and import fixes and featuresElijah Newren, Nov 16, 2018
  76. 03/11 git-fast-export.txt: clarify misleading documentation about rev-list argsElijah Newren, Nov 16, 2018
  77. 07/11 fast-export: when using paths, avoid corrupt stream with non-existent markElijah Newren, Nov 16, 2018
  78. 01/11 fast-export: convert sha1 to oidElijah Newren, Nov 16, 2018
  79. 02/11 git-fast-import.txt: fix documentation for --quiet optionElijah Newren, Nov 16, 2018
  80. 08/11 fast-export: ensure we export requested refsElijah Newren, Nov 16, 2018
  81. 09/11 fast-export: add --reference-excluded-parents optionElijah Newren, Nov 16, 2018
  82. 10/11 fast-import: remove unmaintained duplicate documentationElijah Newren, Nov 16, 2018
  83. 06/11 fast-export: move commit rewriting logic into a function for reuseElijah Newren, Nov 16, 2018
  84. 11/11 fast-export: add a --show-original-ids option to show original namesElijah Newren, Nov 16, 2018
  85. SZEDER GáborNov 16, 2018
  86. 05/11 fast-export: avoid dying when filtering by paths and old tags existElijah Newren, Nov 16, 2018
  87. 04/11 fast-export: use value from correct enumElijah Newren, Nov 16, 2018
  88. Jeff KingNov 16, 2018
  89. Ævar Arnfjörð BjarmasonNov 12, 2018
  90. Elijah NewrenNov 12, 2018

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