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[PATCH 1/7] fsck_tree(): fix shadowed variable

From
Jeff King <peff@peff.net>
Date
Oct 5, 2020, 07:19 UTC
Message-ID
<20201005071905.GA2291074@coredump.intra.peff.net>
In-Reply-To
<20201005071751.GA2290770@coredump.intra.peff.net>

Commit b2f2039c2b (fsck: accept an oid instead of a "struct tree" for fsck_tree(), 2019-10-18) introduced a new "oid" parameter to fsck_tree(), and we pass it to the report() function when we find problems. However, that is shadowed within the tree-walking loop by the existing "oid" variable which we use to store the oid of each tree entry. As a result, we may report the wrong oid for some problems we detect within the loop (the entry oid, instead of the tree oid).

Our tests didn't catch this because they checked only that we found the expected fsck problem, not that it was attached to the correct object.

Let's rename both variables in the function to avoid confusion. This makes the diff a little noisy (e.g., all of the report() calls outside the loop wee already correct but need touched), but makes sure we catch all cases and will avoid similar confusion in the future.

Signed-off-by: Jeff King <peff@peff.net>
---
 fsck.c                     | 40 +++++++++++++++++++-------------------
 t/t7415-submodule-names.sh |  5 +++--
 2 files changed, 23 insertions(+), 22 deletions(-)
diff --git a/fsck.c b/fsck.c
index f82e2fe9e3..46a108839f 100644
--- a/fsck.c
+++ b/fsck.c
@@ -633,7 +633,7 @@ static int verify_ordered(unsigned mode1, const char *name1,
 	return c1 < c2 ? 0 : TREE_UNORDERED;
 }
 
-static int fsck_tree(const struct object_id *oid,
+static int fsck_tree(const struct object_id *tree_oid,
 		     const char *buffer, unsigned long size,
 		     struct fsck_options *options)
 {
@@ -654,7 +654,7 @@ static int fsck_tree(const struct object_id *oid,
 	struct name_stack df_dup_candidates = { NULL };
 
 	if (init_tree_desc_gently(&desc, buffer, size)) {
-		retval += report(options, oid, OBJ_TREE, FSCK_MSG_BAD_TREE, "cannot be parsed as a tree");
+		retval += report(options, tree_oid, OBJ_TREE, FSCK_MSG_BAD_TREE, "cannot be parsed as a tree");
 		return retval;
 	}
 
@@ -664,11 +664,11 @@ static int fsck_tree(const struct object_id *oid,
 	while (desc.size) {
 		unsigned short mode;
 		const char *name, *backslash;
-		const struct object_id *oid;
+		const struct object_id *entry_oid;
 
-		oid = tree_entry_extract(&desc, &name, &mode);
+		entry_oid = tree_entry_extract(&desc, &name, &mode);
 
-		has_null_sha1 |= is_null_oid(oid);
+		has_null_sha1 |= is_null_oid(entry_oid);
 		has_full_path |= !!strchr(name, '/');
 		has_empty_name |= !*name;
 		has_dot |= !strcmp(name, ".");
@@ -678,10 +678,10 @@ static int fsck_tree(const struct object_id *oid,
 
 		if (is_hfs_dotgitmodules(name) || is_ntfs_dotgitmodules(name)) {
 			if (!S_ISLNK(mode))
-				oidset_insert(&gitmodules_found, oid);
+				oidset_insert(&gitmodules_found, entry_oid);
 			else
 				retval += report(options,
-						 oid, OBJ_TREE,
+						 tree_oid, OBJ_TREE,
 						 FSCK_MSG_GITMODULES_SYMLINK,
 						 ".gitmodules is a symbolic link");
 		}
@@ -692,9 +692,9 @@ static int fsck_tree(const struct object_id *oid,
 				has_dotgit |= is_ntfs_dotgit(backslash);
 				if (is_ntfs_dotgitmodules(backslash)) {
 					if (!S_ISLNK(mode))
-						oidset_insert(&gitmodules_found, oid);
+						oidset_insert(&gitmodules_found, entry_oid);
 					else
-						retval += report(options, oid, OBJ_TREE,
+						retval += report(options, tree_oid, OBJ_TREE,
 								 FSCK_MSG_GITMODULES_SYMLINK,
 								 ".gitmodules is a symbolic link");
 				}
@@ -703,7 +703,7 @@ static int fsck_tree(const struct object_id *oid,
 		}
 
 		if (update_tree_entry_gently(&desc)) {
-			retval += report(options, oid, OBJ_TREE, FSCK_MSG_BAD_TREE, "cannot be parsed as a tree");
+			retval += report(options, tree_oid, OBJ_TREE, FSCK_MSG_BAD_TREE, "cannot be parsed as a tree");
 			break;
 		}
 
@@ -751,25 +751,25 @@ static int fsck_tree(const struct object_id *oid,
 	name_stack_clear(&df_dup_candidates);
 
 	if (has_null_sha1)
-		retval += report(options, oid, OBJ_TREE, FSCK_MSG_NULL_SHA1, "contains entries pointing to null sha1");
+		retval += report(options, tree_oid, OBJ_TREE, FSCK_MSG_NULL_SHA1, "contains entries pointing to null sha1");
 	if (has_full_path)
-		retval += report(options, oid, OBJ_TREE, FSCK_MSG_FULL_PATHNAME, "contains full pathnames");
+		retval += report(options, tree_oid, OBJ_TREE, FSCK_MSG_FULL_PATHNAME, "contains full pathnames");
 	if (has_empty_name)
-		retval += report(options, oid, OBJ_TREE, FSCK_MSG_EMPTY_NAME, "contains empty pathname");
+		retval += report(options, tree_oid, OBJ_TREE, FSCK_MSG_EMPTY_NAME, "contains empty pathname");
 	if (has_dot)
-		retval += report(options, oid, OBJ_TREE, FSCK_MSG_HAS_DOT, "contains '.'");
+		retval += report(options, tree_oid, OBJ_TREE, FSCK_MSG_HAS_DOT, "contains '.'");
 	if (has_dotdot)
-		retval += report(options, oid, OBJ_TREE, FSCK_MSG_HAS_DOTDOT, "contains '..'");
+		retval += report(options, tree_oid, OBJ_TREE, FSCK_MSG_HAS_DOTDOT, "contains '..'");
 	if (has_dotgit)
-		retval += report(options, oid, OBJ_TREE, FSCK_MSG_HAS_DOTGIT, "contains '.git'");
+		retval += report(options, tree_oid, OBJ_TREE, FSCK_MSG_HAS_DOTGIT, "contains '.git'");
 	if (has_zero_pad)
-		retval += report(options, oid, OBJ_TREE, FSCK_MSG_ZERO_PADDED_FILEMODE, "contains zero-padded file modes");
+		retval += report(options, tree_oid, OBJ_TREE, FSCK_MSG_ZERO_PADDED_FILEMODE, "contains zero-padded file modes");
 	if (has_bad_modes)
-		retval += report(options, oid, OBJ_TREE, FSCK_MSG_BAD_FILEMODE, "contains bad file modes");
+		retval += report(options, tree_oid, OBJ_TREE, FSCK_MSG_BAD_FILEMODE, "contains bad file modes");
 	if (has_dup_entries)
-		retval += report(options, oid, OBJ_TREE, FSCK_MSG_DUPLICATE_ENTRIES, "contains duplicate file entries");
+		retval += report(options, tree_oid, OBJ_TREE, FSCK_MSG_DUPLICATE_ENTRIES, "contains duplicate file entries");
 	if (not_properly_sorted)
-		retval += report(options, oid, OBJ_TREE, FSCK_MSG_TREE_NOT_SORTED, "not properly sorted");
+		retval += report(options, tree_oid, OBJ_TREE, FSCK_MSG_TREE_NOT_SORTED, "not properly sorted");
 	return retval;
 }
 
diff --git a/t/t7415-submodule-names.sh b/t/t7415-submodule-names.sh
index f70368bc2e..5c95247180 100755
--- a/t/t7415-submodule-names.sh
+++ b/t/t7415-submodule-names.sh
@@ -148,13 +148,14 @@ test_expect_success 'fsck detects symlinked .gitmodules file' '
 		{
 			printf "100644 blob $content\t$tricky\n" &&
 			printf "120000 blob $target\t.gitmodules\n"
-		} | git mktree &&
+		} >bad-tree &&
+		tree=$(git mktree <bad-tree) &&
 
 		# Check not only that we fail, but that it is due to the
 		# symlink detector; this grep string comes from the config
 		# variable name and will not be translated.
 		test_must_fail git fsck 2>output &&
-		test_i18ngrep gitmodulesSymlink output
+		test_i18ngrep "tree $tree: gitmodulesSymlink" output
 	)
 '
 
-- 
2.28.0.1295.g4824feede7
Previous: Jeff KingNext: Jonathan Nieder
Message 2 of 55 in “forbidding symlinked .gitattributes and .gitignore”
  1. 0/7 forbidding symlinked .gitattributes and .gitignoreJeff King, Oct 5, 2020
  2. 1/7 fsck_tree(): fix shadowed variableJeff King, Oct 5, 2020
  3. Jonathan NiederOct 5, 2020
  4. Jeff KingOct 5, 2020
  5. Jonathan NiederOct 5, 2020
  6. 2/7 fsck_tree(): wrap some long linesJeff King, Oct 5, 2020
  7. Jonathan NiederOct 5, 2020
  8. 3/7 t7415: rename to expand scopeJeff King, Oct 5, 2020
  9. Jonathan NiederOct 5, 2020
  10. Jeff KingOct 5, 2020
  11. Jonathan NiederOct 5, 2020
  12. Jeff KingOct 5, 2020
  13. 4/7 t7450: test verify_path() handling of gitmodulesJeff King, Oct 5, 2020
  14. Jonathan NiederOct 5, 2020
  15. Jeff KingOct 5, 2020
  16. Jonathan NiederOct 5, 2020
  17. 5/7 t0060: test obscured .gitattributes and .gitignore matchingJeff King, Oct 5, 2020
  18. Jonathan NiederOct 5, 2020
  19. Jeff KingOct 5, 2020
  20. Johannes SchindelinOct 5, 2020
  21. Jeff KingOct 6, 2020
  22. 6/7 verify_path(): disallow symlinks in .gitattributes and .gitignoreJeff King, Oct 5, 2020
  23. Jonathan NiederOct 5, 2020
  24. Jeff KingOct 5, 2020
  25. 7/7 fsck: complain when .gitattributes or .gitignore is a symlinkJeff King, Oct 5, 2020
  26. Jonathan NiederOct 5, 2020
  27. Jeff KingOct 5, 2020
  28. Jonathan NiederOct 5, 2020
  29. Jeff KingOct 5, 2020
  30. 0/8 forbidding symlinked .gitattributes and .gitignoreJeff King, Oct 5, 2020
  31. 1/8 fsck_tree(): fix shadowed variableJeff King, Oct 5, 2020
  32. 2/8 fsck_tree(): wrap some long linesJeff King, Oct 5, 2020
  33. 3/8 t7415: rename to expand scopeJeff King, Oct 5, 2020
  34. 4/8 t7450: test verify_path() handling of gitmodulesJeff King, Oct 5, 2020
  35. 5/8 t7450: test .gitmodules symlink matching against obscured namesJeff King, Oct 5, 2020
  36. 7/8 verify_path(): disallow symlinks in .gitattributes and .gitignoreJeff King, Oct 5, 2020
  37. Jonathan NiederOct 27, 2020
  38. Jeff KingOct 27, 2020
  39. Junio C HamanoOct 27, 2020
  40. Jeff KingOct 28, 2020
  41. Jonathan NiederOct 27, 2020
  42. Junio C HamanoOct 28, 2020
  43. 6/8 t0060: test obscured .gitattributes and .gitignore matchingJeff King, Oct 5, 2020
  44. 8/8 fsck: complain when .gitattributes or .gitignore is a symlinkJeff King, Oct 5, 2020
  45. Junio C HamanoOct 6, 2020
  46. Philip OakleyOct 20, 2020
  47. documentation symlink restrictions for .git* filesJeff King, Oct 23, 2020
  48. Jeff KingOct 23, 2020
  49. Philip OakleyOct 26, 2020
  50. Jeff KingOct 26, 2020
  51. Junio C HamanoOct 26, 2020
  52. Jeff KingOct 27, 2020
  53. Junio C HamanoOct 27, 2020
  54. Philip OakleyOct 27, 2020
  55. Junio C HamanoOct 28, 2020

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