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[PATCH 02/18] is_refname_available(): explain the reason for an early exit

From
Michael Haggerty <mhagger@alum.mit.edu>
Date
May 1, 2015, 12:25 UTC
Message-ID
<1430483158-14349-3-git-send-email-mhagger@alum.mit.edu>
In-Reply-To
<1430483158-14349-1-git-send-email-mhagger@alum.mit.edu>

The reason why we can exit early if we find a reference in skip whose name is a prefix of refname is a bit subtle, so explain it in a comment.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
---
 refs.c | 14 +++++++++++++-
 1 file changed, 13 insertions(+), 1 deletion(-)
diff --git a/refs.c b/refs.c
index 2bdd93c..ab438a5 100644
--- a/refs.c
+++ b/refs.c
@@ -907,8 +907,20 @@ static int is_refname_available(const char *refname,
 		pos = search_ref_dir(dir, refname, slash - refname);
 		if (pos >= 0) {
 			struct ref_entry *entry = dir->entries[pos];
-			if (entry_matches(entry, skip))
+			if (entry_matches(entry, skip)) {
+				/*
+				 * The fact that entry is a ref whose
+				 * name is a prefix of refname means
+				 * that there cannot be any other ref
+				 * whose name starts with that prefix
+				 * (because it would have been a D/F
+				 * conflict with entry). So, since we
+				 * don't care about entry (because it
+				 * is in skip), we can stop looking
+				 * now and return true.
+				 */
 				return 1;
+			}
 			report_refname_conflict(entry, refname);
 			return 0;
 		}
-- 
2.1.4
Previous: Michael HaggertyNext: Stefan Beller
Message 5 of 25 in “Improve handling of D/F conflicts”
  1. 00/18 Improve handling of D/F conflictsMichael Haggerty, May 1, 2015
  2. 01/18 t1404: new tests of D/F conflicts within ref transactionsMichael Haggerty, May 1, 2015
  3. Eric SunshineMay 5, 2015
  4. Michael HaggertyMay 5, 2015
  5. 02/18 is_refname_available(): explain the reason for an early exitMichael Haggerty, May 1, 2015
  6. Stefan BellerMay 1, 2015
  7. Michael HaggertyMay 5, 2015
  8. 03/18 is_refname_available(): avoid shadowing "dir" variableMichael Haggerty, May 1, 2015
  9. 04/18 is_refname_available(): convert local variable "dirname" to strbufMichael Haggerty, May 1, 2015
  10. 05/18 entry_matches(): inline functionMichael Haggerty, May 1, 2015
  11. 06/18 report_refname_conflict(): inline functionMichael Haggerty, May 1, 2015
  12. 07/18 struct nonmatching_ref_data: store a refname instead of a ref_entryMichael Haggerty, May 1, 2015
  13. 08/18 is_refname_available(): use dirname in first loopMichael Haggerty, May 1, 2015
  14. 09/18 ref_transaction_commit(): use a string_list for detecting duplicatesMichael Haggerty, May 1, 2015
  15. 10/18 refs: check for D/F conflicts among refs processed in a transactionMichael Haggerty, May 1, 2015
  16. 11/18 verify_refname_available(): rename functionMichael Haggerty, May 1, 2015
  17. 12/18 verify_refname_available(): report errors via a "struct strbuf *err"Michael Haggerty, May 1, 2015
  18. 13/18 lock_ref_sha1_basic(): report errors via a "struct strbuf *err"Michael Haggerty, May 1, 2015
  19. 14/18 lock_ref_sha1_basic(): improve diagnostics for D/F conflictsMichael Haggerty, May 1, 2015
  20. 15/18 rename_ref(): integrate lock_ref_sha1_basic() errors into oursMichael Haggerty, May 1, 2015
  21. 16/18 ref_transaction_commit(): provide better error messagesMichael Haggerty, May 1, 2015
  22. 17/18 ref_transaction_commit(): delete extra "the" from error messageMichael Haggerty, May 1, 2015
  23. 18/18 reflog_expire(): integrate lock_ref_sha1_basic() errors into oursMichael Haggerty, May 1, 2015
  24. Junio C HamanoMay 3, 2015
  25. Michael HaggertyMay 5, 2015

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