From: Eli Zaretskii <eliz@gnu.org>
Date: Sat, 9 Nov 2019 19:56:30 +0000 (+0200)
Subject: Fix case-insensitive completion of buffer names
X-Git-Tag: emacs-27.0.90~682
X-Git-Url: http://git.eshelyaron.com/gitweb/?a=commitdiff_plain;h=f2019fc676c2206bbdc53855e3bc4f1086676d3d;p=emacs.git

Fix case-insensitive completion of buffer names

* test/src/minibuf-tests.el (test-try-completion-ignore-case):
New test, suggested by Stefan Monnier <monnier@iro.umontreal.ca>.

* src/minibuf.c (Ftry_completion): Don't treat strings that
are identical but for the case as if they were identical for
the purposes of not counting the same string twice.  This
fixes case-insensitive completion when all the candidates are
identical but for the letter-case.  (Bug#11339)
---

diff --git a/src/minibuf.c b/src/minibuf.c
index f6cf47f1f28..1e87c5044af 100644
--- a/src/minibuf.c
+++ b/src/minibuf.c
@@ -1323,13 +1323,13 @@ is used to further constrain the set of candidates.  */)
 	  else
 	    {
 	      compare = min (bestmatchsize, SCHARS (eltstring));
-	      tem = Fcompare_strings (bestmatch, zero,
-				      make_fixnum (compare),
-				      eltstring, zero,
-				      make_fixnum (compare),
+	      Lisp_Object lcompare = make_fixnum (compare);
+	      tem = Fcompare_strings (bestmatch, zero, lcompare,
+				      eltstring, zero, lcompare,
 				      completion_ignore_case ? Qt : Qnil);
 	      matchsize = EQ (tem, Qt) ? compare : eabs (XFIXNUM (tem)) - 1;
 
+	      Lisp_Object old_bestmatch = bestmatch;
 	      if (completion_ignore_case)
 		{
 		  /* If this is an exact match except for case,
@@ -1363,7 +1363,12 @@ is used to further constrain the set of candidates.  */)
 		    bestmatch = eltstring;
 		}
 	      if (bestmatchsize != SCHARS (eltstring)
-		  || bestmatchsize != matchsize)
+		  || bestmatchsize != matchsize
+		  || (completion_ignore_case
+		      && !EQ (Fcompare_strings (old_bestmatch, zero, lcompare,
+						eltstring, zero, lcompare,
+						Qnil),
+			      Qt)))
 		/* Don't count the same string multiple times.  */
 		matchcount += matchcount <= 1;
 	      bestmatchsize = matchsize;
diff --git a/test/src/minibuf-tests.el b/test/src/minibuf-tests.el
index 12b018b8228..c64892822d6 100644
--- a/test/src/minibuf-tests.el
+++ b/test/src/minibuf-tests.el
@@ -399,5 +399,16 @@
   (minibuf-tests--test-completion-regexp
    #'minibuf-tests--strings-to-symbol-hashtable))
 
+(ert-deftest test-try-completion-ignore-case ()
+  (let ((completion-ignore-case t))
+    (should (equal (try-completion "bar" '("bAr" "barfoo")) "bAr"))
+    (should (equal (try-completion "bar" '("bArfoo" "barbaz")) "bar"))
+    (should (equal (try-completion "bar" '("bArfoo" "barbaz"))
+                   (try-completion "bar" '("barbaz" "bArfoo"))))
+    ;; bug#11339
+    (should (equal (try-completion "baz" '("baz" "bAz")) "baz")) ;And not `t'!
+    (should (equal (try-completion "baz" '("bAz" "baz"))
+                   (try-completion "baz" '("baz" "bAz"))))))
+
 
 ;;; minibuf-tests.el ends here