From d3010f86f8bf6b4e1f805bb366d25adbb6bf7c8b Mon Sep 17 00:00:00 2001
From: Kaz Kylheku <kaz@kylheku.com>
Date: Sat, 26 Jun 2021 12:16:42 -0700
Subject: base-name: bug with empty string suffix.

* stream.c (base_name): We must check for a zero length
suffix, otherwise sub(base, zero, neg(length(suff)))
produces an empty string.

* tests/018/path.tl: Test cases for base-name.
---
 stream.c          |  2 +-
 tests/018/path.tl | 28 ++++++++++++++++++++++++++++
 2 files changed, 29 insertions(+), 1 deletion(-)

diff --git a/stream.c b/stream.c
index 9b329bfb..e4670e10 100644
--- a/stream.c
+++ b/stream.c
@@ -4990,7 +4990,7 @@ val base_name(val path, val suff)
     val base = mkustring(num_fast(end - rsep));
     init_str(base, rsep, self);
     return if3(!null_or_missing_p(suff) && ends_with(suff, base, nil, nil) &&
-               neql(length(suff), length(base)),
+               plusp(length(suff)) && neql(length(suff), length(base)),
                sub(base, zero, neg(length(suff))),
                base);
   }
diff --git a/tests/018/path.tl b/tests/018/path.tl
index bb45d000..16c44d77 100644
--- a/tests/018/path.tl
+++ b/tests/018/path.tl
@@ -68,3 +68,31 @@
   (long-suffix "a.b/c.d.e/f") nil
   (long-suffix "a.b/c.d.e/f.g.h") ".g.h"
   (long-suffix "a.b/c.d.e//") nil)
+
+(mtest
+  (base-name "") ""
+  (base-name "/") "/"
+  (base-name ".") "."
+  (base-name "./") "."
+  (base-name "a") "a"
+  (base-name "a/") "a"
+  (base-name "/a") "a"
+  (base-name "/a/") "a"
+  (base-name "/a/b") "b"
+  (base-name "/a/b/") "b"
+  (base-name "/a/b//") "b"
+  (base-name "/a/b///") "b")
+
+(mtest
+  (base-name "" "") ""
+  (base-name "/" "/") "/"
+  (base-name "/" "") "/"
+  (base-name "." ".") "."
+  (base-name "." "") "."
+  (base-name "./" "/") "."
+  (base-name "a" "a") "a"
+  (base-name "a" "") "a"
+  (base-name "a.b" ".b") "a"
+  (base-name "a.b/" ".b") "a"
+  (base-name "a.b/" ".b/") "a.b"
+  (base-name "a.b/" "a.b") "a.b")
-- 
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