From d7b4c9175e89c68aadd8e4a0e1cfb8530e473533 Mon Sep 17 00:00:00 2001
From: filipe oliveira <filipecosta.90@gmail.com>
Date: Thu, 15 Dec 2022 20:25:38 +0000
Subject: [PATCH] Fixed small distance replies on GEODIST and GEO commands
 WITHDIST (#11631)

Fixes a regression introduced by #11552 in 7.0.6.
it causes replies in the GEO commands to contain garbage when the
result is a very small distance (less than 1)
Includes test to confirm indeed with junk in buffer now we properly reply
---
 src/util.c         | 24 +++++++++++++++++-------
 tests/unit/geo.tcl |  7 +++++++
 2 files changed, 24 insertions(+), 7 deletions(-)

diff --git a/src/util.c b/src/util.c
index d094b3b55..74508a70f 100644
--- a/src/util.c
+++ b/src/util.c
@@ -656,9 +656,7 @@ int fixedpoint_d2string(char *dst, size_t dstlen, double dvalue, int fractional_
     if (dvalue == 0) {
         dst[0] = '0';
         dst[1] = '.';
-        for (int i = 0; i < fractional_digits; i++) {
-            dst[2 + i] = '0';
-        }
+        memset(dst + 2, '0', fractional_digits);
         dst[fractional_digits+2] = '\0';
         return fractional_digits + 2;
     }
@@ -707,10 +705,8 @@ int fixedpoint_d2string(char *dst, size_t dstlen, double dvalue, int fractional_
     }
     dst[integer_digits] = '.';
     int size = integer_digits + 1 + fractional_digits;
-    /* fill with 0 if required until fractional_digits */
-    for (int i = integer_digits + 1; i < fractional_digits; i++) {
-        dst[i] = '0';
-    }
+    /* fill with 0 from fractional digits until size */
+    memset(dst + integer_digits + 1, '0', fractional_digits);
     int next = size - 1;
     while (value >= 100) {
         int const i = (value % 100) * 2;
@@ -1282,6 +1278,20 @@ static void test_fixedpoint_d2string(void) {
     sz = fixedpoint_d2string(buf, sizeof buf, v, 1);
     assert(sz == 3);
     assert(!strcmp(buf, "0.0"));
+    /* set junk in buffer */
+    memset(buf,'A',32);
+    v = 0.0001;
+    sz = fixedpoint_d2string(buf, sizeof buf, v, 4);
+    assert(sz == 6);
+    assert(buf[sz] == '\0');
+    assert(!strcmp(buf, "0.0001"));
+    /* set junk in buffer */
+    memset(buf,'A',32);
+    v = 6.0642951598391699e-05;
+    sz = fixedpoint_d2string(buf, sizeof buf, v, 4);
+    assert(sz == 6);
+    assert(buf[sz] == '\0');
+    assert(!strcmp(buf, "0.0001"));
     v = 0.01;
     sz = fixedpoint_d2string(buf, sizeof buf, v, 4);
     assert(sz == 6);
diff --git a/tests/unit/geo.tcl b/tests/unit/geo.tcl
index a6a6cbcb6..e07a6784c 100644
--- a/tests/unit/geo.tcl
+++ b/tests/unit/geo.tcl
@@ -516,6 +516,13 @@ start_server {tags {"geo"}} {
         assert_equal {point2 point1} [r geosearch points fromlonlat -179 37 bybox 400 400 km asc]
     }
 
+    test {GEOSEARCH with small distance} {
+        r del points
+        r geoadd points -122.407107 37.794300 1
+        r geoadd points -122.227336 37.794300 2
+        assert_equal {{1 0.0001} {2 9.8182}} [r GEORADIUS points -122.407107 37.794300 30 mi ASC WITHDIST]
+    }
+
     foreach {type} {byradius bybox} {
     test "GEOSEARCH fuzzy test - $type" {
         if {$::accurate} { set attempt 300 } else { set attempt 30 }