Unverified Commit 6ceadfb5 authored by Zihao Lin's avatar Zihao Lin Committed by GitHub
Browse files

Improve GETRANGE command behavior (#12272)



Fixed the issue about GETRANGE and SUBSTR command
return unexpected result caused by the `start` and `end` out of
definition range of string.

---
## break change
Before this PR, when negative `end` was out of range (i.e., end <
-strlen), we would fix it to 0 to get the substring, which also resulted
in the first character still being returned for this kind of out of
range.
After this PR, we ensure that `GETRANGE` returns an empty bulk when the
negative end index is out of range.

Closes #11738

---------
Co-authored-by: default avatardebing.sun <debing.sun@redis.com>
parent 7f0a7f0a
...@@ -499,24 +499,15 @@ void getrangeCommand(client *c) { ...@@ -499,24 +499,15 @@ void getrangeCommand(client *c) {
strlen = sdslen(str); strlen = sdslen(str);
} }
/* Convert negative indexes */ if (start < 0) start += strlen;
if (start < 0 && end < 0 && start > end) { if (end < 0) end += strlen;
if (strlen == 0 || start >= (long long)strlen || end < 0 || start > end) {
addReply(c,shared.emptybulk); addReply(c,shared.emptybulk);
return; return;
} }
if (start < 0) start = strlen+start;
if (end < 0) end = strlen+end;
if (start < 0) start = 0; if (start < 0) start = 0;
if (end < 0) end = 0; if (end >= (long long)strlen) end = strlen-1;
if ((unsigned long long)end >= strlen) end = strlen-1;
/* Precondition: end >= 0 && end < strlen, so the only condition where
* nothing can be returned is: start > end. */
if (start > end || strlen == 0) {
addReply(c,shared.emptybulk);
} else {
addReplyBulkCBuffer(c,(char*)str+start,end-start+1); addReplyBulkCBuffer(c,(char*)str+start,end-start+1);
}
} }
void mgetCommand(client *c) { void mgetCommand(client *c) {
......
...@@ -464,6 +464,12 @@ start_server {tags {"string"}} { ...@@ -464,6 +464,12 @@ start_server {tags {"string"}} {
assert_equal "" [r getrange mykey 5 3] assert_equal "" [r getrange mykey 5 3]
assert_equal " World" [r getrange mykey 5 5000] assert_equal " World" [r getrange mykey 5 5000]
assert_equal "Hello World" [r getrange mykey -5000 10000] assert_equal "Hello World" [r getrange mykey -5000 10000]
assert_equal "" [r getrange mykey 0 -100]
assert_equal "" [r getrange mykey 1 -100]
assert_equal "" [r getrange mykey -1 -100]
assert_equal "" [r getrange mykey -100 -99]
assert_equal "" [r getrange mykey -100 -100]
assert_equal "" [r getrange mykey -100 -101]
} }
test "GETRANGE against integer-encoded value" { test "GETRANGE against integer-encoded value" {
...@@ -474,6 +480,12 @@ start_server {tags {"string"}} { ...@@ -474,6 +480,12 @@ start_server {tags {"string"}} {
assert_equal "" [r getrange mykey 5 3] assert_equal "" [r getrange mykey 5 3]
assert_equal "4" [r getrange mykey 3 5000] assert_equal "4" [r getrange mykey 3 5000]
assert_equal "1234" [r getrange mykey -5000 10000] assert_equal "1234" [r getrange mykey -5000 10000]
assert_equal "" [r getrange mykey 0 -100]
assert_equal "" [r getrange mykey 1 -100]
assert_equal "" [r getrange mykey -1 -100]
assert_equal "" [r getrange mykey -100 -99]
assert_equal "" [r getrange mykey -100 -100]
assert_equal "" [r getrange mykey -100 -101]
} }
test "GETRANGE fuzzing" { test "GETRANGE fuzzing" {
......
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