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fix issue 2201: unexpected empty string behavior #2203

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Merged
MuhammadTahaNaveed merged 1 commit into from
Aug 13, 2025
Merged

fix issue 2201: unexpected empty string behavior #2203

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245 changes: 213 additions & 32 deletions regress/expected/expr.out
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Original file line number Diff line number Diff line change
Expand Up @@ -3927,6 +3927,41 @@ SELECT * FROM age_reverse('gnirts a si siht'::cstring);
"this is a string"
(1 row)

-- should return empty string
SELECT * FROM age_reverse('');
age_reverse
-------------
""
(1 row)

SELECT * FROM age_reverse(''::text);
age_reverse
-------------
""
(1 row)

SELECT * FROM age_reverse(''::cstring);
age_reverse
-------------
""
(1 row)

SELECT * FROM cypher('expr', $$
RETURN reverse('')
$$) AS (result agtype);
result
--------
""
(1 row)

SELECT * FROM cypher('expr', $$
RETURN reverse("")
$$) AS (result agtype);
result
--------
""
(1 row)

-- should return null
SELECT * FROM cypher('expr', $$
RETURN reverse(null)
Expand Down Expand Up @@ -4104,6 +4139,75 @@ SELECT * FROM age_tolower('CSTRING'::cstring);
"cstring"
(1 row)

-- should return empty string
SELECT * FROM age_toupper('');
age_toupper
-------------
""
(1 row)

SELECT * FROM age_toupper(''::text);
age_toupper
-------------
""
(1 row)

SELECT * FROM age_toupper(''::cstring);
age_toupper
-------------
""
(1 row)

SELECT * FROM cypher('expr', $$
RETURN toupper('')
$$) AS (result agtype);
result
--------
""
(1 row)

SELECT * FROM cypher('expr', $$
RETURN toupper("")
$$) AS (result agtype);
result
--------
""
(1 row)

SELECT * FROM age_tolower('');
age_tolower
-------------
""
(1 row)

SELECT * FROM age_tolower(''::text);
age_tolower
-------------
""
(1 row)

SELECT * FROM age_tolower(''::cstring);
age_tolower
-------------
""
(1 row)

SELECT * FROM cypher('expr', $$
RETURN tolower('')
$$) AS (result agtype);
result
--------
""
(1 row)

SELECT * FROM cypher('expr', $$
RETURN tolower("")
$$) AS (result agtype);
result
--------
""
(1 row)

-- should return null
SELECT * FROM cypher('expr', $$
RETURN toUpper(null)
Expand Down Expand Up @@ -4211,6 +4315,73 @@ SELECT * FROM age_trim(' string ');
"string"
(1 row)

-- should return empty string
SELECT * FROM cypher('expr', $$
RETURN lTrim('')
$$) AS (results agtype);
results
---------
""
(1 row)

SELECT * FROM cypher('expr', $$
RETURN rTrim('')
$$) AS (results agtype);
results
---------
""
(1 row)

SELECT * FROM cypher('expr', $$
RETURN trim('')
$$) AS (results agtype);
results
---------
""
(1 row)

SELECT * FROM cypher('expr', $$
RETURN lTrim("")
$$) AS (results agtype);
results
---------
""
(1 row)

SELECT * FROM cypher('expr', $$
RETURN rTrim("")
$$) AS (results agtype);
results
---------
""
(1 row)

SELECT * FROM cypher('expr', $$
RETURN trim("")
$$) AS (results agtype);
results
---------
""
(1 row)

SELECT * FROM age_ltrim('');
age_ltrim
-----------
""
(1 row)

SELECT * FROM age_rtrim('');
age_rtrim
-----------
""
(1 row)

SELECT * FROM age_trim('');
age_trim
----------
""
(1 row)

-- should return null
SELECT * FROM cypher('expr', $$
RETURN lTrim(null)
Expand Down Expand Up @@ -4322,15 +4493,16 @@ $$) AS (results agtype);
"123"
(1 row)

-- should return null
-- should return empty string
SELECT * FROM cypher('expr', $$
RETURN left("123456789", 0)
$$) AS (results agtype);
results
---------

""
(1 row)

-- should return null
SELECT * FROM cypher('expr', $$
RETURN left(null, 1)
$$) AS (results agtype);
Expand Down Expand Up @@ -4401,15 +4573,16 @@ $$) AS (results agtype);
"789"
(1 row)

-- should return null
-- should return empty string
SELECT * FROM cypher('expr', $$
RETURN right("123456789", 0)
$$) AS (results agtype);
results
---------

""
(1 row)

-- should return null
SELECT * FROM cypher('expr', $$
RETURN right(null, 1)
$$) AS (results agtype);
Expand Down Expand Up @@ -4508,6 +4681,13 @@ SELECT * FROM age_substring('0123456789', 1);
"123456789"
(1 row)

-- should return empty string
SELECT * FROM age_substring('0123456789', 0, 0);
age_substring
---------------
""
(1 row)

-- should return null
SELECT * FROM cypher('expr', $$
RETURN substring(null, null, null)
Expand Down Expand Up @@ -4747,49 +4927,68 @@ $$) AS (results agtype);
"ababab"
(1 row)

-- should return null
-- should return empty string
SELECT * FROM cypher('expr', $$
RETURN replace(null, null, null)
RETURN replace("", "", "")
$$) AS (results agtype);
results
---------

""
(1 row)

SELECT * FROM cypher('expr', $$
RETURN replace("Hello", null, null)
RETURN replace("Hello", "Hello", "")
$$) AS (results agtype);
results
---------

""
(1 row)

SELECT * FROM cypher('expr', $$
RETURN replace("Hello", "", null)
RETURN replace("", "Hello", "Mellow")
$$) AS (results agtype);
results
---------

""
(1 row)

SELECT * FROM age_replace('', '', '');
age_replace
-------------
""
(1 row)

SELECT * FROM age_replace('Hello', 'Hello', '');
age_replace
-------------
""
(1 row)

SELECT * FROM age_replace('', 'Hello', 'Mellow');
age_replace
-------------
""
(1 row)

-- should return null
SELECT * FROM cypher('expr', $$
RETURN replace("", "", "")
RETURN replace(null, null, null)
$$) AS (results agtype);
results
---------

(1 row)

SELECT * FROM cypher('expr', $$
RETURN replace("Hello", "Hello", "")
RETURN replace("Hello", null, null)
$$) AS (results agtype);
results
---------

(1 row)

SELECT * FROM cypher('expr', $$
RETURN replace("", "Hello", "Mellow")
RETURN replace("Hello", "", null)
$$) AS (results agtype);
results
---------
Expand All @@ -4814,24 +5013,6 @@ SELECT * FROM age_replace('Hello', '', null);

(1 row)

SELECT * FROM age_replace('', '', '');
age_replace
-------------

(1 row)

SELECT * FROM age_replace('Hello', 'Hello', '');
age_replace
-------------

(1 row)

SELECT * FROM age_replace('', 'Hello', 'Mellow');
age_replace
-------------

(1 row)

-- should fail
SELECT * FROM cypher('expr', $$
RETURN replace()
Expand Down
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