jsonb's #> operator segfaulted (dereferencing a null pointer) if the RHS
was a zero-length array, as reported in bug #11207 from Justin Van Winkle.
json's #> operator returns NULL in such cases, so for the moment let's
make jsonb act likewise.
Also add a bunch of regression test queries memorializing the -> and #>
operators' behavior for this and other corner cases.
There is a good argument for changing some of these behaviors, as they
are not very consistent with each other, and throwing an error isn't
necessarily a desirable behavior for operators that are likely to be
used in indexes. However, everybody can agree that a core dump is the
Wrong Thing, and we need test cases even if we decide to change their
expected output later.
The "false" case was really quite useless since all it did was to throw
an error; a definition not helped in the least by making it the default.
Instead let's just have the "true" case, which emits nested objects and
arrays in JSON syntax. We might later want to provide the ability to
emit sub-objects in Postgres record or array syntax, but we'd be best off
to drive that off a check of the target field datatype, not a separate
argument.
For the functions newly added in 9.4, we can just remove the flag arguments
outright. We can't do that for json_populate_record[set], which already
existed in 9.3, but we can ignore the argument and always behave as if it
were "true". It helps that the flag arguments were optional and not
documented in any useful fashion anyway.
populate_recordset_object_start() improperly created a new hash table
(overwriting the link to the existing one) if called at nest levels
greater than one. This resulted in previous fields not appearing in
the final output, as reported by Matti Hameister in bug #10728.
In 9.4 the problem also affects json_to_recordset.
This perhaps missed detection earlier because the default behavior is to
throw an error for nested objects: you have to pass use_json_as_text = true
to see the problem.
In addition, fix query-lifespan leakage of the hashtable created by
json_populate_record(). This is pretty much the same problem recently
fixed in dblink: creating an intended-to-be-temporary context underneath
the executor's per-tuple context isn't enough to make it go away at the
end of the tuple cycle, because MemoryContextReset is not
MemoryContextResetAndDeleteChildren.
Michael Paquier and Tom Lane
Per gripe from Peter Eisentraut and Tom Lane.
The output is slightly different, but still ISO 8601 compliant: to_char
doesn't output the minutes when time zone offset is an integer number of
hours, while EncodeDateTime outputs ":00".
The code is slightly adapted from code in xml.c
Previously, any backslash in text being escaped for JSON was doubled so
that the result was still valid JSON. However, this led to some perverse
results in the case of Unicode sequences, These are now detected and the
initial backslash is no longer escaped. All other backslashes are
still escaped. No validity check is performed, all that is looked for is
\uXXXX where X is a hexidecimal digit.
This is a change from the 9.2 and 9.3 behaviour as noted in the Release
notes.
Per complaint from Teodor Sigaev.
Many JSON processors require timestamp strings in ISO 8601 format in
order to convert the strings. When converting a timestamp, with or
without timezone, to a JSON datum we therefore now use such a format
rather than the type's default text output, in functions such as
to_json().
This is a change in behaviour from 9.2 and 9.3, as noted in the release
notes.
The new format accepts exactly the same data as the json type. However, it is
stored in a format that does not require reparsing the orgiginal text in order
to process it, making it much more suitable for indexing and other operations.
Insignificant whitespace is discarded, and the order of object keys is not
preserved. Neither are duplicate object keys kept - the later value for a given
key is the only one stored.
The new type has all the functions and operators that the json type has,
with the exception of the json generation functions (to_json, json_agg etc.)
and with identical semantics. In addition, there are operator classes for
hash and btree indexing, and two classes for GIN indexing, that have no
equivalent in the json type.
This feature grew out of previous work by Oleg Bartunov and Teodor Sigaev, which
was intended to provide similar facilities to a nested hstore type, but which
in the end proved to have some significant compatibility issues.
Authors: Oleg Bartunov, Teodor Sigaev, Peter Geoghegan and Andrew Dunstan.
Review: Andres Freund
json_build_array() and json_build_object allow for the construction of
arbitrarily complex json trees. json_object() turns a one or two
dimensional array, or two separate arrays, into a json_object of
name/value pairs, similarly to the hstore() function.
json_object_agg() aggregates its two arguments into a single json object
as name value pairs.
Catalog version bumped.
Andrew Dunstan, reviewed by Marko Tiikkaja.
Per discussion on -hackers. We treat Unicode escapes when unescaping
them similarly to the way we treat them in PostgreSQL string literals.
Escapes in the ASCII range are always accepted, no matter what the
database encoding. Escapes for higher code points are only processed in
UTF8 databases, and attempts to process them in other databases will
result in an error. \u0000 is never unescaped, since it would result in
an impermissible null byte.
In 9.2, Unicode escape sequences are not analysed at all other than
to make sure that they are in the form \uXXXX. But in 9.3 many of the
new operators and functions try to turn JSON text values into text in
the server encoding, and this includes de-escaping Unicode escape
sequences. This processing had not taken into account the possibility
that this might contain a surrogate pair to designate a character
outside the BMP. That is now handled correctly.
This also enforces correct use of surrogate pairs, something that is not
done by the type's input routines. This fact is noted in the docs.
The JSON parser is converted into a recursive descent parser, and
exposed for use by other modules such as extensions. The API provides
hooks for all the significant parser event such as the beginning and end
of objects and arrays, and providing functions to handle these hooks
allows for fairly simple construction of a wide variety of JSON
processing functions. A set of new basic processing functions and
operators is also added, which use this API, including operations to
extract array elements, object fields, get the length of arrays and the
set of keys of a field, deconstruct an object into a set of key/value
pairs, and create records from JSON objects and arrays of objects.
Catalog version bumped.
Andrew Dunstan, with some documentation assistance from Merlin Moncure.
This adds the following:
json_agg(anyrecord) -> json
to_json(any) -> json
hstore_to_json(hstore) -> json (also used as a cast)
hstore_to_json_loose(hstore) -> json
The last provides heuristic treatment of numbers and booleans.
Also, in json generation, if any non-builtin type has a cast to json,
that function is used instead of the type's output function.
Andrew Dunstan, reviewed by Steve Singer.
Catalog version bumped.
Instead of identifying error locations only by line number (which could
be entirely unhelpful with long input lines), provide a fragment of the
input text too, placing this info in a new CONTEXT entry. Make the
error detail messages conform more closely to style guidelines, fix
failure to expose some of them for translation, ensure compiler can
check formats against supplied parameters.
The original coding misbehaved if "char" is signed, and also made the
extremely poor decision to print control characters literally when trying
to complain about them. Report and patch by Shigeru Hanada.
In passing, also fix core dump risk in report_parse_error() should the
parse state be something other than what it expects.
First, as noted by Itagaki Takahiro, a datum of type JSON doesn't
need to be escaped. Second, ensure that numeric output not in
the form of a legal JSON number is quoted and escaped.
The hstore and json datatypes both have record-conversion functions that
pay attention to column names in the composite values they're handed.
We used to not worry about inserting correct field names into tuple
descriptors generated at runtime, but given these examples it seems
useful to do so. Observe the nicer-looking results in the regression
tests whose results changed.
catversion bump because there is a subtle change in requirements for stored
rule parsetrees: RowExprs from ROW() constructs now have to include field
names.
Andrew Dunstan and Tom Lane
When written, textanycat, anytextcat, quote_literal, and quote_nullable
were marked volatile, because they could invoke arbitrary type-specific
output functions as part of casting their anyelement arguments to text.
Since then, we have defined a project policy that I/O functions must not
be volatile, as per commit aab353a60b.
So these functions can safely be downgraded to stable. Most of the time
this makes no difference since they'll get inlined anyway, but as noted
by Andrew Dunstan, there are cases where the volatile marking prevents
optimizations that the planner does before function inlining. (I think
I might have overlooked these functions in the earlier commit on the
grounds that inlining would make it moot, but not so --- tgl)
This change results in a change in the expected output of the json
regression tests, because the planner can now flatten a sub-select
that it failed to before. The old output is preferable, but getting
that back will require some as-yet-unfinished work on RowExpr handling.
Marti Raudsepp
Like the XML data type, we simply store JSON data as text, after checking
that it is valid. More complex operations such as canonicalization and
comparison may come later, but this is enough for not.
There are a few open issues here, such as whether we should attempt to
detect UTF-8 surrogate pairs represented as \uXXXX\uYYYY, but this gets
the basic framework in place.
Tom Lane
Robert Haas
Andrew Dunstan
Peter Eisentraut