# Json\_foreach always executes once, even if the json array is empty
**URL:** https://community.mp3tag.de/t/json-foreach-always-executes-once-even-if-the-json-array-is-empty/66005
**Category:** Fixed Bugs
**Tags:** bug-fixed
**Created:** [September 22, 2024, 4:17pm UTC](https://community.mp3tag.de/t/json-foreach-always-executes-once-even-if-the-json-array-is-empty/66005 "2024-09-22T16:17:26Z")
**Posts on this page:** 8
**Page:** 1
### Author:  [@yorickausyps](https://community.mp3tag.de/u/yorickausyps)
#### Post date: [September 22, 2024, 4:17pm UTC](https://community.mp3tag.de/t/json-foreach-always-executes-once-even-if-the-json-array-is-empty/66005/1 "2024-09-22T16:17:26Z")
Hello,
I'm using Mp3tag v3.27a under windows 10 and recently observed during testing of a script for the discogs WS api, that the body of a `json_foreach` loop was executed, although the json array, it was acting on, was empty or even did not exist. AFAIK in other programming languages, `for` or `foreach` loops never iterate, if the stop condition is already met from the start on. So this probably is a bug in the WSS language.
An example for such a foreach loop you can find in the following code snippet:
```auto
outputto "Companies"
json_foreach "companies"
json_select "entity_type_name"
sayrest
say ": "
json_select "name"
sayrest
say "; "
json_foreach_end
```
If you insert this code in the file "`Discogs Release ID.src`" e.g. behind line 50 and use as test case [https://www.discogs.com/de/release/4567531-Albert-Collins-Robert-Cray-Johnny-Copeland-Showdown](https://www.discogs.com/de/release/4567531-Albert-Collins-Robert-Cray-Johnny-Copeland-Showdown) you will get a tag COMPANIES, that contains the string "`: ;` ". This is because the above WS does not contain a section about Companies, but the foreach loop iterates once.
The corresponding debug output it looks like that:
```auto
Script-Line : 54
Command : json_foreach
Parameter 1 : >companies<
JSON objects : ><
JSON loops : >companies: 1/0<
Output : ><
Line and position:
0
^
```
This shows that iteration starts at element 1 of an array with size 0.
I know that there is a workaround by surrounding the foreach loop with
```auto
json_select_many_count "companies" "name" 1
ifgreater 0
outputto "Companies"
json_foreach "companies"
.......
json_foreach_end
endif
```
It would be nice, if this could be fixed, because it would save some lines of code and some run time.
---
### Author:  [@rboss](https://community.mp3tag.de/u/rboss)
#### Post date: [September 22, 2024, 4:37pm UTC](https://community.mp3tag.de/t/json-foreach-always-executes-once-even-if-the-json-array-is-empty/66005/2 "2024-09-22T16:37:08Z")
I came across the same behavior before (but hadn't reported it yet). From my research on this bug I'm theorizing that, for loops with 0 entries, the WSS parser doesn't know how to proceed, and simply ignores the `json_foreach "S"` and `json_foreach_end` lines and runs the rest.
Good job with the bug catching and workaround. 👍
---
### Author:  [@Florian](https://community.mp3tag.de/u/Florian)
#### Post date: [August 3, 2026, 7:26pm UTC](https://community.mp3tag.de/t/json-foreach-always-executes-once-even-if-the-json-array-is-empty/66005/3 "2026-08-03T19:26:39Z")
Thank you for reporting! It's now fixed in [Mp3tag v3.36-beta.3](https://community.mp3tag.de/t/455).
I hope that not too many Tag Sources relied on the behavior that's now fixed.
---
### Author:  [@yorickausyps](https://community.mp3tag.de/u/yorickausyps)
#### Post date: [August 4, 2026, 9:55am UTC](https://community.mp3tag.de/t/json-foreach-always-executes-once-even-if-the-json-array-is-empty/66005/4 "2026-08-04T09:55:19Z")
Thank you for fixing it.
> [@Florian](#):
>
> I hope that not too many Tag Sources relied on the behavior that's now fixed.
One tag source, I know of, that relied on this "feature" was the [[WS] Bandcamp (search by URL)](https://community.mp3tag.de/t/ws-bandcamp-search-by-url/17838/) up to version 0.4.5, if used for single track URLs. In the newer versions from 0.4.6 on this issue had already been handled.
---
### Author:  [@arb](https://community.mp3tag.de/u/arb)
#### Post date: [August 4, 2026, 2:31pm UTC](https://community.mp3tag.de/t/json-foreach-always-executes-once-even-if-the-json-array-is-empty/66005/5 "2026-08-04T14:31:56Z")
Sorry to report that its broken the TMDB script, as it relies on this behaviour in the .inc file to be able to process movies (single track) or TV shows (multiple as an album) with the same code by continuing through this single loop even if there's nothing present, i.e.:
```auto
# Still "season/#" object, get "episodes" #
# but if not found, stays in response body #
json_foreach "episodes"
LENGTH, ITUNESMEDIATYPE, TVEPISODE etc...
json_foreach_end
```
If there's an `episodes` object from a TV show to loop through, great, otherwise it would still process what it could find for a movie. It's been convenient in my case not having to constantly include extra code for a switch between an expected loop to a forced single-run loop of the same code.
I'll still look into a fix but it's worth a try asking if it's possible to have a parameter to decide whether `json_foreach` proceeds with the single loop (empty or `0`) or bypass as has been requested (`1`)? Hopefully that might save issues with other scripts that have sneaked this behaviour in.
---
### Author:  [@arb](https://community.mp3tag.de/u/arb)
#### Post date: [August 4, 2026, 5:54pm UTC](https://community.mp3tag.de/t/json-foreach-always-executes-once-even-if-the-json-array-is-empty/66005/6 "2026-08-04T17:54:50Z")
Update: not a big deal, very easy and cheap to fix actually, just contain each end of a loop with an `If` with an appropriate trigger when needed:
```auto
IfOutput "TVSeason"
json_foreach "episodes"
TVEPISODE, TVEPISODEID etc...
EndIf
LENGTH, ITUNESMEDIATYPE etc...
IfOutput "TVSeason"
json_foreach_end
EndIf
```
Rather than leave `json_foreachend` exposed and swap around custom loop amounts at the start. 🤷
Just a side-note for anyone else needing to update their scripts that a recent upgrade to `json_foreach` without a parameter outside of an array will also stop becoming a quick single loop and will iterate through objects currently loaded. I got a fright when debugs showing `JSON loops : >loops: 1/0<` started to show `>loops: 1/31<` but that's all it is. Just `If` the loops in and out of your script. 😅
---
### Author:  [@Florian](https://community.mp3tag.de/u/Florian)
#### Post date: [August 4, 2026, 8:05pm UTC](https://community.mp3tag.de/t/json-foreach-always-executes-once-even-if-the-json-array-is-empty/66005/7 "2026-08-04T20:05:25Z")
That's great! Glad you found a solution that quickly 👍
I also prefer the fixed behavior and correctly implement normal `foreach` semantics, so that empty or missing targets execute zero times. In the long term, this is the better solution than making the unexpected behavior the default and hiding the corrected behavior behind an optional parameter.
---
### Author:  [@system](https://community.mp3tag.de/u/system)
#### Post date: [August 18, 2026, 8:06pm UTC](https://community.mp3tag.de/t/json-foreach-always-executes-once-even-if-the-json-array-is-empty/66005/8 "2026-08-18T20:06:25Z")
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