From 8c9ffa25eb18f8ccdd3d3aa515a01efaf9814680 Mon Sep 17 00:00:00 2001
From: Kim Alvefur <zash@zash.se>
Date: Sun, 26 Mar 2023 15:20:07 +0200
Subject: util.jsonschema: Implement 'dependentSchemas'

If this object key exists then this schema must validate against the
current object.  Seems useful.
---
 spec/util_jsonschema_spec.lua       | 2 +-
 teal-src/prosody/util/jsonschema.tl | 9 +++++++++
 util/jsonschema.lua                 | 8 ++++++++
 3 files changed, 18 insertions(+), 1 deletion(-)

diff --git a/spec/util_jsonschema_spec.lua b/spec/util_jsonschema_spec.lua
index 7d05af4a..602a2b7f 100644
--- a/spec/util_jsonschema_spec.lua
+++ b/spec/util_jsonschema_spec.lua
@@ -19,7 +19,7 @@ local skip = {
 	["const.json:9"] = "deepcompare",
 	["contains.json:0:5"] = "distinguishing objects from arrays",
 	["defs.json"] = "need built-in meta-schema",
-	["dependentSchemas.json"] = "NYI",
+	["dependentSchemas.json:2:2"] = "NYI", -- minProperties
 	["dynamicRef.json"] = "NYI",
 	["enum.json:1:3"] = "deepcompare",
 	["id.json"] = "NYI",
diff --git a/teal-src/prosody/util/jsonschema.tl b/teal-src/prosody/util/jsonschema.tl
index fa230cac..efdb8f25 100644
--- a/teal-src/prosody/util/jsonschema.tl
+++ b/teal-src/prosody/util/jsonschema.tl
@@ -71,6 +71,7 @@ local record json_schema_object
 	additionalProperties: schema_t
 	patternProperties: schema_t -- NYI
 	propertyNames : schema_t
+	dependentSchemas : { string : schema_t }
 
 	-- xml
 	record xml_t
@@ -333,6 +334,14 @@ function complex_validate (schema : json_schema_object, data : any, root : json_
 			end
 		end
 
+		if schema.dependentSchemas then
+			for k, sub in pairs(schema.dependentSchemas) do
+				if data[k] ~= nil and not validate(sub, data, root) then
+					return false
+				end
+			end
+		end
+
 		if schema.uniqueItems then
 			-- only works for scalars, would need to deep-compare for objects/arrays/tables
 			local values : { any : boolean } = {}
diff --git a/util/jsonschema.lua b/util/jsonschema.lua
index 1c4dcfbd..3160229f 100644
--- a/util/jsonschema.lua
+++ b/util/jsonschema.lua
@@ -244,6 +244,14 @@ function complex_validate(schema, data, root)
 			end
 		end
 
+		if schema.dependentSchemas then
+			for k, sub in pairs(schema.dependentSchemas) do
+				if data[k] ~= nil and not validate(sub, data, root) then
+					return false
+				end
+			end
+		end
+
 		if schema.uniqueItems then
 
 			local values = {}
-- 
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