Bindgen: Generate spec schema if missing

[kraenhansen]

What, How & Why?

This fixes invocation of the Bindgen CLI (npx realm-bindgen) from a clean install of the repository, by adding a check for the existence of the schema before loading it from disk and executing the typescript-json-schema CLI to generate the file if it isn't there.

Because the invocation of the typescript-json-schema was now duplicated in three locations (this new place, in the CMake config for bindgen and package.json of the Realm JS repo), I refactored this into a separate generateSchema function which is exposed through a new generate-schema action on the bindgen CLI.

I considered:

• adding this as a "postinstall" script instead, but having this just before the spec schema is loaded made more sense to me. This also makes it possible to iterate fast, by simply deleting the output file and running the CLI again.
• calling the programatic API of typescript-json-schema instead of starting a child-process invoking its CLI, but this don't output to a file (and this is needed to get editor support for the spec) by default and it seemed a bit more involved TBH.

Ideally, this won't ever run when bindgen is invoked via CMake from an SDK, as the CMake configuration already handles this:

realm-core/bindgen/CMakeLists.txt

Lines 15 to 28 in 816920b

	set(SCHEMA_FILE ${CMAKE_CURRENT_SOURCE_DIR}/generated/spec.schema.json)
	add_custom_command(
	OUTPUT ${SCHEMA_FILE}
	WORKING_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}
	COMMAND ${NPX} typescript-json-schema ${CMAKE_CURRENT_SOURCE_DIR}/tsconfig.json RelaxedSpec --include ${CMAKE_CURRENT_SOURCE_DIR}/src/spec/relaxed-model.ts --out ${SCHEMA_FILE} --required --noExtraProps --aliasRefs
	VERBATIM
	MAIN_DEPENDENCY src/spec/relaxed-model.ts
	DEPENDS
	# Note: The json-schema generation task is extremely slow so we don't want to rerun it any time any TS file is modified.
	# Instead we assume that it will only transitively import the listed files.
	# (Right now there are no imports)
	)
	add_custom_target(BindgenSpecJsonSchema DEPENDS ${SCHEMA_FILE})

☑️ ToDos

• 📝 Changelog update
• 🚦 Tests (or not relevant)
• C-API, if public C++ API changed
• bindgen/spec.yml, if public C++ API changed

[coveralls-official]

Pull Request Test Coverage Report for Build kraen.hansen_69

Details

• 0 of 0 changed or added relevant lines in 0 files are covered.
• 54 unchanged lines in 8 files lost coverage.
• Overall coverage decreased (-0.002%) to 90.732%

---

Files with Coverage Reduction	New Missed Lines	%
src/realm/array_timestamp.cpp	1	97.58%
src/realm/sync/noinst/client_impl_base.cpp	1	82.74%
test/test_query2.cpp	1	98.73%
src/realm/table_view.cpp	2	92.99%
test/test_lang_bind_helper.cpp	2	93.18%
src/realm/sync/noinst/server/server_history.cpp	3	63.51%
src/realm/sync/noinst/server/server.cpp	12	73.71%
test/fuzz_group.cpp	32	43.22%

Totals
Change from base Build 2267:	-0.002%
Covered Lines:	212408
Relevant Lines:	234104

---

💛 - Coveralls