Support `--emit-tsd` in Docker container by default

[merceyz]

The emscripten/emsdk:3.1.57 container doesn't contain tsc so the --emit-tsd flag doesn't work by default.

It would be nice if the Docker container could contain tsc by default.

Reproduction:

touch test.c && docker run --rm -it -v "$(pwd):/src" emscripten/emsdk:3.1.57 emcc -o ./build.js --emit-tsd ./build.d.ts -v ./test.c

 /emsdk/upstream/bin/clang -target wasm32-unknown-emscripten -fignore-exceptions -fvisibility=default -mllvm -combiner-global-alias-analysis=false -mllvm -enable-emscripten-sjlj -mllvm -disable-lsr --sysroot=/emsdk/upstream/emscripten/cache/sysroot -DEMSCRIPTEN -Werror=implicit-function-declaration -Xclang -iwithsysroot/include/fakesdl -Xclang -iwithsysroot/include/compat -v ./test.c -c -o /tmp/emscripten_temp_dmia875v/test_0.o
clang version 19.0.0git (https:/github.com/llvm/llvm-project ccdebbae4d77d3efc236af92c22941de5d437e01)
Target: wasm32-unknown-emscripten
Thread model: posix
InstalledDir: /emsdk/upstream/bin
 (in-process)
 "/emsdk/upstream/bin/clang-19" -cc1 -triple wasm32-unknown-emscripten -emit-obj -mrelax-all -disable-free -clear-ast-before-backend -disable-llvm-verifier -discard-value-names -main-file-name test.c -mrelocation-model static -mframe-pointer=none -ffp-contract=on -fno-rounding-math -mconstructor-aliases -target-cpu generic -debugger-tuning=gdb -fdebug-compilation-dir=/src -v -fcoverage-compilation-dir=/src -resource-dir /emsdk/upstream/lib/clang/19 -D EMSCRIPTEN -isysroot /emsdk/upstream/emscripten/cache/sysroot -internal-isystem /emsdk/upstream/lib/clang/19/include -internal-isystem /emsdk/upstream/emscripten/cache/sysroot/include/wasm32-emscripten -internal-isystem /emsdk/upstream/emscripten/cache/sysroot/include -Werror=implicit-function-declaration -ferror-limit 19 -fvisibility=default -fgnuc-version=4.2.1 -fskip-odr-check-in-gmf -fignore-exceptions -fcolor-diagnostics -iwithsysroot/include/fakesdl -iwithsysroot/include/compat -mllvm -combiner-global-alias-analysis=false -mllvm -enable-emscripten-sjlj -mllvm -disable-lsr -o /tmp/emscripten_temp_dmia875v/test_0.o -x c ./test.c
clang -cc1 version 19.0.0git based upon LLVM 19.0.0git default target x86_64-unknown-linux-gnu
ignoring nonexistent directory "/emsdk/upstream/emscripten/cache/sysroot/include/wasm32-emscripten"
#include "..." search starts here:
#include <...> search starts here:
 /emsdk/upstream/emscripten/cache/sysroot/include/fakesdl
 /emsdk/upstream/emscripten/cache/sysroot/include/compat
 /emsdk/upstream/lib/clang/19/include
 /emsdk/upstream/emscripten/cache/sysroot/include
End of search list.
 /emsdk/upstream/bin/clang --version
cache:INFO: generating system asset: symbol_lists/01e1e9a4c0bd6ca93092d8b7f3eedeb510e4cfc6.json... (this will be cached in "/emsdk/upstream/emscripten/cache/symbol_lists/01e1e9a4c0bd6ca93092d8b7f3eedeb510e4cfc6.json" for subsequent builds)
 /emsdk/node/16.20.0_64bit/bin/node /emsdk/upstream/emscripten/src/compiler.mjs /tmp/tmp4p3ssnds.json --symbols-only
cache:INFO:  - ok
 /emsdk/upstream/bin/wasm-ld -o ./build.wasm -L/emsdk/upstream/emscripten/cache/sysroot/lib/wasm32-emscripten /tmp/emscripten_temp_dmia875v/test_0.o -lGL-getprocaddr -lal -lhtml5 -lstubs-debug -lnoexit -lc-debug -ldlmalloc -lcompiler_rt -lc++-noexcept -lc++abi-debug-noexcept -lsockets -mllvm -combiner-global-alias-analysis=false -mllvm -enable-emscripten-sjlj -mllvm -disable-lsr /tmp/tmpibd69osblibemscripten_js_symbols.so --strip-debug --export=emscripten_stack_get_end --export=emscripten_stack_get_free --export=emscripten_stack_get_base --export=emscripten_stack_get_current --export=emscripten_stack_init --export=_emscripten_stack_alloc --export=__get_temp_ret --export=__set_temp_ret --export=__wasm_call_ctors --export=_emscripten_stack_restore --export-if-defined=__start_em_asm --export-if-defined=__stop_em_asm --export-if-defined=__start_em_lib_deps --export-if-defined=__stop_em_lib_deps --export-if-defined=__start_em_js --export-if-defined=__stop_em_js --export-if-defined=main --export-if-defined=__main_argc_argv --export-if-defined=fflush --export-table -z stack-size=65536 --no-growable-memory --initial-heap=16777216 --no-entry --stack-first --table-base=1
 /emsdk/upstream/bin/llvm-objcopy ./build.wasm ./build.wasm --remove-section=.debug* --remove-section=producers
 /emsdk/upstream/bin/wasm-emscripten-finalize --dyncalls-i64 --pass-arg=legalize-js-interface-exported-helpers ./build.wasm -o ./build.wasm --detect-features
 /emsdk/node/16.20.0_64bit/bin/node /emsdk/upstream/emscripten/src/compiler.mjs /tmp/tmp0xih23ki.json
emcc: error: tsc was not found! Please run "npm install" in Emscripten root directory to set up npm dependencies

[sbc100]

Sounds reasonable. What is the best why to install tsc do you think? Would you have time to set a PR the Dockerfile to ensure it is installed?

[merceyz]

I've opened #1371 which installs the npm dependencies of emscripten during docker build.

[waterbang]

I searched for emcc: error: tsc was not found! Please run “npm install” in Emscripten root directory to set up npm dependencies and found this issues, If someone encounters it again later, they can execute npm install -g typescript make a quick fix. tsc is optional.

[stevenwdv]

Hi, I found this issue and have a related question. Is there a reason that this shouldn't be supported for non-Docker as well? And why is tsc not installed by default? Maybe it should be moved to non-dev dependencies?

[sbc100]

The rational is:

1. tsc is quite large
2. Most users of typescript likely already have tsc somewhere on their system
3. More emsdk users won't be using the --emit-tsc feature