--dependency_mode LOOSE does not work

[je-mos]

Consider the following files:

greet.js:
function greet(msg) { console.log(msg); } exports.greet = greet;

hellogreet.js:
function hellogreet(msg) { console.log("Hello " + msg); } exports.hellogreet = hellogreet;

entrygreet.js:
const greetmod = require("./greet.js"); const myname = "John Doe"; greetmod.greet(myname);

Compile the files with the following command line:

java -jar closure-compiler.jar --formatting PRETTY_PRINT --compilation_level SIMPLE_OPTIMIZATIONS --process_common_js_modules --dependency_mode LOOSE entrygreet.js greet.js hellogreet.js

Expected behaviour: The output should only include contents of files entrygreet.js and greet.js.
Acutal behaviour: The output includes contents of all 3 files, including hellogreet.js.

--dependency_mode LOOSE should add all files that do not goog.provide a namespace and are not modules as --entry_point entries. In this case it is file entrygreet.js. This file depends only on greet.js and nothing depends on hellogreet.js. Therefore the generated output should definitely not include contents of hellogreet.js. So it seems --dependency_mode LOOSE is broken and acts just like --dependency_mode SORT_ONLY.

Can you please investigate and fix the problem?

[tjgq]

--dependency_mode=LOOSE considers every file without a goog.provide or goog.module statement to be an implicit entry point, in addition to the explicit entry points given by the --entry_point flag. If you want --entry_point to be your only entry point, use --dependency_mode=STRICT.

Note: LOOSE and STRICT are deprecated synonyms for PRUNE_LEGACY and PRUNE, respectively. Their behavior is documented in the flags wiki page.

[je-mos]

@tjgq Thanks, but actually that's not the whole truth. The flags wiki page you referenced says:

PRUNE_LEGACY same as PRUNE but files that do not goog.provide a namespace and are not modules will be automatically added as --entry_point entries.

Furthermore the Managing Dependencies wiki page makes it clear that:

--dependency_mode=LOOSE will keep any files that do not goog.provide symbols (whereas --dependency_mode=STRICT will drop them). ES6 and CommonJS modules are rewritten to always have goog.provide statements.

The file hellogreet.js in my above testcase is a CommonJS module (as determined by the exports.hellogreet = hellogreet; statement). It's also not a dependency of any other file in my testcase. So it should definitely not be included in the compiler output.

The option --dependency_mode LOOSE currently does not work correctly and that's causing us some headaches at the moment. Switching to --dependency_mode=STRICT and specifying all possible entry points manually in the --entry_point option is a possible workaround. Nevertheless I'd prefer to be able to just use --dependency_mode LOOSE because this is the easier approach for us and would work perfectly in our environment.

Thanks for your note regarding the deprecation of LOOSE and STRICT in favor of PRUNE_LEGACY and PRUNE. The above testcase also fails with PRUNE_LEGACY, so this doesn't make any difference.

By the way: The help page of the compiler and also the flags wiki page states that the default dependency mode in the absence of --entry_point is NONE. This is not correct. The compiler defaults to --dependency_mode=SORT_ONLY in this case. This is also implied by the section Using Closure Compiler to auto-sort files on the wiki page Managing Dependencies.

It would be very helpful if both the option --dependency_mode LOOSE and the documentation could be fixed.

Thanks!

[rishipal]

Created internal issue - b/145155120