hyperledger-solang_solang/testdata/solang_import_resolution_tests

README

This repo catalogues discrepancies between the import behaviors of solc and solang. Tests were run on:

• solang v0.3.0
• solc 8.13

Running

To run, use the shell script from the root of this repository:

./run.sh

This will run the full test suite and give detailed output of what commands were run for Solc and Solang and how each performed, and a summary of errors encountered. run.sh assumes that solc and solang are on your PATH.

If you only want the errors, run with QUIET=1:

QUIET=1 ./run.sh

You can also specify a specific solang and solc executable:

SOLANG=/path/to/some/solang SOLC=/path/to/some/solc ./run.sh

Overview

To run all tests, run the root directory run.sh. To run an individual test, cd into the corresponding directory and run the nested run.sh.

Note: each run.sh must be in the CWD when run (e.g., running 01_solang_remap_target/run.sh will fail!)

The Tests

01_solang_remap_target

This collection of tests captures a divergence between solc and solang for the semantics of remapping targets:

• solc expands remap targets with simple string replacement; e.g., if remapping lib=node_modules/lib is specified, then import "lib/blah.sol" will expand to node_modules/lib/blah.sol, and this path will be resolved within the VFS (i.e., against base-path/include-paths)

• solang canonicalizes the remap target and resolves it in the host file system; e.g., if remapping lib=node_modules/lib is specified, then node_modules/lib will be expanded to some /abs/path/to/node_modules/lib, and import "lib/blah.sol" will expand to /abs/path/to/node_modules/lib/blah.sol

This can lead to (a) an incorrect blah.sol being imported, or (b) a failure to find blah.sol

02_solang_incorrect_direct_imports

This collection of tests captures a divergence between solc and solang on direct imports.

Consider contracts/Contract.sol that imports import "Foo.sol";. If we run:

solc contracts/Contract.sol --base-path .

then solc will look for Foo.sol in the current working directory.

If we run:

solang compile --target solana contracts/Contract.sol -I .

then solang will look for Foo.sol in contracts.

I believe the most up-to-date version of solang has fixed this, but I'm including this just in case.

03_ambiguous_imports_should_fail

This collection of tests captures a divergence between solc and solang on ambiguous imports. From the solc docs:

Include paths and base path can overlap as long as it does not make import resolution ambiguous... The compiler will only issue an error if the source unit name passed to the Host Filesystem Loader represents an existing path when combined with multiple include paths or an include path and base path.

There are multiple files named Ambiguous.sol:

• Ambiguous.sol
• contracts/Ambiguous.sol

Both of these are placed on the import path. Solc complains about multiple valid imports while solang quietly succeeds and doesn't mention that there is an error.

This can also lead to import path orders mattering, which is bad.