ci(wasi): run ln integration tests

Adds test_ln:: to the wasmtime integration test list and drops ln from
the pending-tools TODO. Documents the read_link-on-absolute-paths gap
in wasi-test-gaps.md.

Author: DePasqualeOrg

.github/workflows/wasi.yml

@@ -50,7 +50,7 @@ jobs:
         # Tests incompatible with WASI are annotated with
         # #[cfg_attr(wasi_runner, ignore)] in the test source files.
         # TODO: add integration tests for these tools as WASI support is extended:
-        #   arch b2sum cat cksum cp csplit date dir dircolors fmt join ln
+        #   arch b2sum cat cksum cp csplit date dir dircolors fmt join
         #   ls md5sum mkdir mv nproc pathchk pr printenv ptx pwd readlink
         #   realpath rm rmdir seq sha1sum sha224sum sha256sum sha384sum
         #   sha512sum shred sleep sort split tail touch tsort uname uniq
@@ -61,7 +61,7 @@ jobs:
           test_base32:: test_base64:: test_basenc:: test_basename:: \
           test_comm:: test_cut:: test_dirname:: test_echo:: \
           test_expand:: test_factor:: test_false:: test_fold:: \
-          test_head:: test_link:: test_nl:: test_numfmt:: \
+          test_head:: test_link:: test_ln:: test_nl:: test_numfmt:: \
           test_od:: test_paste:: test_printf:: test_shuf:: test_sum:: \
           test_tee:: test_tr:: test_true:: test_truncate:: \
           test_unexpand:: test_unlink:: test_wc::

docs/src/wasi-test-gaps.md

@@ -6,7 +6,7 @@ To find all annotated tests: `grep -rn 'wasi_runner, ignore' tests/`
 
 ## Tools not yet covered by integration tests
 
-arch, b2sum, cat, cksum, cp, csplit, date, dir, dircolors, fmt, join, ln, ls, md5sum, mkdir, mv, nproc, pathchk, pr, printenv, ptx, pwd, readlink, realpath, rm, rmdir, seq, sha1sum, sha224sum, sha256sum, sha384sum, sha512sum, shred, sleep, sort, split, tail, touch, tsort, uname, uniq, vdir, yes
+arch, b2sum, cat, cksum, cp, csplit, date, dir, dircolors, fmt, join, ls, md5sum, mkdir, mv, nproc, pathchk, pr, printenv, ptx, pwd, readlink, realpath, rm, rmdir, seq, sha1sum, sha224sum, sha256sum, sha384sum, sha512sum, shred, sleep, sort, split, tail, touch, tsort, uname, uniq, vdir, yes
 
 ## WASI sandbox: host paths not visible
 
@@ -31,3 +31,7 @@ WASI does not support spawning child processes. Tests that shell out to other co
 ## WASI: stdin file position not preserved through wasmtime
 
 When stdin is a seekable file, wasmtime does not preserve the file position between the host and guest. Tests that validate stdin offset behavior after `head` reads are skipped.
+
+## WASI: read_link on absolute paths fails under wasmtime via spawned test harness
+
+`fs::read_link` on an absolute path inside the sandbox (e.g. `/file2`) returns `EPERM` when the WASI binary is launched through `std::process::Command` from the test harness, even though the same call works when wasmtime is invoked directly. This breaks `uucore::fs::canonicalize` for symlink sources, so tests that rely on following a symlink to compute a relative path are skipped.