npm: replace 'npm pack' call by 'tar czf'

'npm pack' is a maintainer tool which tries to execute 'prepare'
and similar scripts.  This fails usually in OE because it requires
completely installed 'node_modules'.

Earlier nodejs versions supported an undocumented 'ignore-scripts'
option.  This has been removed in nodejs 16.

We could patch 'package.json' and remove the unwanted scripts.  But
this might complicate local workflows (applying patches) and installed
packages will contain the modified 'package.json'.

Instead of, package it manually by 'tar czf'.  As a sideeffect,
'do_configure' is running much faster now.

Signed-off-by: Enrico Scholz <enrico.scholz@sigma-chemnitz.de>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta/classes/npm.bbclass

@@ -57,13 +57,36 @@ def npm_global_configs(d):
     configs.append(("cache", d.getVar("NPM_CACHE")))
     return configs
 
+## 'npm pack' runs 'prepare' and 'prepack' scripts. Support for
+## 'ignore-scripts' which prevents this behavior has been removed
+## from nodejs 16.  Use simple 'tar' instead of.
 def npm_pack(env, srcdir, workdir):
-    """Run 'npm pack' on a specified directory"""
-    import shlex
-    cmd = "npm pack %s" % shlex.quote(srcdir)
-    args = [("ignore-scripts", "true")]
-    tarball = env.run(cmd, args=args, workdir=workdir).strip("\n")
-    return os.path.join(workdir, tarball)
+    """Emulate 'npm pack' on a specified directory"""
+    import subprocess
+    import os
+    import json
+
+    src = os.path.join(srcdir, 'package.json')
+    with open(src) as f:
+        j = json.load(f)
+
+    # base does not really matter and is for documentation purposes
+    # only.  But the 'version' part must exist because other parts of
+    # the bbclass rely on it.
+    base = j['name'].split('/')[-1]
+    tarball = os.path.join(workdir, "%s-%s.tgz" % (base, j['version']));
+
+    # TODO: real 'npm pack' does not include directories while 'tar'
+    # does.  But this does not seem to matter...
+    subprocess.run(['tar', 'czf', tarball,
+                    '--exclude', './node-modules',
+                    '--exclude-vcs',
+                    '--transform', 's,^\./,package/,',
+                    '--mtime', '1985-10-26T08:15:00.000Z',
+                    '.'],
+                   check = True, cwd = srcdir)
+
+    return tarball
 
 python npm_do_configure() {
     """