build: remove -Dversion_fallback and introduce .VERSION file

The version script will now first try to read the version from a
.VERSION file in the source root. If that file does not exist, it will
query git. The .VERSION file is not included in the git repository, it
is generated for inclusion in source tarballs.

Package maintainers who had any use for -Dversion_fallback may want to
create the .VERSION file themselves.

Additionally, some git-specific files have been removed from source
tarballs.

.gitignore

@@ -14,3 +14,4 @@ __pycache__
 *~
 *-autosave.kra
 *.swp
+.VERSION

meson.build

@@ -4,10 +4,6 @@ project('taisei', 'c',
     version : run_command([
         files('scripts/version.py'),
         '--rootdir', meson.project_source_root(),
-        '--fallback-version', (
-            get_option('version_fallback').strip() != ''
-                ? get_option('version_fallback').strip()
-                : 'v1.4-dev')
     ], check : true).stdout().strip(),
     meson_version : '>=0.56.2',
     default_options : [

meson_options.txt

@@ -1,8 +1,3 @@
-option(
-    'version_fallback',
-    type : 'string',
-    description : 'Overrides the version string when not building in a git repository'
-)
 
 option(
     'developer',

scripts/meson.build

@@ -1,10 +1,6 @@
 
-ver_fb = get_option('version_fallback').strip()
-version_fallback = ver_fb != '' ? ver_fb : meson.project_version()
-
 common_taiseilib_args = [
     '--rootdir', meson.project_source_root(),
-    '--fallback-version', version_fallback
 ]
 
 common_taiseilib_defs = [
@@ -137,3 +133,6 @@ fix_path_command = [fix_path_script]
 
 format_array_script = find_program(files('format-array.py'))
 format_array_command = [format_array_script]
+
+on_dist_script = find_program(files('on-meson-dist.py'))
+meson.add_dist_script(on_dist_script)

scripts/on-meson-dist.py

@@ -0,0 +1,46 @@
+#!/usr/bin/env python3
+
+import os
+import sys
+import pathlib
+import taiseilib.version
+import shutil
+
+
+def main(args):
+    def env_dir_path(v):
+        try:
+            s = os.environ[v]
+        except KeyError:
+            print("{} is not set".format(v))
+
+        p = pathlib.Path(s)
+        assert p.is_dir()
+        return p
+
+    src_root = env_dir_path('MESON_PROJECT_SOURCE_ROOT')
+    dist_root = env_dir_path('MESON_PROJECT_DIST_ROOT')
+    src_version = taiseilib.version.get(rootdir=src_root)
+
+    (dist_root / taiseilib.version.OVERRIDE_FILE_NAME).write_text(src_version.string)
+
+    remove_files = [
+        '.dockerignore',
+        '.gitattributes',
+        '.gitignore',
+        '.gitmodules',
+        '.mailmap',
+        'checkout',
+        'pull',
+    ]
+
+    for fname in remove_files:
+        (dist_root / fname).unlink(fname)
+
+    shutil.rmtree(str(dist_root / '.github'))
+
+
+if __name__ == '__main__':
+    from taiseilib.common import run_main
+    run_main(main)
+

scripts/taiseilib/version.py

@@ -5,12 +5,17 @@
 import subprocess
 import shlex
 import re
+import  os
 
 
 class VersionFormatError(common.TaiseiError):
     pass
 
 
+VERSION_FALLBACK = 'v1.4-dev'
+OVERRIDE_FILE_NAME = '.VERSION'
+
+
 class Version(object):
     regex = re.compile(r'^v?(\d+)(?:\.(\d+)(?:\.(\d+))?)?(?:[-+](\d+))?(?:[-+](.*))?$')
 
@@ -53,13 +58,23 @@ def format(self, template='{string}'):
         return template.format(**self.__dict__)
 
 
-def get(*, rootdir=None, fallback=None, args=common.default_args):
+def get(*, rootdir=None, fallback=VERSION_FALLBACK, args=common.default_args):
     rootdir = rootdir if rootdir is not None else args.rootdir
-    fallback = fallback if fallback is not None else args.fallback_version
 
     if rootdir is None:
         import pathlib
         rootdir = pathlib.Path(__file__).parent
+    elif not isinstance(rootdir, os.PathLike):
+        rootdir = pathlib.Path(rootdir)
+
+    version_override_path = rootdir / OVERRIDE_FILE_NAME
+
+    try:
+        version_str = version_override_path.read_text().strip()
+    except FileNotFoundError:
+        pass
+    else:
+        return Version(version_str)
 
     try:
         version_str = subprocess.check_output(
@@ -80,6 +95,7 @@ def get(*, rootdir=None, fallback=None, args=common.default_args):
 
         print(e, file=sys.stderr)
         print("Warning: git not found or not a git repository; using fallback version {0}".format(fallback), file=sys.stderr)
+        print("Hint: if you are packaging Taisei, write the appropriate version into", str(version_override_path), file=sys.stderr)
         version_str = fallback
 
     return Version(version_str)