gnulib-tool.py: Fix parsing of gnulib-cache.m4

[Bruno Haible]

I see this test failure:

$ ./test-cache-2-19.sh
Only in tmp1861851-result/lib: Makefile.am
Only in ./test-cache-2-19.result/lib: Makefile.gnulib
Files ./test-cache-2-19.result/m4/gnulib-cache.m4 and 
tmp1861851-result/m4/gnulib-cache.m4 differ
Only in tmp1861851-result/tests: Makefile.am
Only in ./test-cache-2-19.result/tests: Makefile.gnulib
FAIL: gnulib-tool's result has unexpected differences.
$ diff -u ./test-cache-2-19.result/m4/gnulib-cache.m4 
tmp1861851-result/m4/gnulib-cache.m4
--- ./test-cache-2-19.result/m4/gnulib-cache.m4 2024-04-12 13:39:25.060862723 
+0200
+++ tmp1861851-result/m4/gnulib-cache.m4        2024-04-12 16:00:15.271757098 
+0200
@@ -44,7 +44,6 @@
 #  --with-unportable-tests \
 #  --with-all-tests \
 #  --lgpl \
-#  --makefile-name=Makefile.gnulib \
 #  --automake-subdir \
 #  --no-conditional-dependencies \
 #  --libtool \
@@ -75,7 +74,7 @@
 gl_WITH_TESTS
 gl_LIB([libgnu])
 gl_LGPL
-gl_MAKEFILE_NAME([Makefile.gnulib])
+gl_MAKEFILE_NAME([])
 gl_AUTOMAKE_SUBDIR
 gl_LIBTOOL
 gl_MACRO_PREFIX([gl])

The cause is that at GLImport.py:167 the 'result' variable contains
a pair ('gl_LGPL\ngl_MAKEFILE_NAME', 'Makefile.gnulib'). But only
'gl_LGPL' or 'gl_MAKEFILE_NAME' should be parsed as a key, not a
string that contains a newline.

This patch fixes it,


2024-04-12  Bruno Haible  <bruno@clisp.org>

        gnulib-tool.py: Fix parsing of gnulib-cache.m4.
        * pygnulib/GLImport.py (GLImport.__init__): While parsing
        gnulib-cache.m4, stop parsing the identifier starting with 'gl_' when
        encountering a character that is not a uppercase letter, digit, or
        underscore.

diff --git a/pygnulib/GLImport.py b/pygnulib/GLImport.py
index 8a576c2fb1..38f17bb8b4 100644
--- a/pygnulib/GLImport.py
+++ b/pygnulib/GLImport.py
@@ -114,12 +114,12 @@ class GLImport:
 
         # Get other cached variables.
         path = joinpath(self.config['m4base'], 'gnulib-cache.m4')
-        if isfile(joinpath(self.config['m4base'], 'gnulib-cache.m4')):
+        if isfile(path):
             with codecs.open(path, 'rb', 'UTF-8') as file:
                 data = file.read()
 
             # Create regex object and keys.
-            pattern = re.compile(r'^(gl_.*?)\((.*?)\)$', re.S | re.M)
+            pattern = re.compile(r'^(gl_[A-Z0-9_]*)\((.*?)\)$', re.S | re.M)
             keys = \
                 [
                     'gl_LOCAL_DIR', 'gl_MODULES', 'gl_AVOID', 'gl_SOURCE_BASE',