[gimp] tools: improve the install-* meson targets.

[Jehan <jehanp src gnome org>]

commit 8e74a22ce7da0acd906a2e22aec27b5ed7a7b03b
Author: Jehan <jehan girinstud io>
Date:   Sat Sep 14 23:51:12 2019 +0200

    tools: improve the install-* meson targets.
    
    Continue installing the list of files to install even if a failure
    occured. In particular, I encountered a problem where script-fu was
    failing to install because the installed binary was being executed (and
    its memory probably mmap-ed). Hence the copy failed with:
    
    > [Errno 26] Text file busy: '/my/prefix/lib64/gimp/2.99/plug-ins/script-fu/script-fu'
    
    Yet trying to reinstall plug-ins while GIMP is being run, hence
    script-fu is being executed, is a very common development trick (for me
    at least). So instead, when such an error occurs, I simply save it and
    output all the exceptions in the end (where these warnings are properly
    visible), instead of failing everything.
    
    Of course, ideally the subtarget should not even try to install
    script-fu as it is unchanged. This is why I changed shutil.copy() by
    shutil.copy2() to install metadata, which include last access timestamp.
    Maybe this could be used to decide whether the installed file is already
    the last one, thus not retry, though I am actually unsure if this is
    enough (on the other hand, the ultimate check of bit-to-bit comparison
    may obviously be too much/slow which is counter-productive), which is
    why I am not doing this change right now.

 tools/meson_install_subdir.py | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)
---
diff --git a/tools/meson_install_subdir.py b/tools/meson_install_subdir.py
index da220db1b2..7011e92b7a 100755
--- a/tools/meson_install_subdir.py
+++ b/tools/meson_install_subdir.py
@@ -67,6 +67,7 @@ def get_files_of_part(part_name):
     return files_of_part
 
 def install_files(files, verbose):
+    warnings = []
     for file in sorted(files.keys()):
         target = files[file]
         if verbose: print(file + '  →  ' + target, end='\n')
@@ -74,7 +75,14 @@ def install_files(files, verbose):
         if os.path.isdir(file):
             copytree(file, target)
         if os.path.isfile(file):
-            shutil.copy(file, target)
+            try:
+                shutil.copy2(file, target)
+            except Exception as e:
+                warnings += [(file, e)]
+    if len(warnings) > 0:
+        sys.stderr.write("\n*** WARNING: *** Some file installation failed:\n")
+        for (file, e) in warnings:
+            sys.stderr.write("- {}: {}\n".format(file, e))
 
 if __name__ == '__main__':
     parser = argparse.ArgumentParser()