gencontrol: Generalise substitution of debhelper config template

Currently we have two copies of the _substitute_file() method, and
lots of somewhat similar invocations of it since different binary
packages need different sets of debhelper configs.

We already name the templates in a fairly consistent way, so we can
replace this with a loop that tries to expand all possible templates
for a package and ignores those that are missing.  Add a method for
this to the Gencontrol base class and use it in both subclasses
where we prevously used _substitute_file().

4 files changed, 45 insertions, 44 deletions

diff --git a/debian/bin/gencontrol.py b/debian/bin/gencontrol.py
index 9b8f36c29cd5..316e50af4538 100755
--- a/debian/bin/gencontrol.py
+++ b/debian/bin/gencontrol.py
@@ -73,10 +73,6 @@ class Gencontrol(Base):
             if src in data or not optional:
                 makeflags[dst] = data[src]
 
-    def _substitute_file(self, template, vars, target, append=False):
-        with open(target, 'a' if append else 'w') as f:
-            f.write(self.substitute(self.templates[template], vars))
-
     def do_main_setup(self, vars, makeflags, extra):
         super(Gencontrol, self).do_main_setup(vars, makeflags, extra)
         makeflags.update({
@@ -191,9 +187,8 @@ class Gencontrol(Base):
         if self.config.merge('packages').get('tools-versioned', True):
             packages.extend(self.process_packages(
                 self.templates["control.tools-versioned"], vars))
-            self._substitute_file(
-                'perf.lintian-overrides', vars,
-                'debian/linux-perf-%(version)s.lintian-overrides' % vars)
+            self.substitute_debhelper_config('perf', vars,
+                                              'linux-perf-%(version)s' % vars)
             if do_meta:
                 packages.extend(self.process_packages(
                     self.templates["control.tools-versioned.meta"], vars))
@@ -493,12 +488,9 @@ class Gencontrol(Base):
         if do_meta and not build_signed:
             packages_own.extend(self.process_packages(
                 self.templates["control.image.meta"], vars))
-
-            # Include a bug presubj message directing reporters to the real
-            # image package.
-            self._substitute_file(
-                "image.meta.bug-presubj", vars,
-                "debian/linux-image%(localversion)s.bug-presubj" % vars)
+            self.substitute_debhelper_config(
+                "image.meta", vars,
+                "linux-image%(localversion)s" % vars)
 
         package_headers = self.process_package(headers[0], vars)
         package_headers['Depends'].extend(relations_compiler_headers)
@@ -533,10 +525,9 @@ class Gencontrol(Base):
             if do_meta:
                 packages_own.extend(self.process_packages(
                     self.templates["control.image-dbg.meta"], vars))
-                self._substitute_file(
-                    'image-dbg.meta.lintian-overrides', vars,
-                    'debian/linux-image%(localversion)s-dbg.lintian-overrides'
-                    % vars)
+                self.substitute_debhelper_config(
+                    'image-dbg.meta', vars,
+                    'linux-image%(localversion)s-dbg' % vars)
 
         merge_packages(packages, packages_own, arch)
 
@@ -630,22 +621,18 @@ class Gencontrol(Base):
                      cmds=["$(MAKE) -f debian/rules.real %s %s" %
                            (merged_config, makeflags)])
 
-        # Substitute kernel version etc. into maintainer scripts,
-        # translations and lintian overrides
-        self._substitute_file(
-            'headers.postinst', vars,
-            'debian/linux-headers-%(abiname)s%(localversion)s.postinst' % vars)
-        for name in ['postinst', 'postrm', 'preinst', 'prerm']:
-            self._substitute_file('image.%s' % name, vars,
-                                  'debian/%s.%s' %
-                                  (image_main['Package'], name))
+        self.substitute_debhelper_config(
+            'headers', vars,
+            'linux-headers-%(abiname)s%(localversion)s' % vars)
+        self.substitute_debhelper_config('image', vars, image_main['Package'])
         if build_debug:
-            debug_lintian_over = \
-                'debian/linux-image-%(abiname)s%(localversion)s-dbg' \
-                '.lintian-overrides' % vars
-            self._substitute_file('image-dbg.lintian-overrides', vars,
-                                  debug_lintian_over)
-            os.chmod(debug_lintian_over, 0o755)
+            self.substitute_debhelper_config(
+                'image-dbg', vars,
+                'linux-image-%(abiname)s%(localversion)s-dbg' % vars)
+            # XXX Should be done automatically based on template perms?
+            os.chmod('debian/linux-image-%(abiname)s%(localversion)s-dbg'
+                     '.lintian-overrides' % vars,
+                     0o755)
 
     def process_changelog(self):
         version = self.version = self.changelog[0].version
diff --git a/debian/bin/gencontrol_signed.py b/debian/bin/gencontrol_signed.py
index 729309705fea..6b6e192b0c8a 100755
--- a/debian/bin/gencontrol_signed.py
+++ b/debian/bin/gencontrol_signed.py
@@ -54,10 +54,6 @@ class Gencontrol(Base):
 
         self.image_packages = []
 
-    def _substitute_file(self, template, vars, target, append=False):
-        with codecs.open(target, 'a' if append else 'w', 'utf-8') as f:
-            f.write(self.substitute(self.templates[template], vars))
-
     def do_main_setup(self, vars, makeflags, extra):
         makeflags['VERSION'] = self.version.linux_version
         makeflags['GENCONTROL_ARGS'] = (
@@ -216,17 +212,20 @@ class Gencontrol(Base):
                                  "PACKAGE_NAME='%s' %s" %
                                  (packages_meta[0]['Package'], makeflags)]
 
-            # Include a bug presubj message directing reporters to the real
-            # image package.
-            self._substitute_file(
-                "image.meta.bug-presubj", vars,
-                self.template_debian_dir
-                + "/linux-image%(localversion)s.bug-presubj" % vars)
+            self.substitute_debhelper_config(
+                'image', vars,
+                'linux-image%(localversion)s' % vars,
+                output_dir=self.template_debian_dir)
 
         merge_packages(packages, packages_own, arch)
         makefile.add('binary-arch_%s_%s_%s_real' % (arch, featureset, flavour),
                      cmds=cmds_binary_arch)
 
+        self.substitute_debhelper_config(
+            'image', vars,
+            'linux-image-%(abiname)s%(localversion)s' % vars,
+            output_dir=self.template_debian_dir)
+
         os.makedirs(self.package_dir + '/usr/share/lintian/overrides', 0o755,
                     exist_ok=True)
         with open(self.package_dir
@@ -237,8 +236,6 @@ class Gencontrol(Base):
                                + '/linux-image-%s%s.%s'
                                % (vars['abiname'], vars['localversion'],
                                   script_base))
-                self._substitute_file('image.%s' % script_base, vars,
-                                      script_name)
                 lintian_overrides.write('%s: script-not-executable %s\n' %
                                         (vars['template'],
                                          os.path.relpath(script_name,
diff --git a/debian/changelog b/debian/changelog
index e2605493673b..7398cea6b988 100644
--- a/debian/changelog
+++ b/debian/changelog
@@ -6,6 +6,7 @@ linux (5.3.7-2) UNRELEASED; urgency=medium
   * debian/bin/gencontrol{,_signed}.py: Use vars parameter instead of self.vars
   * debian/bin/gencontrol{,_signed}.py: Use %(name)s to format template vars
   * debian/.gitignore, debian/rules: Generalise patterns for generated files
+  * gencontrol: Generalise substitution of debhelper config template
 
  -- Ben Hutchings <ben@decadent.org.uk>  Wed, 23 Oct 2019 18:32:15 +0100
 
diff --git a/debian/lib/python/debian_linux/gencontrol.py b/debian/lib/python/debian_linux/gencontrol.py
index 69619da3ee10..a49b21faa199 100644
--- a/debian/lib/python/debian_linux/gencontrol.py
+++ b/debian/lib/python/debian_linux/gencontrol.py
@@ -350,6 +350,22 @@ class Gencontrol(object):
 
         return re.sub(r'@([-_a-z0-9]+)@', subst, str(s))
 
+    # Substitute kernel version etc. into maintainer scripts,
+    # bug presubj message and lintian overrides
+    def substitute_debhelper_config(self, prefix, vars, package_name,
+                                    output_dir='debian'):
+        for id in ['bug-presubj', 'lintian-overrides',
+                   'postinst', 'postrm', 'preinst', 'prerm']:
+            name = '%s.%s' % (prefix, id)
+            try:
+                template = self.templates[name]
+            except KeyError:
+                continue
+            else:
+                target = '%s/%s.%s' % (output_dir, package_name, id)
+                with open(target, 'w') as f:
+                    f.write(self.substitute(template, vars))
+
     def merge_build_depends(self, packages):
         # Merge Build-Depends pseudo-fields from binary packages into the
         # source package