Bug#582511: [checks/debhelper] check for dh + ${python:Depends} but no Python helper

[Jakub Wilk <jwilk@debian.org>]

Reply-To: 
In-Reply-To: <20110820142645.GA429@jwilk.net>

tags 582511 + patch
thanks

I run the check for all the packages that had "python:Depends" or 
"python3:Depends" in their debian/control and there were:
- at least a dozen of true positives;
- a few sort-of false positives caused by the fact that 
${python:Depends} was used though it wasn't actually needed;
- one "serious" false positive: rpm.

To deal correctly with rpm, one would have to track and expand 
variables. It'd like to postpone it for indefinite future, and I'm 
marking the tags as experimental for the moment.

--
Jakub Wilk

diff --git a/checks/debhelper b/checks/debhelper
--- a/checks/debhelper
+++ b/checks/debhelper
@@ -81,6 +81,9 @@
 my $seenmaintscript = 0;
 my $bdepends_noarch;
 my $bdepends;
+my $seen_dh = 0;
+my $seen_python_helper = 0;
+my $seen_python3_helper = 0;
 
 open(RULES, '<', "$droot/rules") or fail("cannot read debian/rules: $!");
 
@@ -108,13 +111,21 @@
         }
         if ($dhcommand eq 'dh_python') {
             tag 'dh_python-is-obsolete', "line $.";
+            $seen_python_helper = 1;
         }
         if ($dhcommand eq 'dh_pycentral') {
             tag 'dh_pycentral-is-obsolete', "line $.";
+            $seen_python_helper = 1;
         }
         if ($dhcommand eq 'dh_installmanpages') {
             tag 'dh_installmanpages-is-obsolete', "line $.";
         }
+        if ($dhcommand eq 'dh_python3') {
+            $seen_python3_helper = 1;
+        }
+        if ($dhcommand =~ m,^dh_(?:pysupport$|python(?:2$|\$.*)),) {
+            $seen_python_helper = 1;
+        }
 
         # Don't warn about recently deprecated commands in code that may be
         # optional.  It may be there only for backports.
@@ -153,6 +164,7 @@
         $seencommand = 1;
         $needbuilddepends = 1;
     } elsif (m,^\s+dh\s+,) {
+        $seen_dh = 1;
         $seencommand = 1;
         $needbuilddepends = 1;
         $needtomodifyscripts = 1;
@@ -165,8 +177,16 @@
                 if (defined $depends) {
                     $missingbdeps_addons{$depends} = $addon;
                 }
+                if ($addon =~ m,python(?:2|_central|_support)$,) {
+                    $seen_python_helper = 1;
+                } elsif ($addon eq 'python3') {
+                    $seen_python3_helper = 1;
+                }
             }
         }
+        if ($seen_python_helper == 0) {
+            $seen_python_helper = -1; # maybe; we'll check that later
+        }
     } elsif (m,^include\s+/usr/share/cdbs/1/rules/debhelper.mk,) {
         $seencommand = 1;
         $needbuilddepends = 1;
@@ -405,6 +425,37 @@
     tag 'temporary-debhelper-file', "$f$otext";
 }
 
+if ($seen_python_helper == -1 and $level >= 9) {
+    $seen_python_helper = 0;
+}
+if ($seen_dh and $seen_python_helper != 1) {
+    my %python_depends = ();
+    for my $binpkg (keys %$pkgs) {
+        if ($info->binary_relation($binpkg, 'all')->implies('${python:Depends}')) {
+            $python_depends{$binpkg} = 1;
+        }
+    }
+    if (%python_depends) {
+        if ($seen_python_helper == -1) {
+            $seen_python_helper = $bdepends_noarch->implies('python-support');
+        }
+        if (not $seen_python_helper) {
+            tag 'python-depends-but-no-python-helper', sort(keys %python_depends);
+        }
+    }
+}
+if ($seen_dh and $seen_python3_helper != 1) {
+    my %python3_depends = ();
+    for my $binpkg (keys %$pkgs) {
+        if ($info->binary_relation($binpkg, 'all')->implies('${python3:Depends}')) {
+            $python3_depends{$binpkg} = 1;
+        }
+    }
+    if (%python3_depends and not $seen_python3_helper) {
+        tag 'python3-depends-but-no-python3-helper', sort(keys %python3_depends);
+    }
+}
+
 }
 
 1;
diff --git a/checks/debhelper.desc b/checks/debhelper.desc
--- a/checks/debhelper.desc
+++ b/checks/debhelper.desc
@@ -288,3 +288,22 @@
 Info: The package build-depends on cdbs, but does not include any cdbs
  files in <tt>debian/rules</tt>.
 
+Tag: python-depends-but-no-python-helper
+Severity: serious
+Certainty: possible
+Experimental: yes
+Info: The source package declares a dependency on ${python:Depends} in the
+ given binary package's debian/control entry.  However, debian/rules doesn't
+ call any helper that would generate this substitution variable.
+ .
+ When using debhelper compatibility level below 9, dh will call dh_pysupport by
+ default if it's installed, but the build dependency on python-support is still
+ necessary.
+
+Tag: python3-depends-but-no-python3-helper
+Severity: serious
+Certainty: possible
+Experimental: yes
+Info: The source package declares a dependency on ${python3:Depends} in the
+ given binary package's debian/control entry.  However, debian/rules doesn't
+ call any helper that would generate this substitution variable.