Add --force-bad-version to allow installing packages with bogus versions

This allows to install old packages with such versions, to ease
debugging, testing, etc.

debian/changelog

@@ -30,6 +30,8 @@ dpkg (1.16.1) UNRELEASED; urgency=low
     by including the architecture in the debian-split member of a split
     package and using underscores to separate filename parts.
   * Support conffiles with spaces when diffing them. Closes: #147583
+  * Allow installing packages with bogus versions with new
+    --force-bad-version.
 
   [ Updated man page translations ]
   * German (Helge Kreutzmann).

man/dpkg.1

@@ -465,6 +465,9 @@ losing data, use with care.\fP
 \fBarchitecture\fP:
 Process even packages with wrong or no architecture.
 
+\fBbad\-version\fP:
+Process even packages with wrong versions.
+
 \fBbad\-path\fP:
 \fBPATH\fP is missing important programs, so problems are likely.
 

src/main.c

@@ -187,6 +187,7 @@ int fc_conff_old=0, fc_conff_def=0;
 int fc_conff_ask = 0;
 int fc_unsafe_io = 0;
 int fc_badverify = 0;
+int fc_badversion = 0;
 
 int errabort = 50;
 static const char *admindir = ADMINDIR;
@@ -229,6 +230,8 @@ static const struct forceinfo {
     ' ', N_("PATH is missing important programs, problems likely") },
   { "bad-verify",          &fc_badverify,
     ' ', N_("Install a package even if it fails authenticity check") },
+  { "bad-version",         &fc_badversion,
+    ' ', N_("Process even packages with wrong versions") },
   { "overwrite",           &fc_overwrite,
     ' ', N_("Overwrite a file from one package with another") },
   { "overwrite-diverted",  &fc_overwritediverted,

src/main.h

@@ -132,6 +132,7 @@ extern int fc_nonroot, fc_overwritedir, fc_conff_new, fc_conff_miss;
 extern int fc_conff_old, fc_conff_def;
 extern int fc_conff_ask;
 extern int fc_badverify;
+extern int fc_badversion;
 extern int fc_unsafe_io;
 
 extern bool abort_processing;

src/processarc.c

@@ -421,8 +421,8 @@ void process_archive(const char *filename) {
 
   strcpy(cidirrest,CONTROLFILE);
 
-  parsedb(cidir, pdb_recordavailable | pdb_rejectstatus | pdb_ignorefiles,
-          &pkg);
+  parsedb(cidir, pdb_recordavailable | pdb_rejectstatus | pdb_ignorefiles |
+          fc_badversion ? pdb_lax_version_parser : 0, &pkg);
   if (!pkg->files) {
     pkg->files= nfmalloc(sizeof(struct filedetails));
     pkg->files->next = NULL;