PoC: Add native support for vpath-style builds outside the source tree

NOT FOR MERGING YET, proof of concept state.

Add a new %setup switch -s to indicate building in a directory outside
the source directory, known as vpath build in some circles. Add a new
%{sourcesubdir} macro which by default equals %{buildsubdir}, but
when -s is used, we create and switch to a separate directory after
unpacking.

A one gotcha here is that special %doc and %license has traditionally
worked for both built and pre-existing content. With build and source trees
separated, both cannot work. As special %doc/%license is mostly used for
things like README's and COPYING which come as part of the source, we
define %doc on vpath builds to mean source directory, and assume built
content has its own means of installing (eg make install-doc).

Another potential issue is that we redefine %_configure to an absolute
path in the sourcesubdir, this would break some unusual cases where
%configure is used to invoke a configure-script outside the project
top directory. It's mainly redefined here to make testing -s on an
autotools project easy, a final implementation might do something else.

build/files.c

@@ -2389,7 +2389,7 @@ static void processSpecialDir(rpmSpec spec, Package pkg, FileList fl,
     char *mkdocdir = rpmExpand("%{__mkdir_p} $", sdenv, NULL);
     StringBuf docScript = newStringBuf();
     int count = sd->entriesCount;
-    char *basepath = rpmGenPath(spec->rootDir, "%{_builddir}", "%{?buildsubdir}");
+    char *basepath = rpmGenPath(spec->rootDir, "%{_builddir}", "%{?sourcesubdir}");
     ARGV_t *files = xmalloc(sizeof(*files) * count);
     int i, j;
 

build/parsePrep.c

@@ -170,7 +170,7 @@ void doSetupMacro(rpmMacroBuf mb, rpmMacroEntry me, ARGV_t margs, size_t *parsed
     int xx;
     uint32_t num;
     int leaveDirs = 0, skipDefaultAction = 0;
-    int createDir = 0, quietly = 0, autoPath = 0;
+    int createDir = 0, quietly = 0, autoPath = 0, sourceDir = 0;
     char * dirName = NULL;
     struct poptOption optionsTable[] = {
 	    { NULL, 'a', POPT_ARG_STRING, NULL, 'a',	NULL, NULL},
@@ -181,6 +181,7 @@ void doSetupMacro(rpmMacroBuf mb, rpmMacroEntry me, ARGV_t margs, size_t *parsed
 	    { NULL, 'n', POPT_ARG_STRING, &dirName, 0,	NULL, NULL},
 	    { NULL, 'T', 0, &skipDefaultAction, 0,	NULL, NULL},
 	    { NULL, 'q', 0, &quietly, 0,		NULL, NULL},
+	    { NULL, 's', 0, &sourceDir, 0,		NULL, NULL},
 	    { 0, 0, 0, 0, 0,	NULL, NULL}
     };
 
@@ -227,12 +228,14 @@ void doSetupMacro(rpmMacroBuf mb, rpmMacroEntry me, ARGV_t margs, size_t *parsed
 
     if (dirName) {
 	rpmPushMacro(spec->macros, "buildsubdir", NULL, dirName, RMIL_SPEC);
+	rpmPushMacro(spec->macros, "sourcesubdir", NULL, dirName, RMIL_SPEC);
     } else {
 	char * buildSubdir = NULL;
 	rasprintf(&buildSubdir, "%s-%s",
 		  headerGetString(spec->packages->header, RPMTAG_NAME),
 		  headerGetString(spec->packages->header, RPMTAG_VERSION));
 	rpmPushMacro(spec->macros, "buildsubdir", NULL, buildSubdir, RMIL_SPEC);
+	rpmPushMacro(spec->macros, "sourcesubdir", NULL, buildSubdir, RMIL_SPEC);
 	free(buildSubdir);
     }
 
@@ -271,6 +274,19 @@ void doSetupMacro(rpmMacroBuf mb, rpmMacroEntry me, ARGV_t margs, size_t *parsed
 	free(chptr);
     }
 
+    /* if using a separate build/source dirs, set it up now */
+    if (sourceDir) {
+	char *bsub = rpmExpand("%{_target_platform}", NULL);
+	char *ssub = rpmExpand("%{buildsubdir}", NULL);
+	rpmPushMacro(spec->macros, "buildsubdir", NULL, bsub, RMIL_SPEC);
+	rpmPushMacro(spec->macros, "sourcesubdir", NULL, ssub, RMIL_SPEC);
+	buf = rpmExpand("mkdir -p '%{buildsubdir}'", NULL);
+	appendMb(mb, buf, 1);
+	free(buf);
+	free(bsub);
+	free(ssub);
+    }
+
     if (!createDir) {
 	buf = rpmExpand("cd '%{buildsubdir}'", NULL);
 	appendMb(mb, buf, 1);
@@ -290,7 +306,7 @@ void doSetupMacro(rpmMacroBuf mb, rpmMacroEntry me, ARGV_t margs, size_t *parsed
     appendMb(mb, getStringBuf(after), 0);
 
     /* Fix the permissions of the setup build tree */
-    {	char *fix = rpmExpand("%{_fixperms} .", NULL);
+    {	char *fix = rpmExpand("%{_fixperms} %{_builddir}/%{sourcesubdir}", NULL);
 	if (fix && *fix != '%') {
 	    appendMb(mb, fix, 1);
 	}

docs/manual/spec.md

@@ -510,6 +510,7 @@ can just create the directory. It accepts a number of options:
 -D          do not delete the build directory prior to unpacking (used
             when more than one source is to be unpacked with `-a` or `-b`)
 -n DIR      set the name of build directory (default is `%{name}-%{version}`)
+-s          use separate source and build directories (aka vpath build)
 -T          skip the default unpacking of the first source (used with
             `-a` or `-b`)
 -q          operate quietly

macros.in

@@ -1034,7 +1034,7 @@ Supplements:   (%{name} = %{version}-%{release} and langpacks-%{1})\
 # directory structure (--prefix, --libdir etc) and compiler flags
 # such as CFLAGS.
 #
-%_configure ./configure
+%_configure %{_builddir}/%{sourcesubdir}/configure
 %configure \
   %{set_build_flags}; \
   %{_configure} --host=%{_host} --build=%{_build} \\\
@@ -1309,8 +1309,8 @@ end
 #           	usage of git repository and per-patch commits.
 # -N		Disable automatic patch application
 # -p<num>	Use -p<num> for patch application	
-%autosetup(a:b:cCDn:TvNS:p:)\
-%setup %{-a} %{-b} %{-c} %{-C} %{-D} %{-n} %{-T} %{!-v:-q}\
+%autosetup(a:b:cCDn:TvNS:p:s)\
+%setup %{-a} %{-b} %{-c} %{-C} %{-D} %{-n} %{-T} %{!-v:-q} %{-s}\
 %{-S:%global __scm %{-S*}}\
 %{expand:%__scm_setup_%{__scm} %{!-v:-q}}\
 %{!-N:%autopatch %{-v} %{-p:-p%{-p*}}}

tests/rpmspec.at

@@ -335,7 +335,7 @@ fi
 cd 'hello-1.0'
 rm -rf '/build/BUILD/hello-1.0-PKG/SPECPARTS'
 /usr/bin/mkdir -p '/build/BUILD/hello-1.0-PKG/SPECPARTS'
-/usr/bin/chmod -Rf a+rX,u+w,g-w,o-w .
+/usr/bin/chmod -Rf a+rX,u+w,g-w,o-w /build/BUILD/hello-1.0-PKG/hello-1.0
 
 echo "Patch #0 (hello-1.0-modernize.patch):"
 /usr/bin/patch --no-backup-if-mismatch -f -p1 -b --suffix .modernize --fuzz=0 < /build/SOURCES/hello-1.0-modernize.patch