Implement prepend and append modes for all our normal build scriptlets

Allows %build, %install, %check, %clean and %generate_depends to be
augmented arbitrary number of times by appending or prepending to them.
The main use-case is to support automatic population of these sections
(declarative builds) while still allowing packagers to easily tweak them,
but could also be useful for complicated conditional specs and such.

%prep is missing from the list because it's way too special at the
moment, it'll gain this capability when rpm-software-management#2205 is fixed.

Related: rpm-software-management#1087

build/parseSimpleScript.c

@@ -12,17 +12,64 @@
 int parseSimpleScript(rpmSpec spec, const char * name, StringBuf *sbp)
 {
  int res = PART_ERROR;
-
- if (*sbp != NULL) {
+ poptContext optCon = NULL;
+ int argc;
+ const char **argv = NULL;
+ StringBuf *target = sbp;
+ StringBuf buf = NULL;
+ int rc, append = 0, prepend = 0;
+ struct poptOption optionsTable[] = {
+ { NULL, 'a', POPT_ARG_NONE, &append, 'a', NULL, NULL },
+ { NULL, 'p', POPT_ARG_NONE, &prepend, 'p', NULL, NULL },
+ { NULL, 0, 0, NULL, 0, NULL, NULL }
+ };
+
+
+ if ((rc = poptParseArgvString(spec->line, &argc, &argv))) {
+ rpmlog(RPMLOG_ERR, _("line %d: Error parsing script: %s: %s\n"),
+ spec->lineNum, spec->line, poptStrerror(rc));
+ goto exit;
+ }
+
+ optCon = poptGetContext(NULL, argc, argv, optionsTable, 0);
+ while ((rc = poptGetNextOpt(optCon)) > 0) {};
+ if (rc < -1) {
+ rpmlog(RPMLOG_ERR, _("line %d: Bad %s option %s: %s\n"),
+ spec->lineNum, argv[0],
+ poptBadOption(optCon, POPT_BADOPTION_NOALIAS),
+ poptStrerror(rc));
+ goto exit;
+ }
+
+ if (*sbp != NULL && append == 0 && prepend == 0) {
  rpmlog(RPMLOG_ERR, _("line %d: second %s\n"),
  spec->lineNum, name);
  goto exit;
  }
-
- /* There are no options to %build, %install, %check, or %clean */
- res = parseLines(spec, STRIP_NOTHING, NULL, sbp);
-
+
+ if (append && prepend) {
+ rpmlog(RPMLOG_ERR, _("line %d: append and prepend specified: %s\n"),
+ spec->lineNum, spec->line);
+ goto exit;
+ }
+
+ /* Prepend is only special if the section already exists */
+ if (prepend && *sbp) {
+ buf = newStringBuf();
+ target = &buf;
+ }
+
+ res = parseLines(spec, STRIP_NOTHING, NULL, target);
+
+ if (buf) {
+ appendStringBuf(buf, getStringBuf(*sbp));
+ freeStringBuf(*sbp);
+ *sbp = buf;
+ }
+
 exit:
+ free(argv);
+ poptFreeContext(optCon);
 
  return res;
 }

docs/manual/spec.md

@@ -461,6 +461,13 @@ when name is omitted, the description refers to the main package.
 Package build is divided into multiple separate steps, each executed
 in a separate shell.
 
+Only one of each section can be present in a spec, but all build scriptlets
+except for `%prep` accept options `-a` and `-p`, for append and prepend mode.
+Append and prepend append or prepend lines to the section in the order they
+appear in the spec. Both append and prepend can be used multiple times and
+without other restrictions, but a section without either mode can only
+appear first (eg `%build` cannot follow `%build -p`).
+
 ### %prep
 
 %prep prepares the sources for building. This is where sources are

tests/data/SPECS/append.spec

@@ -0,0 +1,33 @@
+Name: append
+Version: 1.0
+Release: 1
+BuildArch: noarch
+Summary: Testing scriptlet append/prepend
+License: GPL
+
+%description
+%{summary}
+
+%build
+echo BBB >> out
+
+%build -a
+echo CCC >> out
+
+%build -p
+echo AAA >> out
+
+%build -a
+echo DDD >> out
+
+%build -p
+echo 000 >> out
+
+%install -a
+cp out ${RPM_BUILD_ROOT}/opt/
+
+%install -p
+mkdir -p ${RPM_BUILD_ROOT}/opt/
+
+%files
+/opt/out

tests/rpmbuild.at

@@ -152,6 +152,24 @@ runroot rpmbuild -bs /data/SPECS/specstep.spec 2>&1|grep ^Executing|cut -d: -f1
 [])
 RPMTEST_CLEANUP
 
+AT_SETUP([rpmbuild script prepend/append])
+AT_KEYWORDS([build])
+RPMDB_INIT
+RPMTEST_CHECK([
+runroot rpmbuild -bb --quiet ${RPMDATA}/SPECS/append.spec
+runroot_other rpm2cpio /build/RPMS/noarch/append-1.0-1.noarch.rpm | cpio -id 2> /dev/null
+cat opt/out
+],
+[0],
+[000
+AAA
+BBB
+CCC
+DDD
+],
+[])
+RPMTEST_CLEANUP
+
 AT_SETUP([rpmbuild -ba autosetup])
 AT_KEYWORDS([build])
 RPMDB_INIT