[PATCH v2] Make sure git repos are usable inside buildchroot

[Jan Kiszka <jan.kiszka@siemens.com>]

From: Jan Kiszka <jan.kiszka@siemens.com>

bitbake clones git repos into the package workdir in shared mode. This
creates an alternates link to the original download folder. However,
that path is invalid inside buildchroot. This disturbs package builds
which try to derive information from the git repo, such as tags or the
delta to the last release.

Bind-mount the downloads folder and patch the alternates file to restore
the git repo access inside buildchroot.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
---

Changes in v2:
 - set stamp-extra-info properly

 meta/classes/dpkg-base.bbclass                   | 11 +++++++++++
 meta/recipes-devtools/buildchroot/buildchroot.bb |  1 +
 2 files changed, 12 insertions(+)

diff --git a/meta/classes/dpkg-base.bbclass b/meta/classes/dpkg-base.bbclass
index a4bdf16..98f25b7 100644
--- a/meta/classes/dpkg-base.bbclass
+++ b/meta/classes/dpkg-base.bbclass
@@ -1,6 +1,16 @@
 # This software is a part of ISAR.
 # Copyright (C) 2017 Siemens AG
 
+do_adjust_git() {
+    if [ -f ${WORKDIR}/${S}/.git/objects/info/alternates ]; then
+        sed -i ${WORKDIR}/${S}/.git/objects/info/alternates \
+            -e 's|${DL_DIR}|/downloads|'
+    fi
+}
+
+addtask adjust_git after do_unpack before do_build
+do_adjust_git[stamp-extra-info] = "${DISTRO}-${DISTRO_ARCH}"
+
 # Add dependency from buildchroot creation
 do_build[depends] = "buildchroot:do_build"
 
@@ -30,6 +40,7 @@ do_build() {
     sudo flock ${MOUNT_LOCKFILE} -c ' \
         if ! grep -q ${BUILDCHROOT_DIR}/isar-apt /proc/mounts; then \
             mount --bind ${DEPLOY_DIR_APT}/${DISTRO} ${BUILDCHROOT_DIR}/isar-apt; \
+            mount --bind ${DL_DIR} ${BUILDCHROOT_DIR}/downloads; \
             mount -t devtmpfs -o mode=0755,nosuid devtmpfs ${BUILDCHROOT_DIR}/dev; \
             mount -t proc none ${BUILDCHROOT_DIR}/proc; \
         fi'
diff --git a/meta/recipes-devtools/buildchroot/buildchroot.bb b/meta/recipes-devtools/buildchroot/buildchroot.bb
index 504d798..520daf9 100644
--- a/meta/recipes-devtools/buildchroot/buildchroot.bb
+++ b/meta/recipes-devtools/buildchroot/buildchroot.bb
@@ -40,6 +40,7 @@ do_build() {
     # re-building a clean image:
     sudo rm -rf ${BUILDCHROOT_DIR}
     mkdir -p ${BUILDCHROOT_DIR}/isar-apt
+    mkdir -p ${BUILDCHROOT_DIR}/downloads
     mkdir -p ${BUILDCHROOT_DIR}/dev
     mkdir -p ${BUILDCHROOT_DIR}/proc
     mkdir -p ${BUILDCHROOT_DIR}/sys