Improve version_string.sh script

Full --help usage message
Better error handling and reporting
Only considers tags that look like version numbers
Does not create and delete local "START" tag
Lots of options, including --ignore-untracked and --unmodified
Suitable for use in Batphone repository

Makefile.in

@@ -82,7 +82,7 @@ sqlite-amalgamation-3070900/sqlite3.o:	sqlite-amalgamation-3070900/sqlite3.c
 
 version.o: *.h *.c version_string.sh
 	@echo CC version_servald.c
-	@V=`./version_string.sh` \
+	@V=`./version_string.sh --ignore-untracked` \
 	 && $(CC) -c version_servald.c -o $@ -DSERVALD_VERSION="\"$$V\""
 
 %.o:	%.c

version_string.sh

@@ -17,48 +17,121 @@
 # along with this program; if not, write to the Free Software
 # Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 
+usage() {
+   echo "Usage: ${0##*/} [options]"'
+
+Produces a version string for the HEAD of the Git repository in the current
+working directory.  The version string has the following form:
+
+   D.D[extra] [ -N-gXXXXXXX ] [ +USER-YYYYMMDDHHMMSS ]
+
+Where:
+   D.D[extra]              is the most recent version tag prior to HEAD, eg,
+                           0.91.RC2; if there is no tag, then a default tag
+                           of "START" is used to represent the first commit in
+                           the repository
+   -N-gXXXXXXX             is appended if there are any commits since the
+                           version tag; N is the number of commits, XXXXXXX is
+                           the abbreviated Git commit Id
+   +USER-YYYYMMDDHHMMSS    is appended if there are any local modifications;
+                           USER is the email address of the user who owns the
+                           repository, YYYYMMDDHHMMSS is the current local time
+
+Options:
+   --help               Show this message
+   --ignore-untracked   Do not count any untracked local changes to determine
+                        whether the version is locally modified
+   --unmodified         Fail with an error if there are any local modifications
+                        instead of appending the +USER-YYYYMMDDHHMMSS suffix
+   --no-default-tag     If no version tag is found, then fail with an error
+                        instead of producing a version relative to the default
+                        "START" tag
+   --default-tag=TAG    Use "TAG" instead of "START" for the default tag if no
+                        version tag is found
+   --repository=PATH    Produce a version string for the repository in the
+                        directory at PATH instead of the current working
+                        directory
+'
+}
+
 set -e
 
+allow_modified=true
+untracked_files=normal
+default_tag="START"
+repo_path=.
+version_tag_glob='[0-9].[0-9]*'
+
+while [ $# -gt 0 ]; do
+   case "$1" in
+   --help) usage; exit 0;;
+   --ignore-untracked) untracked_files=no; shift;;
+   --unmodified) allow_modified=false; shift;;
+   --no-default-tag) default_tag=; shift;;
+   --default-tag=*) default_tag="${1#*=}"; shift;;
+   --repository=*) repo_path="${1#*=}"; shift;;
+   *)
+      echo "$0: unrecognised option: $1" >&2
+      echo "Try \`${0##*/} --help' for more information." >&2
+      exit 1
+      ;;
+   esac
+done
+
+cd "$repo_path" >/dev/null
+
 get_author_label() {
    # See git-commit-tree(1) for the semantics of working out the author's email
    # address when committing.
    local email
-   email="${GIT_AUTHOR_EMAIL:-${GIT_COMMITTER_EMAIL:-${EMAIL:-$(git config --get user.email || true)}}}"
+   email="${GIT_AUTHOR_EMAIL:-${GIT_COMMITTER_EMAIL:-${EMAIL:-$(git config --get user.email 2>/dev/null || true)}}}"
    # Serval Project email addresses get special treatment, to reduce day-to-day
    # version string verbosity.
    case "$email" in
-   '') author_label="${LOGNAME?}@$(hostname --fqdn)";;
+   '') author_label="${LOGNAME?}@$(hostname --fqdn)";; #" <-- fix Vim syntax highlighting
-   *@servalproject.org) author_label="${email%@*}";;
+   *@servalproject.org) author_label="${email%@*}";; #" <-- fix Vim syntax highlighting
    *) author_label="$email";;
    esac
 }
 
+# The --dirty option to "git describe" always counts untracked changes as dirt.
+# In order to implement the --ignore-untracked and --unmodified options, use the
+# "git status" command to detect local modifications.
 dirty=
-dirtyfiles=$(git status --short --untracked-files=no)
+if [ $(git status --porcelain --untracked-files=$untracked_files 2>/dev/null | wc -l) -ne 0 ]; then
-if [ -n "$dirtyfiles" ]; then
    get_author_label
    dirty="+$author_label-$(date '+%Y%m%d%H%M%S')"
 fi
-
+if [ -n "$dirty" ] && ! $allow_modified; then
-if ! git describe "${dirty:+--dirty=$dirty}" 2>/dev/null; then
+   echo "$0: cannot form version string for repository: $(pwd -P)" >&2
-   original_commit=$(git rev-list --reverse --max-parents=0 --abbrev-commit HEAD 2>/dev/null | head -n 1)
+   echo "$0: repository has local modifications" >&2
-   if [ -z "$original_commit" ]; then
+   exit 3
-      original_commit=$(git rev-list --reverse --abbrev-commit HEAD | head -n 1)
-   fi
-   if [ -z "$original_commit" ]; then
-      echo "$0: original commit unknown" >&2
-      exit 1
-   fi
-   existing_start_tag="$(git rev-list --no-walk START 2>/dev/null | true)"
-   if [ -n "$(git tag --list START 2>/dev/null)" -a "$existing_start_tag" != "$original_commit" ]; then
-      echo "$0: tag 'START' is already in use" >&2
-      exit 1
-   fi
-   if [ -z "$existing_start_tag" ]; then
-      git tag START $original_commit
-   fi
-   git describe --dirty="$dirty" --tags
-   if [ -z "$existing_start_tag" ]; then
-      git tag -d START >/dev/null
-   fi
 fi
+
+# Use the "git describe" command to form the version string.
+if error="$(git describe --match="$version_tag_glob" "${dirty:+--dirty=$dirty}" HEAD 2>&1 1>&5)" 5>&1; then
+   exit 0
+fi
+
+# If the describe failed because there are no annotated version tags in the
+# ancestry, and we know a default tag, then we synthesize the version string
+# ourselves.
+case "$error" in
+*[Nn]'o names found'* | \
+*[Nn]'o tags can describe'* | \
+*[Cc]'annot describe'* )
+   if [ -n "$default_tag" ]; then
+      commit=$(git rev-list --abbrev-commit --max-count 1 HEAD)
+      count=$(git rev-list HEAD | wc -l)
+      count=$((count-1))
+      version="$default_tag-$count-g$commit"
+      [ $(git status --short --untracked-files=normal | wc -l) -ne 0 ] && version="$version$dirty"
+      echo "$version"
+      exit 0
+   fi
+   ;;
+esac
+
+echo "$0: cannot form version string for repository: $(pwd -P)" >&2
+echo "$0: git returned: ${error#fatal: }" >&2
+exit 2