Remove useless branches in a repository

The purpose of `clear-local` command is to remove branches that have
unexisting upstreams. And it starts asking for deleting branches if they
aren't merged. But this behavior is overengineering and, usually, all
these branches have to be removed.

As the solution, the `prune-repository` command is introduced which
makes safe automatic cleanup of all useless branches. Also, it doesn't
try to save your working state by using pipes. This is because that if
`prune-repository` is executed, then the repository should not have
uncommitted changes, otherwise, it will fail.

docs/commands.md

@@ -18,7 +18,7 @@ There are commands used in various situations such as
     clone-repository     Clones a repository and configures it.
     init-repository      Initializes a new repository and configures it.
     acquire-repository   Configures current repository.
-    clear-local          Removes obsolete local branches.
+    prune-repository     Removes useless local branches.
 
  manage a personal work
     start-work           Creates a new branch.
@@ -118,29 +118,6 @@ git diff --cached --check
 git commit --amend
 ```
 
-# `clear-local`
-
-```bash
-usage: git elegant clear-local
-```
-
-Identifies local branches for which remote branches were removed. Then, it
-removes them by invoking `git branch -d`. If there are unmerged branches, you
-have to choose either batch or one-by-one deletion procedure using
-`git branch -D`.
-
-Prior to the execution, a current state is saved (a branch with modifications).
-After the successful accepting a work, the state will be restored. In the case
-of a failure, you need to go to the desired branch and apply a stash if needed.
-
-Approximate commands flow is
-```bash
-==>> git elegant clear-local
-git branch -d task-24
-git branch -d 2349
-git branch -D task-1
-```
-
 # `clone-repository`
 
 ```bash
@@ -243,6 +220,33 @@ Approximate commands flow is
 git rebase --interactive @~5
 ```
 
+# `prune-repository`
+
+```bash
+usage: git elegant prune-repository
+```
+
+Identifies useless branches within the current repository and removes them. A
+branch is useless if it either has configured an unavailable upstream branch (1)
+or does not have new commits comparing to `master` branch (2).
+
+1 - Usually, a local branch has this state when an appropriate remote branch was
+merged to a remote target branch and was removed. Since these manipulations were
+made on server side, the local branch is still present, but useless.
+
+2 - This kind of branches appears when a branch is created for some purposes but
+does not have any commits nowadays. So, it is useless.
+
+Approximate commands flow is
+```bash
+==>> git elegant prune-repository
+git checkout master
+git fetch --all
+git branch --delete --force task-24
+git branch --delete --force 2349
+git branch --delete --force task-1
+```
+
 # `release-work`
 
 ```bash

libexec/git-elegant

@@ -40,40 +40,6 @@ _error-if-empty() {
     fi
 }
 
-__loop_ask() {
-    local c="$1"; shift
-    local m="$1"; shift
-    [ -z "$1" ] && return 0
-    for i in $@; do
-        question-text "$m [$i] (y/n):"
-        read answer
-        if [[ "${answer}" == "y" ]]; then
-            eval "$c $i"
-        fi
-    done
-}
-
-__loop() {
-    local c="$1"; shift
-    [ -z "$1" ] && return 0
-    for i in $@; do
-        eval "$c $i"
-    done
-}
-
-__batch() {
-    local MM="$1"; shift
-    local AM="$1"; shift
-    local CM="$1"; shift
-    question-text "$MM (y/n): "
-    read answer
-    if [[ "${answer}" == "y" ]]; then
-        __loop "$CM" $@
-    else
-        __loop_ask "$CM" "$AM" $@
-    fi
-}
-
 branch-from-remote-reference() {
     # usage: branch-from-remote-reference <full reference name>
     echo ${1} | sed "s|^[a-zA-Z0-9_-]*/||g"
@@ -109,7 +75,7 @@ There are commands used in various situations such as
 $(--print-command-in-usage clone-repository)
 $(--print-command-in-usage init-repository)
 $(--print-command-in-usage acquire-repository)
-$(--print-command-in-usage clear-local)
+$(--print-command-in-usage prune-repository)
 
  manage a personal work
 $(--print-command-in-usage start-work)

libexec/git-elegant-prune-repository

@@ -0,0 +1,59 @@
+#!/usr/bin/env bash
+set -e
+
+command-purpose() {
+    cat <<MESSAGE
+Removes useless local branches.
+MESSAGE
+}
+
+command-synopsis() {
+    cat <<MESSAGE
+usage: git elegant prune-repository
+MESSAGE
+}
+
+command-description() {
+    cat<<MESSAGE
+Identifies useless branches within the current repository and removes them. A
+branch is useless if it either has configured an unavailable upstream branch (1)
+or does not have new commits comparing to \`master\` branch (2).
+
+1 - Usually, a local branch has this state when an appropriate remote branch was
+merged to a remote target branch and was removed. Since these manipulations were
+made on server side, the local branch is still present, but useless.
+
+2 - This kind of branches appears when a branch is created for some purposes but
+does not have any commits nowadays. So, it is useless.
+
+Approximate commands flow is
+\`\`\`bash
+==>> git elegant prune-repository
+git checkout master
+git fetch --all
+git branch --delete --force task-24
+git branch --delete --force 2349
+git branch --delete --force task-1
+\`\`\`
+MESSAGE
+}
+
+default() {
+    git-verbose checkout ${MASTER}
+    git-verbose fetch --all
+    for branch in $(git for-each-ref --format "%(refname:short)" refs/heads/**); do
+        if [[ ${branch} == ${MASTER} ]]; then continue; fi
+        if [[ -n $(git config --get branch.${branch}.merge) ]]; then
+            if git rev-parse --abbrev-ref ${branch}@{upstream} >/dev/null  2>&1; then
+                # the branch has existing upstream; keep it
+                continue
+            fi
+        else
+            if [[ ! $(git merge-base ${MASTER} ${branch}) == $(git rev-parse ${branch}) ]]; then
+                # the branch has new commits; keep it
+                continue
+            fi
+        fi
+        git-verbose branch --delete --force ${branch}
+    done
+}

tests/git-elegant-prune-repository.bats

@@ -0,0 +1,50 @@
+#!/usr/bin/env bats -ex
+
+load addons-common
+load addons-read
+load addons-fake
+load addons-repo
+
+setup() {
+    repo-new
+}
+
+teardown() {
+    fake-clean
+    repo-clean
+}
+
+@test "'prune-repository': a branch is removed when it doesn't have an upstream and new commits" {
+    repo "git checkout -b equal-to-master"
+    repo "git checkout master"
+    check git-elegant prune-repository
+    [[ ${status} -eq 0 ]]
+    [[ ${lines[@]} =~ "git branch --delete --force equal-to-master" ]]
+}
+
+@test "'prune-repository': a branch is alive when it doesn't have an upstream and has a new commit" {
+    repo "git checkout -b commit"
+    repo-commit-file "commit"
+    check git-elegant prune-repository
+    [[ ${status} -eq 0 ]]
+    [[ ! ${lines[@]} =~ "git branch --delete --force commit" ]]
+}
+
+@test "'prune-repository': a branch is removed when it has a gone upstream" {
+    repo "git checkout -b upstream"
+    repo "git checkout master"
+    fake-pass "git config --get branch.upstream.merge" "upstream"
+    fake-fail "git rev-parse --abbrev-ref upstream@{upstream}"
+    check git-elegant prune-repository
+    [[ ${status} -eq 0 ]]
+    [[ ${lines[@]} =~ "git branch --delete --force upstream" ]]
+}
+
+@test "'prune-repository': a branch is alive when it has an active upstream" {
+    repo "git checkout -b upstream"
+    fake-pass "git config --get branch.upstream.merge" "upstream"
+    fake-pass "git rev-parse --abbrev-ref upstream@{upstream}"
+    check git-elegant prune-repository
+    [[ ${status} -eq 0 ]]
+    [[ ! ${lines[@]} =~ "git branch --delete --force upstream" ]]
+}

tests/git-elegant-show-commands.bats

@@ -18,7 +18,7 @@ teardown() {
         "deliver-work"
         "accept-work"
         "obtain-work"
-        "clear-local"
+        "prune-repository"
         "show-commands"
         "amend-work"
         "show-release-notes"