gradle: extract simple task names from subproject tasks (#5704)

Currently, only tasks with complete subproject specifier are added to
.gradletasknamecache. Gradle commands can be called for all (sub-)projects
they are defined for, using their name as defined in the subproject, here
called "simple" task names. One example is "gradle clean".

This patch adds support for parsing out those "simple" task names from the list
of fully specified task names. The .gradletasknamecache file will contain
both the fully specified names, and the "simple" names for your autocompletion
pleasure.

plugins/gradle/gradle.plugin.zsh

@@ -61,7 +61,7 @@ _gradle_does_task_list_need_generating () {
 }
 
 ##############
-# Parse the tasks from `gradle(w) tasks --all` into .gradletasknamecache
+# Parse the tasks from `gradle(w) tasks --all` and return them to the calling function.
 # All lines in the output from gradle(w) that are between /^-+$/ and /^\s*$/
 # are considered to be tasks. If and when gradle adds support for listing tasks
 # for programmatic parsing, this method can be deprecated.
@@ -76,7 +76,7 @@ _gradle_parse_tasks () {
       task_name_buffer=""
     elif [[ $line =~ ^\s*$ ]]; then
       if [[ "$lines_might_be_tasks" = true ]]; then
-        # If a newline is found, send the buffer to .gradletasknamecache
+        # If a newline is found, echo the buffer to the calling function
         while read -r task; do
           echo $task | awk '/[a-zA-Z0-9:-]+/ {print $1}'
         done <<< "$task_name_buffer"
@@ -90,6 +90,25 @@ _gradle_parse_tasks () {
   done <<< "$1"
 }
 
+
+##############
+# Gradle tasks from subprojects are allowed to be executed without specifying
+# the subproject; that task will then be called on all subprojects.
+# gradle(w) tasks --all only lists tasks per subproject, but when autocompleting
+# we often want to be able to run a specific task on all subprojects, e.g.
+# "gradle clean".
+# This function uses the list of tasks from "gradle tasks --all", and for each
+# line grabs everything after the last ":" and combines that output with the original
+# output. The combined list is returned as the result of this function.
+##############
+_gradle_parse_and_extract_tasks () {
+  # All tasks
+  tasks=$(_gradle_parse_tasks "$1")
+  # Task name without sub project(s) prefix
+  simple_tasks=$(echo $tasks | awk 'BEGIN { FS = ":" } { print $NF }')
+  echo "$tasks\n$simple_tasks"
+}
+
 ##############################################################################
 # Discover the gradle tasks by running "gradle tasks --all"
 ############################################################################
@@ -97,7 +116,7 @@ _gradle_tasks () {
   if [[ -f build.gradle ]]; then
     _gradle_arguments
     if _gradle_does_task_list_need_generating; then
-      _gradle_parse_tasks "$(gradle tasks --all)" > .gradletasknamecache
+      _gradle_parse_and_extract_tasks "$(gradle tasks --all)" > .gradletasknamecache
     fi
     compadd -X "==== Gradle Tasks ====" $(cat .gradletasknamecache)
   fi
@@ -107,7 +126,7 @@ _gradlew_tasks () {
   if [[ -f build.gradle ]]; then
     _gradle_arguments
     if _gradle_does_task_list_need_generating; then
-      _gradle_parse_tasks "$(./gradlew tasks --all)" > .gradletasknamecache
+      _gradle_parse_and_extract_tasks "$(./gradlew tasks --all)" > .gradletasknamecache
     fi
     compadd -X "==== Gradlew Tasks ====" $(cat .gradletasknamecache)
   fi