Handle empty filename completions better

Bash 4.4 hangs in an awkward way (probably outputting the literal null
char in some unexpected context) without this; I'm not sure if this is a
bug or whether it's just been tolerated behaviour until now.

7 files changed, 56 insertions, 29 deletions

diff --git a/bash/bash_completion.d/bd.bash b/bash/bash_completion.d/bd.bash
index 4b3d4a94..86146a4e 100644
--- a/bash/bash_completion.d/bd.bash
+++ b/bash/bash_completion.d/bd.bash
@@ -16,7 +16,7 @@ _bd() {
     local dirname
     for dirname in "${dirnames[@]}" ; do
         [[ $dirname == "${COMP_WORDS[COMP_CWORD]}"* ]] || continue
-        COMPREPLY=("${COMPREPLY[@]}" "$(printf %q "$dirname")")
+        COMPREPLY[${#COMPREPLY[@]}]=$(printf %q "$dirname")
     done
 }
 complete -F _bd bd
diff --git a/bash/bash_completion.d/eds.bash b/bash/bash_completion.d/eds.bash
index 0395fd4c..3829e157 100644
--- a/bash/bash_completion.d/eds.bash
+++ b/bash/bash_completion.d/eds.bash
@@ -5,6 +5,7 @@ _eds() {
     edspath=${EDSPATH:-"$HOME"/.local/bin}
     [[ -d $edspath ]] || return
     while IFS= read -rd '' executable ; do
+        [[ -n $executable ]] || continue
         COMPREPLY[${#COMPREPLY[@]}]=$executable
     done < <(
         shopt -s dotglob nullglob
@@ -15,8 +16,15 @@ _eds() {
             [[ -f $file && -x $file ]] || continue
             executables[${#executables[@]}]=${file##*/}
         done
-        ((${#executables[@]})) || exit 1
-        printf '%q\0' "${executables[@]}"
+
+        # Print quoted entries, null-delimited, if there was at least one;
+        # otherwise, just print a null character to stop this hanging in Bash
+        # 4.4
+        if ((${#executables[@]})) ; then
+            printf '%q\0' "${executables[@]}"
+        else
+            printf '\0'
+        fi
     )
 }
 complete -F _eds eds
diff --git a/bash/bash_completion.d/man.bash b/bash/bash_completion.d/man.bash
index 7456f69b..9861e9dd 100644
--- a/bash/bash_completion.d/man.bash
+++ b/bash/bash_completion.d/man.bash
@@ -19,6 +19,7 @@ _man() {
     # Read completion results from a subshell and add them to the COMPREPLY
     # array individually
     while IFS= read -rd '' page ; do
+        [[ -n $page ]] || continue
         COMPREPLY[${#COMPREPLY[@]}]=$page
     done < <(
 
@@ -51,12 +52,14 @@ _man() {
         pages=("${pages[@]%.@([glx]z|bz2|lzma|Z)}")
         pages=("${pages[@]%.[0-9]*}")
 
-        # Bail out if we ended up with no pages somehow to prevent us from
-        # printing
-        ((${#pages[@]})) || exit 1
-
-        # Print the pages array to stdout, quoted and null-delimited
-        printf '%q\0' "${pages[@]}"
+        # Print quoted entries, null-delimited, if there was at least one;
+        # otherwise, just print a null character to stop this hanging in Bash
+        # 4.4
+        if ((${#pages[@]})) ; then
+            printf '%q\0' "${pages[@]}"
+        else
+            printf '\0'
+        fi
     )
 }
 complete -F _man -o default man
diff --git a/bash/bash_completion.d/mysql.bash b/bash/bash_completion.d/mysql.bash
index f64b6f32..9755f033 100644
--- a/bash/bash_completion.d/mysql.bash
+++ b/bash/bash_completion.d/mysql.bash
@@ -12,6 +12,7 @@ _mysql() {
     # Return the names of the .cnf files sans prefix as completions
     local db
     while IFS= read -rd '' db ; do
+        [[ -n $db ]] || continue
         COMPREPLY[${#COMPREPLY[@]}]=$db
     done < <(
 
@@ -24,11 +25,14 @@ _mysql() {
         cnfs=("${cnfs[@]#"$dirname"/}")
         cnfs=("${cnfs[@]%.cnf}")
 
-        # Bail if no files to prevent empty output
-        ((${#cnfs[@]})) || exit 1
-
-        # Print the conf names, null-delimited
-        printf '%q\0' "${cnfs[@]}"
+        # Print quoted entries, null-delimited, if there was at least one;
+        # otherwise, just print a null character to stop this hanging in Bash
+        # 4.4
+        if ((${#cnfs[@]})) ; then
+            printf '%q\0' "${cnfs[@]}"
+        else
+            printf '\0'
+        fi
     )
 }
 complete -F _mysql -o default mysql
diff --git a/bash/bash_completion.d/pass.bash b/bash/bash_completion.d/pass.bash
index 28941952..feff78ae 100644
--- a/bash/bash_completion.d/pass.bash
+++ b/bash/bash_completion.d/pass.bash
@@ -15,6 +15,7 @@ _pass()
     # doesn't seem to do this properly with a null delimiter)
     local entry
     while IFS= read -rd '' entry ; do
+        [[ -n $entry ]] || continue
         COMPREPLY[${#COMPREPLY[@]}]=$entry
     done < <(
 
@@ -29,11 +30,14 @@ _pass()
         entries=("${entries[@]#"$passdir"/}")
         entries=("${entries[@]%.gpg}")
 
-        # Bail if no entries to prevent empty output
-        ((${#entries[@]})) || exit 1
-
-        # Print all the entries, null-delimited
-        printf '%q\0' "${entries[@]}"
+        # Print quoted entries, null-delimited, if there was at least one;
+        # otherwise, just print a null character to stop this hanging in Bash
+        # 4.4
+        if ((${#entries[@]})) ; then
+            printf '%q\0' "${entries[@]}"
+        else
+            printf '\0'
+        fi
     )
 }
 complete -F _pass pass
diff --git a/bash/bash_completion.d/path.bash b/bash/bash_completion.d/path.bash
index 60b36844..e0e7732d 100644
--- a/bash/bash_completion.d/path.bash
+++ b/bash/bash_completion.d/path.bash
@@ -19,6 +19,7 @@ _path() {
             insert|append|check)
                 local dirname
                 while IFS= read -rd '' dirname ; do
+                    [[ -n $dirname ]] || continue
                     COMPREPLY[${#COMPREPLY[@]}]=$dirname
                 done < <(
 
@@ -30,11 +31,14 @@ _path() {
                     dirnames=("${COMP_WORDS[COMP_CWORD]}"*/)
                     dirnames=("${dirnames[@]%/}")
 
-                    # Bail if no results to prevent empty output
-                    ((${#dirnames[@]})) || exit 1
-
-                    # Print results, quoted and null-delimited
-                    printf '%q\0' "${dirnames[@]}"
+                    # Print quoted entries, null-delimited, if there was at
+                    # least one; otherwise, just print a null character to stop
+                    # this hanging in Bash 4.4
+                    if ((${#dirnames[@]})) ; then
+                        printf '%q\0' "${dirnames[@]}"
+                    else
+                        printf '\0'
+                    fi
                 )
                 ;;
 
diff --git a/bash/bash_completion.d/sd.bash b/bash/bash_completion.d/sd.bash
index f8017591..0c59f544 100644
--- a/bash/bash_completion.d/sd.bash
+++ b/bash/bash_completion.d/sd.bash
@@ -9,6 +9,7 @@ _sd() {
 
     # Build list of matching sibiling directories
     while IFS= read -rd '' dirname ; do
+        [[ -n $dirname ]] || continue
         COMPREPLY[${#COMPREPLY[@]}]=$dirname
     done < <(
 
@@ -29,11 +30,14 @@ _sd() {
             sibs[${#sibs[@]}]=$dirname
         done
 
-        # Bail if no results to prevent empty output
-        ((${#sibs[@]})) || exit 1
-
-        # Print results, null-delimited
-        printf '%q\0' "${sibs[@]}"
+        # Print quoted sibs, null-delimited, if there was at least one;
+        # otherwise, just print a null character to stop this hanging in Bash
+        # 4.4
+        if ((${#sibs[@]})) ; then
+            printf '%q\0' "${sibs[@]}"
+        else
+            printf '\0'
+        fi
     )
 }
 complete -F _sd sd