Avoid setting $FZF_DEFAULT_COMMAND

So that it's not propagated to the child processes and affect the
behavior of fzf started by them.

fzf 0.41.0 or above is required as it fixed the issue where
'become' process is not given a proper tty device.

Close #3299

2 files changed, 35 insertions, 38 deletions

diff --git a/ADVANCED.md b/ADVANCED.md
index eb3e809d..661bac11 100644
--- a/ADVANCED.md
+++ b/ADVANCED.md
@@ -1,8 +1,8 @@
 Advanced fzf examples
 ======================
 
-* *Last update: 2023/02/15*
-* *Requires fzf 0.38.0 or above*
+* *Last update: 2023/05/26*
+* *Requires fzf 0.41.0 or above*
 
 ---
 
@@ -336,9 +336,8 @@ projects, and it will free up memory as you narrow down the results.
 # 3. Open the file in Vim
 RG_PREFIX="rg --column --line-number --no-heading --color=always --smart-case "
 INITIAL_QUERY="${*:-}"
-FZF_DEFAULT_COMMAND="$RG_PREFIX $(printf %q "$INITIAL_QUERY")" \
-fzf --ansi \
-    --disabled --query "$INITIAL_QUERY" \
+: | fzf --ansi --disabled --query "$INITIAL_QUERY" \
+    --bind "start:reload:$RG_PREFIX {q}" \
     --bind "change:reload:sleep 0.1; $RG_PREFIX {q} || true" \
     --delimiter : \
     --preview 'bat --color=always {1} --highlight-line {2}' \
@@ -348,11 +347,11 @@ fzf --ansi \
 
 ![image](https://user-images.githubusercontent.com/700826/113684212-f9ff0a00-96ff-11eb-8737-7bb571d320cc.png)
 
-- Instead of starting fzf in `rg ... | fzf` form, we start fzf without an
-  explicit input, but with a custom `FZF_DEFAULT_COMMAND` variable. This way
-  fzf can kill the initial Ripgrep process it starts with the initial query.
-  Otherwise, the initial Ripgrep process will keep consuming system resources
-  even after `reload` is triggered.
+- Instead of starting fzf in the usual `rg ... | fzf` form, we start fzf with
+  an empty input (`: | fzf`), then we make it start the initial Ripgrep
+  process immediately via `start:reload` binding. This way, fzf owns the
+  initial Ripgrep process so it can kill it on the next `reload`. Otherwise,
+  the process will keep running in the background.
 - Filtering is no longer a responsibility of fzf; hence `--disabled`
 - `{q}` in the reload command evaluates to the query string on fzf prompt.
 - `sleep 0.1` in the reload command is for "debouncing". This small delay will
@@ -376,12 +375,11 @@ fzf-only search mode by *"unbinding"* `reload` action from `change` event.
 # 3. Open the file in Vim
 RG_PREFIX="rg --column --line-number --no-heading --color=always --smart-case "
 INITIAL_QUERY="${*:-}"
-FZF_DEFAULT_COMMAND="$RG_PREFIX $(printf %q "$INITIAL_QUERY")" \
-fzf --ansi \
-    --color "hl:-1:underline,hl+:-1:underline:reverse" \
-    --disabled --query "$INITIAL_QUERY" \
+: | fzf --ansi --disabled --query "$INITIAL_QUERY" \
+    --bind "start:reload:$RG_PREFIX {q}" \
     --bind "change:reload:sleep 0.1; $RG_PREFIX {q} || true" \
     --bind "alt-enter:unbind(change,alt-enter)+change-prompt(2. fzf> )+enable-search+clear-query" \
+    --color "hl:-1:underline,hl+:-1:underline:reverse" \
     --prompt '1. ripgrep> ' \
     --delimiter : \
     --preview 'bat --color=always {1} --highlight-line {2}' \
@@ -421,14 +419,12 @@ CTRL-F.
 rm -f /tmp/rg-fzf-{r,f}
 RG_PREFIX="rg --column --line-number --no-heading --color=always --smart-case "
 INITIAL_QUERY="${*:-}"
-FZF_DEFAULT_COMMAND="$RG_PREFIX $(printf %q "$INITIAL_QUERY")" \
-fzf --ansi \
-    --color "hl:-1:underline,hl+:-1:underline:reverse" \
-    --disabled --query "$INITIAL_QUERY" \
+: | fzf --ansi --disabled --query "$INITIAL_QUERY" \
+    --bind "start:reload($RG_PREFIX {q})+unbind(ctrl-r)" \
     --bind "change:reload:sleep 0.1; $RG_PREFIX {q} || true" \
     --bind "ctrl-f:unbind(change,ctrl-f)+change-prompt(2. fzf> )+enable-search+rebind(ctrl-r)+transform-query(echo {q} > /tmp/rg-fzf-r; cat /tmp/rg-fzf-f)" \
     --bind "ctrl-r:unbind(ctrl-r)+change-prompt(1. ripgrep> )+disable-search+reload($RG_PREFIX {q} || true)+rebind(change,ctrl-f)+transform-query(echo {q} > /tmp/rg-fzf-f; cat /tmp/rg-fzf-r)" \
-    --bind "start:unbind(ctrl-r)" \
+    --color "hl:-1:underline,hl+:-1:underline:reverse" \
     --prompt '1. ripgrep> ' \
     --delimiter : \
     --header '╱ CTRL-R (ripgrep mode) ╱ CTRL-F (fzf mode) ╱' \
@@ -471,16 +467,17 @@ Kubernetes pods.
 
 ```bash
 pods() {
-  FZF_DEFAULT_COMMAND="kubectl get pods --all-namespaces" \
-    fzf --info=inline --layout=reverse --header-lines=1 \
-        --prompt "$(kubectl config current-context | sed 's/-context$//')> " \
-        --header $'╱ Enter (kubectl exec) ╱ CTRL-O (open log in editor) ╱ CTRL-R (reload) ╱\n\n' \
-        --bind 'ctrl-/:change-preview-window(80%,border-bottom|hidden|)' \
-        --bind 'enter:execute:kubectl exec -it --namespace {1} {2} -- bash > /dev/tty' \
-        --bind 'ctrl-o:execute:${EDITOR:-vim} <(kubectl logs --all-containers --namespace {1} {2}) > /dev/tty' \
-        --bind 'ctrl-r:reload:$FZF_DEFAULT_COMMAND' \
-        --preview-window up:follow \
-        --preview 'kubectl logs --follow --all-containers --tail=10000 --namespace {1} {2}' "$@"
+  : | command='kubectl get pods --all-namespaces' fzf \
+    --info=inline --layout=reverse --header-lines=1 \
+    --prompt "$(kubectl config current-context | sed 's/-context$//')> " \
+    --header $'╱ Enter (kubectl exec) ╱ CTRL-O (open log in editor) ╱ CTRL-R (reload) ╱\n\n' \
+    --bind 'start:reload:$command' \
+    --bind 'ctrl-r:reload:$command' \
+    --bind 'ctrl-/:change-preview-window(80%,border-bottom|hidden|)' \
+    --bind 'enter:execute:kubectl exec -it --namespace {1} {2} -- bash > /dev/tty' \
+    --bind 'ctrl-o:execute:${EDITOR:-vim} <(kubectl logs --all-containers --namespace {1} {2}) > /dev/tty' \
+    --preview-window up:follow \
+    --preview 'kubectl logs --follow --all-containers --tail=10000 --namespace {1} {2}' "$@"
 }
 ```
 
diff --git a/README.md b/README.md
index e72c3fd0..21f235e7 100644
--- a/README.md
+++ b/README.md
@@ -630,8 +630,8 @@ more details.
 #### 1. Update the list of processes by pressing CTRL-R
 
 ```sh
-FZF_DEFAULT_COMMAND='ps -ef' \
-  fzf --bind 'ctrl-r:reload(eval "$FZF_DEFAULT_COMMAND")' \
+ps -ef |
+  fzf --bind 'ctrl-r:reload(ps -ef)' \
       --header 'Press CTRL-R to reload' --header-lines=1 \
       --height=50% --layout=reverse
 ```
@@ -653,12 +653,12 @@ expression `{q}`. Also, note that we used `--disabled` option so that fzf
 doesn't perform any secondary filtering.
 
 ```sh
-INITIAL_QUERY=""
-RG_PREFIX="rg --column --line-number --no-heading --color=always --smart-case "
-FZF_DEFAULT_COMMAND="$RG_PREFIX '$INITIAL_QUERY'" \
-  fzf --bind "change:reload:$RG_PREFIX {q} || true" \
-      --ansi --disabled --query "$INITIAL_QUERY" \
-      --height=50% --layout=reverse
+: | rg_prefix='rg --column --line-number --no-heading --color=always --smart-case' \
+    fzf --bind 'start:reload:$rg_prefix ""' \
+        --bind 'change:reload:$rg_prefix {q} || true' \
+        --bind 'enter:become(vim {1} +{2})' \
+        --ansi --disabled \
+        --height=50% --layout=reverse
 ```
 
 If ripgrep doesn't find any matches, it will exit with a non-zero exit status,
@@ -666,7 +666,7 @@ and fzf will warn you about it. To suppress the warning message, we added
 `|| true` to the command, so that it always exits with 0.
 
 See ["Using fzf as interactive Ripgrep launcher"](https://github.com/junegunn/fzf/blob/master/ADVANCED.md#using-fzf-as-interactive-ripgrep-launcher)
-for a fuller example with preview window options.
+for more sophisticated examples.
 
 ### Preview window