Optimize rehash times by not running the rehash.rb script if discover…

…ed Gemfiles haven't changed

This is achieved by comparing the modification times of Gemfile manifests against their Gemfiles.

etc/rbenv.d/bundler/includes.sh

@@ -68,6 +68,81 @@ function find_bundled_executable {
     return -- 1
 }
 
+# Gets whether the heavyweight, script-based rehash operation is needed by comparing the modification times of Gemfile
+# manifests against their Gemfiles.
+function needs_rehash_script {
+
+    local -- manifest_dir=$1
+
+    if [[ ! -f "${manifest_dir}/manifest.txt" ]]; then
+        return -- 0
+    fi
+
+    local -- acc=$PWD
+
+    while [[ "$acc" != "$(dirname -- "$acc")" ]]; do
+
+        if [[ -f "${acc}/Gemfile" ]]; then
+            return -- 0
+        fi
+
+        acc=$(dirname -- "$acc")
+    done
+
+    local -- manifest_entries=$(cat -- "${manifest_dir}/manifest.txt")
+    local -- ifs_save=$IFS
+
+    IFS=$'\n'
+    manifest_entries=($manifest_entries)
+    IFS=$ifs_save
+
+    for (( i = 0; i < ${#manifest_entries[@]}; i += 2 )); do
+
+        if [[ "${manifest_dir}/${manifest_entries[$(($i + 1))]}" -ot "${manifest_entries[$i]}" ]]; then
+            return -- 0
+        fi
+    done
+
+    return -- 1
+}
+
+# Generates shims for the executables listed in Gemfile manifests.
+function make_gemfile_shims {
+
+    local -- manifest_dir=$1
+    local -- manifest_entries=$(cat -- "${manifest_dir}/manifest.txt")
+
+    ifs_save=$IFS
+
+    IFS=$'\n'
+    manifest_entries=($manifest_entries)
+    IFS=$ifs_save
+
+    for (( i = 0; i < ${#manifest_entries[@]}; i += 2 )); do
+
+        gemspec_entries=$(cat -- "${manifest_dir}/${manifest_entries[$(($i + 1))]}")
+
+        ifs_save=$IFS
+
+        IFS=$'\n'
+        gemspec_entries=($gemspec_entries)
+        IFS=$ifs_save
+
+        for (( j = 0; j < ${#gemspec_entries[@]}; j += 2 )); do
+
+            gem_executable="${gemspec_entries[$(($j + 1))]}/${gemspec_entries[$j]}"
+
+            if [[ ! -f "$gem_executable" ]]; then
+                continue
+            fi
+
+            cd -- "$SHIM_PATH" && make_shims "$gem_executable"; cd -- "$PWD"
+        done
+    done
+
+    return -- 0
+}
+
 # The plugins root directory.
 plugin_root_dir=$(dirname -- "$(dirname -- "$(dirname -- "$(dirname -- "${BASH_SOURCE[0]}")")")")
 

etc/rbenv.d/bundler/rehash.rb

@@ -184,8 +184,6 @@ def self.rbenv_version(dir = Pathname.new("."))
   # @param [Hash] manifest_map the `Hash` from Bundler-controlled directories to gemspec manifests.
   # @param [Pathname] out_dir the output directory.
   def self.rehash(ruby_profile_map, manifest_map, out_dir = Pathname.new("."))
-    raise "The output directory does not exist" if !out_dir.directory?
-
     Pathname.new("manifest.txt").expand_path(out_dir).open("wb") do |f|
       manifest_map.each do |gemfile, manifest_file|
         next if !gemfile.file?
@@ -411,7 +409,10 @@ def self.ruby_scope
     end
 
     opt_spec.on("-o", "--out-dir OUT_DIR", "output metadata files to this directory") do |out_dir|
-      opts[:out_dir] = Pathname.new(out_dir)
+      p = Pathname.new(out_dir)
+      p.mkpath
+
+      opts[:out_dir] = p
     end
   end.parse(ARGV)
 

etc/rbenv.d/rehash/bundler.bash

@@ -21,39 +21,10 @@ if [[ -n "$plugin_disabled" ]]; then
 fi
 
 manifest_dir="${plugin_root_dir}/share/rbenv/bundler"
-rehash_rb_script="${plugin_root_dir}/etc/rbenv.d/bundler/rehash.rb"
+rehash_script="${plugin_root_dir}/etc/rbenv.d/bundler/rehash.rb"
 
-mkdir -p -- "$manifest_dir"
-touch -- "${manifest_dir}/manifest.txt"
-
-"$rehash_rb_script" --refresh --verbose --out-dir "$manifest_dir" -- "$PWD" || true
-
-manifest_entries=$(cat -- "${manifest_dir}/manifest.txt")
-
-ifs_save=$IFS
-
-IFS=$'\n'
-manifest_entries=($manifest_entries)
-IFS=$ifs_save
-
-for (( i = 0; i < ${#manifest_entries[@]}; i += 2 )); do
-
-    gemspec_entries=$(cat -- "${manifest_dir}/${manifest_entries[$(($i + 1))]}")
-
-    ifs_save=$IFS
-
-    IFS=$'\n'
-    gemspec_entries=($gemspec_entries)
-    IFS=$ifs_save
-
-    for (( j = 0; j < ${#gemspec_entries[@]}; j += 2 )); do
-
-        gem_executable="${gemspec_entries[$(($j + 1))]}/${gemspec_entries[$j]}"
-
-        if [[ ! -f "$gem_executable" ]]; then
-            continue
-        fi
+if { needs_rehash_script "$manifest_dir"; } then
+    "$rehash_script" --refresh --verbose --out-dir "$manifest_dir" -- "$PWD" || true
+fi
 
-        cd -- "$SHIM_PATH" && make_shims "$gem_executable"; cd -- "$PWD"
-    done
-done
+make_gemfile_shims "$manifest_dir"