Add option to ignore missing source files

This is useful when using dynamic fresh lines:

    fresh zsh/$PROFILE --file=~/.zshrc --ignore-missing

Fixes #88.

bin/fresh

@@ -162,7 +162,7 @@ EOF
   if [[ $(find "$SOURCE_DIR" -path "$SOURCE_DIR/$FILE_NAME" | wc -l) -lt 1 ]]; then
     # but not if we are locking to a git ref
     # since we would be checking the working tree
-    if [[ ! -n "$REF" ]] && [[ "$FILE_NAME" != '.' ]]; then
+    if [[ ! -n "$REF" ]] && [[ "$FILE_NAME" != '.' ]] && [[ -z "$IGNORE_MISSING" ]]; then
       _fatal_error "Could not find \"$FILE_NAME\" source file."
     fi
   fi
@@ -200,7 +200,7 @@ _file_list() {
       fi
     done < <(git ls-tree -r --name-only "$REF")
     cd "$OLDPWD"
-    if [[ "$MATCHED" == 0 ]]; then
+    if [[ "$MATCHED" == 0 ]] && [[ -z "$IGNORE_MISSING" ]]; then
       _fatal_error "Could not find \"$FILE_NAME\" source file."
     fi
   else
@@ -440,6 +440,7 @@ _dsl_fresh_options() {
   DEFAULT_REF=
   DEFAULT_MARKER=
   DEFAULT_FILTER=
+  DEFAULT_IGNORE_MISSING=
 
   if [[ $# -gt 0 ]]; then
     # __FRESH_OPTIONS__ placeholder as _parse_fresh_dsl_args expects a filename
@@ -450,6 +451,7 @@ _dsl_fresh_options() {
     DEFAULT_REF="$REF"
     DEFAULT_MARKER="$MARKER"
     DEFAULT_FILTER="$FILTER"
+    DEFAULT_IGNORE_MISSING="$IGNORE_MISSING"
   fi
 }
 
@@ -466,6 +468,7 @@ _parse_fresh_dsl_args() {
   REF="$DEFAULT_REF"
   MARKER="$DEFAULT_MARKER"
   FILTER="$DEFAULT_FILTER"
+  IGNORE_MISSING="$DEFAULT_IGNORE_MISSING"
 
   while [ $# -gt 0 ]
   do
@@ -502,6 +505,9 @@ _parse_fresh_dsl_args() {
       --filter)
         _fatal_error "You must specify a filter program."
         ;;
+      --ignore-missing)
+        IGNORE_MISSING="1"
+        ;;
       -*)
         _fatal_error "Unknown option: $1"
         ;;

test/fresh_test.sh

@@ -1,16 +1,16 @@
 #!/bin/bash
 
-it_builds_local_shell_files() {
+_build_local_shell_files() {
   echo fresh aliases/git >> $FRESH_RCFILE
   echo fresh aliases/ruby >> $FRESH_RCFILE
 
   mkdir -p $FRESH_LOCAL/aliases
   echo "alias gs='git status'" >> $FRESH_LOCAL/aliases/git
   echo "alias gl='git log'" >> $FRESH_LOCAL/aliases/git
   echo "alias rake='bundle exec rake'" >> $FRESH_LOCAL/aliases/ruby
+}
 
-  runFresh
-
+_assert_local_shell_files() {
   assertFileMatches $FRESH_PATH/build/shell.sh <<EOF
 export PATH="\$HOME/bin:\$PATH"
 export FRESH_PATH="$FRESH_PATH"
@@ -29,6 +29,12 @@ EOF
   assertFalse 'not writable' '[ -w $FRESH_PATH/build/shell.sh ]'
 }
 
+it_builds_local_shell_files() {
+  _build_local_shell_files
+  runFresh
+  _assert_local_shell_files
+}
+
 it_builds_local_shell_files_with_spaces() {
   echo "fresh 'aliases/foo bar'" >> $FRESH_RCFILE
 
@@ -90,6 +96,13 @@ it_errors_with_missing_local_file() {
   runFresh fails
 }
 
+it_builds_local_shell_files_with_ignore_missing() {
+  echo fresh aliases/haskell --ignore-missing >> $FRESH_RCFILE
+  _build_local_shell_files
+  runFresh
+  _assert_local_shell_files
+}
+
 it_preserves_existing_compiled_file_when_failing() {
   mkdir -p $FRESH_PATH/build
   echo 'existing file' > $FRESH_PATH/build/shell.sh
@@ -294,6 +307,39 @@ git ls-tree -r --name-only abc1237
 EOF
 }
 
+it_does_not_error_if_source_file_missing_at_ref_with_ignore_missing() {
+  echo fresh repo/name bad-file --ref=abc1237 --ignore-missing >> $FRESH_RCFILE
+  mkdir -p $FRESH_PATH/source/repo/name
+  stubGit
+
+  runFresh
+
+  assertFileMatches $SANDBOX_PATH/git.log <<EOF
+cd $FRESH_PATH/source/repo/name
+git ls-tree -r --name-only abc1237
+EOF
+}
+
+it_builds_files_with_ref_and_ignore_missing() {
+  echo 'fresh repo/name ackrc --file --ref=abc1237 --ignore-missing' >> $FRESH_RCFILE
+  echo 'fresh repo/name missing --file --ref=abc1237 --ignore-missing' >> $FRESH_RCFILE
+  mkdir -p $FRESH_PATH/source/repo/name
+  stubGit
+
+  runFresh
+
+  assertFileMatches $SANDBOX_PATH/git.log <<EOF
+cd $FRESH_PATH/source/repo/name
+git ls-tree -r --name-only abc1237
+cd $FRESH_PATH/source/repo/name
+git show abc1237:ackrc
+cd $FRESH_PATH/source/repo/name
+git ls-tree -r --name-only abc1237
+EOF
+  assertTrue 'exists' '[ -e $FRESH_PATH/build/ackrc ]'
+  assertFalse 'does not exist' '[ -e $FRESH_PATH/missing ]'
+}
+
 it_ignores_subdirectories_when_globbing_from_working_tree() {
   echo "fresh 'recursive-test/*'" >> $FRESH_RCFILE
 
@@ -438,6 +484,18 @@ EOF
   assertFalse 'not writable' '[ -w $FRESH_PATH/build/vimrc ]'
 }
 
+it_does_not_create_a_file_when_single_source_is_missing_with_ignore_missing() {
+  echo 'fresh tmux.conf --file --ignore-missing' >> $FRESH_RCFILE
+  echo 'fresh ghci --file --ignore-missing' >> $FRESH_RCFILE
+  mkdir -p $FRESH_LOCAL
+  touch $FRESH_LOCAL/tmux.conf
+
+  runFresh
+
+  assertTrue 'exists' '[ -e $FRESH_PATH/build/tmux.conf ]'
+  assertFalse 'does not exist' '[ -e $FRESH_PATH/build/ghci ]'
+}
+
 it_builds_generic_files_with_globbing() {
   echo "fresh 'file*' --file" >> $FRESH_RCFILE