How to set path that contains spaces in a YAML file in a GitHub workflow?

Question

I have a repository that has a LaTex file inside a folder. The folder is named Literature Review and the file is named Review.tex. I'm new to docker and GitHub Actions. I have tried a lot of different combinations to set the file path:

Literature Review/Review.tex

I have tried a lot of methods suggested on StackOverflow but it seems I'm too naive to understand the implementation correctly xD

I read somewhere that to avoid an escape sequence, we can use a \ before the space. This, however, did not make much difference.

The workflow returns the following error while building:

Run echo ${MANUSCRIPT_PATH}.tex
  echo ${MANUSCRIPT_PATH}.tex
  ${LATEX} ${MANUSCRIPT_PATH}.tex
  ${BIBTEX} ${MANUSCRIPT_PATH}.aux
  ${LATEX} ${MANUSCRIPT_PATH}.tex
  ${LATEX} ${MANUSCRIPT_PATH}.tex
  shell: /bin/bash -e {0}
  env:
    MANUSCRIPT_PATH: Literature\ Review/Review
    LATEX: pdflatex -shell-escape
    BIBTEX: bibtex
Literature\ Review/Review.tex
This is pdfTeX, Version 3.14159265-2.6-1.40.18 (TeX Live 2017/Debian) (preloaded format=pdflatex)
 \write18 enabled.
entering extended mode
! I can't find file `Literature'.
<to be read again> 
                   \ 
<*> Literature\ 
                Review/Review.tex
(Press Enter to retry, or Control-D to exit)
Please type another input file name: 
! Emergency stop.
<to be read again> 
                   \ 
<*> Literature\ 
                Review/Review.tex
!  ==> Fatal error occurred, no output PDF file produced!
Transcript written on texput.log.
Error: Process completed with exit code 1.

My yml file looks like this:

name: paper-maker

on: push

jobs:
  build:
    runs-on: ubuntu-latest
    env:
      # This needs fixing
      MANUSCRIPT_PATH: 'Literature\ Review/Review' # exclude the '.tex' / '.pdf' extension!
      LATEX: pdflatex -shell-escape
      BIBTEX: bibtex
    steps: 
    - uses: actions/checkout@v1
    - name: Install texlive
      run: |
        sudo apt-get install texlive-publishers \
                             texlive-latex-recommended \
                             texlive-latex-extra \
                             texlive-fonts-recommended \
                             texlive-fonts-extra
    - name: Build paper
      run: |
        echo ${MANUSCRIPT_PATH}.tex
        ${LATEX} ${MANUSCRIPT_PATH}.tex
        ${BIBTEX} ${MANUSCRIPT_PATH}.aux
        ${LATEX} ${MANUSCRIPT_PATH}.tex
        ${LATEX} ${MANUSCRIPT_PATH}.tex
    - name: Push paper
      run: |
        git checkout --orphan ${GITHUB_REF##*/}-pdf
        git rm -rf .github/
        git rm -rf . 
        git add -f ${MANUSCRIPT_PATH##*/}.pdf
        git -c user.name='paper-maker' -c user.email='paper-maker' commit -m "update pdf"
        git push -q -f https://${{ github.actor }}:${{ secrets.GITHUB_TOKEN }}@github.com/${{ github.repository }} ${GITHUB_REF##*/}-pdf

Answer 1

Don't try to individually escape space characters, just put the resulting path in double quotes:

MANUSCRIPT_PATH: Literature Review/Review

${LATEX} "${MANUSCRIPT_PATH}.tex"
${BIBTEX} "${MANUSCRIPT_PATH}.aux"
${LATEX} "${MANUSCRIPT_PATH}.tex"
${LATEX} "${MANUSCRIPT_PATH}.tex"

It seems that backslash-escapes are processed before variable substitution, which is why your approach doesn't work.

In any case, putting the final path in double quotes is long-established best practice.

---

Edit: To elaborate a bit, this has nothing to do with Docker or YAML. Just try this piece of code in bash:

mkdir -p a\ b && echo "foo" > a\ b/c.txt
P='a\ b/c' cat $P.txt

You will get

cat: a\: No such file or directory
cat: b/c.txt: No such file or directory

As you can see, the backslash is not escaping the following space in variable substitution. Instead, the shell acts like you gave the two parameters 'a\' and 'b/c.txt'.

Answer 2

Use double quotation marks inside of the single quotation marks like this: '"Literature Review/Review"'. Parsing the YAML removes the single quotation marks and the value of your environment variable will be "Literature Review/Review". This in turn will make pdflatex receive Literature Review/Review as a single argument.

jobs:
  build:
    runs-on: ubuntu-latest
    env:
      # fixed
      MANUSCRIPT_PATH_TEX: '"Literature Review/Review.tex"'
[...]
    - name: Build paper
      run: |
        echo ${MANUSCRIPT_PATH_TEX}
        ${LATEX} ${MANUSCRIPT_PATH_TEX}
        ${BIBTEX} ${MANUSCRIPT_PATH_TEX}
        ${LATEX} ${MANUSCRIPT_PATH_TEX}
        ${LATEX} ${MANUSCRIPT_PATH_TEX}