How to limit file size on commit?

Question

I'm fully aware of this question which technically makes this a duplicate but the answers only offer a solution on push, which would be too late for my requirements.

Is there an option to limit the file size when committing?

For example: file sizes above 500K would produce a warning. File sizes above 10M would stop the commit.

Answer 1

There is a general pre-commit hook. You can write a script to check file size and then accept or reject the commit. Git however gives the user the ability to bypass the check) from the command line type "git help hooks" for more information. Here is the relevant info on the pre-commit hook.

pre-commit

This hook is invoked by git commit, and can be bypassed with --no-verify option. It takes no parameter, and is invoked before obtaining the proposed commit log message and making a commit. Exiting with non-zero status from this script causes the git commit to abort.

Answer 2

You need to implement eis script you already look for in the pre-commit hook.

From documentation, we learned that pre-commit hook

takes no parameters, and is invoked before obtaining the proposed commit log message and making a commit. Exiting with a non-zero status from this script causes the git commit command to abort before creating a commit.

Basically, the hook is called to check if the user is allowed to commit his changes.

The script originally made by eis on other post becomes

#!/bin/bash
# File size limit is meant to be configured through 'hooks.filesizelimit' setting
filesizelimit=$(git config hooks.filesizelimit)

# If we haven't configured a file size limit, use default value of about 10M
if [ -z "$filesizelimit" ]; then
        filesizelimit=10000000
fi

# You specify a warning limit
filesizewarning=500000

# With this command, we can find information about the file coming in that has biggest size
# We also normalize the line for excess whitespace
biggest_checkin_normalized=$(git ls-tree --full-tree -r -l HEAD | sort -k 4 -n -r | head -1 | sed 's/^ *//;s/ *$//;s/\s\{1,\}/ /g' )

# Based on that, we can find what we are interested about
filesize=`echo $biggest_checkin_normalized | cut -d ' ' -f4,4`

# Actual comparison
# To cancel a push, we exit with status code 1
# It is also a good idea to print out some info about the cause of rejection
if [ $filesize -gt $filesizelimit ]; then

        # To be more user-friendly, we also look up the name of the offending file
        filename=`echo $biggest_checkin_normalized | cut -d ' ' -f5,5`

        echo "Error: Too large push attempted." >&2
        echo  >&2
        echo "File size limit is $filesizelimit, and you tried to push file named $filename of size $filesize." >&2
        echo "Contact configuration team if you really need to do this." >&2
        exit 1
elif [ $filesize -gt $filesizewarning ]; then
        echo "WARNING ! A file size is bigger that $filesizewarning"
fi
exit 0

Answer 3

A shorter, bash-specific version of @Leon's script, which prints the file sizes in a human-readable format. It requires a newer git for the --diff-filter=d option:

#!/bin/bash
hard_limit=$(git config hooks.filesizehardlimit)
soft_limit=$(git config hooks.filesizesoftlimit)
: ${hard_limit:=10000000}
: ${soft_limit:=1000000}

status=0

bytesToHuman() {
  b=${1:-0}; d=''; s=0; S=({,K,M,G,T,P,E,Z,Y}B)
  while ((b > 1000)); do
    d="$(printf ".%01d" $((b % 1000 * 10 / 1000)))"
    b=$((b / 1000))
    let s++
  done
  echo "$b$d${S[$s]}"
}

# Iterate over the zero-delimited list of staged files.
while IFS= read -r -d '' file ; do
  hash=$(git ls-files -s "$file" | cut -d ' ' -f 2)
  size=$(git cat-file -s "$hash")

  if (( $size > $hard_limit )); then
    echo "Error: Cannot commit '$file' because it is $(bytesToHuman $size), which exceeds the hard size limit of $(bytesToHuman $hard_limit)."
    status=1
  elif (( $size > $soft_limit )); then
    echo "Warning: '$file' is $(bytesToHuman $size), which exceeds the soft size limit of $(bytesToHuman $soft_limit). Please double check that you intended to commit this file."
  fi
done < <(git diff -z --staged --name-only --diff-filter=d)
exit $status

As with the other answers, this must be saved with execute permissions as .git/hooks/pre-commit.

Example output:

Error: Cannot commit 'foo' because it is 117.9MB, which exceeds the hard size limit of 10.0MB.

Answer 4

This pre-commit hook will do the file size check:

.git/hooks/pre-commit

#!/bin/sh
hard_limit=$(git config hooks.filesizehardlimit)
soft_limit=$(git config hooks.filesizesoftlimit)
: ${hard_limit:=10000000}
: ${soft_limit:=500000}

list_new_or_modified_files()
{
    git diff --staged --name-status|sed -e '/^D/ d; /^D/! s/.\s\+//'
}

unmunge()
{
    local result="${1#\"}"
    result="${result%\"}"
    env echo -e "$result"
}

check_file_size()
{
    n=0
    while read -r munged_filename
    do
        f="$(unmunge "$munged_filename")"
        h=$(git ls-files -s "$f"|cut -d' ' -f 2)
        s=$(git cat-file -s "$h")
        if [ "$s" -gt $hard_limit ]
        then
            env echo -E 1>&2 "ERROR: hard size limit ($hard_limit) exceeded: $munged_filename ($s)"
            n=$((n+1))
        elif [ "$s" -gt $soft_limit ]
        then
            env echo -E 1>&2 "WARNING: soft size limit ($soft_limit) exceeded: $munged_filename ($s)"
        fi
    done

    [ $n -eq 0 ]
}

list_new_or_modified_files | check_file_size

Above script must be saved as .git/hooks/pre-commit with execution permissions enabled (chmod +x .git/hooks/pre-commit).

The default soft (warning) and hard (error) size limits are set to 500,000 and 10,000,000 bytes but can be overriden through the hooks.filesizesoftlimit and hooks.filesizehardlimit settings respectively:

$ git config hooks.filesizesoftlimit 100000
$ git config hooks.filesizehardlimit 4000000