The builder did not detect syntax errors in substitusions in the
Dockerfile, causing those values to be processed incorrectly instead of
producing an error.
Example 1: missing `}`
docker build --no-cache -<<'EOF'
FROM busybox
ARG var=${aaa:-bbb
RUN echo $var
EOF
Before:
Step 3/3 : RUN echo $var
---> Running in f06571e77146
bbb
After:
Step 2/3 : ARG var=${aaa:-bbb
failed to process "${aaa:-bbb": syntax error: missing '}'
Example 2: missing closing `}`, no default value
docker build --no-cache -<<'EOF'
FROM busybox
ARG var=${aaa
RUN echo $var
EOF
Before:
Step 2/3 : ARG var=${aaa
failed to process "${aaa": missing ':' in substitution
After:
Step 2/3 : ARG var=${aaa
failed to process "${aaa": syntax error: missing '}'
Example 3: double opening bracket (`{`)
docker build --no-cache -<<'EOF'
FROM busybox
ARG var=${{aaa:-bbb}
RUN echo $var
EOF
Before:
Step 2/3 : ARG var=${{aaa:-bbb}
failed to process "${{aaa:-bbb}": missing ':' in substitution
After:
Step 2/3 : ARG var=${{aaa:-bbb}
failed to process "${{aaa:-bbb}": syntax error: bad substitution
Example 4: double opening bracket (`{`), no default value
docker build --no-cache -<<'EOF'
FROM busybox
ARG var=${{aaa}
RUN echo $var
EOF
Before:
Step 2/3 : ARG var=${{aaa}
failed to process "${{aaa}": missing ':' in substitution
After:
Step 2/3 : ARG var=${{aaa}
failed to process "${{aaa}": syntax error: bad substitution
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
Upstream-commit: 955a6ad95f7891a45692d975793abf1eeb07cdd5
Component: engine
c8db46ad05