Description

Provides a command that runs configured tools on the contents of modified files, writing back any fixes to the working copy or replacing changesets.

Fixer tools are run in the repository's root directory. This allows them to read configuration files from the working copy, or even write to the working copy. The working copy is not updated to match the revision being fixed. In fact, several revisions may be fixed in parallel. Writes to the working copy are not amended into the revision being fixed; fixer tools MUST always read content to be fixed from stdin, and write fixed file content back to stdout.

Here is an example configuration that causes hg fix to apply automatic formatting fixes to modified lines in C++ code:

[fix]
clang-format:command=clang-format --assume-filename={rootpath}
clang-format:linerange=--lines={first}:{last}
clang-format:pattern=set:**.cpp or **.hpp

The :command suboption forms the first part of the shell command that will be used to fix a file. The content of the file is passed on standard input, and the fixed file content is expected on standard output. Any output on standard error will be displayed as a warning. If the exit status is not zero, the file will not be affected. A placeholder warning is displayed if there is a non-zero exit status but no standard error output. Some values may be substituted into the command:

{rootpath}  The path of the file being fixed, relative to the repo root
{basename}  The name of the file being fixed, without the directory path

If the :linerange suboption is set, the tool will only be run if there are changed lines in a file. The value of this suboption is appended to the shell command once for every range of changed lines in the file. Some values may be substituted into the command:

{first}   The 1-based line number of the first line in the modified range
{last}    The 1-based line number of the last line in the modified range

Deleted sections of a file will be ignored by :linerange, because there is no corresponding line range in the version being fixed.

By default, tools that set :linerange will only be executed if there is at least one changed line range. This is meant to prevent accidents like running a code formatter in such a way that it unexpectedly reformats the whole file. If such a tool needs to operate on unchanged files, it should set the :skipclean suboption to false.

The :pattern suboption determines which files will be passed through each configured tool. See hg help patterns for possible values. However, all patterns are relative to the repo root, even if that text says they are relative to the current working directory. If there are file arguments to hg fix, the intersection of these patterns is used.

There is also a configurable limit for the maximum size of file that will be processed by hg fix:

[fix]
maxfilesize = 2MB

Normally, execution of configured tools will continue after a failure (indicated by a non-zero exit status). It can also be configured to abort after the first such failure, so that no files will be affected if any tool fails. This abort will also cause hg fix to exit with a non-zero status:

[fix]
failure = abort

When multiple tools are configured to affect a file, they execute in an order defined by the :priority suboption. The priority suboption has a default value of zero for each tool. Tools are executed in order of descending priority. The execution order of tools with equal priority is unspecified. For example, you could use the 'sort' and 'head' utilities to keep only the 10 smallest numbers in a text file by ensuring that 'sort' runs before 'head':

[fix]
sort:command = sort -n
head:command = head -n 10
sort:pattern = numbers.txt
head:pattern = numbers.txt
sort:priority = 2
head:priority = 1

To account for changes made by each tool, the line numbers used for incremental formatting are recomputed before executing the next tool. So, each tool may see different values for the arguments added by the :linerange suboption.

Each fixer tool is allowed to return some metadata in addition to the fixed file content. The metadata must be placed before the file content on stdout, separated from the file content by a zero byte. The metadata is parsed as a JSON value (so, it should be UTF-8 encoded and contain no zero bytes). A fixer tool is expected to produce this metadata encoding if and only if the :metadata suboption is true:

[fix]
tool:command = tool --prepend-json-metadata
tool:metadata = true

The metadata values are passed to hooks, which can be used to print summaries or perform other post-fixing work. The supported hooks are:

"postfixfile"
  Run once for each file in each revision where any fixer tools made changes
  to the file content. Provides "$HG_REV" and "$HG_PATH" to identify the file,
  and "$HG_METADATA" with a map of fixer names to metadata values from fixer
  tools that affected the file. Fixer tools that didn't affect the file have a
  value of None. Only fixer tools that executed are present in the metadata.

"postfix"
  Run once after all files and revisions have been handled. Provides
  "$HG_REPLACEMENTS" with information about what revisions were created and
  made obsolete. Provides a boolean "$HG_WDIRWRITTEN" to indicate whether any
  files in the working copy were updated. Provides a list "$HG_METADATA"
  mapping fixer tool names to lists of metadata values returned from
  executions that modified a file. This aggregates the same metadata
  previously passed to the "postfixfile" hook.

Commands

hg fix [OPTION]... [FILE]...