git/run-command.h, branch v2.4.9

run-command: introduce capture_command helper

2015-03-23T04:38:31Z

Something as simple as reading the stdout from a command turns out to be rather hard to do right. Doing: cmd.out = -1; run_command(&cmd); strbuf_read(&buf, cmd.out, 0); can result in deadlock if the child process produces a large amount of output. What happens is: 1. The parent spawns the child with its stdout connected to a pipe, of which the parent is the sole reader. 2. The parent calls wait(), blocking until the child exits. 3. The child writes to stdout. If it writes more data than the OS pipe buffer can hold, the write() call will block. This is a deadlock; the parent is waiting for the child to exit, and the child is waiting for the parent to call read(). So we might try instead: start_command(&cmd); strbuf_read(&buf, cmd.out, 0); finish_command(&cmd); But that is not quite right either. We are examining cmd.out and running finish_command whether start_command succeeded or not, which is wrong. Moreover, these snippets do not do any error handling. If our read() fails, we must make sure to still call finish_command (to reap the child process). And both snippets failed to close the cmd.out descriptor, which they must do (provided start_command succeeded). Let's introduce a run-command helper that can make this a bit simpler for callers to get right. Signed-off-by: Jeff King Signed-off-by: Junio C Hamano

Merge branch 'jc/hook-cleanup'

2014-12-22T20:27:10Z

Remove unused code. * jc/hook-cleanup: run-command.c: retire unused run_hook_with_custom_index()

run-command.c: retire unused run_hook_with_custom_index()

2014-12-01T16:39:43Z

This was originally meant to be used to rewrite run_commit_hook() that only special cases the GIT_INDEX_FILE environment, but the run_hook_ve() refactoring done earlier made the implementation of run_commit_hook() thin and clean enough. Nobody uses this, so retire it as an unfinished clean-up made unnecessary. Signed-off-by: Junio C Hamano

run-command: add env_array, an optional argv_array for env

2014-10-19T22:26:31Z

Similar to args, add a struct argv_array member to struct child_process that simplifies specifying the environment for children. It is freed automatically by finish_command() or if start_command() encounters an error. Suggested-by: Jeff King Signed-off-by: Rene Scharfe Signed-off-by: Junio C Hamano

run-command: introduce child_process_init()

2014-08-20T16:54:58Z

Add a helper function for initializing those struct child_process variables for which the macro CHILD_PROCESS_INIT can't be used. Suggested-by: Jeff King Signed-off-by: Rene Scharfe Signed-off-by: Junio C Hamano

run-command: introduce CHILD_PROCESS_INIT

2014-08-20T16:53:37Z

Most struct child_process variables are cleared using memset first after declaration. Provide a macro, CHILD_PROCESS_INIT, that can be used to initialize them statically instead. That's shorter, doesn't require a function call and is slightly more readable (especially given that we already have STRBUF_INIT, ARGV_ARRAY_INIT etc.). Helped-by: Johannes Sixt Signed-off-by: Rene Scharfe Signed-off-by: Junio C Hamano

run-command: store an optional argv_array

2014-05-15T16:49:09Z

All child_process structs need to point to an argv. For flexibility, we do not mandate the use of a dynamic argv_array. However, because the child_process does not own the memory, this can make memory management with a separate argv_array difficult. For example, if a function calls start_command but not finish_command, the argv memory must persist. The code needs to arrange to clean up the argv_array separately after finish_command runs. As a result, some of our code in this situation just leaks the memory. To help such cases, this patch adds a built-in argv_array to the child_process, which gets cleaned up automatically (both in finish_command and when start_command fails). Callers may use it if they choose, but can continue to use the raw argv if they wish. Signed-off-by: Jeff King Signed-off-by: Junio C Hamano

run-command: mark run_hook_with_custom_index as deprecated

2014-03-18T18:26:12Z

Signed-off-by: Benoit Pierre Signed-off-by: Junio C Hamano

commit: fix patch hunk editing with "commit -p -m"

2014-03-18T18:25:12Z

Don't change git environment: move the GIT_EDITOR=":" override to the hook command subprocess, like it's already done for GIT_INDEX_FILE. Signed-off-by: Benoit Pierre Signed-off-by: Junio C Hamano

Add the LAST_ARG_MUST_BE_NULL macro

2013-07-19T16:26:15Z

The sentinel function attribute is not understood by versions of the gcc compiler prior to v4.0. At present, for earlier versions of gcc, the build issues 108 warnings related to the unknown attribute. In order to suppress the warnings, we conditionally define the LAST_ARG_MUST_BE_NULL macro to provide the sentinel attribute for gcc v4.0 and newer. Signed-off-by: Ramsay Jones Signed-off-by: Junio C Hamano