[pacman-dev] [PATCH] Give informative error message when the to-be-downloaded file cannot be created

[Dan McGee]

On Wed, Feb 8, 2012 at 10:52 PM, Nagy Gabor <ngaba at bibl.u-szeged.hu> wrote:
> It can happen that the to-be-downloaded file cannot be created in cachedir.
> For example, I am an -Sup user, and it is comfortable to set --cachedir to
> /mnt/pendrive, which is a FAT filesystem, so files like
> capseo-1:0.3-2-i686.pkg.tar.xz cannot be downloaded to there.
>
> Before this patch, pacman didn't give clear output about what happens when
> the download code could not create the necessary file. This can be confusing
> with -Su. An example output:
> ***
> $ sudo pacman -S capseo bochs --cachedir /c/TEMP
>
> resolving dependencies...
> looking for inter-conflicts...
>
> Targets (2): bochs-2.4.6-1  capseo-1:0.3-2
>
> Total Download Size:    0.61 MiB
> Total Installed Size:   2.61 MiB
>
> Proceed with installation? [Y/n]
> :: Retrieving packages from extra...
> warning: failed to retrieve some files from extra
>  bochs-2.4.6-1-i686       611.5 KiB   118K/s 00:05 [------------------]  97%
> error: failed to commit transaction (unexpected error)
> Errors occurred, no packages were upgraded.
> ***
>
> After the patch, pacman will give more informative error message (and
> pm_errno is set properly):
> ***
> error: failed to create file '/c/TEMP/capseo-1:0.3-2-i686.pkg.tar.xz.part' for download
> error: failed to commit transaction (failed to retrieve some files)
> ***
>
> Unfortunately, the "failed to create file" error message is printed for
> every mirror (that can be dozens of lines), which is ugly, but at least
> informative... Without modifying the download logic (for example, by
> introducing -2 return value for _alpm_download() to indicate giving up),
> this ugliness cannot be eliminated.
I'm all for modifying the download logic in this fashion.

>
> Signed-off-by: Nagy Gabor <ngaba at bibl.u-szeged.hu>
> ---
>  lib/libalpm/dload.c |    3 +++
>  1 files changed, 3 insertions(+), 0 deletions(-)
>
> diff --git a/lib/libalpm/dload.c b/lib/libalpm/dload.c
> index 97778c2..9b57b97 100644
> --- a/lib/libalpm/dload.c
> +++ b/lib/libalpm/dload.c
> @@ -422,6 +422,9 @@ static int curl_download_internal(struct dload_payload *payload,
>        if(localf == NULL) {
>                localf = fopen(payload->tempfile_name, payload->tempfile_openmode);
>                if(localf == NULL) {
> +                       handle->pm_errno = ALPM_ERR_RETRIEVE;
> +                       _alpm_log(handle, ALPM_LOG_ERROR,
> +                                       _("failed to create file '%s' for download\n"), payload->tempfile_name);
Not a huge fan of the phrasing of this message. In most cases, I'd
rather the filename or variable part of the message be at the front or
the end, not in the middle. Perhaps
_("could not open file '%s': %s\n"), tempfile_name, strerror(errno))
?
>                        goto cleanup;
>                }
>        }
> --
> 1.7.9
>
>