Fix pg_basebackup so that it accepts 0 as a valid compression level.

MasaoFujii · MasaoFujii · commit 928e92fda30f · 2016-08-01T17:37:18.000+09:00
The help message for pg_basebackup specifies that the numbers 0 through 9
are accepted as valid values of -Z option. But, previously -Z 0 was rejected
as an invalid compression level.

Per discussion, it's better to make pg_basebackup treat 0 as valid
compression level meaning no compression, like pg_dump.

Back-patch to all supported versions.

Reported-By: Jeff Janes
Reviewed-By: Amit Kapila
Discussion: CAMkU=1x+GwjSayc57v6w87ij6iRGFWt=hVfM0B64b1_bPVKRqg@mail.gmail.com
diff --git a/doc/src/sgml/ref/pg_basebackup.sgml b/doc/src/sgml/ref/pg_basebackup.sgml
@@ -343,7 +343,7 @@ PostgreSQL documentation
       <listitem>
        <para>
         Enables gzip compression of tar file output, and specifies the
-        compression level (1 through 9, 9 being best
+        compression level (0 through 9, 0 being no compression and 9 being best
         compression). Compression is only available when using the tar
         format.
        </para>
diff --git a/src/bin/pg_basebackup/pg_basebackup.c b/src/bin/pg_basebackup/pg_basebackup.c
@@ -2050,7 +2050,7 @@ main(int argc, char **argv)
 				break;
 			case 'Z':
 				compresslevel = atoi(optarg);
-				if (compresslevel <= 0 || compresslevel > 9)
+				if (compresslevel < 0 || compresslevel > 9)
 				{
 					fprintf(stderr, _("%s: invalid compression level \"%s\"\n"),
 							progname, optarg);

Original file line number	Diff line number	Diff line change
`@@ -2050,7 +2050,7 @@ main(int argc, char **argv)`
`2050`	`2050`	`break;`
`2051`	`2051`	`case 'Z':`
`2052`	`2052`	`compresslevel = atoi(optarg);`
`2053`		`- if (compresslevel <= 0 \|\| compresslevel > 9)`
	`2053`	`+ if (compresslevel < 0 \|\| compresslevel > 9)`
`2054`	`2054`	`{`
`2055`	`2055`	`fprintf(stderr, _("%s: invalid compression level \"%s\"\n"),`
`2056`	`2056`	`progname, optarg);`