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[PATCHv6 7/8] Improve error handling when parsing dirstat parameters

From
Johan Herland <johan@herland.net>
Date
Apr 29, 2011, 09:36 UTC
Message-ID
<1304069783-22739-8-git-send-email-johan@herland.net>
In-Reply-To
<1304069783-22739-1-git-send-email-johan@herland.net>

When encountering errors or unknown tokens while parsing parameters to the --dirstat option, it makes sense to die() with an error message informing the user of which parameter did not make sense. However, when parsing the diff.dirstat config variable, we cannot simply die(), but should instead (after warning the user) ignore the erroneous or unrecognized parameter. After all, future Git versions might add more dirstat parameters, and using two different Git versions on the same repo should not cripple the older Git version just because of a parameter that is only understood by a more recent Git version.

This patch fixes the issue by refactoring the dirstat parameter parsing so that parse_dirstat_params() keeps on parsing parameters, even if an earlier parameter was not recognized. When parsing has finished, it returns zero if all parameters were successfully parsed, and non-zero if one or more parameters were not recognized (with appropriate error messages appended to the 'errmsg' argument).

The parse_dirstat_params() callers then decide (based on the return value from parse_dirstat_params()) whether to warn and ignore (in case of diff.dirstat), or to warn and die (in case of --dirstat).

The patch also adds a couple of tests verifying the correct behavior of --dirstat and diff.dirstat in the face of unknown (possibly future) dirstat parameters.

Suggested-by: Junio C Hamano <gitster@pobox.com>
Improved-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Johan Herland <johan@herland.net>
---
 diff.c                  |   71 +++++++++++++++++++++++++++--------------------
 t/t4047-diff-dirstat.sh |   37 ++++++++++++++++++++++++
 2 files changed, 78 insertions(+), 30 deletions(-)
diff --git a/diff.c b/diff.c
index 8703763..b290543 100644
--- a/diff.c
+++ b/diff.c
@@ -67,52 +67,56 @@ static int parse_diff_color_slot(const char *var, int ofs)
 	return -1;
 }
 
-static int parse_dirstat_params(struct diff_options *options, const char *params)
+static int parse_dirstat_params(struct diff_options *options, const char *params,
+				struct strbuf *errmsg)
 {
 	const char *p = params;
+	int p_len, ret = 0;
+
 	while (*p) {
-		if (!prefixcmp(p, "changes")) {
-			p += 7;
+		p_len = strchrnul(p, ',') - p;
+		if (!memcmp(p, "changes", p_len)) {
 			DIFF_OPT_CLR(options, DIRSTAT_BY_LINE);
 			DIFF_OPT_CLR(options, DIRSTAT_BY_FILE);
-		} else if (!prefixcmp(p, "lines")) {
-			p += 5;
+		} else if (!memcmp(p, "lines", p_len)) {
 			DIFF_OPT_SET(options, DIRSTAT_BY_LINE);
 			DIFF_OPT_CLR(options, DIRSTAT_BY_FILE);
-		} else if (!prefixcmp(p, "files")) {
-			p += 5;
+		} else if (!memcmp(p, "files", p_len)) {
 			DIFF_OPT_CLR(options, DIRSTAT_BY_LINE);
 			DIFF_OPT_SET(options, DIRSTAT_BY_FILE);
-		} else if (!prefixcmp(p, "noncumulative")) {
-			p += 13;
+		} else if (!memcmp(p, "noncumulative", p_len)) {
 			DIFF_OPT_CLR(options, DIRSTAT_CUMULATIVE);
-		} else if (!prefixcmp(p, "cumulative")) {
-			p += 10;
+		} else if (!memcmp(p, "cumulative", p_len)) {
 			DIFF_OPT_SET(options, DIRSTAT_CUMULATIVE);
 		} else if (isdigit(*p)) {
 			char *end;
-			options->dirstat_permille = strtoul(p, &end, 10) * 10;
-			p = end;
-			if (*p == '.' && isdigit(*++p)) {
+			int permille = strtoul(p, &end, 10) * 10;
+			if (*end == '.' && isdigit(*++end)) {
 				/* only use first digit */
-				options->dirstat_permille += *p - '0';
+				permille += *end - '0';
 				/* .. and ignore any further digits */
-				while (isdigit(*++p))
+				while (isdigit(*++end))
 					; /* nothing */
 			}
-		} else
-			return error("Unknown --dirstat parameter '%s'", p);
-
-		if (*p) {
-			/* more parameters, swallow separator */
-			if (*p != ',')
-				return error("Missing comma separator at char "
-					"%"PRIuMAX" of '%s'",
-					(uintmax_t) (p - params), params);
-			p++;
+			if (end - p == p_len)
+				options->dirstat_permille = permille;
+			else {
+				strbuf_addf(errmsg, "  Failed to parse dirstat cut-off percentage '%.*s'\n",
+					    p_len, p);
+				ret++;
+			}
+		} else {
+			strbuf_addf(errmsg, "  Unknown dirstat parameter '%.*s'\n",
+				    p_len, p);
+			ret++;
 		}
+
+		p += p_len;
+
+		if (*p)
+			p++; /* more parameters, swallow separator */
 	}
-	return 0;
+	return ret;
 }
 
 static int git_config_rename(const char *var, const char *value)
@@ -195,8 +199,12 @@ int git_diff_basic_config(const char *var, const char *value, void *cb)
 	}
 
 	if (!strcmp(var, "diff.dirstat")) {
+		struct strbuf errmsg = STRBUF_INIT;
 		default_diff_options.dirstat_permille = diff_dirstat_permille_default;
-		(void) parse_dirstat_params(&default_diff_options, value);
+		if (parse_dirstat_params(&default_diff_options, value, &errmsg))
+			warning("Found errors in 'diff.dirstat' config variable:\n%s",
+				errmsg.buf);
+		strbuf_release(&errmsg);
 		diff_dirstat_permille_default = default_diff_options.dirstat_permille;
 		return 0;
 	}
@@ -3245,8 +3253,11 @@ static int stat_opt(struct diff_options *options, const char **av)
 
 static int parse_dirstat_opt(struct diff_options *options, const char *params)
 {
-	if (parse_dirstat_params(options, params))
-		die("Failed to parse --dirstat/-X option parameter");
+	struct strbuf errmsg = STRBUF_INIT;
+	if (parse_dirstat_params(options, params, &errmsg))
+		die("Failed to parse --dirstat/-X option parameter:\n%s",
+		    errmsg.buf);
+	strbuf_release(&errmsg);
 	/*
 	 * The caller knows a dirstat-related option is given from the command
 	 * line; allow it to say "return this_function();"
diff --git a/t/t4047-diff-dirstat.sh b/t/t4047-diff-dirstat.sh
index b8ad92a..cc947fd 100755
--- a/t/t4047-diff-dirstat.sh
+++ b/t/t4047-diff-dirstat.sh
@@ -939,4 +939,41 @@ test_expect_success 'diff.dirstat=0,lines' '
 	test_cmp expect_diff_dirstat_CC actual_diff_dirstat_CC
 '
 
+test_expect_success '--dirstat=future_param,lines,0 should fail loudly' '
+	test_must_fail git diff --dirstat=future_param,lines,0 HEAD^..HEAD >actual_diff_dirstat 2>actual_error &&
+	test_debug "cat actual_error" &&
+	test_cmp /dev/null actual_diff_dirstat &&
+	grep -q "future_param" actual_error &&
+	grep -q "\--dirstat" actual_error
+'
+
+test_expect_success '--dirstat=dummy1,cumulative,2dummy should report both unrecognized parameters' '
+	test_must_fail git diff --dirstat=dummy1,cumulative,2dummy HEAD^..HEAD >actual_diff_dirstat 2>actual_error &&
+	test_debug "cat actual_error" &&
+	test_cmp /dev/null actual_diff_dirstat &&
+	grep -q "dummy1" actual_error &&
+	grep -q "2dummy" actual_error &&
+	grep -q "\--dirstat" actual_error
+'
+
+test_expect_success 'diff.dirstat=future_param,0,lines should warn, but still work' '
+	git -c diff.dirstat=future_param,0,lines diff --dirstat HEAD^..HEAD >actual_diff_dirstat 2>actual_error &&
+	test_debug "cat actual_error" &&
+	test_cmp expect_diff_dirstat actual_diff_dirstat &&
+	grep -q "future_param" actual_error &&
+	grep -q "diff\\.dirstat" actual_error &&
+
+	git -c diff.dirstat=future_param,0,lines diff --dirstat -M HEAD^..HEAD >actual_diff_dirstat_M 2>actual_error &&
+	test_debug "cat actual_error" &&
+	test_cmp expect_diff_dirstat_M actual_diff_dirstat_M &&
+	grep -q "future_param" actual_error &&
+	grep -q "diff\\.dirstat" actual_error &&
+
+	git -c diff.dirstat=future_param,0,lines diff --dirstat -C -C HEAD^..HEAD >actual_diff_dirstat_CC 2>actual_error &&
+	test_debug "cat actual_error" &&
+	test_cmp expect_diff_dirstat_CC actual_diff_dirstat_CC &&
+	grep -q "future_param" actual_error &&
+	grep -q "diff\\.dirstat" actual_error
+'
+
 test_done

-- 
1.7.5.rc1.3.g4d7b
Previous: Johan HerlandNext: Johan Herland
Message 88 of 91 in “BUG? in --dirstat when rearranging lines in a file”
  1. Johan HerlandApr 7, 2011
  2. Linus TorvaldsApr 7, 2011
  3. Junio C HamanoApr 7, 2011
  4. Linus TorvaldsApr 7, 2011
  5. Johan HerlandApr 8, 2011
  6. 1/3 --dirstat: Document shortcomings compared to --stat or regular diffJohan Herland, Apr 8, 2011
  7. Junio C HamanoApr 8, 2011
  8. 2/3 --dirstat-by-file: Make it faster and more correctJohan Herland, Apr 8, 2011
  9. 3/3 Teach --dirstat to not completely ignore rearranged linesJohan Herland, Apr 8, 2011
  10. Linus TorvaldsApr 8, 2011
  11. Junio C HamanoApr 8, 2011
  12. 0/3 --dirstat fixesJohan Herland, Apr 10, 2011
  13. 1/3 --dirstat: Describe non-obvious differences relative to --stat or regular diffJohan Herland, Apr 10, 2011
  14. 2/3 --dirstat-by-file: Make it faster and more correctJohan Herland, Apr 10, 2011
  15. Junio C HamanoApr 11, 2011
  16. 3/3 Teach --dirstat to not completely ignore rearranged lines within a fileJohan Herland, Apr 10, 2011
  17. Junio C HamanoApr 11, 2011
  18. Johan HerlandApr 11, 2011
  19. Junio C HamanoApr 11, 2011
  20. Johan HerlandApr 12, 2011
  21. 4/3 --dirstat: In case of renames, use target filename instead of source filenameJohan Herland, Apr 12, 2011
  22. Linus TorvaldsApr 12, 2011
  23. 5/3 Alternative --dirstat implementation, based on diffstat analysisJohan Herland, Apr 12, 2011
  24. Linus TorvaldsApr 12, 2011
  25. Linus TorvaldsApr 12, 2011
  26. Johan HerlandApr 12, 2011
  27. Linus TorvaldsApr 12, 2011
  28. Junio C HamanoApr 12, 2011
  29. 0/6 --dirstat fixes, part 2Johan Herland, Apr 26, 2011
  30. 1/6 Add several testcases for --dirstat and friendsJohan Herland, Apr 26, 2011
  31. 2/6 Make --dirstat=0 output directories that contribute < 0.1% of changesJohan Herland, Apr 26, 2011
  32. 3/6 Refactor --dirstat parsing; deprecate --cumulative and --dirstat-by-fileJohan Herland, Apr 26, 2011
  33. Junio C HamanoApr 26, 2011
  34. Johan HerlandApr 27, 2011
  35. Junio C HamanoApr 27, 2011
  36. Junio C HamanoApr 27, 2011
  37. Junio C HamanoApr 27, 2011
  38. 4/6 Add config variable for specifying default --dirstat behaviorJohan Herland, Apr 26, 2011
  39. Junio C HamanoApr 26, 2011
  40. Johan HerlandApr 27, 2011
  41. 5/6 Use floating point for --dirstat percentagesJohan Herland, Apr 26, 2011
  42. Junio C HamanoApr 26, 2011
  43. Johan HerlandApr 27, 2011
  44. Junio C HamanoApr 27, 2011
  45. Linus TorvaldsApr 27, 2011
  46. Junio C HamanoApr 27, 2011
  47. 6/6 New --dirstat=lines mode, doing dirstat analysis based on diffstatJohan Herland, Apr 26, 2011
  48. Junio C HamanoApr 26, 2011
  49. Johan HerlandApr 27, 2011
  50. Linus TorvaldsApr 26, 2011
  51. 0/6 --dirstat fixes, part 2Johan Herland, Apr 27, 2011
  52. 1/6 Add several testcases for --dirstat and friendsJohan Herland, Apr 27, 2011
  53. 2/6 Make --dirstat=0 output directories that contribute < 0.1% of changesJohan Herland, Apr 27, 2011
  54. 3/6 Refactor --dirstat parsing; deprecate --cumulative and --dirstat-by-fileJohan Herland, Apr 27, 2011
  55. 4/6 Add config variable for specifying default --dirstat behaviorJohan Herland, Apr 27, 2011
  56. 5/6 Use floating point for --dirstat percentagesJohan Herland, Apr 27, 2011
  57. Linus TorvaldsApr 27, 2011
  58. 6/6 New --dirstat=lines mode, doing dirstat analysis based on diffstatJohan Herland, Apr 27, 2011
  59. 0/6 --dirstat fixes, part 2Johan Herland, Apr 27, 2011
  60. 1/6 Add several testcases for --dirstat and friendsJohan Herland, Apr 27, 2011
  61. 2/6 Make --dirstat=0 output directories that contribute < 0.1% of changesJohan Herland, Apr 27, 2011
  62. 3/6 Refactor --dirstat parsing; deprecate --cumulative and --dirstat-by-fileJohan Herland, Apr 27, 2011
  63. 4/6 Add config variable for specifying default --dirstat behaviorJohan Herland, Apr 27, 2011
  64. 5/6 Allow specifying --dirstat cut-off percentage as a floating point numberJohan Herland, Apr 27, 2011
  65. Linus TorvaldsApr 27, 2011
  66. 5/6 Allow specifying --dirstat cut-off percentage as a floating point numberJohan Herland, Apr 27, 2011
  67. 6/6 New --dirstat=lines mode, doing dirstat analysis based on diffstatJohan Herland, Apr 27, 2011
  68. 0/7 --dirstat fixes, part 2Johan Herland, Apr 28, 2011
  69. 1/7 Add several testcases for --dirstat and friendsJohan Herland, Apr 28, 2011
  70. 2/7 Make --dirstat=0 output directories that contribute < 0.1% of changesJohan Herland, Apr 28, 2011
  71. 3/7 Refactor --dirstat parsing; deprecate --cumulative and --dirstat-by-fileJohan Herland, Apr 28, 2011
  72. 4/7 Add config variable for specifying default --dirstat behaviorJohan Herland, Apr 28, 2011
  73. 5/7 Allow specifying --dirstat cut-off percentage as a floating point numberJohan Herland, Apr 28, 2011
  74. 6/7 New --dirstat=lines mode, doing dirstat analysis based on diffstatJohan Herland, Apr 28, 2011
  75. 7/7 Improve error handling when parsing dirstat parametersJohan Herland, Apr 28, 2011
  76. Junio C HamanoApr 28, 2011
  77. Junio C HamanoApr 28, 2011
  78. Johan HerlandApr 28, 2011
  79. Johan HerlandApr 28, 2011
  80. Junio C HamanoApr 29, 2011
  81. 0/8 --dirstat fixes, part 2Johan Herland, Apr 29, 2011
  82. 1/8 Add several testcases for --dirstat and friendsJohan Herland, Apr 29, 2011
  83. 2/8 Make --dirstat=0 output directories that contribute < 0.1% of changesJohan Herland, Apr 29, 2011
  84. 3/8 Refactor --dirstat parsing; deprecate --cumulative and --dirstat-by-fileJohan Herland, Apr 29, 2011
  85. 4/8 Add config variable for specifying default --dirstat behaviorJohan Herland, Apr 29, 2011
  86. 5/8 Allow specifying --dirstat cut-off percentage as a floating point numberJohan Herland, Apr 29, 2011
  87. 6/8 New --dirstat=lines mode, doing dirstat analysis based on diffstatJohan Herland, Apr 29, 2011
  88. 7/8 Improve error handling when parsing dirstat parametersJohan Herland, Apr 29, 2011
  89. 8/8 Mark dirstat error messages for translationJohan Herland, Apr 29, 2011
  90. Junio C HamanoApr 12, 2011
  91. Linus TorvaldsApr 10, 2011

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